Method for removing phosphorus from water

Abstract

The present invention relates to a method of removing phosphorus from water, comprising: immersing an electrochemical cell in phosphorus-containing water to form treated water comprising a phosphorus-containing salt, where the phosphorus-containing salt comprises AlPO4 or a hydrate thereof and optionally further comprises aluminum hydroxide or a hydrate thereof, the AlPO4 and aluminum hydroxide comprising Al from an anode, the electrochemical cell is a galvanic cell, the electrochemical cell comprising: an anode comprising Al; two cathodes having a different composition than the anode, the two cathodes comprising Cu, where no external potential is applied across the anode and the two cathodes, where the two cathodes comprise a mesh; an electrically conductive connector electrically and physically connecting the anode and the two cathodes; wherein the electrochemical cell comprises a gap between the anode and each of the cathodes; and separating the phosphorus-containing salt from the treated water to form separated water having a lower phosphorus concentration than the phosphorus-containing water.

Description

[0001] This application is a divisional application of Chinese patent application No. 202080053751.3, filed on June 12, 2020, with the invention name “Removing Materials from Water”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 62 / 860,433, filed on June 12, 2019, the disclosure of which is incorporated herein by reference in its entirety. Background Art

[0004] Phosphorus is a common component of agricultural fertilizers, manure, and organic waste in sewage and industrial effluents. It is essential for plant life, and when too much is present in water, it can lead to plant and algae growth and consume oxygen in the water at a rate beyond what the ecosystem can handle, with potentially severe ecological impacts, including toxic algal blooms, die-offs of native aquatic species, and loss of biodiversity (eutrophication). While a variety of methods are available to remove phosphorus from water, existing methods can be expensive, inconvenient, inefficient, lack scalability, or may not be environmentally friendly. Summary of the invention

[0005] Various embodiments of the present invention provide a method for removing phosphorus from water. The method includes immersing an electrochemical cell in phosphorus-containing water to form treated water containing a phosphorus-containing salt. The electrochemical cell includes an anode comprising Mg, Al, Fe, Zn, or a combination thereof; and a cathode having a different composition from the anode, the cathode comprising Cu, Ni, Fe, or a combination thereof. The method also includes separating the phosphorus-containing salt from the treated water to form separated water having a lower phosphorus concentration than the phosphorus-containing water.

[0006] Various embodiments of the present invention provide a method for removing phosphorus from water. The method includes immersing an electrochemical cell in phosphorus-containing water having a pH of about 5 to about 7 to form treated water containing a phosphorus-containing salt. The phosphorus-containing salt includes AlPO4 or a hydrate thereof, the AlPO4 containing phosphorus and Al from the anode; aluminum hydroxide or a hydrate thereof, the aluminum hydroxide containing Al from the anode; or a combination thereof. The electrochemical cell includes an anode containing Al, wherein the anode is about 90 wt % to about 100 wt % Al. The electrochemical cell includes a cathode containing Cu, wherein the cathode is about 90 wt % to about 100 wt % Cu. The electrochemical cell also includes a conductive connector electrically connecting the anode and the cathode, the conductive connector including an alloy containing Cu and Zn. The method also includes separating the phosphorus-containing salt from the treated water to form separated water having a phosphorus concentration lower than that of the phosphorus-containing water.

[0007] Various embodiments of the present invention provide a method for removing phosphorus from water. The method includes immersing an electrochemical cell in phosphorus-containing water having a pH of about 10 to about 11 to form treated water containing a phosphorus-containing salt. The phosphorus-containing salt includes magnesium phosphate, potassium magnesium phosphate, a hydrate thereof, or a combination thereof; NH4MgPO4 or a hydrate thereof, the NH4MgPO4 containing phosphorus and Mg from an anode; Mg(OH)2, which contains Mg from an anode; or a combination thereof. The electrochemical cell includes an anode containing Mg, wherein the anode is about 90 wt % to about 100 wt % Mg. The electrochemical cell includes a cathode containing Cu, wherein the cathode is about 90 wt % to about 100 wt % Cu. The electrochemical cell also includes a conductive connector electrically connecting the anode and the cathode, the conductive connector including an alloy containing Cu and Zn. The method also includes separating the phosphorus-containing salt from the treated water to form separated water having a phosphorus concentration lower than that of the phosphorus-containing water.

[0008] Various embodiments of the present invention provide an electrochemical cell for performing embodiments of the methods described herein. The electrochemical cell includes a cathode comprising Cu, Ni, Fe, or a combination thereof, wherein the cathode comprises a planar frame of the electrochemical cell having a polygonal perimeter and a porous material contained within the perimeter of the frame, the porous material being a wire mesh or wire screen in direct contact with the frame. The electrochemical cell also includes a plurality of anodes having a different composition from the cathode, the anodes comprising Mg, Al, Fe, Zn, or a combination thereof; and a plurality of conductive connectors electrically connecting the anodes and cathodes, the conductive connectors comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb, or a combination thereof. Each anode is a strip fastened to the planar frame at two opposite edges of the planar frame on the face of the frame, wherein each of the anodes is fastened to the planar frame at each of the two edges of the planar frame using at least one of the conductive connectors, so that each of the anodes on the face is approximately parallel to each other on the face and spans the porous material contained within the perimeter of the planar frame, thereby forming a gap between the porous material contained within the perimeter of the planar frame and the anode strips. Each anode directly contacts the cathode frame at each of the edges of the planar frame, wherein the anode is fastened to the planar frame by at least one conductive connector. A plurality of anodes are spaced apart across the face so that they are not in physical contact with each other. The gap is about 1 mm to about 110 mm.

[0009] Various embodiments of the present invention provide a method for preparing magnesium ammonia phosphate (struvite). The method includes immersing an electrochemical cell in phosphorus-containing water having a pH of about 10 to about 11 to form treated water containing a phosphorus-containing salt. The phosphorus-containing salt includes magnesium ammonia phosphate, which includes phosphorus and Mg from an anode. The electrochemical cell includes an anode containing Mg, wherein the anode is about 90% to about 100% by weight Mg. The electrochemical cell includes a cathode containing Cu, wherein the cathode is about 90% to about 100% by weight Cu. The method also includes separating the phosphorus-containing salt from the treated water to obtain separated magnesium ammonia phosphate and forming separated water having a phosphorus concentration lower than that of the phosphorus-containing water.

[0010] Various embodiments of the present invention provide a method for preparing AlPO4, aluminum hydroxide, or a combination thereof. The method includes immersing an electrochemical cell in phosphorus-containing water having a pH of about 5 to about 7 to form treated water containing a phosphorus-containing salt. The phosphorus-containing salt includes AlPO4 or a hydrate thereof, the AlPO4 containing phosphorus and Al from an anode; aluminum hydroxide or a hydrate thereof, the aluminum hydroxide containing Al from an anode; or a combination thereof. The electrochemical cell includes an anode containing Al, wherein the anode is about 90 wt % to about 100 wt % Al. The electrochemical cell includes a cathode containing Cu, wherein the cathode is about 90 wt % to about 100 wt % Cu. The method includes separating the phosphorus-containing salt from the treated water to form separated water having a phosphorus concentration lower than that of the phosphorus-containing water.

[0011] Various embodiments of the present invention provide a method for preparing magnesium phosphate, Mg(OH)2, or a combination thereof. The method includes immersing an electrochemical cell in phosphorus-containing water having a pH of about 10 to about 11 to form treated water comprising a phosphorus-containing salt. The salt includes magnesium phosphate, potassium magnesium phosphate, a hydrate thereof, or a combination thereof; Mg(OH)2, which contains Mg from an anode; or a combination thereof. The electrochemical cell includes an anode comprising Mg, wherein the anode is about 90 wt % to about 100 wt % Mg. The electrochemical cell includes a cathode comprising Cu, wherein the cathode is about 90 wt % to about 100 wt % Cu. The method also includes separating the phosphorus-containing salt from the treated water to form separated water having a phosphorus concentration lower than that of the phosphorus-containing water.

[0012] Various embodiments of the present invention provide a method for removing one or more dissolved transition metals, post-transition metals or metalloids from water. The method includes immersing an electrochemical cell in water containing one or more dissolved transition metals, post-transition metals or metalloids to form treated water containing hydroxide salts containing one or more transition metals, post-transition metals or metalloids. The electrochemical cell includes an anode containing Mg, Al, Fe, Zn or a combination thereof. The electrochemical cell includes a cathode containing Cu, Ni, Fe or a combination thereof. The method also includes separating the salts (including hydroxide salts) containing one or more transition metals, post-transition metals or metalloids to form separated water having a lower concentration of one or more transition metals, post-transition metals or metalloids than the water containing one or more transition metals, post-transition metals or metalloids.

[0013] In various embodiments, the phosphorus removal methods of the present invention have certain advantages over other methods of removing phosphorus from water. For example, in some embodiments, the phosphorus removal methods of the present invention can remove larger amounts of phosphorus, achieve lower phosphorus concentrations, achieve phosphorus removal with higher efficiency or lower cost, utilize a smaller footprint, or a combination thereof, compared to other methods.

[0014] In various embodiments, the phosphorus removal methods of the present invention can be performed with less oxidizing influent water than other methods, or with non-oxidizing influent water. In some embodiments comprising an electrochemical cell comprising an anode comprising Al, the higher pH near the anode caused by the generation of hydroxide ions can induce or enhance the precipitation of aluminum salts (e.g., AlPO4, aluminum hydroxide, or a combination thereof). In some embodiments, the ratio of Al to P for removing phosphorus from water is lower than those reported by other methods, such as methods using the addition of aluminum salts. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings generally illustrate various embodiments of the invention by way of example and not limitation.

[0016] Figure 1A A view of an electrochemical cell from a major side is shown according to various embodiments.

[0017] Figure 1B An enlarged cross-sectional edge view of an electrochemical cell according to various embodiments is shown.

[0018] Figure 2A Shown are photographs along the edge of an Al-Cu electrochemical cell according to various embodiments.

[0019] Figure 2BShown are photographs along the edges of multiple Al-Cu electrochemical cells according to various embodiments.

[0020] Figure 2C Shown are photographs of major surfaces of Mg-Cu electrochemical cells according to various embodiments.

[0021] Figure 2D Shown is a photograph of the edge of a Mg-Cu electrochemical cell according to various embodiments.

[0022] Figure 2E Shown is a photograph of the edge of a Mg-Cu electrochemical cell according to various embodiments.

[0023] Figure 2F Photographs showing a top view of a system for removing material from water according to various embodiments are shown.

[0024] Figure 2G A photograph showing a side view of a system for removing material from water according to various embodiments is shown.

[0025] Figure 3 The current produced by an Al-Cu cell versus time for solutions having various conductivities is shown according to various embodiments.

[0026] Figure 4 The current produced by an Al-Cu cell versus time for solutions having various pH levels according to various embodiments is shown.

[0027] Figure 5A The current produced by a Mg-Cu cell versus time for solutions having various conductivities is shown according to various embodiments.

[0028] Figure 5B The current produced by a Mg-Cu cell versus time for solutions having various pH levels according to various embodiments is shown. DETAILED DESCRIPTION

[0029] Reference will now be made in detail to certain embodiments of the disclosed subject matter.While the disclosed subject matter will be described in conjunction with the enumerated claims, it will be understood that the illustrated subject matter is not intended to limit the claims to the disclosed subject matter.

[0030] In this document, values ​​expressed in range format should be interpreted in a flexible manner to include not only the values ​​explicitly cited as range limits, but also all individual values ​​or sub-ranges contained within the range, as if each value and sub-range were explicitly stated. For example, a range of "about 0.1% to about 5%" or "about 0.1% to 5%" should be interpreted as including not only about 0.1% to about 5%, but also individual values ​​(e.g., 1%, 2%, 3% and 4%) and sub-ranges within the specified range (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%). Unless otherwise specified, a statement of "about X to Y" has the same meaning as "about X to about Y". Similarly, unless otherwise specified, a statement of "about X, Y or about Z" has the same meaning as "about X, about Y or about Z".

[0031] In this document, unless the context clearly dictates otherwise, the terms "a", "an", or "the" are used to include one or more than one. Unless otherwise specified, the term "or" is used to refer to a non-exclusive "or". The statement "at least one of A and B" or "at least one of A or B" has the same meaning as "A, B, or A and B". In addition, it should be understood that the words or terms used herein and not otherwise defined are for descriptive purposes only and not for limiting purposes. The use of any section headings is intended to aid in reading the document and should not be construed as limiting; information related to the section heading may appear inside or outside that particular section.

[0032] In the methods described herein, except where time or order of operations is explicitly stated, the actions may be performed in any order without departing from the principles of the invention. In addition, specified actions may be performed simultaneously unless explicit claim language states that they are performed separately. For example, a claimed action to perform X and a claimed action to perform Y may be performed simultaneously in a single operation, and the resulting process would fall within the literal scope of the claimed process.

[0033] As used herein, the term "about" can allow for a certain degree of variability within a value or range, such as within 10%, 5% or 1% of a specified value or specified limit, and includes the exact specified value or range. As used herein, the term "substantially" refers to a majority or a large portion, such as at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%. As used herein, the term "substantially free" can mean having no or insignificant amounts such that the amount of material present does not affect the material properties of the composition containing the material, such that from about 0 weight percent to about 5 weight percent of the composition is the material, or from about 0 weight percent to about 1 weight percent, or about 5 weight percent or less, or less than or equal to about 4.5 weight percent, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.01, or about 0.001 weight percent or less, or about 0 weight percent of the composition is the material.

[0034] In various embodiments, the salt with a positively charged counterion can include any suitable positively charged counterion. For example, the counterion can be ammonium (NH4 + ), or sodium (Na + ), potassium (K + ) or lithium (Li + In some embodiments, the counterion may have a positive charge greater than +1, which in some embodiments may be combined with a multiply ionizable group (e.g., Zn 2+ 、Al 3+ ) or such as Ca 2+ or Mg 2+ Alkaline earth metal complex.

[0035] Unless otherwise stated, all concentrations of phosphorus, magnesium and aluminum mentioned are dissolved concentrations of these materials in elemental or non-elemental form (e.g., in the form of compounds or ions containing the materials). Unless otherwise stated, all concentrations given herein are by weight.

[0036] Unless otherwise indicated, as used herein, "total phosphorus concentration" refers to the concentration of all forms of phosphorus as measured by US-EPA 365.1: Determination of Phosphorus by Semi-Automated Colorimetry or an equivalent method.

[0037] Unless otherwise indicated, as used herein, "dissolved phosphorus concentration" refers to the concentration of all forms of phosphorus that can pass through a 0.45 micron filter and as measured by US-EPA 365.1: Semi-Automated Colorimetric Determination of Phosphorus or an equivalent method.

[0038] Unless otherwise indicated, as used herein, "active phosphorus concentration" refers to the soluble active phosphorus (eg, orthophosphate) in solution as measured by US-EPA 365.1: Semi-Automated Colorimetric Determination of Phosphorus or an equivalent method.

[0039] Methods of removing phosphorus from water.

[0040] In various embodiments, the present invention provides a method for removing phosphorus from water. Phosphorus can be removed in the form of a salt containing phosphorus using an electrochemical cell (e.g., one or more electrochemical cells). The method may include immersing the electrochemical cell in phosphorus-containing water to form treated water containing a salt containing phosphorus. The electrochemical cell may include an anode containing Mg, Al, Fe, Zn, or a combination thereof. The electrochemical cell may include a cathode containing Cu, Ni, Fe, or a combination thereof. The method may also include separating the phosphorus-containing salt from the treated water to form a separated water having a phosphorus concentration lower than that of the phosphorus-containing water. In some embodiments, the electrochemical cell may also include a conductive connector electrically connecting the anode and the cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb, or a combination thereof. In some embodiments, the anode and the cathode may be in direct contact with each other and the electrochemical cell may not have a conductive connector.

[0041] The electrochemical cell may be a primary cell. The method may not apply a potential across the anode and cathode of the electrochemical cell (e.g., a potential applied from a source outside the electrochemical cell). In some embodiments, the electrochemical cell may be an electrolytic cell. The method may include applying a potential across the anode and cathode of the electrochemical cell. The applied potential may be greater than the galvanic corrosion potential of the electrochemical cell (e.g., the potential reached by the anode and cathode without applying an external potential when immersed in phosphorus-containing water). The applied potential may be less than the galvanic corrosion potential of the electrochemical cell. The applied potential may be equal to the galvanic corrosion potential of the electrochemical cell.

[0042] The method may include immersing the electrochemical cell in water containing phosphorus. Immersing the electrochemical cell in water containing phosphorus may include partial immersion such that any suitable proportion of the surface area of ​​the electrochemical cell is in contact with water, such as from about 1% to about 100%, 80% to about 100%, or less than, equal to, or greater than about 1%, 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, 96, 97, 98, or about 99% or more. Immersing the electrochemical cell in water containing phosphorus may include full immersion such that about 100% of the surface area of ​​the electrochemical cell is in contact with water.

[0043] The phosphorus-containing water may be taken from any suitable source. For example, the phosphorus-containing water may be taken from a source including a natural water source in the environment, drinking water (e.g., for removing magnesium ammonium phosphate to prevent formation in pipes), industrial wastewater, industrial cooling water, or a combination thereof. The phosphorus-containing water may be water taken from a source including a natural water source in the environment (e.g., a pond, lake, river, stream, etc.). In some embodiments, the method may include taking water from the source, returning the water to the source after removing the phosphorus, or a combination thereof.

[0044] The phosphorus in the phosphorus-containing water may be in any suitable form. For example, the phosphorus may be in the form of elemental phosphorus, inorganic phosphorus, organic phosphorus, dissolved phosphorus, solid phosphorus, oxidized phosphorus or a combination thereof. The phosphorus-containing water can have a total phosphorus concentration, a dissolved phosphorus concentration, a reactive phosphorus concentration, or a combination thereof of about 0.001 ppm to about 10,000 ppm, about 0.01 ppm to about 20 ppm, or about 0.001 ppm or less, or less than, equal to, or greater than about 0.005 ppm, 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.15, 0.2, 0.4, 0.6, 0.8, 1, 2, 4, 6, 8, 10, 15, 20, 40, 60, 80, 100, 150, 200, 400, 600, 800, 1,000, 1,500, 2,000, 4,000, 6,000, 8,000, or about 10,000 ppm or more.

[0045] The separated water may have a total phosphorus concentration, a dissolved phosphorus concentration, an active phosphorus concentration, or a combination thereof of about 0 ppm to about 1 ppm, about 0.0001 ppm to 0.1 ppm, about 0.0001 ppm to 0.05 ppm, or about 0 ppm, or less than, equal to, or greater than about 0.0001 ppm, 0.0002, 0.0004, 0.0006, 0.0008, 0.0010, 0.0012, 0.0014, 0.0016, 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.2, 0.4, 0.6, 0.8 or about 1.0 ppm or more. The separated water may have a total phosphorus concentration, dissolved phosphorus concentration, active phosphorus concentration, or a combination thereof that is about 0% to 70%, or about 0% to about 20%, or about 0%, or less than, equal to, or greater than about 0.001%, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, or about 70% or more of the corresponding total phosphorus concentration, dissolved phosphorus concentration, active phosphorus concentration, or a combination thereof of the phosphorus-containing water that initially contacts the electrochemical cell.

[0046] During immersion of the electrochemical cell in the phosphorus-containing water, the phosphorus-containing water may have any suitable pH value. The pH can be from about 2 to about 14, from about 5 to about 11, from about 5 to about 7, from about 10 to about 11, or less than, equal to, or greater than about 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11, 11.5, 12, 12.5, 13, 13.5, or about 14 or more.

[0047] The method may include adding an acid, a base, or a combination thereof to the phosphorus-containing water to adjust or control its pH. In some embodiments, the method does not add an acid, a base, or a combination thereof to the phosphorus-containing water. The acid, a base, or a combination thereof may be added to the phosphorus-containing water before immersing the electrochemical cell in the phosphorus-containing water, during immersing the electrochemical cell in the phosphorus-containing water, after immersing the electrochemical cell in the phosphorus-containing water, or a combination thereof.

[0048] The method may include recirculating the phosphorus-containing water that immerses the electrochemical cell so that the phosphorus-containing water contacts the electrochemical cell multiple times. The water may optionally be filtered during the recirculation, for example to remove phosphorus-containing salts from the water.

[0049] Immersing an electrochemical cell in phosphorus-containing water can form treated water containing phosphorus-containing salts. Contact between the phosphorus-containing water and the electrochemical cell can result in the formation of phosphorus-containing salts. At least some of the phosphorus-containing salts in the treated water can include solids. The formation of phosphorus-containing solids can include precipitation, flocculation, or a combination thereof.

[0050] Separating the phosphorus-containing salt from the treated water to form separated water having a phosphorus concentration lower than that of the phosphorus-containing water can be performed in any suitable manner. The separation may include decantation, sedimentation, filtration, or a combination thereof. Separation may include separating the treated water from the electrochemical cell (e.g., removing the water that immerses the cell, which has been filtered or otherwise separated from the phosphorus-containing salt). Separation may occur during water recycling back to the electrochemical cell. Separation may be performed during contact between the electrochemical cell and the water, such as by a filter that is immersed in the water and continuously filters the water during contact. After removing the water from the water immersing the electrochemical cell, separation may occur, such as by a filter on an outlet line outside the system. Filtering may be performed using a glass frit, a fabric filter, a paper filter, a disc filter, a rotary filter, a drum filter, a screen, a sieve, a particle filter medium, a filter aid, or a combination thereof. The separated water may optionally be further treated, such as by further contacting, filtering, treating to remove one or more other non-phosphorus materials, pH adjustment, or a combination thereof with the same or different electrochemical cell.

[0051] The anode may be a sacrificial anode that is consumed during treatment of the phosphorus-containing water. The phosphorus-containing salt formed when the phosphorus-containing water is contacted with the electrochemical cell may contain material from the anode. The method may include forming a hydroxide salt containing material from the anode during immersion of the electrochemical cell in the phosphorus-containing water. Separating the phosphorus-containing salt from the treated water may further include separating the hydroxide salt containing material from the anode from the treated water.

[0052] The phosphorus-containing water may further comprise dissolved transition metals, post-transition metals, metalloids, or combinations thereof. The method may comprise forming a hydroxide salt comprising a transition metal, post-transition metal, or metalloid during immersion of the electrochemical cell in the phosphorus-containing water. Separating the phosphorus-containing salt from the treated water may comprise separating a hydroxide salt comprising a transition metal, post-transition metal, or metalloid from the treated water. The transition metal, post-transition metal, or metalloid may be Sc, Y, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, Rf, Db, Sg, Bh, Hs, Al, Zn, Ga, Cd, In, Sn, Hg, Ti, Pb, Bi, Po, Cn, B, Si, Ge, As, Sb, Te, At, or combinations thereof. The transition metal, post-transition metal or metalloid can be Hg, Fe, Cr, Ni, Zn, Cd, As or a combination thereof. The method can remove any suitable amount of a transition metal, post-transition metal, metalloid or a combination thereof from water. The separated water can have a concentration of transition metal, post-transition metal, metalloid or combination thereof that is from about 0% to about 70% of the concentration of the transition metal, post-transition metal, metalloid or combination thereof in the water comprising one or more dissolved transition metals, post-transition metals or metalloids, or from about 0% to about 20%, or about 0%, or about 1% or less, or less than, equal to, or greater than about 2%, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, 26, 28, 30, 35, 40, 45, 50, 55, 60, 65, or about 70% or more of the concentration of the transition metal, post-transition metal, metalloid or combination thereof in the water comprising one or more dissolved transition metals, post-transition metals or metalloids.

[0053] The method may include forming H2 and HO- at the anode (e.g., on the surface of the anode, generated from the water) during immersion of the electrochemical cell in the phosphorus-containing water. The method may include forming H2 and HO- at the cathode (e.g., on the surface of the cathode, generated from the water) during immersion of the electrochemical cell in the phosphorus-containing water. The method may include forming H2O2, HO2 at the cathode (e.g., on the surface of the cathode) during immersion of the electrochemical cell in the phosphorus-containing water. -, or a combination thereof. The method may include applying shear to the phosphorus-containing water during immersion of the electrochemical cell in the phosphorus-containing water. The shear can be sufficient to expel at least some bubbles (e.g., including H2) from the surface of the anode, cathode, or a combination thereof. The shear can be sufficient to at least partially prevent or reduce oxide formation at the anode surface. The method may include applying a mechanical force, such as tapping, knocking, stirring, vibration, ultrasound, etc., to the electrochemical cell immersed in phosphorus-containing water. The mechanical force can be sufficient to expel at least some bubbles including H2 from the surface of the anode, cathode, or a combination thereof; at least partially prevent oxide formation at the surface of the anode; at least partially prevent the phosphorus-containing salt from agglomerating on the surface of the anode; or a combination thereof.

[0054] The phosphorus-containing water may further comprise nitrogen. The nitrogen in the phosphorus-containing water may be in any suitable form, such as elemental nitrogen, inorganic nitrogen, organic nitrogen, dissolved nitrogen, solid nitrogen, nitrogen oxides or a combination thereof. The total nitrogen concentration, dissolved nitrogen concentration or a combination thereof in the phosphorus-containing water may be about 0.001ppm to about 20ppm, about 1ppm to about 5ppm or about 0.001ppm or less, or less than, equal to or greater than about 0.005ppm, 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.15, 0.2, 0.4, 0.6, 0.8, 1, 2, 4, 6, 8, 10, 12, 14, 16, 18 or about 20ppm or higher. The separated water may have a total nitrogen concentration, a dissolved nitrogen concentration, or a combination thereof of about 0 ppm to about 2 ppm, about 0 ppm to about 1 ppm, or about 0 ppm, or less than, equal to, or greater than about 0.001 ppm, 0.0012, 0.0014, 0.0016, 0.0018, 0.0020, 0.0022, 0.0024, 0.0026, 0.0028, 0.0030, 0.0031, 0.0033, 0.0034, 0.0035, 0.0036, 0.0037, 0.0038, 0.0039, 0.010, 0.011, 0.012, 0.013, 0.014, 0.01 0.0030, 0.0032, 0.0034, 0.0036, 0.0038, 0.0040, 0.0045, 0.0050, 0.0060, 0.0080, 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.2, 0.4, 0.6, 0.8, 1, 1.1, 1.2, 1.4, 1.6, 1.8 or about 2 ppm or more. The separated water may have a total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof that is between about 0% and 70%, or between about 0% and about 30%, or about 0%, or less than, equal to, or greater than about 0.001%, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, or about 70% or more of the corresponding total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof in the phosphorus-containing water.

[0055] The method may further include forming NH3, NH4 at the cathode (e.g., on the surface of the cathode) + , or a combination thereof, wherein NH3 and NH4 + The method may include forming a nitrogen-containing salt during immersion of the electrochemical cell in the phosphorus-containing water. Separating the phosphorus-containing salt from the treated water may include separating the nitrogen-containing salt from the treated water. The nitrogen-containing salt may include NH4MgPO4 or a hydrate thereof (e.g., magnesium ammonium phosphate).

[0056] The cathode of the electrochemical cell can include Cu, Ni, Fe or a combination thereof, such as Cu or a Cu alloy. The cathode can be a solid material that is mainly Cu, Ni, Fe, their alloys or their combinations, or another material that is mainly coated with Cu, Ni, Fe, their alloys or their combinations. The cathode can be substantially free of materials other than Cu, Ni, Fe, their alloys or their combinations. The cathode can be about 50% by weight to about 100% by weight of Cu, Ni, Fe, their alloys or their combinations, about 90% by weight to about 100% by weight, or less than, equal to or greater than about 50% by weight, 55, 60, 65, 70, 75, 80, 82, 84, 86, 88, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99 or about 99.999% by weight or more. In some embodiments, the cathode includes Cu, and the anode includes Mg. In some embodiments, the cathode includes Cu, and the anode includes Al.

[0057] The anode can be a solid material of approximately uniform composition, or can be a coating on another material. The anode has a composition different from that of the cathode. The anode can contain Mg, Al, Fe, Zn, or a combination thereof. The anode can include an alloy containing Mg, Al, Fe, Zn, or an alloy thereof. Mg, Al, Fe, Zn, an alloy thereof, or a combination thereof can be about 50% to about 100% by weight of the anode, or less than, equal to, or greater than about 50%, 55, 60, 65, 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, or about 99, 99.5, 99.9, 99.99, or about 99.999% by weight or more. The anode can be substantially free of materials other than Mg, Al, Fe, Zn, an alloy thereof, or a combination thereof.

[0058] The anode may further comprise Ag, Pt, Au, or a combination thereof. Ag, Pt, Au, or a combination thereof is about 0.0001 wt % to about 20 wt %, about 0.0001 wt % to about 5 wt %, or about 0 wt %, or about 0.0001 wt % or less, or 0.0002, 0.0004, 0.0006, 0.0008, 0.0010, 0.0012, 0.0014, 0.0016, 0.0018, 0.0020, 0.0022, 0.0024, 0.0026 %, 0.0028, 0.0030, 0.0032, 0.0034, 0.0036, 0.0038, 0.0040, 0.0045, 0.0050, 0.0060, 0.0080, 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.2, 0.4, 0.6, 0.8, 1, 1.5, 2, 4, 6, 8, 10, 12, 14, 16, 18 or about 20% by weight or more.

[0059] The anode may contain magnesium or a magnesium alloy. The anode may be substantially free of materials other than Mg or its alloy. The anode may be a magnesium alloy AZ91, which is about 90 wt % Mg, about 9 wt % Al, and about 1 wt % Zn. The anode may be about 50 wt % to about 100 wt % Mg or a Mg alloy, about 90 wt % to about 100 wt % Mg or a Mg alloy, or less than, equal to, or greater than about 50 wt %, 55, 60, 65, 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or about 99.999 wt % or more Mg or a Mg alloy. The phosphorus-containing salt may include magnesium phosphate, potassium magnesium phosphate (e.g., "K-struvite"), hydrates thereof, or combinations thereof, wherein the magnesium phosphate or potassium magnesium phosphate includes Mg from the anode. The magnesium phosphate may be in any suitable form, such as magnesium dihydrogen phosphate (Mg(H2PO4)2), dimagnesium phosphate (MgHPO4), trimagnesium phosphate (Mg3(PO4)2), hydrates thereof, or combinations thereof. Separating the phosphorus-containing salt from the treated water may include separating magnesium phosphate from the treated water. The phosphorus-containing water may further contain nitrogen, wherein the phosphorus-containing salt comprises NH4MgPO4 or a hydrate thereof (e.g., magnesium ammonium phosphate), wherein the NH4MgPO4 comprises phosphorus and Mg from the anode. The method may include forming Mg(OH)2 comprising Mg from the anode during immersion of the electrochemical cell in the phosphorus-containing water. Separating the phosphorus-containing salt from the treated water may include separating Mg(OH)2 from the treated water. During immersion of the electrochemical cell in the phosphorus-containing water, the phosphorus-containing water may have a pH of about 9.5 to about 11.5, or about 10 to about 11, or less than, equal to, or greater than 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, or about 11.5 or more. The method may include adjusting the rate at which fresh water containing phosphorus is introduced into the electrochemical cell so that the phosphorus-containing water in which the electrochemical cell is immersed is maintained at a pH of about 9.5 to about 11.5, or about 10 to about 11, or less than, equal to, or greater than 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, or about 11.5 or greater.The method may include immersing the electrochemical cell in phosphorus-containing water until the phosphorus-containing water reaches a pH of about 9.5 to about 11.5, or about 10 to about 11, and then adjusting the rate at which fresh water containing phosphorus is introduced into the electrochemical cell so that the phosphorus-containing water in which the electrochemical cell is immersed is maintained at a pH of about 9.5 to about 11.5, or about 10 to about 11.

[0060] The anode may contain Al. The anode may be substantially free of materials other than Al. The anode may be about 50% to about 100% by weight Al, about 90% to about 100% by weight Al, or less than, equal to, or greater than about 50%, 55, 60, 65, 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or about 99.999% by weight or more Al. The phosphorus-containing salt may include AlPO4 or a hydrate thereof. Separating the phosphorus-containing salt from the treated water may include separating AlPO4 from the treated water. The method may include forming aluminum hydroxide or a hydrate thereof (e.g., Al(OH)3 or polyaluminum hydroxide) during immersion of the electrochemical cell in phosphorus-containing water, the aluminum hydroxide comprising Al from the anode. Separating the phosphorus-containing salt from the treated water may include separating aluminum hydroxide from the treated water. During immersion of the electrochemical cell in the phosphorus-containing water, the phosphorus-containing water has a pH of about 4 to about 8, or about 5 to about 7, or about 4 or less, or about 4.2, 4.4, 4.6, 4.8, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.2, 7.4, 7.6, 7.8, or about 8 or more. The method may include adjusting the rate of introducing the acid into the phosphorus-containing water so that the phosphorus-containing water in which the electrochemical cell is immersed is maintained at a pH of about 4 to about 8, or about 5 to about 7, or about 4 or less, or about 4.2, 4.4, 4.6, 4.8, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.2, 7.4, 7.6, 7.8, or about 8 or more. The acid may be added to the phosphorus-containing water before the electrochemical cell is immersed in the phosphorus-containing water, during the electrochemical cell is immersed in the phosphorus-containing water, after the electrochemical cell is immersed in the phosphorus-containing water, or a combination of the above times. The acid may be any suitable acid of any suitable concentration. The acid may include sulfuric acid, acetic acid, hydrochloric acid, or a combination thereof. The method may include flocculating aluminum-containing salts from the treated water.

[0061] The cathode may have a work function greater than the work function of the anode. For example, Cu has a work function of about 4.53-5.10 eV, Mg has a work function of about 3.66 eV, and Al has a work function of about 4.06-4.26 eV. The conductive connector may have a work function between the work function of the cathode and the work function of the cathode.

[0062] The electrochemical cell may include a conductive connector that electrically connects the anode and cathode. The conductive connector has a composition different from that of the anode or cathode. The conductive connector may be a solid material with a uniform composition, or may be a coating on another material. The conductive connector may contain Cu, Zn, Fe, Cd, Ni, Sn, Pb, or a combination thereof. The conductive connector may contain Cu. The conductive connector may contain Zn. The conductive connector may include an alloy containing Cu and Zn. The conductive connector may contain brass. The conductive connector may contain brass and may be substantially free of other materials. The conductive connector may be about 50% to about 100% brass by weight, about 90% to about 100% brass by weight, or less than, equal to, or greater than about 50%, 55, 60, 65, 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or about 99.999% or more brass by weight.

[0063] During immersion of the electrochemical cell in the phosphorus-containing water, the phosphorus-containing water can have any suitable conductivity, such as from about 100 μS to about 1,000,000 μS, or from about 300 μS to about 100,000 μS, or from about 100 μS to about 1,200 μS, or less than, equal to, or greater than about 100 μS, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1200 μS, or less than, equal to, or greater than about 100 μS, 200, 300, 400, 500, 600, 700, 800, 9 ... 00, 1,000, 1,100, 1,200, 1,500, 2,000, 4,000, 6,000, 10,000, 15,000, 20,000, 50,000, 100,000, 150,000, 200,000, 250,000, 500,000, 750,000 or about 1,000,000 μS or more. The method may not adjust the conductivity of the phosphorus-containing water. In some embodiments, the method includes adjusting the conductivity of the phosphorus-containing water so that the conductivity is maintained at about 100 μS to about 1,000,000 μS, or about 300 μS to about 100,000 μS, or about 100 μS to about 1,200 μS, or less than, equal to, or greater than about 100 μS, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1200, 1500, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 15000, 16000, 17000, 18000, 19000, 20000, 20000, 30000, 40000, 50000, 60000, 70000, 80000, 90000 00, 1,000, 1,100, 1,200, 1,500, 2,000, 4,000, 6,000, 10,000, 15,000, 20,000, 50,000, 100,000, 150,000, 200,000, 250,000, 500,000, 750,000, or about 1,000,000 μS or more. Adjusting the conductivity of the phosphorus-containing water may include adjusting the rate at which fresh water containing phosphorus is introduced into the electrochemical cell. Adjusting the conductivity of the phosphorus-containing water may include adding one or more salts to the phosphorus-containing water. The salt may be added to the phosphorus-containing water before the electrochemical cell is immersed in the phosphorus-containing water, during the electrochemical cell is immersed in the phosphorus-containing water, after the electrochemical cell is immersed in the phosphorus-containing water, or a combination of these times. The one or more salts added to the phosphorus-containing water to adjust its conductivity may include halogen salts, sodium salts, potassium salts, or combinations thereof. The one or more salts added to the phosphorus-containing water to adjust its conductivity may include sodium chloride.

[0064] When immersed in water containing phosphorus, the electrochemical cell can generate an electric current. The amount of current generated by the cell can be any suitable amount of current, such as about 0.001 mA / cm 2 to about 10mA / cm 2 , 0.01mA / cm 2 to about 0.5 mA / cm 2 , or less than, equal to, or greater than about 0.001 mA / cm 2, 0.005, 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9 or about 10 mA / cm 2 or more.

[0065] Immersing the electrochemical cell in phosphorus-containing water can be sufficient to oxidize the phosphorus in the phosphorus-containing water. The method can treat the phosphorus-containing water without using an oxidizing agent or an oxidizing treatment other than any oxidation that occurs due to immersing the electrochemical cell in the phosphorus-containing water. In some embodiments, the method includes oxidizing the phosphorus in the phosphorus-containing water before immersing the electrochemical cell in the phosphorus-containing water, during immersing the electrochemical cell in the phosphorus-containing water, or a combination of these times. The method may include oxidizing the phosphorus in the phosphorus-containing water before immersing the electrochemical cell in the phosphorus-containing water. Oxidizing the phosphorus in the phosphorus-containing water may include contacting an oxidizing agent with the phosphorus-containing water to oxidize the phosphorus (e.g., to oxidize phosphorus in an organic substance or solid substance containing phosphorus). An aqueous solution of an oxidizing agent may be added to the phosphorus-containing water. The aqueous solution of the oxidant has an oxidant concentration of about 0.001 ppm to about 999,999 ppm, about 50,000 ppm to about 140,000 ppm, or less than, equal to, or greater than about 0.001 ppm, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 1.5, 2, 5, 10, 15, 20, 50, 100, 150, 200, 500, 1,000, 1,100, 1,200, 1,500, 2,000, 2,500, 5,000, 10,000, 15,000, 20,000, 50,000, 100,000, 150,000, 200,000, 500,000, 750,000, or about 999,999 ppm or more. The oxidant can be any suitable oxidant that oxidizes phosphorus. The oxidant can include ferrate, ozone, ferric chloride (FeCl3), potassium permanganate, potassium dichromate, potassium chlorate, potassium persulfate, sodium persulfate, perchloric acid, peracetic acid, potassium persulfate, hydrogen peroxide, sodium hypochlorite, potassium hypochlorite, hydroxides, sulfites, free radicals generated by their decomposition, or combinations thereof. Sufficient oxidant can be added, and sufficient treatment conditions used, such that the oxidant converts substantially all of the dissolved phosphorus in the phosphorus-containing water into an oxidized form of phosphorus.

[0066] Byproducts of the oxidation process may include negatively charged ionic compounds that readily accept electrons and are therefore preferentially reduced at the surface of the copper in the galvanic cell. Many of these compounds have very low regulatory limits, and a galvanic process may be used to remove or reduce the concentration of one or more of these highly regulated compounds prior to discharge or reuse of the treated water. Examples of the most common compounds that may be reduced or removed are chloramines, chlorates, perchlorates, bromates, hypochlorous acid, bleaching agents, etc., organic compounds, and combinations thereof. In addition, the galvanic process may reduce the oxygen level in the water to values ​​below 1 ppm, thereby creating attractive conditions for subsequent anoxic or anaerobic processes.

[0067] The method may not perform any steps to adjust the pH of the treated water. In some embodiments, the method may include adjusting the pH of the treated water to about 6 to 8, or about 7, or less than, equal to, or greater than about 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, or about 8 or greater.

[0068] The method may include immersing one or more of the electrochemical cells in a housing containing the phosphorus-containing water. The method may include filtering the phosphorus-containing salt from the treated water through one or more filters at least partially immersed in the phosphorus-containing water in which the electrochemical cells are immersed. The filter may include a glass frit, a fabric filter, a paper filter, a disc filter, a rotary filter, a drum filter, a screen, a sieve, a particle filter medium, a filter aid, or a combination thereof. The filter may be a rotary disc filter. Filtration may include forming a filter cake on the filter, the filter cake including the phosphorus-containing salt. Filtration may include backwashing the filter to remove the filter cake from the filter and forming a backwash solution including the removed filter cake. Any suitable water may be used to backwash the filter, such as using a portion of the water containing the precipitate to backwash the filter.

[0069] One or more electrochemical cells may be located in the phosphorus-containing water at a side of the housing, wherein the filter is located approximately in a center portion of the housing, in the phosphorus-containing water, such that the filter is between the plurality of electrochemical cells. The method may include using a plurality of filters. The plurality of filters may include a plurality of rotating disk filters.

[0070] In embodiments of the galvanic cell comprising aluminum in the anode, dissolution of the aluminum anode during operation of the galvanic cell produces a high local concentration of aluminum ions on or very near the surface of the electrode, which is supersaturated and thermodynamically favorable for precipitation of aluminum phosphate compounds. Such surface conditions produce a low molar ratio of metal to phosphorus even if the phosphorus level in the water is less than 0.1 ppm. The resulting equilibrium concentration of the remaining phosphate in the solution may be much lower than the equilibrium concentration obtained by simply adding aluminum salts to the water. When aluminum salts are added to phosphate-containing water to obtain a phosphorus concentration of less than about 0.1 ppm, the molar ratio of metal to phosphorus must be close to 8. In contrast, in the galvanic method described herein, the molar ratio of metal to phosphorus can be less than 8, such as about 1.

[0071] Electrochemical Cells

[0072] In various embodiments, the present invention provides an electrochemical cell. The electrochemical cell can be any suitable electrochemical cell that can be used to perform the embodiments of the methods described herein. The method of removing phosphorus from water may include immersing an electrochemical cell (e.g., one or more electrochemical cells) in phosphorus-containing water to form treated water containing phosphorus-containing salts. The electrochemical cell may include an anode comprising Mg, Al, Fe, Zn, or a combination thereof. The electrochemical cell may include a cathode comprising Cu, Ni, Fe, or a combination thereof.

[0073] The electrochemical cell can also include a conductive connector electrically connecting the anode and cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof. In some embodiments, the anode and cathode are in direct contact with each other and the electrochemical cell does not have a conductive connector, so that the electrode is in an "electroless" configuration. In an electroless configuration, a sacrificial anode material can be electrochemically plated or deposited on a non-sacrificial cathode material, thereby not requiring a conductive connector to electrically connect anode and cathode. An advantage of various embodiments of the electroless configuration is that less metallic copper can be used and the electrical drop between the electrodes can be reduced compared to a configuration including a conductive connector.

[0074] The electrochemical cell may include a cathode, or multiple cathodes. The electrochemical cell may include an anode, or multiple anodes. The electrochemical cell may not include a conductive connector, include a conductive connector, or multiple conductive connectors. The electrochemical cell may include multiple conductive connectors, each of which independently electrically connects the anode and the cathode (e.g., in a parallel configuration rather than a series configuration). Multiple conductive connectors may be roughly evenly distributed around the periphery of the electrochemical cell. The conductive connector may include a connector or a fastener, such as a screw, a bolt, a nut, a washer, or a combination thereof.

[0075] The electrochemical cell may have any suitable size or configuration such that the surface area of ​​the electrochemical cell per unit volume of water containing phosphorus to be removed is sufficient to achieve phosphorus removal during the residence time of the water in the container. The electrochemical cell may have any suitable total surface area per electrochemical cell, or total anode surface area exposed to water per cell, such as about 1 cm 2 to about 1,000,000cm 2 、About 5cm 2 to about 200,000cm 2 , about 10cm 2 to about 50,000cm 2 、About 20cm 2 to about 40,000cm 2 or about 1cm 2 or less, or less than, equal to or greater than 2 cm2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 75, 100, 150, 200, 250, 500, 750, 1,000, 1,500, 2,000, 2,500, 5,000, 7,500, 10,000, 15,000, 20,000, 25,000, 30,000, 35,000, 40,000, 45,000, 50,000, 75,000, 100,000, 150,000, 200,000, 500,000, 750,000 or about 1,000,000 cm 2The electrochemical cell can have any suitable ratio of anode surface area to cathode surface area, such as a ratio of anode surface area exposed to water to cathode surface area exposed to water, such as about 0.1 to about 10, 0.5 to 2, or less than, equal to, or greater than about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.8, 3, 3.5, 4, 4.5, 5, 5.5, 6, 7, 8, 9, or about 10 or more. In some embodiments, the anode, cathode, or combination thereof comprises a roughened or etched surface to increase the surface area. For the methods described herein, any suitable number of electrochemical cells can be used, such as 1, 1 to 1,000,000, 1 to 1,000, 1 to 20, or less than, equal to, or greater than 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 125, 150, 175 , 200, 225, 250, 300, 400, 500, 750, 1,000, 1,250, 1,500, 1,750, 2,000, 2,500, 3,000, 4,000, 5,000, 10,000, 20,000, 50,000, 100,000, 250,000, 500,000 or about 1,000,000 or more. The cells can be used in a series or parallel electrical arrangement.

[0076] The electrochemical cell can include a spacing between a surface of the anode and a surface of the cathode (e.g., between the cathode and at least about 50% to 100% of the surface area of ​​the anode, or about 80% to about 100%, or less than, equal to, or greater than about 50%, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, or about 99% or more of the surface area of ​​the anode) of about 1 mm to about 110 mm, or about 2 mm to about 30 mm. , or less than, equal to, or greater than about 1 mm, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 32, 34, 36, 38, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, or 110 mm, or more.

[0077] The electrochemical cell can be planar in form, having a thickness less than the height and width. The electrochemical cell can include a planar frame of the electrochemical cell and a cathode material contained within the periphery of the frame, wherein the cathode material is electrically connected to the frame (e.g., by direct contact therewith). The frame can be a structural component of the electrochemical cell. The frame is structurally sufficient to maintain its shape in the absence of any or all anodes. Both the planar frame and the cathode material contained within the periphery of the frame can be cathodes.

[0078] The planar frame can be a non-porous solid material. The planar frame can be one or more cathode material strips assembled to form a frame. The planar frame can have a polygonal perimeter, such as a square or rectangle. The cathode material contained within the perimeter of the planar frame can include a porous cathode material, for example, including a wire, a mesh, a screen, a sheet including one or more through holes, or a combination thereof. The porous cathode material can include a wire mesh or a wire screen containing the porous cathode material. The porous cathode material contained within the perimeter of the planar frame can have an edge sandwiched between two planar frames, which are held together by compression, or by a conductive connector passing through one or more through holes of the porous cathode material, or by a combination thereof, with one or more of the conductive connectors fixing the porous cathode material therebetween.

[0079] The electrochemical cell may include a plurality of pairs of planar frames (e.g., 2 to 20 pairs, or 2 to 10 pairs, or less than, equal to, or greater than 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 or more pairs), each pair of planar frames being held together to secure a porous cathode material therebetween using one or more of the conductive connectors, and each pair of planar frames being separated by one or more of the anodes spanning the porous cathode material contained within the perimeter of the planar frames. The one or more anodes separating each pair of planar frames from each other may directly contact a face of each pair of planar frames separated by them. The one or more anodes separating each pair of planar frames from each other may directly contact a face of one of each pair of planar frames separated by them, and may not directly contact a face of another of each pair of planar frames separated by them.

[0080] The anode may be a strip fastened to the planar frame at two edges of the planar frame, wherein the anode is fastened to the planar frame at each of the two edges of the planar frame using at least one of the conductive connectors so that the anode spans the cathode material contained within the perimeter of the planar frame, forming a gap between the cathode material contained within the perimeter of the planar frame and the anode strip. The anode and cathode may directly contact each other at each of the edges of the planar frame, wherein the anode is fastened to the planar frame by at least one conductive connector.

[0081] The electrochemical cell may include a plurality of anodes, wherein each anode is a strip fastened to the planar frame at two edges of a planar frame on a face of the frame, wherein each of the anodes is fastened to the planar frame at each of the two edges of the planar frame using at least one of the conductive connectors so that each of the anodes spans the cathode material contained within the perimeter of the planar frame, forming a gap between the cathode material contained within the perimeter of the planar frame and the anode strips, wherein the plurality of anodes are spaced apart across the face so that they are not in physical contact with each other. Each of the anodes may span the cathode material contained within the perimeter of the planar frame substantially parallel to each other on the face; the anodes on the other face of the planar frame may be parallel or perpendicular to the anodes on the first face. The two edges of the planar frame to which each anode is fastened may be opposite edges of the planar frame. The electrochemical cell may have all of its anodes on a single major face of the planar frame, or some anodes may be on one major face of the planar frame and other anodes on another major face of the frame.

[0082] Figure 1A An electrochemical cell 110 from a main face is shown according to various embodiments. The electrochemical cell 110 includes a cathode, wherein the cathode includes a planar frame 120 of the electrochemical cell having a polygonal perimeter and a porous material 130 contained within the perimeter of the frame, the porous material being a wire mesh or wire screen in direct contact with the frame. The electrochemical cell 110 includes a plurality of anodes 140, wherein each anode is a strip fastened to the planar frame at two opposite edges of the planar frame on the face of the planar frame. Each of the anodes is fastened to the planar frame at each of the two edges of the planar frame using at least one of the conductive connectors 150, so that each of the anodes is approximately parallel to each other and spans the porous material contained within the perimeter of the planar frame, forming a gap (not shown) between the porous material and the anode strip contained within the perimeter of the planar frame. Each anode directly contacts the cathode frame at each of the edges of the planar frame, wherein the anode is fastened to the planar frame by at least one conductive connector. A conductive connector (not shown) that only passes through the planar frame 120 can also be used to fix the porous material 130 therebetween. The plurality of anodes are spaced across the face such that they are not in physical contact with each other and wherein the gap (not shown) is from about 1 mm to about 110 mm.

[0083] Figure 1B Shown along Figure 1AThe right side shows an enlarged cross-sectional view of an electrochemical cell 110 viewed from a perspective view. The electrochemical cell may include a plurality of pairs of planar frames 120, wherein each pair of planar frames is held together to secure a porous cathode material 130 therebetween using one or more of the conductive connectors (not shown). The anode 140 spans the porous cathode material 130 contained within the perimeter of the planar frames 120. Each pair of planar frames 120 is supported by the anode 140 ( Figure 1B The one or more anodes 140 that separate each pair of planar frames from each other may directly contact the surface of each pair of planar frames 120 that are separated by them.

[0084] Method for preparing magnesium ammonium phosphate

[0085] In various embodiments, the present invention provides methods for preparing magnesium ammonium phosphate (e.g., NH4MgPO4·6H2O) using electrochemical cells and methods using electrochemical cells described herein. The method may include immersing the electrochemical cell in phosphorus-containing water having a pH of about 10 to about 11 to form treated water containing a phosphorus-containing salt. The phosphorus-containing salt may include magnesium ammonium phosphate. Magnesium ammonium phosphate may include phosphorus from water and Mg from an anode. The electrochemical cell may include an anode containing Mg, wherein the anode is about 90% by weight to about 100% by weight Mg. The electrochemical cell may include a cathode containing Cu, wherein the cathode is about 90% by weight to about 100% by weight Cu. The method may include separating the phosphorus-containing salt from the treated water to obtain separated magnesium ammonium phosphate and forming separated water having a phosphorus concentration lower than that of the phosphorus-containing water.

[0086] If there is enough ammonia or ammonium ion in the water to meet the stoichiometric requirements for forming magnesium ammonium phosphate, then the phosphorus-containing salt can include magnesium ammonium phosphate. In various embodiments, magnesium ammonium phosphate can be produced when ammonia or ammonium ion is not present in the phosphorus-containing water source or is only present in low concentrations, such as due to the formation of ammonia or ammonium ion by the reduction process of nitrogen-containing compounds (e.g., nitrates or nitrites) on the cathode surface of the electrochemical cell.

[0087] The electrochemical cell may also include a conductive connector electrically connecting the anode and cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof. In some embodiments, the anode and cathode are in direct contact with each other and the electrochemical cell has no conductive connector.

[0088] The method may include purifying the separated magnesium ammonium phosphate, for example by recrystallization (e.g., solid dissolution to form a mother liquor followed by crystallization, leaving at least some impurities in the mother liquor), liquid extraction, filtration, or a combination thereof.

[0089] Phosphorus-containing water may further comprise nitrogen. The nitrogen may be from any suitable source. Nitrogen may be naturally present in the phosphorus-containing water, may be added to the water, or a combination thereof. Adding nitrogen to the phosphorus-containing water may include adding nitrogen in any suitable form. For example, nitrogen may be added to the phosphorus-containing water by adding KNO , HNO , an organic nitrogen compound, or a combination thereof.

[0090] The method may include adding phosphorus to water to form phosphorus-containing water.Any suitable phosphorus-containing material may be added to water to form the phosphorus-containing water, such as phosphoric acid, an organic phosphorus-containing material, or a combination thereof.

[0091] Method for preparing AlPO4, aluminum hydroxide or a combination thereof

[0092] In various embodiments, the present invention provides methods for preparing AlPO4, aluminum hydroxide, or a combination thereof using embodiments of electrochemical cells and methods of using electrochemical cells described herein. The method may include immersing the electrochemical cell in phosphorus-containing water having a pH of about 5 to about 7 to form treated water containing a phosphorus-containing salt. The phosphorus-containing salt may include AlPO4 or a hydrate thereof, the AlPO4 containing phosphorus and Al from the anode; aluminum hydroxide or a hydrate thereof, the aluminum hydroxide containing Al from the anode; or a combination thereof. The electrochemical cell may include an anode containing Al, wherein the anode is about 90 wt % to about 100 wt % Al. The electrochemical cell may include a cathode containing Cu, wherein the cathode is about 90 wt % to about 100 wt % Cu. The method may also include separating the phosphorus-containing salt from the treated water to form separated water having a phosphorus concentration lower than that of the phosphorus-containing water.

[0093] The electrochemical cell may also include a conductive connector electrically connecting the anode and cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof. In some embodiments, the anode and cathode are in direct contact with each other and the electrochemical cell has no conductive connector.

[0094] The method may include adding phosphorus to water to form phosphorus-containing water.Any suitable phosphorus-containing material may be added to water to form phosphorus-containing water, such as phosphoric acid, an organic phosphorus-containing material, or a combination thereof.

[0095] The method may include purifying the phosphorus-containing salt to provide purified AlPO, purified aluminum hydroxide, or a purified mixture of AlPO and aluminum hydroxide. Purification may be performed in any suitable manner, such as by recrystallization (e.g., dissolution of the solid to form a mother liquor followed by crystallization, leaving at least some impurities in the mother liquor), liquid extraction, filtration, or a combination thereof.

[0096] Method for preparing magnesium phosphate, Mg(OH)2 or a combination thereof

[0097] In various embodiments, the present invention provides methods for preparing magnesium phosphate, Mg(OH)2, or a combination thereof using embodiments of electrochemical cells and methods of using electrochemical cells described herein. The method for preparing magnesium phosphate, Mg(OH)2, or a combination thereof may include immersing the electrochemical cell in phosphorus-containing water having a pH of about 10 to about 11 to form treated water containing a phosphorus-containing salt. The phosphorus-containing salt may include magnesium phosphate, potassium magnesium phosphate, a hydrate thereof, or a combination thereof; Mg(OH)2, which contains Mg from an anode; or a combination thereof. The electrochemical cell may include an anode containing Mg, wherein the anode is about 90 wt % to about 100 wt % Mg. The electrochemical cell may include a cathode containing Cu, wherein the cathode is about 90 wt % to about 100 wt % Cu. The method may also include separating the phosphorus-containing salt from the treated water to form separated water having a phosphorus concentration lower than that of the phosphorus-containing water.

[0098] The electrochemical cell may also include a conductive connector electrically connecting the anode and cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof. In some embodiments, the anode and cathode are in direct contact with each other and the electrochemical cell has no conductive connector.

[0099] The method may include adding phosphorus to water to form phosphorus-containing water.Any suitable phosphorus-containing material may be added to water to form phosphorus-containing water, such as phosphoric acid, an organic phosphorus-containing material, or a combination thereof.

[0100] The method may include purifying the phosphorus-containing salt to provide purified magnesium phosphate, purified Mg(OH) 2, or a purified mixture of magnesium phosphate and Mg(OH) 2. Purification may be performed in any suitable manner, such as by recrystallization (e.g., dissolution of the solid to form a mother liquor followed by crystallization, leaving at least some impurities in the mother liquor), liquid extraction, filtration, or a combination thereof. Get out of the water Method for removing one or more dissolved transition metals, post-transition metals or metalloids

[0101] In various embodiments, the present invention provides methods for removing one or more dissolved transition metals, post-transition metals or metalloids from water using embodiments of electrochemical cells and methods of using electrochemical cells described herein. The water may contain any suitable amount of phosphorus, or the water may be substantially free of phosphorus. In the context of removing phosphorus from water, any suitable embodiment of the electrochemical cell described herein or the method using it may be included in a method for removing one or more dissolved transition metals, post-transition metals or metalloids from water. The method may include immersing the electrochemical cell in water containing one or more dissolved transition metals, post-transition metals or metalloids to form treated water containing hydroxide salts containing one or more transition metals, post-transition metals or metalloids. The electrochemical cell may include an anode containing Mg, Al, Fe, Zn or a combination thereof. The electrochemical cell may include a cathode containing Cu, Ni, Fe or a combination thereof. The method may include separating salts (including hydroxide salts) containing one or more transition metals, post-transition metals or metalloids to form separated water having a lower concentration of one or more transition metals, post-transition metals or metalloids than water containing one or more transition metals, post-transition metals or metalloids.

[0102] The electrochemical cell may also include a conductive connector electrically connecting the anode and cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof. In some embodiments, the anode and cathode are in direct contact with each other and the electrochemical cell has no conductive connector.

[0103] One or more transition metals, post transition metals or metalloids can be any suitable transition metal, post transition metal or metalloid that can be removed using an electrochemical cell. One or more transition metals, post transition metals or metalloids can include Sc, Y, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, Rf, Db, Sg, Bh, Hs, Al, Zn, Ga, Cd, In, Sn, Hg, Tl, Pb, Bi, Po, Cn, B, Si, Ge, As, Sb, Te, At or a combination thereof. One or more transition metals, post transition metals or metalloids can include Hg, Fe, Cr, Ni, Zn, Cd, As or a combination thereof.

[0104] The method can remove any suitable amount of transition metals, post-transition metals, metalloids, or combinations thereof from water. The separated water can have a concentration of transition metal, post-transition metal, metalloid or combination thereof that is about 0% to about 70% of the concentration of the transition metal, post-transition metal, metalloid or combination thereof in the water comprising one or more dissolved transition metals, post-transition metals or metalloids, or a concentration of transition metal, post-transition metal, metalloid or combination thereof that is about 0% to about 20%, or about 0%, or about 1% or less, or less than, equal to, or greater than about 2%, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, 26, 28, 30, 35, 40, 45, 50, 55, 60, 65, or about 70% or more of the concentration of the transition metal, post-transition metal, metalloid or combination thereof in the water comprising one or more dissolved transition metals, post-transition metals or metalloids.

[0105] Example

[0106] Various embodiments of the present invention may be better understood by reference to the following examples which are provided by way of illustration.The present invention is not limited to the examples given herein.

[0107] Various sizes of galvanic cells were used to evaluate various aspects of the process outlined in the examples. The galvanic cells are referred to as "small", "medium" and "large" as defined below. The magnesium anode is AZ91 with 90 wt% Mg, 9 wt% Al and 1 wt% Zn and is 99.9% pure. The aluminum anode is 99.9 wt% pure aluminum. The copper used in the copper frame and copper mesh is 99.9 wt% pure copper.

[0108] For small cells with copper cathodes and aluminum or magnesium anodes, the final size is 5cmx20cm, the thickness is about 4mm, and copper mesh and anode each having a thickness of about 1mm are used. The small size battery includes a single pair of copper meshes with an anode sandwiched between them, and the copper mesh and anode are separated from the copper mesh by 0.5cm using electrically insulating plastic screws. The copper meshes are electrically connected to each other by copper wires. The anode and cathode are not electrically connected to each other (except through a multimeter and surrounding water). The resulting surface area of ​​the sacrificial anode exposed to water is about 400mm per battery. 2 . Figure 2A A photograph along the edge of an Al-Cu electrochemical cell is shown.

[0109] For a medium-sized cell with a copper cathode and an aluminum or magnesium anode, the final dimensions are 300 cm x 45 cm, with a thickness of about 10 mm, and a single pair of copper mesh with the anode sandwiched between them is used. The copper mesh directly contacts the anode and is connected to the anode by a brass bolt (plain brass, 67 wt% copper and 33 wt% Zn). The resulting surface area of ​​the sacrificial anode exposed to water is about 31,400 mm per cell. 2 . Figure 2B Shown are photographs along the edges of several mesoscale Al-Cu electrochemical cells.

[0110] The large-size electrochemical cell used in the embodiment includes a cathode, which is a pair of planar solid copper frames sandwiching a copper mesh, wherein a brass connector fixes the copper frames together to fix the copper mesh between the frames. The solid copper frame forms the rigid structural periphery of the battery, wherein the copper mesh fills the entire area within the periphery of each pair of copper frames. A plurality of anode strips (which are magnesium alloys or aluminum) are fixed to the periphery of the frame with brass fasteners so that they span from one edge of the frame to another frame, directly contact the frame and form a gap between the anode and the copper mesh. Each electrochemical cell includes two pairs of copper frames (i.e., a total of four copper frames, with two copper meshes) with a copper mesh therebetween. The first pair of copper frames has an anode fixed to its single main face, and the second pair of copper frames has an anode fixed to its two main faces, wherein the two pairs of copper frames are fixed to each other with brass fasteners so that they will not directly contact each other, and so that they clamp the anode fixed to one main face of the second pair of copper frames. The brass fasteners are ordinary brass, and are 67% by weight copper and 33% by weight Zn. The anodes are horizontally across each major face of the copper frame and parallel to each other, with 6 anodes fixed on each face. From one major face of the electrochemical cell to another, the order of the components is 1) anodes fixed to one major face of the first pair of copper frames, 2) the first pair of copper frames with copper mesh between them, 3) anodes fixed to one major face of the second pair of copper frames, 4) the second pair of copper frames with copper mesh between them, and 5) anodes fixed to the other major face of the second pair of copper frames. The ratio of the anode surface area to the cathode surface area of ​​the electrochemical cell is about 1:1.

[0111] For large-size batteries, each copper frame has a thickness of 3.175 mm (1 / 8 inch). The height of the copper frame is 400 mm and the length of the copper frame is 400 mm. The copper mesh has a thickness of 1.5875 mm, so that each pair of copper frames sandwiching the copper mesh has a thickness of about 8 mm. The anode strip has a length of 400 mm, a width of 45 mm and a thickness of 6 mm. The thickness of the entire electrochemical cell is about 30 mm. The gap between the anodes on each face of the copper frame is 12-18 mm. The gap between the anode fixed to each pair of copper frames and the copper mesh sandwiched therebetween is 12-18 mm. Large-size batteries using aluminum anodes include about 290,000 mm 2The anode surface area exposed to water for large-scale batteries using magnesium includes approximately 868,000 mm 2 of the anode surface area exposed to water.

[0112] Figure 2C A photograph showing the main surface of a large-scale Mg-Cu electrochemical cell used in Examples. Figure 2D and 2E Shown is a close-up photograph of the edge of a large-scale Mg-Cu electrochemical cell used in the Examples.

[0113] In the embodiments herein, the Al-Cu or Mg-Cu electrochemical cell is completely immersed in the water in the container so that the electrochemical cell is oriented vertically and the anode extends vertically. When multiple electrochemical cells are used, they are separated by about 25 mm using a wooden frame. In the middle of the container, the water therein is stirred using a mechanical stirrer. The water is filtered and pumped into the container using a pump. Another pump is used to circulate water and filter water (e.g., to remove sediment therefrom) in the container, and the water is pumped from one side of the container and recirculated to the other side. HCl is added to the container using a pump connected to a reservoir of 10% HCl to adjust the pH of the water therein. The water in the container is measured to determine its pH, which is used to determine the amount of acid that needs to be added from the reservoir to maintain a specific pH. The water fed into the container is analyzed to determine the initial pH, initial conductivity, and initial active phosphorus content. For the Mg-Cu battery, the water fed into the container is also analyzed to determine the initial dissolved magnesium content. The pH and conductivity of the water in the container are measured. The container includes a drain at the water level of the container to allow water to leave the system. The water leaving the system is analyzed to determine the final pH, final conductivity, and final active phosphorus content. For Al-Cu cells, the water leaving the container is analyzed to determine total Al and dissolved Al. For Mg-Cu cells, the water leaving the container is analyzed to determine dissolved magnesium content. Figure 2F A photograph showing a top view of the system used in the Examples is shown, wherein the specific embodiment shown in the photograph has 12 electrochemical cells (6 in the front and 6 in the back arranged side by side with the 6 in the front). Figure 2G A photograph showing a side view of the system used in the Examples is shown, with a specific embodiment having 12 electrochemical cells therein.

[0114] "Active phosphorus concentration" refers to the soluble active phosphorus (e.g., orthophosphate) in solution and is measured by US-EPA 365.1: Semi-automated colorimetric determination of phosphorus. The pH 700 meter measures pH. Thermo Scientific CON 150 meters measure conductivity. TM Dionex TM AquionTM Ion chromatography system to measure dissolved magnesium content. Using Hach Aluminum TNT plus TM The vial test measures total and dissolved aluminum content. Dissolved Al is determined at the pH of the water leaving the container. Total Al content is determined by adjusting the pH to 2.

[0115] Example 1. Removal of phosphorus using Al-Cu battery, initial P concentration is 0.033 ppm

[0116] The residence time in the galvanic method was modified by taking water from one of the channels of a local lake and adjusting the water flow to provide a specific residence time while keeping the other variables of the system (pH, conductivity and phosphorus concentration) constant. The residence time (i.e., the volume of the container divided by the flow rate) was gradually reduced until the removal performance decreased and then remained constant in this example. For low initial phosphorus concentrations (0.033 ppm), the residence time was reduced to about 15 minutes while maintaining an average phosphorus removal of about 90%. The Al-Cu cell was of medium size. The results are shown in Table 1.

[0117] Table 1. Phosphorus removal using Al-Cu cells, initial P concentration 0.033 ppm.

[0118]

[0119] Example 2. Removal of phosphorus using Al-Cu battery, initial P concentration is 0.451 ppm

[0120] Water from a local inland wastewater treatment facility was treated to evaluate the effect of increasing solution conductivity. During this example, the residence time was kept constant at 21 minutes. The conductivity was varied by adding NaCl. This example demonstrates the beneficial effect of increased conductivity on phosphorus removal efficiency. The Al-Cu cell is of medium size. The results are shown in Table 2.

[0121] Table 2. Phosphorus removal using Al-Cu cells, initial P concentration 0.451 ppm, cell size = medium

[0122]

[0123] Example 3. Phosphorus removal using Al-Cu battery, initial P concentration is 0.392ppm.

[0124] A coastal wastewater treatment plant effluent with high conductivity was treated using a moderate Al-Cu cell. As noted in Example 2 above, increased conductivity is beneficial. The water treated in this example came from a coastal area where salt (NaCl) concentrations resulted in increased conductivity. The purpose of this example was to evaluate the loss of sacrificial electrode material in the treated aqueous solution and to evaluate this relationship as a function of pH. The final phosphorus removal efficiency remained unchanged; however, the concentration of total aluminum (dissolved and solid) decreased when the pH was changed from pH 7 to pH 6.5. This example demonstrates the ability to control the loss of material from the sacrificial electrode by adjusting the pH. The results are shown in Table 3.

[0125] Table 3. Phosphorus removal using Al-Cu cells, initial P concentration 0.392 ppm, cell size = medium

[0126]

[0127] Example 4. Removal of phosphorus using Al-Cu battery, initial P concentration is 0.648-0.762 ppm

[0128] Water from a local freshwater reservoir was spiked with phosphoric acid to obtain a phosphorus concentration of 0.75 ppm and treated using multiple galvanic cells in a continuous flow unit with a flow rate of about 2 gallons per minute (GPM) (large cells). The pH of the water was gradually adjusted down to values ​​between 7 and 6. An increase in the percent removal from 82% at pH = 7 to 97% at pH = 6 was observed, with a concomitant reduction in the soluble aluminum remaining in the treated water. The results are shown in Table 4.

[0129] Table 4. Phosphorus removal using Al-Cu cells, initial P concentration 0.648-0.762 ppm, cell size = large

[0130]

[0131] Example 5. Effect of conductivity on the current generated by Al-Cu battery and its relationship with time

[0132] Using a small cell, aluminum foil and copper screen measuring 5cm X 2cm were separated by 0.5cm using plastic screws. The aluminum foil / copper was placed in a simple compartment with magnetic stirring, which contained 30mL of water from a local freshwater reservoir. The current was measured using a Keithley 175 multimeter in series. The initial conductivity was adjusted with NaCl. The current generated by the Al-Cu galvanic couple in the Al-Cu cell was measured. This current is a measure of the amount of anode material converted in the electrode over time, such as aluminum oxidation reaction to produce aluminum ions and water decomposition on the copper electrode to produce hydrogen and hydroxide ions.

[0133] Figure 3The current generated by the Al-Cu galvanic couple is shown as a function of the conductivity of the solution. The initial pH of the water did not change and was about 7. Increasing the initial conductivity of the solution to a value of 1000 μS increases the current due to the reduced resistance between the electrodes, thereby increasing the rate of the chemical reaction at the electrode surface. Similar results were obtained in Example 2. Increasing the conductivity to values ​​above 1000 μS resulted in almost no change in the current, because at higher conductivity values ​​the rate-limiting step of the reaction is the kinetics of the chemical process at the surface of the electrode.

[0134] Example 6. Effect of pH on the Current Generated by Al-Cu Battery and Time

[0135] The same experimental conditions as in Example 5 were used, but the initial pH was adjusted with NaOH, where the initial conductivity of the water was adjusted to about 1000 μS with NaCl. Figure 4 The current generated by the Al-Cu galvanic couple varies with the pH of the solution. Lowering the pH of the solution favors the decomposition kinetics of water on the copper electrode, which is converted into an increase in the current through the Al-Cu galvanic couple.

[0136] Example 7. Effect of conductivity on the current generated by Mg-Cu battery as a function of time

[0137] The same experimental conditions as in Example 5 were used, the pH was not changed, and the conductivity was changed using NaCl. Figure 5A The current circulating in the Mg-Cu galvanic couple is shown as a function of the water conductivity of a local freshwater reservoir. An increase in the water conductivity results in a significant increase in the current flowing through the electrochemical cell. Figure 5B The effect of this conductivity increase on the kinetics of chemical reactions is shown in , where it improves the kinetics of the pH increase.

[0138] Example 8. Mg-Cu battery, initial P concentration is 0.392-0.451

[0139] Two water bodies from treatment plants were compared; the conductivity of water collected from a coastal wastewater treatment plant (WWTP) was three times that of water from an inland WWTP due to the presence of salt water in the treatment system. Higher conductivity favors reaction kinetics, and so for the same residence time, more phosphorus removal occurs in the higher conductivity water while consuming the same amount of sacrificial anodes as the lower conductivity (resulting in the same amount of magnesium ions in solution). The Mg-Cu cell is of medium size. The results are shown in Table 5.

[0140] Table 5. Mg-Cu cells, initial P concentration 0.392-0.451, cell size = medium.

[0141] Inland WWTP Coastal WWTP Flow rate (mL / min) 370 370 Dwell time (minutes) 50 50 electrode 8 8 Initial pH 7.69 9.06 Final pH 10.90 10.94 Initial conductivity(uS) 960 3100 Final conductivity(uS) 1124 3148 Initial activity P (ppm) 0.451 0.392 Final active P (ppm) 0.122 0.061 P removal % 72.9 84.4 Initial dissolved magnesium (ppm) 17 56 Final dissolved magnesium (ppm) 44 95

[0142] The terms and expressions used are used as terms of description rather than limitation, and the use of these terms and expressions is not intended to exclude any equivalents of the features shown and described or parts thereof, but it should be recognized that various modifications can be made without departing from the scope of the embodiments of the present invention. Therefore, it should be understood that although the present invention has been specifically disclosed through specific embodiments and optional features, those of ordinary skill in the art may make modifications and changes to the concepts disclosed herein, and such modifications and changes are considered to be within the scope of the embodiments of the present invention.

[0143] Exemplary embodiments

[0144] The following exemplary embodiments are provided, the numbering of which should not be construed as designating a level of importance:

[0145] Embodiment 1 provides a method for removing phosphorus from water, the method comprising:

[0146] immersing an electrochemical cell in phosphorus-containing water to form treated water comprising a phosphorus-containing salt, the electrochemical cell comprising an anode comprising Mg, Al, Fe, Zn, or a combination thereof,

[0147] a cathode having a different composition than the anode, the cathode comprising Cu, Ni, Fe, or a combination thereof; and

[0148] The phosphorus-containing salt is separated from the treated water to form separated water having a lower phosphorus concentration than the phosphorus-containing water.

[0149] Embodiment 2 provides the method of embodiment 1, wherein the anode and cathode are in direct contact with each other.

[0150] Embodiment 3 provides the method of any one of Embodiments 1-2, wherein the electrochemical cell further comprises a conductive connector electrically connecting the anode and the cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof.

[0151] Embodiment 4 provides the method of any one of embodiments 1-3, wherein the electrochemical cell is a galvanic cell.

[0152] Embodiment 5 provides the method of any one of embodiments 1-4, wherein no potential is applied across the anode and cathode of the electrochemical cell.

[0153] Embodiment 6 provides the method of any one of embodiments 1-5, wherein the electrochemical cell is an electrolytic cell.

[0154] Embodiment 7 provides the method of any one of embodiments 1-6, comprising applying a potential across an anode and a cathode of the electrochemical cell.

[0155] Embodiment 8 provides the method of any of Embodiments 1-7, comprising applying a potential across an anode and a cathode of the electrochemical cell that is greater than a galvanic corrosion potential of the electrochemical cell.

[0156] Embodiment 9 provides the method of any of embodiments 1-8, comprising applying a potential across an anode and a cathode of the electrochemical cell that is less than a galvanic corrosion potential of the electrochemical cell.

[0157] Embodiment 10 provides the method of any one of embodiments 1-9, wherein the potential across the anode and cathode is equal to the galvanic corrosion potential of the electrochemical cell.

[0158] Embodiment 11 provides the method of any of Embodiments 1-10, wherein immersing the electrochemical cell in water containing phosphorus comprises partial immersion.

[0159] Embodiment 12 provides the method of any of embodiments 1-11, wherein immersing the electrochemical cell in the phosphorus-containing water comprises complete immersion.

[0160] Embodiment 13 provides the method of any one of embodiments 1-12, wherein the phosphorus in the phosphorus-containing water is in the form of elemental phosphorus, inorganic phosphorus, organic phosphorus, dissolved phosphorus, solid phosphorus, oxidized phosphorus, or a combination thereof.

[0161] Embodiment 14 provides the method of any of embodiments 1-13, wherein the phosphorus-containing water has a total phosphorus concentration of about 0.001 ppm to about 10,000 ppm.

[0162] Embodiment 15 provides the method of any one of embodiments 1-14, wherein the phosphorus-containing water has a total phosphorus concentration of about 0.01 ppm to about 20 ppm.

[0163] Embodiment 16 provides the method of any one of embodiments 1-15, wherein the separated water has a total phosphorus concentration of about 0 ppm to about 1 ppm.

[0164] Embodiment 17 provides the method of any one of embodiments 1-16, wherein the separated water has a total phosphorus concentration of about 0.0001 ppm to about 0.1 ppm.

[0165] Embodiment 18 provides the method of any one of embodiments 1-17, wherein the separated water has a total phosphorus concentration of about 0.0001 ppm to about 0.05 ppm.

[0166] Embodiment 19 provides the method of any one of embodiments 1-18, wherein the separated water has a dissolved phosphorus concentration of about 0 ppm to about 1 ppm.

[0167] Embodiment 20 provides the method of any one of embodiments 1-19, wherein the separated water has a dissolved phosphorus concentration of about 0.0001 ppm to about 0.1 ppm.

[0168] Embodiment 21 provides the method of any one of embodiments 1-20, wherein the separated water has a dissolved phosphorus concentration of about 0.0001 ppm to about 0.05 ppm.

[0169] Embodiment 22 provides the method of any one of Embodiments 1-21, wherein the separated water has a total phosphorus concentration of about 0% to about 70% of the total phosphorus concentration of the phosphorus-containing water.

[0170] Embodiment 23 provides the method of any one of Embodiments 1-22, wherein the separated water has a total phosphorus concentration of about 0% to about 20% of the total phosphorus concentration of the phosphorus-containing water.

[0171] Embodiment 24 provides the method of any one of embodiments 1-23, wherein the separated water has a dissolved phosphorus concentration of about 0% to about 70% of the dissolved phosphorus concentration of the phosphorus-containing water.

[0172] Embodiment 25 provides the method of any one of embodiments 1-24, wherein the separated water has a dissolved phosphorus concentration of about 0% to about 20% of the dissolved phosphorus concentration of the phosphorus-containing water.

[0173] Embodiment 26 provides the method of any of Embodiments 1-25, wherein the phosphorus-containing water has an active phosphorus concentration of about 0.001 ppm to about 10,000 ppm.

[0174] Embodiment 27 provides the method of any one of embodiments 1-26, wherein the phosphorus-containing water has an active phosphorus concentration of about 0.01 ppm to about 20 ppm.

[0175] Embodiment 28 provides the method of any one of embodiments 1-27, wherein the separated water has an active phosphorus concentration of about 0 ppm to about 1 ppm.

[0176] Embodiment 29 provides the method of any one of embodiments 1-28, wherein the separated water has an active phosphorus concentration of about 0.0001 ppm to 0.1 ppm.

[0177] Embodiment 30 provides the method of any one of embodiments 1-29, wherein the separated water has an active phosphorus concentration of about 0.0001 ppm to 0.05 ppm.

[0178] Embodiment 31 provides the method of any one of Embodiments 1-30, wherein the separated water has an active phosphorus concentration of about 0% to about 20% of the total phosphorus concentration of the phosphorus-containing water.

[0179] Embodiment 32 provides the method of any one of Embodiments 1-31, wherein the separated water has an active phosphorus concentration of about 0% to about 70% of the dissolved phosphorus concentration of the phosphorus-containing water.

[0180] Embodiment 33 provides the method of any one of embodiments 1-32, wherein during immersion of the electrochemical cell in the phosphorus-containing water, the phosphorus-containing water has a pH of about 2 to about 14.

[0181] Embodiment 34 provides the method of any one of embodiments 1-33, wherein during immersion of the electrochemical cell in the phosphorus-containing water, the phosphorus-containing water has a pH of about 5 to about 11.

[0182] Embodiment 35 provides the method of any one of embodiments 1-34, wherein during immersion of the electrochemical cell in the phosphorus-containing water, the phosphorus-containing water has a pH of about 5 to about 7.

[0183] Embodiment 36 provides the method of any one of embodiments 1-35, wherein during immersion of the electrochemical cell in the phosphorus-containing water, the phosphorus-containing water has a pH of about 10 to about 11.

[0184] Embodiment 37 provides the method of any one of embodiments 1-36, further comprising adding an acid, a base, or a combination thereof to the phosphorus-containing water to adjust its pH.

[0185] Embodiment 38 provides the method of embodiment 37, wherein an acid, a base, or a combination thereof is added to the phosphorus-containing water before immersing the electrochemical cell in the phosphorus-containing water, during immersing the electrochemical cell in the phosphorus-containing water, after immersing the electrochemical cell in the phosphorus-containing water, or a combination of these times.

[0186] Embodiment 39 provides the method of any one of Embodiments 1-38, further comprising recirculating the phosphorus-containing water that immerses the electrochemical cell so that the phosphorus-containing water contacts the electrochemical cell multiple times.

[0187] Embodiment 40 provides the method of any one of Embodiments 1-39, wherein at least some of the phosphorus-containing salts in the treated water comprise solids.

[0188] Embodiment 41 provides the method of any of Embodiments 1-40, wherein a phosphorus-containing solid is formed during immersion of the electrochemical cell in water containing phosphorus.

[0189] Embodiment 42 provides the method of embodiment 41, wherein the forming of the phosphorus-containing solid comprises precipitation, flocculation, or a combination thereof.

[0190] Embodiment 43 provides the method of any one of embodiments 1-42, wherein separating the phosphorus-containing salts from the treated water comprises decantation, sedimentation, filtration, or a combination thereof.

[0191] Embodiment 44 provides the method of any of Embodiments 1-43, further comprising separating the treated water from the electrochemical cell.

[0192] Embodiment 45 provides the method of any one of Embodiments 1-44, wherein the anode is a sacrificial anode.

[0193] Embodiment 46 provides the method of any one of Embodiments 1-45, wherein the phosphorus-containing salt comprises material from an anode.

[0194] Embodiment 47 provides the method of any of Embodiments 1-46, further comprising forming a hydroxide salt comprising material from the anode during immersion of the electrochemical cell in water containing phosphorus.

[0195] Embodiment 48 provides the method of Embodiment 47, wherein separating the phosphorus-containing salts from the treated water further comprises separating hydroxide salts comprising material from the anode from the treated water.

[0196] Embodiment 49 provides the method of any one of embodiments 1-48, wherein the phosphorus-containing water further comprises dissolved transition metals, post-transition metals, metalloids, or combinations thereof, further comprising forming a hydroxide salt comprising a transition metal, post-transition metal, or metalloid during immersion of the electrochemical cell in the phosphorus-containing water.

[0197] Embodiment 50 provides the method of embodiment 49, wherein separating the phosphorus-containing salt from the treated water further comprises separating a hydroxide salt comprising a transition metal, a post-transition metal, or a metalloid from the treated water.

[0198] Embodiment 51 provides the method of any of Embodiments 49-50, wherein the transition metal, post-transition metal, or metalloid is Sc, Y, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, Rf, Db, Sg, Bh, Hs, Al, Zn, Ga, Cd, In, Sn, Hg, Tl, Pb, Bi, Po, Cn, B, Si, Ge, As, Sb, Te, At, or a combination thereof.

[0199] Embodiment 52 provides the method of any one of Embodiments 49-51, wherein the transition metal, post-transition metal, or metalloid is Hg, Fe, Cr, Ni, Zn, Cd, As, or a combination thereof.

[0200] Embodiment 53 provides a method of any one of Embodiments 49-52, wherein the concentration of the transition metal, post-transition metal, metalloid or combination thereof in the separated water is from about 0% to about 70% of the concentration of the transition metal, post-transition metal, metalloid or combination thereof in the phosphorus-containing water.

[0201] Embodiment 54 provides a method of any one of Embodiments 49-53, wherein the concentration of the transition metal, post-transition metal, metalloid or combination thereof in the separated water is from about 0% to about 20% of the concentration of the transition metal, post-transition metal, metalloid or combination thereof in the phosphorus-containing water.

[0202] Embodiment 55 provides the method of any one of Embodiments 1-54, comprising forming H2 and HO- at the anode during immersion of the electrochemical cell in water containing phosphorus.

[0203] Embodiment 56 provides the method of any of Embodiments 1-55, comprising forming H2 and HO- at the cathode during immersion of the electrochemical cell in water containing phosphorus.

[0204] Embodiment 57 provides the method of any one of embodiments 1-56, comprising forming H2O2, HO2 at the cathode during immersion of the electrochemical cell in water containing phosphorus. - or a combination thereof.

[0205] Embodiment 58 provides the method of any of Embodiments 1-57, further comprising applying shear to the phosphorus-containing water during immersion of the electrochemical cell in the phosphorus-containing water.

[0206] Embodiment 59 provides the method of embodiment 58, wherein the shearing is sufficient to drive at least some bubbles containing H2 from the surface of the anode, cathode, or a combination thereof.

[0207] Embodiment 60 provides the method of any of Embodiments 58-59, wherein the shearing is sufficient to at least partially prevent oxide formation at the surface of the anode.

[0208] Embodiment 61 provides the method of any of Embodiments 58-60, wherein the shearing is sufficient to at least partially prevent agglomeration of the phosphorus-containing salt on the surface of the anode.

[0209] Embodiment 62 provides the method of any one of embodiments 1-61, further comprising applying a mechanical force to the electrochemical cell sufficient to:

[0210] expelling at least some bubbles comprising H from the surface of the anode, cathode, or a combination thereof,

[0211] at least partially preventing oxide formation at the surface of the anode,

[0212] at least partially preventing agglomeration of the phosphorus-containing salt on the surface of the anode, or

[0213] A combination of them.

[0214] Embodiment 63 provides the method of any one of Embodiments 1-62, wherein the phosphorus-containing water further comprises nitrogen.

[0215] Embodiment 64 provides the method of embodiment 63, wherein the nitrogen in the phosphorus-containing water is in the form of elemental nitrogen, inorganic nitrogen, organic nitrogen, dissolved nitrogen, solid nitrogen, nitrogen oxides, or a combination thereof.

[0216] Embodiment 65 provides the method of any one of Embodiments 63-64, wherein the phosphorus-containing water has a total nitrogen concentration of about 0.001 ppm to about 20 ppm.

[0217] Embodiment 66 provides the method of any one of Embodiments 63-65, wherein the phosphorus-containing water has a total nitrogen concentration of about 1 ppm to about 5 ppm.

[0218] Embodiment 67 provides the method of any one of Embodiments 63-66, wherein the separated water has a total nitrogen concentration of about 0 ppm to about 2 ppm.

[0219] Embodiment 68 provides the method of any one of Embodiments 63-67, wherein the separated water has a total nitrogen concentration of about 0 ppm to about 1 ppm.

[0220] Embodiment 69 provides the method of any one of Embodiments 63-68, wherein the separated water has a dissolved nitrogen concentration of about 0 ppm to about 2 ppm.

[0221] Embodiment 70 provides the method of any one of Embodiments 63-69, wherein the separated water has a dissolved nitrogen concentration of about 0 ppm to about 1 ppm.

[0222] Embodiment 71 provides the method of any one of Embodiments 63-70, wherein the total nitrogen concentration of the separated water is from about 0% to about 70% of the total nitrogen concentration of the phosphorus-containing water.

[0223] Embodiment 72 provides the method of any one of Embodiments 63-71, wherein the total nitrogen concentration of the separated water is from about 0% to about 30% of the total nitrogen concentration of the phosphorus-containing water.

[0224] Embodiment 73 provides the method of any one of Embodiments 63-72, wherein the dissolved nitrogen concentration of the separated water is from about 0% to about 70% of the dissolved nitrogen concentration of the phosphorus-containing water.

[0225] Embodiment 74 provides the method of any one of Embodiments 63-73, wherein the total nitrogen concentration of the separated water is from about 0% to about 30% of the dissolved nitrogen concentration of the phosphorus-containing water.

[0226] Embodiment 75 provides the method of any one of embodiments 63-74, further comprising forming NH3, NH4 at the cathode + or a combination thereof, wherein the NH3 and NH4 + Nitrogen from said phosphorus-containing water is included.

[0227] Embodiment 76 provides the method of any one of Embodiments 63-75, further comprising forming a nitrogen-containing salt during immersion of the electrochemical cell in water containing phosphorus.

[0228] Embodiment 77 provides the method of embodiment 76, wherein separating phosphorus-containing salts from the treated water further comprises separating nitrogen-containing salts from the treated water.

[0229] Embodiment 78 provides the method of any one of Embodiments 76-77, wherein the nitrogen-containing salt comprises NH4MgPO4 or a hydrate thereof.

[0230] Embodiment 79 provides the method of any one of Embodiments 1-78, wherein the cathode comprises Cu.

[0231] Embodiment 80 provides the method of any one of Embodiments 1-79, wherein the cathode is substantially free of materials other than Cu.

[0232] Embodiment 81 provides the method of any of Embodiments 1-80, wherein the cathode is about 50 wt % to about 100 wt % Cu.

[0233] Embodiment 82 provides the method of any of Embodiments 1-81, wherein the cathode is about 90 wt % to about 100 wt % Cu.

[0234] Embodiment 83 provides the method of any one of Embodiments 1-82, wherein the anode comprises an alloy comprising Mg and Al.

[0235] Embodiment 84 provides the method of any one of Embodiments 1-83, wherein Mg and Al are from about 50 wt % to about 100 wt % of the anode.

[0236] Embodiment 85 provides the method of any one of Embodiments 1-84, wherein the anode is substantially free of materials other than Mg, Mg alloys, and Al.

[0237] Embodiment 86 provides the method of any one of Embodiments 1-85, wherein the anode further comprises Ag, Pt, Au, or a combination thereof.

[0238] Embodiment 87 provides the method of Embodiment 86, wherein Ag, Pt, Au, or a combination thereof is about 0.0001 wt % to about 20 wt % of the anode.

[0239] Embodiment 88 provides the method of any one of Embodiments 86-87, wherein Ag, Pt, Au, or a combination thereof is about 0.0001 wt % to about 5 wt % of the anode.

[0240] Embodiment 89 provides the method of any one of Embodiments 1-88, wherein the anode comprises Mg.

[0241] Embodiment 90 provides the method of Embodiment 89, wherein the anode is substantially free of materials other than Mg or its alloys.

[0242] Embodiment 91 provides the method of any of Embodiments 89-90, wherein the anode is about 50 wt % to about 100 wt % Mg or an alloy thereof.

[0243] Embodiment 92 provides the method of any of Embodiments 89-91, wherein the anode is from about 90 wt % to about 100 wt % Mg or an alloy thereof.

[0244] Embodiment 93 provides the method of any one of Embodiments 89-92, wherein the cathode comprises Cu.

[0245] Embodiment 94 provides the method of any one of Embodiments 89-93, wherein the phosphorus-containing salt comprises magnesium phosphate, potassium magnesium phosphate, hydrates thereof, or combinations thereof, wherein the magnesium phosphate or potassium magnesium phosphate comprises Mg from the anode.

[0246] Embodiment 95 provides the method of embodiment 94, wherein separating phosphorus-containing salts from the treated water further comprises separating magnesium phosphate from the treated water.

[0247] Embodiment 96 provides the method of any one of Embodiments 89-95, wherein the phosphorus-containing water further comprises nitrogen, wherein the phosphorus-containing salt comprises NH4MgPO4 or a hydrate thereof, the NH4MgPO4 comprising phosphorus and Mg from the anode.

[0248] Embodiment 97 provides the method of any one of Embodiments 89-96, further comprising forming Mg(OH)2 comprising Mg from the anode during immersion of the electrochemical cell in the phosphorus-containing water.

[0249] Embodiment 98 provides the method of Embodiment 97, wherein separating the phosphorus-containing salt from the treated water further comprises separating Mg(OH)2 from the treated water.

[0250] Embodiment 99 provides the method of any one of embodiments 89-98, wherein during immersion of the electrochemical cell in the phosphorus-containing water, the phosphorus-containing water has a pH of about 9.5 to about 11.5.

[0251] Embodiment 100 provides the method of any one of embodiments 89-99, wherein during immersion of the electrochemical cell in the phosphorus-containing water, the phosphorus-containing water has a pH of about 10 to about 11.

[0252] Embodiment 101 provides the method of any of Embodiments 89-100, further comprising adjusting the rate of introduction of fresh water containing phosphorus into the electrochemical cell such that the phosphorus-containing water submerging the electrochemical cell is maintained at a pH of about 10 to about 11.

[0253] Embodiment 102 provides the method of any one of embodiments 89-101, further comprising immersing the electrochemical cell in phosphorus-containing water until the phosphorus-containing water reaches a pH of about 10 to about 11, and then adjusting the rate at which fresh water containing phosphorus is introduced into the electrochemical cell so that the phosphorus-containing water in which the electrochemical cell is immersed is maintained at a pH of about 10 to about 11.

[0254] Embodiment 103 provides the method of any one of Embodiments 1-102, wherein the anode comprises Al.

[0255] Embodiment 104 provides the method of embodiment 103, wherein the anode is substantially free of materials other than Al.

[0256] Embodiment 105 provides the method of any of Embodiments 103-104, wherein the anode is about 50 wt % to about 100 wt % Al.

[0257] Embodiment 106 provides the method of any of Embodiments 103-105, wherein the anode is about 90 wt % to about 100 wt % Al.

[0258] Embodiment 107 provides the method of any one of Embodiments 103-106, wherein the cathode comprises Cu.

[0259] Embodiment 108 provides the method of any one of Embodiments 103-107, wherein the phosphorus-containing salt comprises AlPO4 or a hydrate thereof.

[0260] Embodiment 109 provides the method of embodiment 108, wherein separating phosphorus-containing salts from the treated water further comprises separating AlPO4 from the treated water.

[0261] Embodiment 110 provides the method of any of Embodiments 103-109, further comprising forming aluminum hydroxide or a hydrate thereof during immersion of the electrochemical cell in water containing phosphorus, the aluminum hydroxide comprising Al from the anode.

[0262] Embodiment 111 provides the method of embodiment 110, wherein separating the phosphorus-containing salts from the treated water further comprises separating aluminum hydroxide from the treated water.

[0263] Embodiment 112 provides the method of any of Embodiments 103-111, wherein during immersion of the electrochemical cell in the phosphorus-containing water, the phosphorus-containing water has a pH of about 4 to about 8.

[0264] Embodiment 113 provides the method of any of Embodiments 103-112, wherein during immersion of the electrochemical cell in the phosphorus-containing water, the phosphorus-containing water has a pH of about 5 to about 7.

[0265] Embodiment 114 provides the method of any of Embodiments 103-113, further comprising adjusting the rate of introducing the acid into the phosphorus-containing water such that the phosphorus-containing water in which the electrochemical cell is immersed is maintained at a pH of about 5 to about 7.

[0266] Embodiment 115 provides the method of embodiment 114, wherein the acid is added to the phosphorus-containing water before immersing the electrochemical cell in the phosphorus-containing water, during immersing the electrochemical cell in the phosphorus-containing water, after immersing the electrochemical cell in the phosphorus-containing water, or a combination of these times.

[0267] Embodiment 116 provides the method of any one of embodiments 103-115, wherein the acid comprises sulfuric acid, acetic acid, hydrochloric acid, or a combination thereof.

[0268] Embodiment 117 provides the method of any one of Embodiments 103-116, comprising flocculating an Al-containing salt from the treated water.

[0269] Embodiment 118 provides the method of any one of embodiments 1-117, wherein the cathode has a work function greater than the work function of the anode.

[0270] Embodiment 119 provides the method of any one of Embodiments 3-118, wherein the conductive connector has a work function between the work function of the anode and the work function of the cathode.

[0271] Embodiment 120 provides the method of any one of Embodiments 3-119, wherein the conductive connector comprises Cu.

[0272] Embodiment 121 provides the method of any one of Embodiments 3-120, wherein the conductive connector comprises Zn.

[0273] Embodiment 122 provides the method of any of Embodiments 3-121, wherein the conductive connector comprises an alloy comprising Cu and Zn.

[0274] Embodiment 123 provides the method of any of Embodiments 3-122, wherein the conductive connector comprises brass.

[0275] Embodiment 124 provides the method of any of Embodiments 3-123, wherein the conductive connector comprises brass, wherein the conductive connector is substantially free of other materials.

[0276] Embodiment 125 provides the method of any one of Embodiments 3-124, wherein the electrochemical cell comprises a plurality of conductive connectors, each conductive connector independently electrically connecting the anode and cathode.

[0277] Embodiment 126 provides the method of embodiment 125, wherein the plurality of conductive connectors are substantially evenly distributed around the periphery of the electrochemical cell.

[0278] Embodiment 127 provides the method of any one of embodiments 3-126, wherein the conductive connector comprises a screw, a bolt, a nut, a washer, or a combination thereof.

[0279] Embodiment 128 provides the method of any one of embodiments 3-127, wherein the conductive connector comprises a screw or a bolt.

[0280] Embodiment 129 provides the method of any one of embodiments 1-128, wherein the electrochemical cell comprises a plurality of said cathodes.

[0281] Embodiment 130 provides the method of any one of Embodiments 1-129, wherein the electrochemical cell comprises a plurality of said anodes.

[0282] Embodiment 131 provides the method of any of Embodiments 1-130, wherein the ratio of the anode surface area to the cathode surface area of ​​the electrochemical cell is from about 0.1 to about 10.

[0283] Embodiment 132 provides the method of any of Embodiments 1-131, wherein the ratio of the anode surface area to the cathode surface area of ​​the electrochemical cell is from about 0.5 to about 2.

[0284] Embodiment 133 provides the method of any of Embodiments 1-132, wherein the cathode comprises a roughened or etched surface.

[0285] Embodiment 134 provides the method of any of Embodiments 1-133, wherein during immersion of the electrochemical cell in the phosphorus-containing water, the conductivity of the phosphorus-containing water is from about 100 μS to about 1,000,000 μS.

[0286] Embodiment 135 provides the method of any of Embodiments 1-134, wherein during immersion of the electrochemical cell in the phosphorus-containing water, the conductivity of the phosphorus-containing water is from about 300 μS to about 100,000 μS.

[0287] Embodiment 136 provides the method of any of Embodiments 1-135, further comprising adjusting the conductivity of the phosphorus-containing water so that the conductivity is from about 100 μS to about 1,200 μS.

[0288] Embodiment 137 provides the method of embodiment 136, wherein adjusting the conductivity of the phosphorus-containing water comprises adjusting the rate at which fresh water containing phosphorus is introduced into the electrochemical cell.

[0289] Embodiment 138 provides the method of any of Embodiments 136-137, wherein adjusting the conductivity of the phosphorus-containing water comprises adding one or more salts to the phosphorus-containing water.

[0290] Embodiment 139 provides the method of any one of embodiments 136-138, wherein the salt is added to the phosphorus-containing water before immersing the electrochemical cell in the phosphorus-containing water, during immersing the electrochemical cell in the phosphorus-containing water, after immersing the electrochemical cell in the phosphorus-containing water, or a combination of these times.

[0291] Embodiment 140 provides the method of any of Embodiments 136-139, wherein the one or more salts added to the phosphorus-containing water to adjust its conductivity include halogen salts, sodium salts, potassium salts, or combinations thereof.

[0292] Embodiment 141 provides the method of any of Embodiments 136-140, wherein the one or more salts added to the phosphorus-containing water to adjust its conductivity include sodium chloride.

[0293] Embodiment 142 provides the method of any of Embodiments 1-141, wherein the electrochemical cell comprises a spacing of about 1 mm to about 110 mm between the surface of the anode and the surface of the cathode.

[0294] Embodiment 143 provides the method of Embodiment 142, wherein the electrochemical cell comprises a spacing of about 1 mm to about 110 mm between the cathode and at least about 80% of the total surface area of ​​the anode.

[0295] Embodiment 144 provides the method of any of Embodiments 142-143, wherein the electrochemical cell comprises a spacing between a surface of the anode and a surface of the cathode of about 2 mm to about 30 mm.

[0296] Embodiment 145 provides the method of any of embodiments 1-144, wherein the phosphorus-containing water is water taken from a source including natural water sources in the environment, drinking water, industrial wastewater, industrial cooling water, or a combination thereof.

[0297] Embodiment 146 provides the method of any of Embodiments 1-145, wherein the phosphorus-containing water is water taken from a source including a natural water source in the environment.

[0298] Embodiment 147 provides the method of any of Embodiments 1-146, wherein the method treats the phosphorus-containing water without using an oxidizing agent or an oxidative treatment other than any oxidation that occurs as a result of immersing the electrochemical cell in the phosphorus-containing water.

[0299] Embodiment 148 provides the method of any of embodiments 1-147, further comprising oxidizing phosphorus in the phosphorus-containing water before immersing the electrochemical cell in the phosphorus-containing water, during immersing the electrochemical cell in the phosphorus-containing water, after immersing the electrochemical cell in the phosphorus-containing water, or a combination of these times.

[0300] Embodiment 149 provides the method of embodiment 148, wherein immersing the electrochemical cell in phosphorus-containing water is sufficient to oxidize phosphorus in the phosphorus-containing water.

[0301] Embodiment 150 provides the method of any of Embodiments 148-149, comprising oxidizing phosphorus in the phosphorus-containing water prior to immersing the electrochemical cell in the phosphorus-containing water.

[0302] Embodiment 151 provides the method of embodiment 150, wherein oxidizing the phosphorus in the phosphorus-containing water comprises contacting an oxidant and the phosphorus-containing water to oxidize the phosphorus.

[0303] Embodiment 152 provides the method of any of Embodiments 150-151, wherein an aqueous solution of an oxidizing agent is added to the phosphorus-containing water.

[0304] Embodiment 153 provides the method of any of Embodiments 150-152, wherein the aqueous solution of the oxidant has an oxidant concentration of about 0.001 ppm to about 999,999 ppm.

[0305] Embodiment 154 provides the method of any of Embodiments 150-153, wherein the aqueous solution of the oxidant has an oxidant concentration of about 50,000 ppm to about 140,000 ppm.

[0306] Embodiment 155 provides the method of any of embodiments 150-154, wherein the oxidant comprises ferrate, ozone, ferric chloride (FeCl3), potassium permanganate, potassium dichromate, potassium chlorate, potassium persulfate, sodium persulfate, perchloric acid, peracetic acid, potassium persulfate, hydrogen peroxide, sodium hypochlorite, potassium hypochlorite, hydroxide, sulfite, free radicals generated by their decomposition, or a combination thereof.

[0307] Embodiment 156 provides the method of any of Embodiments 150-155, wherein the oxidizing agent converts substantially all of the dissolved phosphorus in the phosphorus-containing water into an oxidized form of phosphorus.

[0308] Embodiment 157 provides the method of any of Embodiments 1-156, further comprising adjusting the pH of the separated water to about 6 to about 8.

[0309] Embodiment 158 ​​provides the method of any one of Embodiments 1-157, further comprising adjusting the pH of the separated water to about 7.

[0310] Embodiment 159 provides the method of any one of embodiments 1-158, wherein the method does not subject the separated water to pH treatment.

[0311] Embodiment 160 provides the method of any one of Embodiments 1-159, wherein the method comprises immersing a plurality of said electrochemical cells in said phosphorus-containing water.

[0312] Embodiment 161 provides the method of any one of Embodiments 1-160, wherein the electrochemical cell is planar.

[0313] Embodiment 162 provides the method of any of Embodiments 1-161, wherein the electrochemical cell has a thickness that is less than the height and width of the electrochemical cell.

[0314] Embodiment 163 provides the method of any of Embodiments 1-162, wherein the cathode comprises a planar frame of the electrochemical cell and a cathode material contained within the perimeter of the frame, wherein the cathode material is electrically connected to the frame.

[0315] Embodiment 164 provides a method of embodiment 163, wherein the frame is a structural component of the electrochemical cell, the frame comprises cathode material, and wherein the frame is structurally sufficient to maintain its shape in the absence of any or all of the anodes.

[0316] Embodiment 165 provides the method of any one of embodiments 163-164, wherein the planar framework is a non-porous solid material.

[0317] Embodiment 166 provides the method of any of Embodiments 163-165, wherein the planar framework is one or more strips of cathode material.

[0318] Embodiment 167 provides the method of any one of embodiments 163-166, wherein the planar frame has a polygonal perimeter.

[0319] Embodiment 168 provides the method of any one of embodiments 163-167, wherein the planar frame is square or rectangular.

[0320] Embodiment 169 provides the method of any one of embodiments 163-168, wherein the cathode material contained within the perimeter of the planar frame comprises a porous cathode material.

[0321] Embodiment 170 provides the method of embodiment 169, wherein the porous cathode material comprises a wire, a mesh, a screen, a sheet comprising one or more through holes, or a combination thereof.

[0322] Embodiment 171 provides the method of embodiment 170, wherein the porous cathode material comprises a wire mesh or a wire screen comprising a porous cathode material.

[0323] Embodiment 172 provides a method of any one of embodiments 170-171, wherein the electrochemical cell further includes a conductive connector electrically connecting the anode and the cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof; wherein the porous cathode material contained within the periphery of the planar frame has an edge sandwiched between two planar frames, and the two planar frames are held together to fix the porous cathode material therebetween using one or more of the conductive connectors.

[0324] Embodiment 173 provides a method of embodiment 172, wherein the electrochemical cell comprises a plurality of pairs of planar frames, each pair of planar frames being held together to secure the porous cathode material therebetween using one or more of the conductive connectors, and each pair of planar frames being separated by one or more of the anodes of the porous cathode material spanning the periphery of the planar frames.

[0325] Embodiment 174 provides the method of embodiment 173, wherein the one or more anodes separating each pair of planar frames from each other are in direct contact with the faces of each pair of planar frames separated therefrom.

[0326] Embodiment 175 provides the method of any of embodiments 173-174, wherein one or more anodes separating each pair of planar frames from each other directly contact a face of one of each pair of planar frames separated by them, and do not directly contact a face of another of each pair of planar frames separated by them.

[0327] Embodiment 176 provides a method of any one of embodiments 170-175, wherein the electrochemical cell further comprises a conductive connector electrically connecting the anode and the cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof, wherein the anode is a strip fastened to the planar frame at two edges of the planar frame, wherein the anode is fastened to the planar frame at each of the two edges of the planar frame using at least one of the conductive connectors such that the anode spans the cathode material contained within the periphery of the planar frame, forming a gap between the cathode material contained within the periphery of the planar frame and the anode strip.

[0328] Embodiment 177 provides the method of embodiment 176, wherein the anode and cathode are in direct contact with each other at each of the edges of the planar frame, wherein the anode is fastened to the planar frame by at least one conductive connector.

[0329] Embodiment 178 provides a method according to any one of embodiments 170-177, wherein the electrochemical cell further comprises a conductive connector electrically connecting the anode and the cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof, wherein the electrochemical cell comprises a plurality of anodes, wherein each anode is a strip fastened to the planar frame at two edges of a planar frame on a face of the frame, wherein each of the anodes is fastened to the planar frame at each of the two edges of the planar frame using at least one of the conductive connectors such that each of the anodes spans the cathode material contained within the periphery of the planar frame, forming a gap between the cathode material contained within the periphery of the planar frame and the anode strips, wherein a plurality of the anodes are spaced apart across the face such that they are not in physical contact with each other.

[0330] Embodiment 179 provides the method of embodiment 178, wherein each of the anodes spans the cathode material contained within the perimeter of the planar frame substantially parallel to each other on the face.

[0331] Embodiment 180 provides the method of any one of Embodiments 178-179, wherein the two edges of the planar frame to which each of the anodes is fastened are opposite edges of the planar frame.

[0332] Embodiment 181 provides the method of any of Embodiments 178-180, wherein all of the anodes are on a single major face of the planar frame.

[0333] Embodiment 182 provides the method of any of Embodiments 178-181, wherein some of the anodes are on one major face of the planar frame and other anodes are on another major face of the frame.

[0334] Embodiment 183 provides the method of any one of Embodiments 3-182, wherein the electrochemical cell comprises

[0335] a cathode, wherein the cathode comprises a planar frame of an electrochemical cell having a polygonal perimeter and a porous material contained within the perimeter of said frame, said porous material being a wire mesh or a wire screen in direct contact with said frame;

[0336] A plurality of anodes, wherein each anode is a strip fastened to a planar frame at two opposite edges of the planar frame on a face of the planar frame, wherein each of the anodes is fastened to the planar frame at each of the two edges of the planar frame using at least one of the conductive connectors, so that each of the anodes is approximately parallel to each other and spans a porous material contained within the perimeter of the planar frame, forming a gap between the porous material contained within the perimeter of the planar frame and the anode strips, wherein each anode directly contacts a cathode frame at each of the edges of the planar frame, wherein the anodes are fastened to the planar frame via at least one of the conductive connectors, wherein a plurality of the anodes are spaced apart across the face so that they are not in physical contact with each other, and wherein the gap is about 1 mm to about 110 mm.

[0337] Embodiment 184 provides the method of any one of embodiments 1-183, comprising

[0338] immersing one or more of the electrochemical cells in a housing containing water containing phosphorus;

[0339] The phosphorus-containing salt is filtered from the treated water through one or more filters at least partially immersed in the phosphorus-containing water in which the electrochemical cell is immersed.

[0340] Embodiment 185 provides the method of embodiment 184, wherein the filter comprises a frit, a fabric filter, a paper filter, a disc filter, a rotary filter, a drum filter, a screen, a sieve, a particulate filter media, a filter aid, or a combination thereof.

[0341] Embodiment 186 provides the method of any one of embodiments 184-185, wherein the filter is a rotating disk filter.

[0342] Embodiment 187 provides the method of any of Embodiments 184-186, wherein the filtering comprises forming a filter cake on a filter, the filter cake comprising the phosphorus-containing salt.

[0343] Embodiment 188 provides the method of Embodiment 187, further comprising backwashing the filter to remove filter cake from the filter and forming a backwash liquid comprising the removed filter cake.

[0344] Embodiment 189 provides the method of embodiment 188, wherein a portion of the water containing the precipitate is used to backwash the filter.

[0345] Embodiment 190 provides the method of any one of embodiments 184-189, wherein one or more of the electrochemical cells are located in phosphorus-containing water at the side of the housing, wherein the filter is located approximately in the center portion of the housing, in the phosphorus-containing water, such that the filter is between multiple of the electrochemical cells.

[0346] Embodiment 191 provides the method of any of embodiments 184-190, comprising a plurality of filters.

[0347] Embodiment 192 provides the method of embodiment 191, wherein the one or more filters include a plurality of rotating disk filters.

[0348] Embodiment 193 provides a method for removing phosphorus from water, the method comprising:

[0349] The electrochemical cell is immersed in phosphorus-containing water having a pH of about 5 to about 7 to form treated water containing a phosphorus-containing salt comprising

[0350] AlPO4 or a hydrate thereof, the AlPO4 comprising phosphorus and Al from the anode,

[0351] Aluminum hydroxide or a hydrate thereof, the aluminum hydroxide containing Al from the anode, or

[0352] Their combination,

[0353] The electrochemical cell comprises

[0354] an anode comprising Al, wherein the anode is from about 90 wt % to about 100 wt % Al,

[0355] a cathode comprising Cu, wherein the cathode is from about 90 wt % to about 100 wt % Cu, and

[0356] a conductive connector electrically connecting the anode and the cathode, the conductive connector comprising an alloy comprising Cu and Zn; and

[0357] The phosphorus-containing salt is separated from the treated water to form separated water having a lower phosphorus concentration than the phosphorus-containing water.

[0358] Embodiment 194 provides a method for removing phosphorus from water, the method comprising:

[0359] The electrochemical cell is immersed in phosphorus-containing water having a pH of about 10 to about 11 to form treated water containing a phosphorus-containing salt comprising

[0360] Magnesium phosphate, magnesium potassium phosphate, their hydrates or their combinations,

[0361] NH4MgPO4 or a hydrate thereof, the NH4MgPO4 comprising phosphorus and Mg from the anode,

[0362] Mg(OH)2 containing magnesium from the anode, or

[0363] Their combination,

[0364] The electrochemical cell comprises

[0365] an anode comprising Mg, wherein the anode is from about 90 wt % to about 100 wt % Mg,

[0366] a cathode comprising Cu, wherein the cathode is from about 90 wt % to about 100 wt % Cu, and

[0367] a conductive connector electrically connecting the anode and cathode, the conductive connector comprising an alloy comprising Cu and Zn; and

[0368] The phosphorus-containing salt is separated from the treated water to form separated water having a lower phosphorus concentration than the phosphorus-containing water.

[0369] Embodiment 195 provides an electrochemical cell for performing the method of any one of embodiments 1-194, the electrochemical cell comprising:

[0370] A cathode comprising Cu, Ni, Fe or a combination thereof, wherein the cathode comprises a planar frame of an electrochemical cell having a polygonal perimeter and a porous material contained within the perimeter of the frame, the porous material being a wire mesh or wire screen in direct contact with the frame; and

[0371] A plurality of anodes comprising Mg, Al, Fe, Zn or a combination thereof, and a plurality of conductive connectors electrically connecting the anodes and cathodes, the conductive connectors comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof;

[0372] wherein each anode is a strip fastened to the planar frame at two opposite edges of the planar frame on a face of the frame, wherein each of the anodes is fastened to the planar frame at each of the two edges of the planar frame using at least one of the conductive connectors such that each of the anodes on the face are substantially parallel to each other on the face and span the porous material contained within the perimeter of the planar frame, forming a gap between the porous material contained within the perimeter of the planar frame and the anode strips, wherein each anode directly contacts the cathode frame at each of the edges of the planar frame, wherein the anodes are fastened to the planar frame via at least one conductive connector, wherein a plurality of the anodes are spaced apart across the face such that they are not in physical contact with each other, and wherein the gap is about 1 mm to about 110 mm.

[0373] Embodiment 196 provides a method for preparing magnesium ammonium phosphate, the method comprising:

[0374] immersing an electrochemical cell in phosphorus-containing water having a pH of about 10 to about 11 to form treated water comprising a phosphorus-containing salt, the salt comprising ammonium magnesium phosphate comprising phosphorus and Mg from an anode, the electrochemical cell comprising an anode comprising Mg, wherein the anode is about 90 wt % to about 100 wt % Mg,

[0375] a cathode comprising Cu, wherein the cathode is from about 90 wt % to about 100 wt % Cu; and

[0376] The phosphorus-containing salt is separated from the treated water to obtain separated magnesium ammonium phosphate and to form separated water having a phosphorus concentration lower than that of the phosphorus-containing water.

[0377] Embodiment 197 provides a method of embodiment 196, wherein the electrochemical cell further comprises a conductive connector electrically connecting the anode and the cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof.

[0378] Embodiment 198 provides the method of any of Embodiments 196-197, wherein the anode and cathode are in direct contact with each other.

[0379] Embodiment 199 provides the method of any one of Embodiments 196-198, further comprising purifying the separated magnesium ammonium phosphate.

[0380] Embodiment 200 provides the method of any one of embodiments 196-199, wherein the phosphorus-containing water further comprises nitrogen.

[0381] Embodiment 201 provides the method of embodiment 200, further comprising adding nitrogen to the phosphorus-containing water.

[0382] Embodiment 202 provides the method of embodiment 201, wherein the nitrogen added to the phosphorus-containing water is added in the form of KNO3, HNO3, an organic nitrogen compound, or a combination thereof.

[0383] Embodiment 203 provides the method of any one of embodiments 196-202, further comprising adding phosphorus to the water to form phosphorus-containing water.

[0384] Embodiment 204 provides a method for preparing AlPO4, aluminum hydroxide, or a combination thereof, the method comprising:

[0385] The electrochemical cell is immersed in phosphorus-containing water having a pH of about 5 to about 7 to form treated water containing a phosphorus-containing salt comprising

[0386] AlPO4 or a hydrate thereof, the AlPO4 comprising phosphorus and Al from the anode,

[0387] Aluminum hydroxide or a hydrate thereof, the aluminum hydroxide containing Al from the anode, or

[0388] Their combination,

[0389] The electrochemical cell comprises

[0390] an anode comprising Al, wherein the anode is from about 90 wt % to about 100 wt % Al,

[0391] a cathode comprising Cu, wherein the cathode is from about 90 wt % to about 100 wt % Cu; and

[0392] The phosphorus-containing salt is separated from the treated water to form separated water having a lower phosphorus concentration than the phosphorus-containing water.

[0393] Embodiment 205 provides a method of embodiment 204, wherein the electrochemical cell further comprises a conductive connector electrically connecting the anode and the cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof.

[0394] Embodiment 206 provides the method of any one of embodiments 204-205, wherein the anode and cathode are in direct contact with each other.

[0395] Embodiment 207 provides the method of any one of embodiments 204-206, further comprising adding phosphorus to the water to form phosphorus-containing water.

[0396] Embodiment 208 provides the method of any of Embodiments 204-207, further comprising purifying the phosphorus-containing salt to provide purified AlPO4, purified aluminum hydroxide, or a purified mixture of AlPO4 and aluminum hydroxide.

[0397] Embodiment 209 provides a method for preparing magnesium phosphate, Mg(OH)2, or a combination thereof, the method comprising:

[0398] The electrochemical cell is immersed in phosphorus-containing water having a pH of about 10 to about 11 to form treated water containing a phosphorus-containing salt comprising

[0399] Magnesium phosphate, magnesium potassium phosphate, their hydrates or their combinations,

[0400] Mg(OH)2 containing magnesium from the anode, or

[0401] Their combination,

[0402] The electrochemical cell comprises

[0403] an anode comprising Mg, wherein the anode is from about 90 wt % to about 100 wt % Mg,

[0404] a cathode comprising Cu, wherein the cathode is from about 90 wt % to about 100 wt % Cu; and

[0405] The phosphorus-containing salt is separated from the treated water to form separated water having a lower phosphorus concentration than the phosphorus-containing water.

[0406] Embodiment 210 provides a method of embodiment 209, wherein the electrochemical cell further comprises a conductive connector electrically connecting the anode and the cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof.

[0407] Embodiment 211 provides the method of any of Embodiments 209-210, wherein the anode and cathode are in direct contact with each other.

[0408] Embodiment 212 provides the method of any of Embodiments 209-211, further comprising adding phosphorus to the water to form phosphorus-containing water.

[0409] Embodiment 213 provides the method of any of Embodiments 209-212, further comprising purifying the phosphorus-containing salt to provide purified magnesium phosphate, purified Mg(OH)2, or a purified mixture of magnesium phosphate and Mg(OH)2.

[0410] Embodiment 214 provides a method for removing one or more dissolved transition metals, post-transition metals, or metalloids from water, the method comprising:

[0411] immersing an electrochemical cell in water containing one or more dissolved transition metals, post-transition metals, or metalloids to form treated water containing a hydroxide salt containing the one or more transition metals, post-transition metals, or metalloids, the electrochemical cell comprising

[0412] an anode comprising Mg, Al, Fe, Zn or a combination thereof,

[0413] a cathode having a different composition than the anode, the cathode comprising Cu, Ni, Fe, or a combination thereof; and

[0414] Separating salts (including hydroxide salts) comprising one or more transition metals, post-transition metals or metalloids to form separated water having a lower concentration of the one or more transition metals, post-transition metals or metalloids than water comprising the one or more transition metals, post-transition metals or metalloids.

[0415] Embodiment 215 provides a method of embodiment 214, wherein the electrochemical cell further comprises a conductive connector electrically connecting the anode and the cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof.

[0416] Embodiment 216 provides the method of any of Embodiments 214-215, wherein the anode and cathode are in direct contact with each other.

[0417] Embodiment 217 provides the method of any of Embodiments 214-215, wherein the one or more transition metals, post-transition metals, or metalloids include Sc, Y, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, Rf, Db, Sg, Bh, Hs, Al, Zn, Ga, Cd, In, Sn, Hg, Tl, Pb, Bi, Po, Cn, B, Si, Ge, As, Sb, Te, At, or a combination thereof.

[0418] Embodiment 218 provides the method of any of Embodiments 214-216, wherein the one or more transition metals, post-transition metals, or metalloids include Hg, Fe, Cr, Ni, Zn, Cd, As, or a combination thereof.

[0419] Embodiment 219 provides the method of any one of Embodiments 214-217, wherein the concentration of the transition metal, post-transition metal, metalloid, or combination thereof in the separated water is from about 0% to about 70% of the concentration of the transition metal, post-transition metal, metalloid, or combination thereof in water comprising one or more dissolved transition metals, post-transition metals, metalloids.

[0420] Embodiment 220 provides the method of any one of embodiments 214-218, wherein the concentration of the transition metal, post-transition metal, metalloid, or combination thereof in the separated water is from about 0% to about 20% of the concentration of the transition metal, post-transition metal, metalloid, or combination thereof in water comprising one or more dissolved transition metals, post-transition metals, metalloids.

[0421] Embodiment 219 provides a method or electrochemical cell according to any one or any combination of embodiments 1-218, optionally configured such that all of the listed elements or options are available for use or selection therefrom.

Claims

1. A method for removing phosphorus from water, the method comprising: The electrochemical cell is immersed in phosphorus-containing water to form treated water comprising a phosphorus-containing salt, wherein the phosphorus-containing salt comprises AlPO or a hydrate thereof and optionally further comprises aluminum hydroxide or a hydrate thereof, wherein the AlPO and aluminum hydroxide comprise Al from the anode, the electrochemical cell being a galvanic cell, the electrochemical cell comprising: Contains the anode of A1, two cathodes having a different composition than the anode and sandwiching the anode therebetween, the two cathodes comprising Cu, wherein no external potential is applied across the anode and the two cathodes, wherein the two cathodes comprise a mesh; a conductive connector electrically and physically connecting the anode and the two cathodes, wherein the conductive connector comprises a screw or bolt extending between the anode and the cathode, and the screw or bolt comprises Cu, Zn, Fe, Cd, Ni, Sn, Pb, or a combination thereof; wherein said electrochemical cell comprises a gap between said anode and each of said cathodes; and The phosphorus-containing salt is separated from the treated water to form separated water having a lower phosphorus concentration than the phosphorus-containing water.

2. The method of claim 1, wherein the conductive connector comprises a brass bolt.

3. The method of claim 1, wherein the phosphorus-containing water has a pH of 5-7.

4. The method of claim 1, wherein the phosphorus-containing water has a pH of 5 to 5.

7.

5. The method of claim 1, wherein the electrochemical cell further comprises a plastic connector physically connecting the anode and the two cathodes. The method of claim 5 , wherein the plastic connector comprises a plastic screw.

7. The method according to claim 1, wherein the separated water having a total phosphorus concentration of 0% to 20% of the total phosphorus concentration of the phosphorus-containing water, or having a dissolved phosphorus concentration of 0% to 20% of the dissolved phosphorus concentration of the phosphorus-containing water, or having an active phosphorus concentration of 0% to 20% of the total phosphorus concentration of the phosphorus-containing water, or A combination of them.

8. The method of claim 1, wherein the phosphorus-containing water further comprises dissolved transition metals, post-transition metals, metalloids, or combinations thereof, the method further comprising forming a hydroxide salt comprising the transition metal, post-transition metal, or metalloid during immersion of the electrochemical cell in the phosphorus-containing water, wherein separating the phosphorus-containing salt from the treated water further comprises separating the hydroxide salt comprising the transition metal, post-transition metal, or metalloid from the treated water.

9. The method of claim 1, further comprising applying a mechanical force to the electrochemical cell during immersion of the electrochemical cell in the phosphorus-containing water, or applying shear to the phosphorus-containing water during immersion of the electrochemical cell in the phosphorus-containing water, or a combination thereof, wherein the mechanical force and / or shear is sufficient to expelling at least some of the bubbles comprising H from the surface of the anode, the two cathodes, or a combination thereof, or at least partially preventing the formation of oxides at the surface of the anode, or at least partially preventing agglomeration of the phosphorus-containing salt on the surface of the anode, or A combination of them.

10. The method of claim 1, further comprising forming a nitrogen-containing salt from the phosphorus-containing water during immersion of the electrochemical cell in the phosphorus-containing water, wherein separating the phosphorus-containing salt from the treated water further comprises separating the nitrogen-containing salt from the treated water.

11. The method according to claim 1, comprising: immersing one or more of the electrochemical cells in a housing containing the phosphorus-containing water; as well as The phosphorus-containing salts are filtered from the treated water through one or more filters at least partially immersed in the phosphorus-containing water in which the electrochemical cell is immersed.

12. The method according to claim 1, wherein The anode is 90 wt % to 100 wt % Al, and The cathode is 90 wt % to 100 wt % Cu.

13. The method of claim 1, further comprising adding hydrogen peroxide to the phosphorus-containing water before or during immersion of the electrochemical cell in the phosphorus-containing water.

14. The method according to claim 1, wherein the gap is 1 mm to 110 mm.

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