Electrolytic removal of nitrogen from water.

Abstract

Apparatus for removing nitrogen from water and method of using the apparatus. The apparatus for removing nitrogen from water includes an electrolytic cell including an anode, a cathode, and two or more bipolar electrodes disposed between the anode and the cathode.

Description

[Background technology]

[0001] Nitrogen is a common component of agricultural fertilizers, manures, and organic waste in sewage and industrial runoff, and it is an essential element for plant life. However, too much nitrogen in water can cause plant and algal growth that depletes oxygen from the water at a rate faster than the ecosystem can process it, causing serious ecological impacts, including toxic algal blooms, death of native aquatic species, and loss of biodiversity (eutrophication). Simple particle removal processes, such as filtration, may remove particles and reduce total nitrogen concentrations; however, these processes will not reduce the concentration of soluble forms of nitrogen. Various methods are available for removing soluble nitrogen from water, but these methods are costly, complex, and difficult to control. Summary of the Invention

[0002] The present invention provides an apparatus for removing nitrogen from water, the apparatus comprising an electrolytic cell comprising an anode, a cathode, and two or more bipolar plates disposed between the anode and the cathode.

[0003] The present invention provides an apparatus for removing nitrogen from water. The apparatus includes an electrolytic cell with an anode plate comprising titanium, the anode plate comprising a catalytic coating comprising TiO2, RuO2, and IrO2. The electrolytic cell includes a cathode plate comprising titanium. The electrolytic cell also includes two or more bipolar electrode plates disposed between the anode and the cathode. A major surface of the anode, a major surface of the cathode, and a major surface of the bipolar plates are parallel to one another. Each bipolar plate comprises a catalytic coating on one major surface of the bipolar plate facing the cathode plate. The catalytic coating comprises TiO2, RuO2, and IrO2. The other major surface of each bipolar plate does not have a catalytic coating or comprises another catalytic coating having a different composition than the catalytic coating on the major surface facing the cathode plate.

[0004] The present invention provides an apparatus for removing nitrogen from water. The apparatus includes a first electrolytic cell with a first anode plate comprising titanium, the first anode plate comprising a catalytic coating comprising TiO2, RuO2, and IrO2. The first electrolytic cell includes a first cathode plate comprising titanium. The first electrolytic cell also includes two or more first bipolar plates disposed between the first anode plate and the first cathode plate. A major surface of the first anode plate, a major surface of the first cathode plate, and a major surface of the first bipolar plate are parallel to each other. Each first bipolar plate comprises a catalytic coating on one major surface of the bipolar plate facing the first cathode plate. The catalytic coating comprises TiO2, RuO2, and IrO2. The other major surface of each first bipolar plate does not have a catalytic coating or comprises another catalytic coating having a different composition than the catalytic coating on the major surface facing the first cathode plate. The apparatus also includes a second electrolytic cell comprising the first cathode plate, two or more second bipolar plates, and a second anode plate, the second anode plate being provided with a catalytic coating comprising the catalytic coating. The second bipolar plate is between the first cathode plate and the second anode plate. A major surface of the first cathode plate, a major surface of the second bipolar plate, and a major surface of the second anode plate are parallel to one another. Each second bipolar plate is provided with the catalytic coating on one major surface of the bipolar plate facing towards the first cathode plate. The other major surface of each second bipolar plate is either free of a catalytic coating or is provided with a different catalytic coating having a different composition than the catalytic coating on the major surface facing towards the first cathode plate.

[0005] The present invention provides an apparatus for removing nitrogen from water. The apparatus includes a first electrolytic cell with a first anode plate comprising titanium, the first anode plate comprising a catalytic coating comprising TiO2, RuO2, and IrO2. The first electrolytic cell includes a first cathode plate comprising titanium. The first electrolytic cell also includes two or more first bipolar plates disposed between the first anode plate and the first cathode plate. A major surface of the first anode plate, a major surface of the first cathode plate, and a major surface of the first bipolar plate are parallel to each other. Each first bipolar plate comprises a catalytic coating on one major surface of the bipolar plate facing the first cathode plate. The catalytic coating comprises TiO2, RuO2, and IrO2. The other major surface of each first bipolar plate does not have a catalytic coating or comprises another catalytic coating having a different composition than the catalytic coating on the major surface facing the first cathode plate. The apparatus also includes a second electrolytic cell comprising the first anode plate, two or more second bipolar plates, and a second cathode plate. The second bipolar plate is between the first anode plate and the second cathode plate. A major surface of the first anode plate, a major surface of the second bipolar plate, and a major surface of the second cathode plate are parallel to each other. Each second bipolar plate is provided with the catalytic coating on one major surface of the bipolar plate facing towards the second cathode plate. The other major surface of each second bipolar plate is either without a catalytic coating or is provided with another catalytic coating having a different composition than the catalytic coating on the major surface facing towards the second cathode plate.

[0006] The present invention provides a method for removing nitrogen from water, the method comprising immersing an electrolytic cell of an apparatus for removing nitrogen from water described herein in nitrogen-containing water, the method also comprising applying an electrical potential between the anode and the cathode of the electrolytic cell to generate nitrogen gas and produce a product water having a lower nitrogen concentration than the nitrogen-containing water.

[0007] The present invention provides a method for removing nitrogen from water. The method includes immersing an electrolytic cell in nitrogen-containing water, the water containing ammonia and / or ammonium ions, and the water further containing chloride ions. The electrolytic cell includes an anode plate including titanium, the anode plate including a catalytic coating including TiO2, RuO2, and IrO2. The electrolytic cell includes a cathode plate including titanium. The electrolytic cell includes two or more bipolar electrode plates disposed between the anode and the cathode. A major surface of the anode, a major surface of the cathode, and a major surface of the bipolar plates are parallel to each other. Each bipolar plate includes a catalytic coating on one major surface of the bipolar plate facing the cathode plate. The catalytic coating includes TiO2, RuO2, and IrO2. The other major surface of each bipolar plate includes either no catalytic coating or another catalytic coating having a different composition than the catalytic coating on the major surface facing the cathode plate. The method also includes applying an electrical potential between the anode plate and the cathode plate of the electrolytic cell to generate nitrogen gas and produce a product water having a lower concentration of nitrogen than the nitrogen-containing water.

[0008] The apparatus and methods of using the apparatus for removing nitrogen from water of the present invention have various advantages over other apparatus and methods of using the apparatus. For example, in various embodiments, the two or more bipolar plates of the electrolytic cell of the present invention may enable highly efficient conversion of ammonium and / or ammonia to nitrogen gas via the generation of chlorine and / or hypochlorite from chloride in the water, for example by producing chlorine and / or hypochlorite at concentrations two to three times greater than that obtained when using an electrolytic cell lacking a bipolar plate or having only one bipolar plate, resulting in higher treatment rates. In various embodiments, the present invention may remove nitrate and / or nitrite from water, for example by reduction to ammonia and / or ammonium and subsequent reaction of the ammonia and / or ammonium with hypochlorite produced in the electrolytic cell. In various embodiments, the present invention incorporates a pH control system that may prevent acidic conditions that increase the risk of producing toxic substances. [Brief description of the drawings]

[0009] The drawings illustrate generally, by way of example, but not by way of limitation, various aspects of the present invention. [Figure 1] FIG. 1 illustrates an electrolytic cell according to various embodiments of the present invention. [Diagram 2] FIG. 2 illustrates two electrolytic cells according to various embodiments of the present invention. [Diagram 3] FIG. 3 illustrates two electrolytic cells according to various embodiments of the present invention. [Figure 4] FIG. 4 illustrates multiple electrolytic cells according to various embodiments of the present invention. [Figure 5A] FIG. 5A illustrates a side view of multiple electrolytic cells according to various embodiments of the present invention. [Figure 5B] FIG. 5B illustrates a front view of multiple electrolytic cells according to various embodiments of the present invention. [Figure 5C] FIG. 5C illustrates a top view of multiple electrolytic cells according to various embodiments of the present invention. [Figure 5D] FIG. 5D illustrates front, side and top views of multiple electrolytic cells according to various embodiments of the present invention. [Figure 6] FIG. 6 illustrates three arrays of ten electrolytic cells according to various embodiments of the present invention. [Figure 7] FIG. 7 illustrates a close-up of ten electrolytic cells according to various embodiments of the present invention. [Figure 8] FIG. 8 illustrates chlorine concentration versus time during electrolysis using an electrolytic cell having two bipolar plates, according to various embodiments of the present invention. [Figure 9] FIG. 9 illustrates the pH versus charge used during electrolysis using an electrolytic cell with two bipolar plates. [Figure 10] FIG. 10 illustrates the ammonia concentration versus charge used during electrolysis using an electrolytic cell with two bipolar plates. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Reference will now be made in detail to certain aspects of the presently disclosed subject matter, examples of which are illustrated in part in the accompanying drawings. While the presently disclosed subject matter may be described in conjunction with the enumerated claims, it will be understood that the exemplary subject matter is not intended to limit the scope of the claims to the presently disclosed subject matter.

[0011] Reference will now be made in detail to certain aspects of the presently disclosed subject matter. While the presently disclosed subject matter will be described in conjunction with the enumerated claims, it will be understood that the exemplary subject matter is not intended to limit the scope of the claims to the presently disclosed subject matter.

[0012] Throughout this document, numerical values ​​expressed in range format should be interpreted in an open manner to include not only the numerical values ​​expressly recited as limits of that range, but also all individual numerical values ​​or all subranges subsumed within that range, if each numerical value and each subrange is expressly recited. For example, the range "about 0.1% to about 5%" or "about 0.1% to 5%" should be interpreted to include not only about 0.1% to about 5%, but also the individual numerical values ​​(e.g., 1%, 2%, 3%, and 4%) and subranges thereof (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the stated range. A statement "about X to Y" has the same meaning as "about X to about Y" unless otherwise indicated. For example, a statement "about X, Y, or about Z" has the same meaning as "about X, about Y, or about Z" unless otherwise indicated.

[0013] In this document, the terms "a," "an," or "the" are used to include one or more unless the content clearly dictates otherwise. The term "or" is used to refer to a non-exclusive "or" unless otherwise indicated. The statements "at least one of A and B" or "at least one of A or B" have the same meaning as "A, B, or A and B." In addition, any terminology or terminology employed herein, and not otherwise defined, is to be understood as being for descriptive purposes only and not for purposes of limitation. Any use of section headings is intended to aid in the reading of this document and is not intended to be construed as limiting, and information regarding a section heading may occur within or outside that particular section.

[0014] In the methods described herein, the acts may be performed in any order (except when a temporal or operational order is explicitly recited) without departing from the principles of the invention. Moreover, specific acts may be performed in parallel unless explicit claim language recites that they are performed separately. For example, a claimed act of doing X and a claimed act of doing Y may be performed simultaneously in a single operation, with the resulting process falling within the literal scope of the claimed process.

[0015] The term "about" as used herein allows for some variation in a numerical value or range, e.g., within 10%, 5%, or 1% of a stated value or stated range limit, including the exact stated numerical value or stated range. The term "substantially" as used herein means majority or majority (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%). The term "substantially free" as used herein can mean completely absent or having only a small amount, for example the amount of a substance present does not affect the physical properties of a composition including that substance, for example from about 0 wt% to about 5 wt% of the composition is that material, or from about 0 wt% to about 1 wt%, or less than or equal to about 5 wt%, or less than or equal to about 4.5 wt%, 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 less than about 0.001 wt%, or about 0 wt%.

[0016] In various embodiments, the salts having a positively charged counterion can include any suitable positively charged counterion. For example, the counterion can be ammonium (NH + ), or alkali metals (e.g., sodium ions (Na + ), potassium ion (K + ), or lithium ion (Li + In some embodiments, the counterion can have a positive charge greater than +1 (e.g., Zn 2+ , Al 3+ , or alkaline earth metals (e.g., Ca 2+ or Mg 2+ ) which in some embodiments may be complexed to multiple ionizable groups.

[0017] All concentrations of nitrogen, chloride, chlorine, ammonia and ammonium referred to are dissolved concentrations of these substances in elemental or non-elemental form (e.g., as compounds or ions containing these substances) unless otherwise indicated. All concentrations given herein are weight concentrations unless otherwise indicated.

[0018] As used herein, "total nitrogen" refers to the sum of nitrate nitrogen (NO3), nitrite nitrogen (NO2), ammonia nitrogen (NH3), and organic nitrogen. Total nitrogen can be measured by summing total Kjeldahl nitrogen (TKN), nitrate nitrogen, and nitrite nitrogen. Nitrate nitrogen and nitrite nitrogen can be measured by US-EPA 353.2 Rev. 2.0 (automated colorimetric determination of nitrite-nitrate nitrogen). Total Kjeldahl nitrogen (TKN), which is the sum of ammonia nitrogen + organic nitrogen (organically bonded nitrogen), does not include nitrate nitrogen or nitrite nitrogen. Total Kjeldahl nitrogen can be measured by US-EPA 351.2 Rev. 2.0 (semi-automated colorimetric determination of total Kjeldahl nitrogen).

[0019] Apparatus for removing nitrogen from water Various aspects of the invention provide an electrolytic cell or cells for removing nitrogen from water. Various aspects of the invention provide an apparatus for removing nitrogen from water, the apparatus comprising or being the electrolytic cell or cells. The electrolytic cell may comprise an anode, a cathode, and two or more bipolar electrodes disposed between the anode and the cathode.

[0020] The anode, cathode, and bipolar electrodes may independently have any suitable physical shape (e.g., rods, screens, or plates). The anode, cathode, and bipolar electrodes each have the shape of a plate, each of which is arranged parallel to one another. The anode plates, cathode plates, and bipolar plates may independently have any suitable thickness (e.g., 0.1 mm to 50 mm, 1 mm to 30 mm, or less than or equal to 50 mm and greater than or equal to 0.1 mm, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, or 45 mm). The anode plates, cathode plates, and bipolar plates may have different thicknesses or the same thickness.

[0021] The anode, the cathode, and the bipolar electrode may be in no physical contact with each other. The anode, the cathode, and the bipolar electrode may be in no electrical connection with each other (except for any aqueous liquid in which the electrolytic cell is immersed and any electrical potential applied between the anode and the cathode). The electrolytic cell may include a gap between the anode and the bipolar electrode (e.g., the most recent electrode of the two or more bipolar electrodes) and a gap between the cathode and the bipolar electrode (e.g., the most recent electrode of the two or more electrodes). These gaps may independently be of any suitable size (e.g., between 0.1 mm and 20 mm, between 0.1 mm and 5 mm, or less than or equal to 20 mm, and greater than or equal to 0.1 mm, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10, 12, 14, 16, or 18 mm). The electrolytic cell may include a gap between the bipolar electrodes (e.g., a gap between 0.1 mm and 20 mm, between 0.1 mm and 5 mm, or less than or equal to 20 mm, and a gap greater than or equal to 0.1 mm, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10, 12, 14, 16, or 18 mm).

[0022] One or more of the anode, the cathode, and the bipolar plate may be held in place via any suitable means such that gaps are maintained between the anode and the bipolar plate, between the bipolar plates, and / or between the bipolar plate and the cathode. In various embodiments, one or more non-conductive connectors may hold one or more of the anode, the cathode, and the bipolar plate together and / or in place. For example, the cell may include a non-conductive rod that passes through the bipolar plate and also passes through one or both of the anode and the cathode. The non-conductive rod may be formed of any suitable material, such as, for example, plastic, or a conductive material (e.g., a metal such as stainless steel) that is coated or otherwise coated with a non-conductive material (e.g., rubber or plastic). The non-conductive rod may be a threaded rod onto which one or more nuts are threaded to prevent the anode, the cathode, and the bipolar plate from sliding longitudinally along the rod. The one or more non-conductive rods may connect and maintain the gap between the anode, the cathode, and the bipolar plate, and may pass through multiple cells, thereby holding multiple cells together.

[0023] The electrolytic cell may comprise two or more bipolar electrodes. The electrolytic cell may comprise two of the bipolar electrodes. The electrolytic cell may comprise three of the bipolar electrodes. The electrolytic cell may comprise more than two of the bipolar electrodes.

[0024] The anode of the electrolytic cell may be formed from any suitable material, such as titanium, stainless steel, graphite, conductive carbon material, or combinations thereof. The anode may include titanium. The anode may include a catalytic coating, such as a coating on both major surfaces of an anode plate. The anode may be titanium having a catalytic coating thereon. The catalytic coating may be any suitable catalytic coating. The catalytic coating may include one or more transition metal oxides. The catalytic coating may include TiO2, RuO2, IrO2, or combinations thereof (e.g., alloys thereof). The catalytic coating may include TiO2, RuO2, and IrO2 in a TiO2:RuO:IrO2 ratio of, for example, (50-90):(10-50):(0.1-20) or (60-80):(20-30):(1-6). The catalytic coating may include TiO2:RuO:IrO2 in a ratio of 70:27:3. The catalytic coating may include Cu / Co (e.g., an alloy of copper and cobalt). The catalytic coating may include Cu / Ni (e.g., an alloy of copper and nickel).

[0025] The cathode of the electrolytic cell may be formed of any suitable material, such as titanium, stainless steel, or a combination thereof. The cathode may include or be titanium. The cathode may be free of a coating, such as a catalytic coating. The cathode may include a catalytic coating, such as Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or combinations thereof (e.g., alloys thereof).

[0026] The bipolar electrodes may include titanium, stainless steel, or a combination thereof. The bipolar electrodes may include titanium. The bipolar electrodes may be free of a coating, such as a catalytic coating. The bipolar electrodes may include a catalytic coating. The bipolar electrodes may be titanium electrodes having a catalytic coating thereon. The bipolar electrodes may include the catalytic coating on both major surfaces of a bipolar plate. The bipolar electrodes may include the catalytic coating on one major surface of each of the bipolar plates (e.g., the major surface facing the cathode) and the other surface of each of the bipolar plates (e.g., the major surface facing the anode) may be free of a catalytic coating or may include a catalytic coating having a different composition than the catalytic coating on the other major surface. The catalytic coating may be any suitable catalytic coating. The catalytic coating may include one or more transition metal oxides. The catalytic coating may include TiO2, RuO2, IrO2, Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or combinations thereof (e.g., alloys thereof). The catalytic coating may include TiO2, RuO2, and IrO2, for example, in a TiO2:RuO:IrO2 ratio of (50-90):(10-50):(0.1-20) or (60-80):(20-30):(1-6). The catalytic coating may include TiO2:RuO:IrO2 in a ratio of 70:27:3. The catalytic coating may include Cu / Co. The catalytic coating may include Cu / Ni. The bipolar plate may have one coating on a major surface facing the cathode (e.g., TiO2, RuO2, IrO2, or combinations thereof) and a different coating on a major surface facing the anode (e.g., Cu, Ag, Co, Ni, Fe, Mo, or combinations thereof (e.g., Cu / Co and / or Cu / Ni)).

[0027] When a potential is applied between the anode and the cathode to the electrolytic cell immersed in chloride ion-containing water, the electrolyte may have a high and sustained faradaic efficiency for producing chlorine from the chloride ions, for example, a faradaic efficiency for producing chlorine gas from chloride ions is 50% to 100%, 70% to 90%, or less than or equal to 100%, and is greater than or equal to 50, 55, 60, 65, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, or 98%.

[0028] When an electrical potential is applied between the anode and the cathode of the electrolytic cell immersed in water containing chloride ions and ammonium ions and / or ammonia, the electrolytic cell may be effective in removing the ammonium ions and / or ammonia from the water in the form of nitrogen gas. For example, the chloride ions may react with the ammonium ions and / or ammonia to generate nitrogen gas. For example, the chlorine may produce hypochlorite (e.g., via oxidation of chloride at the anode and the resulting hydrolysis of chlorine), which may react with ammonium ions and / or ammonia to generate nitrogen gas.

[0029] The apparatus may include a single electrolytic cell. The apparatus may include a plurality of the electrolytic cells. For example, the apparatus may include two electrolytic cells, or 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 or more electrolytic cells. The apparatus may include 2 to 1,000 electrolytic cells.

[0030] The apparatus may include at least two of the electrolytic cells. The anode, the cathode, and the bipolar electrode may be a first anode, a first cathode, and a first bipolar electrode, and the electrolytic cell may be a first electrolytic cell. The apparatus may further include a second electrolytic cell including the first cathode, two or more second bipolar electrodes, and a second anode, the second bipolar electrode being between the first cathode and the second anode. In various embodiments, the apparatus further includes a third electrolytic cell including a second anode, two or more third bipolar electrodes, and a second cathode.

[0031] The anode, the cathode, and the bipolar electrode may be a first anode, a first cathode, and a first bipolar electrode, and the electrolytic cell may be a first electrolytic cell. The apparatus may further comprise a second electrolytic cell comprising the first anode, two or more second bipolar electrodes, and a second cathode. The second bipolar electrode is between the first anode and the second cathode. In various embodiments, the apparatus further comprises a third electrolytic cell comprising a second cathode, two or more third bipolar electrodes, and a second anode.

[0032] In various embodiments, the apparatus further comprises a pH control system that raises and / or maintains the pH of the water in which the electrolytic cell is immersed. For example, the pH control system may add a base to the water and optionally measure the pH of the water. The pH control system prevents the pH from dropping so low that there is a significant risk of toxic substance formation. For example, the pH system may raise or maintain the pH of the water in which the electrolytic cell is immersed to between 4 and 12, between 5 and 8, or less than 12, and greater than or equal to 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, or 11.5.

[0033] 1 illustrates an electrolytic cell 100. The electrolytic cell comprises an anode plate 110. The electrolytic cell comprises a cathode plate 120. The anode plate comprises a catalytic coating. The electrolytic cell comprises two bipolar plates 130, which are arranged between the anode plate 110 and the cathode plate 120. The two bipolar plates 130 each comprise a catalytic coating on one of their main surfaces 140 facing the cathode plate 120.

[0034] 2 illustrates two electrolytic cells comprising a first electrolytic cell 200 and a second electrolytic cell 201. The first electrolytic cell 200 comprises a first cathode plate 220, a first anode plate 210, and two first bipolar plates 230 arranged between the first cathode plate 220 and the first anode plate 210. The first anode plate 210 comprises a catalytic coating. The two first bipolar plates 230 comprise a catalytic coating on one main surface 240 of the bipolar plate facing towards the first cathode plate 220. The second electrolytic cell 201 comprises a first anode plate 210, a second cathode plate 250, and two second bipolar plates 260. The two second bipolar plates 260 each include a catalytic coating on one major surface 270 of the bipolar plate facing towards the second cathode plate 250 .

[0035] FIG. 3 illustrates two electrolytic cells, comprising a first electrolytic cell 300 and a second electrolytic cell 301. The first electrolytic cell 300 comprises a first anode plate 310, a first cathode plate 320 and two first bipolar plates 330 arranged between the first anode plate 310 and the first cathode plate 320. The first anode plate 310 is provided with a catalytic coating. The two first bipolar plates 330 are provided with a catalytic coating on one main surface 340 of the bipolar plates facing the first cathode plate 320. The second electrolytic cell 301 comprises a first cathode plate 320, a second anode plate 350 and two second bipolar plates 360. The second bipolar plates 360 are between the first cathode plate 320 and the second anode plate 350. The second anode plates 350 are provided with a catalytic coating. Each of the second bipolar plates 330 includes a catalytic coating on one major surface 370 of the bipolar plate that faces toward the first cathode plate 320 .

[0036] Figure 4 illustrates a number of electrolytic cells 400. Each cell comprises an anode 410, a cathode 420, and two bipolar plates 430. The anode 410 comprises a catalytic coating. Each of the bipolar plates comprises a catalytic coating on one major surface 440 of the bipolar plate that faces the nearest cathode 420. Figure 4 illustrates ten electrolytic cells.

[0037] How to remove nitrogen from water In various aspects, the invention provides a method for removing nitrogen from water. The method includes immersing the electrolytic cell, or cells, described herein in nitrogen-containing water. The water may contain nitrogen in the form of ammonia and / or ammonium. The water may further contain chloride ions. The electrolytic cell may be partially or fully submerged / immersed in the water. The method may include applying an electrical potential between an anode and a cathode of the electrolytic cell to generate nitrogen gas and produce a product water having a lower concentration of nitrogen than the nitrogen-containing water.

[0038] The potential may be a unipolar potential such that it generates a DC current in the electrolytic cell. The potential may be of alternating polarity such that it generates an AC current in the electrolytic cell. The method may be performed by providing the electrolytic cell with any suitable current density, for example, between 0.001 and 0.1 A / cm. 2 , 0.02~0.04A / cm 2 , or 0.001A / cm 2 or greater than, equal to, or greater than 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, or 0.1 A / cm 2 The method may include operating the electrolytic cell and applying a sufficient electrical potential between the anode and the cathode so as to have

[0039] The nitrogen-containing water may contain chloride ions and ammonium ions and / or ammonia. The nitrogen-containing water may have any suitable ammonia and / or ammonium ion concentration, such as, for example, 50 ppm to 5,000 ppm, 150 ppm to 400 ppm, or 50 ppm or more, or less than or equal to or greater than 100 ppm, 150, 200, 250, 300, 350, 400, 450, 500, 600, 750, 1,000, 2,000, 3,000, 4,000, or 5,000 ppm or less. The nitrogen-containing water may have any suitable chloride ion concentration, such as, for example, from 50 ppm to 40,000 ppm, from 200 ppm to 10,000 ppm, or greater than 50 ppm, or less than or equal to or greater than 100 ppm, 200, 500, 1,000, 2,000, 4,000, 6,000, 8,000, 10,000, 15,000, 20,000, 30,000, or less than 40,000 ppm. The method may further include adding chloride ions to the nitrogen-containing water (e.g., via the addition of a chloride salt such as sodium chloride and / or potassium chloride), for example, adding sufficient chloride ions to bring the chloride ion concentration to between 50 ppm and 40,000 ppm, between 200 ppm and 10,000 ppm, or greater than 50 ppm, or less than or equal to or greater than 100 ppm, 200, 500, 1,000, 2,000, 4,000, 6,000, 8,000, 10,000, 15,000, 20,000, 30,000, or less than 40,000 ppm.

[0040] The nitrogen-containing water may have any suitable pH, such as a pH between 4 and 12, between 5 and 8, or less than or equal to 12, and greater than or equal to 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, or 11.5. The method may include the step of adjusting the pH of the water, such as by adding one or more bases to the nitrogen-containing water to increase or maintain the pH of the water. For example, adding the one or more bases to the nitrogen-containing water may be sufficient to achieve a pH between 4 and 12, between 5 and 8, or less than or equal to 12, and greater than or equal to 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, or 11.5.

[0041] The produced water may have any suitable total nitrogen concentration, dissolved nitrogen concentration, or combination thereof, and may be from 0 ppm to 2 ppm, or from 0 ppm to about 1 ppm, or about 0 ppm, or 0.001 ppm, 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, 1.1, 1.2, 1.4, 1.6, 1.8, or less than, equal to or greater than about 2 ppm.

[0042] The produced water can have any suitable amount of ammonia and / or ammonium ions removed from the nitrogen-containing water, for example, 80%-100%, or 99%-100%, or 80%-100%, 99%-100%, or greater than 80%, or 81%, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.9, less than or equal to or greater than 99.999%, or less than 99.999%.

[0043] The produced water can have a total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof reduced to any suitable percentage of the concentration of the nitrogen-containing water, for example, the total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof of the nitrogen-containing water can be reduced by 0% to 70%, or about 0% to about 30%, or about 0%, or 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 less than or equal to or greater than about 70%.

[0044] The method can produce any suitable concentration of hypochlorite from chloride in nitrogen-containing water, such as from 100 ppm to 20,000 ppm, or from 2,000 ppm to 2,500 ppm or more, or less than or equal to or greater than 200 ppm, 400, 600, 800, 1,000, 1,200, 1,400, 1,600, 1,800, 2,000, 2,100, 2,200, 2,300, 2,400, 2,500, 2,600, 2,800, 3,000, 4,000, 6,000, 8,000, 10,000, 15,000, or less than or equal to 20,000 ppm. The method is not limited to any particular mechanism for removing nitrogen from the water as ammonia using the electrolytic cell. The step of removing nitrogen as nitrogen gas may include converting ammonia and / or ammonium in the water to nitrogen gas using the electrolytic cell. By passing the water through the electrolytic nitrogen removal step, hypochlorous acid can be produced in the water (e.g., via oxidation of chloride ions to chlorine at the anode, which is then hydrolyzed to produce hypochlorite), which can react with ammonia and / or ammonium in the water to generate nitrogen gas, which can be released into the environment. This reaction is carried out to produce NH4 + +1.5HOCl → 0.5N2 + 1.5H2O + 2.5H + +1.5Cl -The water is passed through the electrolytic nitrogen removal step to produce chlorine gas in the water, which can react with ammonia and / or ammonium in the water to produce nitrogen gas, which can be released into the environment. This reaction is + +3Cl2→N2+6Cl - +8H + It is described as:

[0045] The produced water may have any suitable chloride concentration, such as a chloride concentration of 1 ppm to 40,000 ppm, or 50 ppm to 10,000 ppm, or for example 50 ppm to 40,000 ppm, 200 ppm to 10,000 ppm, or greater than 50 ppm, or less than or equal to or greater than 100 ppm, 200, 500, 1,000, 2,000, 4,000, 6,000, 8,000, 10,000, 15,000, 20,000, 30,000, or less than 40,000 ppm.

[0046] The produced water may have any suitable pH, such as a pH between 4 and 12, between 5 and 8, or less than or equal to 12, and greater than or equal to 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, or 11.5.

[0047] The method may provide a faradaic efficiency for producing chlorine gas from chloride ions in nitrogen-containing water, which may be between 50% and 100%, between 70% and 90%, or less than or equal to 100%, and greater than or equal to 50, 55, 60, 65, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, or 98%.

[0048] The method may include circulating and / or agitating and / or shearing the nitrogen-containing water in which the electrolytic cell is immersed, which may help to displace bubbles on the anode, cathode, and / or bipolar electrodes and increase contact between the water and the anode, cathode, and bipolar electrodes.

[0049] The electrolytic cell may be a flow-through cell, and the method may include passing a continuous flow of nitrogen-containing water through the cell at a rate that allows for the desired degree of nitrogen removal. After the water exits the cell, it may be optionally recycled for repeated passes through the cell at a recirculation rate that provides the desired degree of nitrogen removal. In methods that include recirculation, the term "product water" may refer to the water after it has been recycled through the cell one or more times.

[0050] The method may treat the nitrogen-containing water to product water at any suitable rate. For example, the method may treat the nitrogen-containing water to product water at a rate of 1 gallon per minute (GPM) to 1,000,000 CPM (3.79 L / min to 3,785,411 L / min), or 10 GPM to 100,000 GPM, or 100 GPM to 5,000 GPM.

[0051] The method may remove nitrogen in the form of ammonia and / or ammonium from nitrogen-containing water at any suitable rate, such as from 0.01 kWh / kg N removal to 200 kWh / kg (36,000 J to 7,200,000,000 J), or from 1 kWh / kg to 100 kWh / kg, or from 30 kWh / kg to 50 kWh / kg, or less than or equal to 200 kWh / kg, and greater than or equal to 0.01, 0.05, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 55, 60, 65, 70, 80, 90, 100, or 150 kWh / kg. The method may include venting the nitrogen gas to the atmosphere.

[0052] In various embodiments, the method comprises the steps of: extracting nitrates (NO3 - ) and / or nitrite (NO2 -) can be removed. The method is not limited to any particular mechanism by which the electrolytic cell is used to remove nitrates and / or nitrites. In various embodiments, nitrates and / or nitrites can be reduced (e.g., at the cathode) to form ammonia and / or ammonium, which can then react with hypochlorite produced in the electrolytic cell to generate nitrogen gas (e.g., via oxidation of chloride ions at the anode to generate chlorine, which is then hydrolyzed to produce hypochlorite). In various embodiments, the nitrates and / or the nitrites are removed without generating nitrous oxide or with generating more nitrogen than nitrous oxide.

[0053] The method may include immersing a single said electrolytic cell in nitrogen-containing water.The method may include immersing a plurality of said electrolytic cells in nitrogen-containing water. example Various aspects of the invention may be better understood with reference to the following examples, which are provided by way of illustration, but the invention is not limited to the examples given herein.

[0054] In this example, a multi-cell apparatus was used. The apparatus had an anodic section, a cathodic section, and a bipolar section. These sections were clamped together and insulated with 30 mm nylon rods. The anodic and cathodic sections were connected via 165 mm x 382 mm x 6.4 mm ASTM Grade 1 titanium plates, which had vertical 165 mm x 600 mm x 6.4 mm ASTM Grade 1 titanium bus bars for connection to a power supply.

[0055] The anode section comprises five titanium plates, has dimensions of 410mm x 660mm x 2mm, and is 2.5m long per section. 2 The cathode sections had an active anode surface area of ​​2.5 m per section, with dimensions of 410 mm x 660 mm x 2 mm, and were comprised of six titanium plates. 2 The bipolar section had an active cathode surface area of ​​10 m. The bipolar section had 20 titanium plates, each bipolar plate having an active cathode surface area of ​​10 m.2 (5m 2 Anode surface and 5m 2 The bipolar plate had an active surface area of ​​100 nm (cathode surface of 100 nm). The anode was provided with a catalytic coating of TiO2:RuO:IrO2 in the ratio of 70:27:3. The bipolar plate also had the catalytic coating on one major surface of the bipolar plate facing the nearest cathode plate, while the other major surface of the bipolar plate did not have a catalytic coating.

[0056] The apparatus contained ten electrolytic cells. Figures 5A-D show side, front, top and combined side / front / top views of the apparatus. Figure 6 illustrates a front view, showing three arrays of ten cells. Figure 7 shows a close-up side view of the apparatus.

[0057] Example 1. Yield of chlorine production in an electrolytic cell with two bipolar electrodes The results obtained with the electrolysis of a solution containing a chloride concentration of 6 g / L using said electrolysis cell are shown in FIG. 8. The conditions include I=16 Amp (A), E=14 V, and pH=7.3. FIG. 8 illustrates the linear change in chlorine concentration as a function of electrolysis time with a slope of 43 ppmCl2 / min, a value of which represents 80% of the value obtained according to the Faraday equation. The results confirm that the use of two bipolar plates increases the amount of chlorine generated by a factor of three compared to an electrode of comparable dimensions but with only one bipolar plate, thereby maintaining an efficiency of 80%, which is the maximum efficiency reported by other authors for electrochemical chlorine generation. This efficiency value is achieved because the current density in the cell is smaller than the diffusion current density and hydrodynamic conditions of 6 g / L chloride ions, which are impossible to achieve in an electrolysis cell lacking a bipolar plate or with only one bipolar plate.

[0058] Example 2. pH change of water during the breakpoint reaction of ammonia by electrochemical method The results obtained for the electrolysis of chloride and ammonia ion containing water in the electrolysis cell are shown in FIG. 9. The conditions include an initial concentration of 57.9 ppm NH3, 6 g / L chloride ion, I=3 Amp(A), and E=7.6 V. FIG. 9 shows the linear drop in pH of the water as a function of the charge used in the electrolysis of the ammonia containing water. FIG. 10 shows the change in ammonia concentration in the same range of charges used in FIG. 9. These results show a correlation between the drop in pH of the water and the decrease in ammonia concentration during the electrolysis process, and the breakpoint reaction of ammonia with the in situ electrochemical generation of chlorine leads to a drop in pH, which may support the generation of undesirable products such as chlorate and chloramines, which can be prevented by implementing a pH control tank in combination with the electrolysis cell.

[0059] The terms and expressions employed are used as terms of description and not of limitation, and the use of such terms and expressions is not intended to exclude any equivalents of the features shown and described or portions thereof, but is considered to be capable of various modifications within the scope of the aspects of the present invention.Thus, although the present invention has been specifically disclosed by specific embodiments and optional features, it is to be understood that modifications and variations of the concepts disclosed herein may be employed by those skilled in the art, and such modifications and variations are considered to be within the scope of the aspects of the present invention.

[0060] Exemplary Aspects The following illustrative aspects are provided, the numbering of which is not to be construed as designating any degree of importance.

[0061]

[0013] Aspect 1 provides an apparatus for removing nitrogen from water, the apparatus comprising: An anode; A cathode; two or more bipolar electrodes disposed between the anode and the cathode; The electrolytic cell includes:

[0062] Aspect 2 provides the apparatus of aspect 1, wherein the anode, the cathode, and the bipolar electrode are each in the form of plates arranged parallel to one another. Aspect 3 provides the apparatus of any one of Aspects 1-2, wherein the anode plate, the cathode plate, and the bipolar plate each independently have a thickness of about 0.1 mm to 50 mm.

[0063] Aspect 4 provides the apparatus of any one of Aspects 1-3, wherein the anode plate, the cathode plate, and the bipolar plate each independently have a thickness of about 1 mm to 30 mm.

[0064] Example 5 provides the device of any one of Examples 1-4, wherein the anode plate, the cathode plate, and the bipolar plate have approximately the same thickness. Example 6 provides the apparatus of any one of Examples 1-5, wherein the anode, cathode, and bipolar electrode are in no physical contact with one another and are in no electrical contact with one another, except for an optional aqueous liquid in which the electrolytic cell is immersed and an optional electrical potential applied between the anode and cathode.

[0065] Aspect 7 provides the apparatus of any one of Aspects 1 to 6, wherein the electrolytic cell comprises a gap between the anode and the bipolar electrode, and a gap between the bipolar electrode and the cathode, each of which is independently 0.1 mm to 20 mm.

[0066] An embodiment 8 provides the apparatus as recited in embodiment 7, wherein the gap between the anode and the bipolar electrode of the electrolytic cell, and the gap between the bipolar electrode and the cathode are each independently 0.1 mm to 5 mm.

[0067] Aspect 9 provides the apparatus of any one of Aspects 1 to 7, wherein the electrolytic cell includes a gap between the bipolar electrodes, the gap being between 0.1 mm and 20 mm. A tenth aspect provides the apparatus of a ninth aspect, wherein the gap between the bipolar electrodes is between 0.1 mm and 5 mm.

[0068] Example 11 provides the apparatus of any one of Examples 1 to 10, wherein the electrolytic cell includes a non-conductive connector that physically connects the anode, the bipolar plate, and the cathode to one another and maintains a gap between the anode and the bipolar plate, a gap between the bipolar plates, and a gap between the bipolar plate and the cathode.

[0069] A twelfth aspect provides the device according to any one of the first to eleventh aspects, further comprising two of the bipolar electrodes disposed between the anode and the cathode. A thirteenth aspect of the present invention provides the device according to any one of the first to twelfth aspects, comprising three or more of the bipolar electrodes disposed between the anode and the cathode.

[0070] Example 14 provides the device of any one of Examples 1 to 13, wherein the anode comprises titanium, stainless steel, graphite, a conductive carbon material, or a combination thereof. Example 15 provides the device of any one of Examples 1 to 14, wherein the anode comprises Ti.

[0071] Example 16 provides the apparatus of any one of Examples 1 to 15, wherein the anode comprises a catalytic coating. Example 17 provides the apparatus of example 16, wherein the anode comprises the catalytic coating on both major surfaces of the anode.

[0072] Example 18 provides the device of any one of Examples 16-17, wherein the catalytic coating comprises one or more transition metal oxides. Example 19 provides the device of any one of Examples 16-18, wherein the catalytic coating comprises TiO2, RuO2, and IrO2, or a combination thereof.

[0073] Example 20 provides the device of any one of Examples 16-19, wherein the catalytic coating comprises TiO2:RuO2:IrO2. Example 21 provides the device of any one of Examples 16-20, wherein the catalytic coating comprises TiO2:RuO2:IrO2 in a ratio of 70:27:3.

[0074] Example 22 provides the apparatus of any one of Examples 1-21, wherein the cathode comprises titanium, stainless steel, or a combination thereof. Example 23 provides the device of any one of Examples 1 to 22, wherein the cathode comprises Ti.

[0075] Example 24 provides the device of any one of Examples 1 to 23, wherein the cathode does not have a coating. Example 25 provides the device of any one of Examples 1-24, wherein the cathode does not have a catalytic coating or the cathode includes a catalytic coating, such as, for example, Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or combinations thereof (e.g., alloys thereof).

[0076] Example 26 provides the device of any one of Examples 1-25, wherein the bipolar electrodes comprise titanium, stainless steel, or a combination thereof. Example 27 provides the device of any one of Examples 1-26, wherein the bipolar electrode comprises Ti.

[0077] Example 28 provides the device of any one of Examples 1-27, wherein the bipolar electrode does not have a coating. Example 29 provides the device of any one of Examples 1-28, wherein the bipolar electrode does not have a catalytic coating.

[0078] Example 30 provides the device of any one of Examples 1-29, wherein the bipolar electrode comprises a catalytic coating. Example 31 provides the apparatus of Example 30, wherein the bipolar electrodes include the catalytic coating on both major surfaces of each of the bipolar plates.

[0079] Example 32 provides the apparatus of Example 30, wherein the bipolar electrode comprises the catalytic coating on one major surface of each of the bipolar plates (e.g., the surface facing the nearest cathode) and the other major surface of each of the bipolar plates (e.g., the surface facing the nearest anode) does not have a catalytic coating or comprises a catalytic coating having a different composition than the catalytic coating on the opposite surface.

[0080] Example 33 provides the apparatus of any one of Examples 30-32, wherein the catalytic coating comprises one or more transition metal oxides. Example 34 provides the device of any one of Examples 30-33, wherein the catalytic coating comprises TiO2, RuO2, IrO2, Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or a combination thereof.

[0081] Example 35 provides the device of any one of Examples 30-34, wherein the catalytic coating comprises TiO2:RuO2:IrO2. In various embodiments, the bipolar electrode comprises a catalytic coating comprising TiO2:RuO2:IrO2 on a major surface of the bipolar electrode facing a nearest cathode, and an opposite major surface of the bipolar plate either has no catalytic coating or comprises a coating comprising Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or a combination thereof on the opposite major surface of the bipolar plate.

[0082] Example 36 provides the device of any one of Examples 30-35, wherein the catalytic coating comprises TiO2:RuO2:IrO2 in a ratio of 70:27:3. Aspect 37 provides the device of any one of Aspects 1 to 36, in which, when a potential is applied between the anode and the cathode while the electrolytic cell is immersed in chloride ion-containing water, the faradaic efficiency of the electrolytic cell for producing chlorine gas from chloride ions is maintained at 50% to 100%.

[0083] Aspect 38 provides the device of any one of Aspects 1 to 37, wherein when a potential is applied between the anode and the cathode while the electrolytic cell is immersed in chloride ion-containing water, the electrolytic cell maintains a faradaic efficiency of 70% to 90% for producing chlorine gas from chloride ions.

[0084] Example 39 provides the apparatus of any one of Examples 1 to 38, wherein when the electrolytic cell is immersed in water containing chloride ions and ammonium ions and an electrical potential is applied between the anode and the cathode, the electrolytic cell is effective to remove the ammonium ions in the form of nitrogen gas from the water.

[0085] Example 40 provides the apparatus of any one of Examples 1 to 39, wherein the apparatus comprises a plurality of the electrolytic cells. Example 41 provides the apparatus of any one of Examples 1 to 40, wherein the apparatus comprises 2 to 1,000 electrolytic cells.

[0086] Example 42 provides the apparatus of any one of Examples 1-41, wherein the anode, the cathode, and the bipolar electrode are a first anode, a first cathode, and a first bipolar electrode, and the apparatus further comprises a second electrolytic cell comprising a first cathode, two or more second bipolar electrodes, and a second anode, the second bipolar electrode being between the first cathode and the second anode.

[0087] Example 43 provides the apparatus of example 42, wherein the apparatus further comprises a third electrolytic cell comprising a second anode, two or more third bipolar electrodes, and a second cathode. Example 44 provides the apparatus of any one of Examples 1-43, wherein the anode, the cathode, and the bipolar electrode are a first anode, a first cathode, and a first bipolar electrode, and the apparatus further comprises a second electrolytic cell comprising a first anode, two or more second bipolar electrodes, and a second cathode, the second bipolar electrode being between the first anode and the second cathode.

[0088] Example 45 provides the apparatus of example 44, wherein the apparatus further comprises a third electrolytic cell comprising a second cathode, two or more third bipolar electrodes, and a second anode. Example 46 provides the apparatus of any one of Examples 1-45, further comprising a pH control system for increasing and / or maintaining the pH of water in which the electrolytic cell is immersed.

[0089] Example 47 illustrates the apparatus of Example 46, wherein the pH control system adds a base to the water and optionally measures the pH of the water.

[0023] Embodiment 48 provides an apparatus for removing nitrogen from water, the apparatus comprising: An electrolytic cell comprising: an anode plate comprising titanium, the anode plate being provided with a catalytic coating comprising TiO2, RuO2, and IrO2; a cathode plate comprising titanium; two or more bipolar electrode plates disposed between the anode and the cathode, a major surface of the anode, a major surface of the cathode, and a major surface of the bipolar plates being parallel to one another, each bipolar plate comprising a catalytic coating on one major surface of the bipolar plate facing the cathode plate, the catalytic coating comprising TiO2, RuO2, and IrO2, and the other major surface of each bipolar plate either not having a catalytic coating or comprising another catalytic coating having a different composition than the catalytic coating on the major surface facing the cathode plate; Equipped with.

[0090]

[0023] An embodiment 49 provides an apparatus for removing nitrogen from water, the apparatus comprising: A first electrolytic cell and a second electrolytic cell are provided, The first electrolytic cell is a first anode plate comprising titanium, the first anode plate having a catalytic coating comprising TiO2, RuO2, and IrO2; a first cathode plate comprising titanium; two or more first bipolar plates disposed between the first anode plate and the first cathode plate, the first anode plate, the first cathode plate, and the first bipolar plate being parallel to one another, each first bipolar plate comprising a catalytic coating on one major surface of the bipolar plate facing the first cathode plate, the catalytic coating comprising TiO2, RuO2, IrO2, and the other major surface of each first bipolar plate either not having a catalytic coating or comprising another catalytic coating having a different composition than the catalytic coating on the major surface facing the first cathode plate; Equipped with The second electrolytic cell is A first cathode plate; two or more second bipolar plates; a second anode plate comprising the catalytic coating thereon, the second bipolar plate being between the first cathode plate and the second anode plate, a major surface of the first cathode plate, a major surface of the second bipolar plate, and a major surface of the second anode plate being parallel to one another, each second bipolar plate comprising the catalytic coating on one major surface of the bipolar plate facing towards the first cathode plate, and the other major surface of each second bipolar plate having no catalytic coating or comprising another catalytic coating having a different composition than the catalytic coating on the major surface facing towards the first cathode plate; Equipped with.

[0091]

[0023] Embodiment 50 provides an apparatus for removing nitrogen from water, the apparatus comprising: A first electrolytic cell and a second electrolytic cell are provided, The first electrolytic cell is a first anode plate comprising titanium, the first anode plate having a catalytic coating comprising TiO2, RuO2, and IrO2; a first cathode plate comprising titanium; two or more first bipolar plates disposed between the first anode plate and the first cathode plate, a main surface of the first anode plate, a main surface of the first cathode plate, and a main surface of the first bipolar plate being parallel to each other, each first bipolar plate comprising a catalytic coating on one main surface of the bipolar plate facing the first cathode plate, the catalytic coating comprising TiO2, RuO2, IrO2, and the other main surface of each first bipolar plate either not having a catalytic coating or comprising another catalytic coating having a different composition than the catalytic coating on the main surface facing the first cathode plate; Equipped with The second electrolytic cell is A first anode plate; two or more second bipolar plates; a second cathode plate, the second bipolar plate being between the first anode plate and the second cathode plate, a major surface of the first anode plate, a major surface of the second bipolar plate and a major surface of the second cathode plate being parallel to one another, each second bipolar plate comprising the catalytic coating on one major surface of the bipolar plate facing towards the second cathode plate, and the other major surface of each second bipolar plate either not having a catalytic coating or comprising another catalytic coating having a different composition than the catalytic coating on the major surface facing towards the second cathode plate; Equipped with.

[0092]

[0023] Embodiment 51 provides a method for removing nitrogen from water, the method comprising: immersing an electrolytic cell according to any one of aspects 1 to 48 or a plurality of electrolytic cells according to any one of aspects 49 to 50 in nitrogen-containing water; applying a potential between the anode and the cathode of the electrolytic cell to generate nitrogen gas and produce product water having a lower concentration of nitrogen than the nitrogen-containing water; Includes.

[0093] Example 52 provides the method of example 51, wherein the electrical potential generates a DC current in the electrolytic cell. Example 53 provides the method of any one of Examples 51-52, wherein the electrical potential generates an AC current in the electrolytic cell.

[0094] Example 54 provides the method of any one of Examples 51 to 53, wherein the nitrogen-containing water comprises chloride ions and ammonium ions. Example 55 provides the method of any one of Examples 51 to 54, wherein the nitrogen-containing water has an ammonia and / or ammonium ion concentration of 50 ppm to 5,000 ppm.

[0095] Example 56 provides the method of any one of Examples 51 to 55, wherein the nitrogen-containing water has an ammonia and / or ammonium ion concentration of 150 ppm to 400 ppm. Example 57 provides the method of any one of Examples 51 to 56, wherein the nitrogen-containing water has a chloride concentration of 50 ppm to 40,000 ppm.

[0096] Example 58 provides the method of any one of Examples 51 to 57, wherein the nitrogen-containing water has a chloride concentration of 200 ppm to 10,000 ppm. Example 59 provides the method of any one of Examples 51 to 58, further comprising adding chloride ions to the nitrogen-containing water.

[0097] Example 60 provides the method of example 59, wherein adding chloride ions comprises adding sodium chloride, potassium chloride, or a combination thereof. Example 61 provides the method of any one of Examples 51 to 60, wherein the nitrogen-containing water has a pH of 4 to 12.

[0098] Example 62 provides the method of any one of Examples 51 to 61, wherein the nitrogen-containing water has a pH of 5 to 8. Example 63 provides the method of any one of Examples 51 to 62, further comprising adding one or more bases to the nitrogen-containing water to adjust the pH of the water.

[0099] Aspect 64 provides the method of any one of Aspects 51 to 63, wherein the product water has an ammonia and / or ammonium ion concentration of between 0 ppm and 2 ppm. Example 65 provides the method of any one of Examples 51 to 64, wherein the product water has a total nitrogen concentration, a dissolved nitrogen concentration, or a combination thereof, between 0 ppm and 2 ppm.

[0100] Example 66 provides the method of any one of Examples 51 to 65, wherein the method removes between 80% and 100% of the ammonia and / or ammonium from the nitrogen-containing water. Example 67 provides the method of any one of Examples 51 to 66, wherein the method removes between 99% and 100% of the ammonia and / or ammonium from the nitrogen-containing water.

[0101] Example 68 provides the method of any one of Examples 51 to 67, wherein the method reduces the total nitrogen concentration, the dissolved nitrogen concentration, or a combination thereof to between 0% and 70% of the concentration in the nitrogen-containing water.

[0102] Example 69 provides the method of any one of Examples 51 to 68, wherein the method reduces the total nitrogen concentration, the dissolved nitrogen concentration, or a combination thereof to between 0% and 30% of the concentration of the nitrogen-containing water.

[0103] Example 70 provides the method of any one of Examples 51-69, wherein the method further comprises contacting the product water with a galvanic cell to produce galvanic cell-treated water. Example 71 provides a method as set forth in any one of Examples 51 to 70, wherein the galvanic cell comprises a copper-containing cathode and an aluminum-containing anode, and the method optionally includes a step of adding hydrogen peroxide to the produced water before or during contact of the produced water with the galvanic cell.

[0104] Example 72 provides the method of any one of Examples 51 to 71, wherein the method produces between 100 ppm and 20,000 ppm of hypochlorous acid from chloride in the nitrogen-containing water. Example 73 provides the method of any one of Examples 51 to 72, wherein the method produces between 2,000 ppm and 2,500 ppm of hypochlorous acid from chloride in the water.

[0105] Example 74 provides the method of any one of Examples 51 to 73, wherein the product water has a chloride concentration between 1 ppm and 40,000 ppm. Example 75 provides the method of any one of Examples 51 to 74, wherein the product water has a chloride concentration between 50 ppm and 10,000 ppm.

[0106] Example 76 provides the method of any one of Examples 51 to 72, wherein the produced water has a pH of 4 to 12. Example 77 provides the method of any one of Examples 51 to 76, wherein the produced water has a pH of 5-8.

[0107] Example 78 provides the method of any one of Examples 51 to 77, wherein the method provides a sustained faradaic efficiency of 50% to 100% for chlorine gas production from chloride ions in the nitrogen-containing water.

[0108] Example 79 provides the method of any one of Examples 51 to 78, wherein the method provides a sustained faradaic efficiency of 70%-90% for chlorine gas production from chloride ions. Example 80 provides the method of any one of Examples 51 to 79, wherein the method includes circulating and / or stirring and / or shearing the nitrogen-containing water in which the electrolytic cell is immersed.

[0109] Example 81 provides the method of any one of Examples 51 to 80, wherein the method comprises flowing the nitrogen-containing water through the tank. Example 82 provides the method of any one of Examples 51 to 81, wherein the method treats the nitrogen-containing water to become product water at a rate of between 1 GPM and 1,000,000 GPM.

[0110] Example 83 provides the method of any one of Examples 51 to 82, wherein the method treats the nitrogen-containing water to become product water at a rate of between 100 GPM and 5,000 GPM. Example 84 provides the method of any one of Examples 51 to 83, wherein the method removes nitrogen in the form of ammonia and / or ammonium from the nitrogen-containing water at a conversion efficiency of 0.01 kWh / kg N removal to 200 kWh / kg N removal.

[0111] Example 85 provides the method of any one of Examples 51 to 84, wherein the method removes nitrogen in the form of ammonia and / or ammonium from the nitrogen-containing water at a conversion efficiency of 30 kWh / kg to 50 kWh / kg.

[0112] Example 86 provides the method of any one of Examples 51 to 85, further comprising venting the nitrogen gas to the atmosphere. In embodiment 87, the current is 0.001 to 0.1 A / cm 2 The method of any one of aspects 51 to 86, further comprising operating the electrolytic cell at a current density of

[0113] In embodiment 88, the current is 0.02 to 0.04 A / cm 2 The method of any one of aspects 51 to 87, further comprising operating the electrolytic cell at a current density of Example 89 provides the method of any one of Examples 51 to 88, wherein the method comprises immersing a plurality of the electrolytic cells in the nitrogen-containing water.

[0114]

[0023] Embodiment 90 provides a method for removing nitrogen from water, the method comprising: immersing an electrolytic cell in nitrogen-containing water, the water containing ammonia and / or ammonium ions, and the water further containing chloride ions, the electrolytic cell comprising: an anode plate comprising titanium, the anode plate being provided with a catalytic coating comprising TiO2, RuO2, and IrO2; a cathode plate comprising titanium; two or more bipolar electrode plates disposed between the anode and the cathode, a major surface of the anode, a major surface of the cathode, and a major surface of the bipolar plates being parallel to one another, each bipolar plate comprising a catalytic coating on one major surface of the bipolar plate facing the cathode plate, the catalytic coating comprising TiO2, RuO2, and IrO2, and the other major surface of each bipolar plate either not having a catalytic coating or comprising another catalytic coating having a different composition than the catalytic coating on the major surface facing the cathode plate; the immersion step comprising: and applying an electrical potential between the anode plate and the cathode plate of the electrolytic cell to generate nitrogen gas and produce a product water having a lower concentration of nitrogen than the nitrogen-containing water.

[0115]

[0023] Embodiment 91 provides a method for removing nitrogen from water, the method comprising: immersing an electrolytic cell in nitrogen-containing water, the water containing ammonia and / or ammonium ions, and the water further containing chloride ions, the electrolytic cell comprising: an anode plate comprising titanium, the anode plate being provided with a catalytic coating comprising TiO2, RuO2, and IrO2; a cathode plate comprising titanium, the cathode plate being provided with a catalytic coating comprising Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or a combination thereof, or the cathode plate being free of a catalytic coating; two or more bipolar electrode plates disposed between the anode and the cathode, a major surface of the anode, a major surface of the cathode, and a major surface of the bipolar plates being parallel to one another, each bipolar plate comprising a catalytic coating on one major surface of the bipolar plate facing the cathode plate, the catalytic coating comprising TiO2, RuO2, and IrO2, and the other major surface of each bipolar plate either not having a catalytic coating or comprising another catalytic coating comprising Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or a combination thereof; the immersion step comprising: and applying an electrical potential between the anode plate and the cathode plate of the electrolytic cell to generate nitrogen gas and produce a product water having a lower concentration of nitrogen than the nitrogen-containing water.

[0116] Aspect 92 provides an apparatus or method of any one of aspects 1-91 or any combination thereof, optionally configured such that all of the elements or options described are available for use or selection.

Claims

1. 1. An apparatus for removing nitrogen from water, the apparatus comprising: An electrolytic cell comprising: An anode; A cathode; two or more bipolar electrodes disposed between the anode and the cathode; An apparatus comprising:

2. 2. The apparatus of claim 1, wherein the electrolytic cell comprises a gap between the anode and the bipolar electrode and a gap between the bipolar electrode and the cathode, each of which is independently 0.1 to 20 mm, and the electrolytic cell comprises a gap between the bipolar electrodes that is 0.1 mm to 20 mm.

3. 2. The apparatus of claim 1, wherein the electrolytic cell comprises a non-conductive connector that physically connects the anode, the bipolar plate, and the cathode to one another and maintains a gap between the anode and the bipolar plate, a gap between the bipolar plates, and a gap between the bipolar plate and the cathode.

4. The apparatus of claim 1 , comprising two or more of the bipolar electrodes disposed between the anode and the cathode.

5. 10. The apparatus of claim 1, wherein the anode comprises titanium, stainless steel, graphite, a conductive carbon material, or a combination thereof, and the anode comprises a catalytic coating.

6. The catalytic coating is TiO ２ , RuO ２ , IrO ２ or a combination thereof.

7. The apparatus of claim 1 , wherein the cathode comprises titanium, stainless steel, or a combination thereof.

8. The device of claim 1 , wherein the bipolar electrodes comprise titanium, stainless steel, or a combination thereof.

9. The bipolar electrode is TiO ２ , RuO ２ , IrO ２ 13. The apparatus of claim 1, further comprising a catalytic coating comprising: Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or combinations thereof.

10. The bipolar electrode comprises the catalytic coating on both major surfaces of each of the bipolar plates, the catalytic coating on the major surface of the bipolar plate facing the cathode being TiO ２ , RuO ２ , IrO ２ or combinations thereof, and the catalytic coating on a major surface of the bipolar plate facing the anode comprises Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or combinations thereof.

11. 10. The apparatus of claim 9, wherein the bipolar electrodes include the catalytic coating on one major surface of each of the bipolar plates and the other major surface of each of the bipolar plates does not have a catalytic coating.

12. 10. The apparatus of claim 1, further comprising a pH control system for increasing and / or maintaining the pH of water in which the electrolytic cell is immersed.

13. 1. An apparatus for removing nitrogen from water, the apparatus comprising: An electrolytic cell comprising: An anode plate comprising titanium, the anode plate being TiO ２ , RuO ２ , and IrO ２ the anode plate having a catalytic coating comprising: a cathode plate comprising titanium; Two or more bipolar electrode plates arranged between the anode and the cathode, a major surface of the anode, a major surface of the cathode and a major surface of the bipolar plate are parallel to each other, and each bipolar plate is provided with a catalytic coating on one major surface of the bipolar plate facing the cathode plate, the catalytic coating being TiO ２ , RuO ２ and IrO ２ wherein the other major surface of each bipolar plate does not have a catalytic coating or is provided with another catalytic coating having a different composition than the catalytic coating on the major surface facing the cathode plate; An apparatus comprising:

14. 1. A method for removing nitrogen from water, the method comprising: immersing the electrolytic cell of claim 1 in nitrogen-containing water; applying a potential between the anode and the cathode of the electrolytic cell to generate nitrogen gas and produce product water having a nitrogen concentration lower than that of the nitrogen-containing water; A method comprising:

15. 15. The method of claim 14, wherein the nitrogen-containing water has an ammonia and / or ammonium ion concentration of 50 ppm to 5,000 ppm and the product water has an ammonia and / or ammonium ion concentration of 0 ppm to 2 ppm.

16. 15. The method of claim 14, wherein the method removes between 80% and 100% of the ammonia and / or ammonium from the nitrogen-containing water.

17. 15. The method of claim 14, wherein the product water has a total nitrogen concentration, a dissolved nitrogen concentration, or a combination thereof between 0 ppm and 2 ppm, and the method reduces the total nitrogen concentration, the dissolved nitrogen concentration, or a combination thereof to between 0% and 70% of the concentration of the nitrogen-containing water.

18. 15. The method of claim 14, wherein the nitrogen-containing water has a chloride concentration of from 50 ppm to 40,000 ppm, and the method produces from 100 ppm to 20,000 ppm of hypochlorous acid from the chloride in the nitrogen-containing water.

19. The method of claim 14 further comprising venting the nitrogen gas to the atmosphere.

20. 1. A method for removing nitrogen from water, the method comprising: immersing an electrolytic cell in nitrogen-containing water, the water containing ammonia and / or ammonium ions, the water further containing chloride ions, the electrolytic cell comprising: An anode plate comprising titanium, the anode plate being TiO ２ , RuO ２ , and IrO ２ the anode plate having a catalytic coating comprising: a cathode plate comprising titanium; Two or more bipolar electrode plates arranged between the anode and the cathode, a major surface of the anode, a major surface of the cathode and a major surface of the bipolar plate are parallel to each other, and each bipolar plate is provided with a catalytic coating on one major surface of the bipolar plate facing the cathode plate, the catalytic coating being TiO ２ , RuO ２ and IrO ２ wherein the other major surface of each bipolar plate does not have a catalytic coating or is provided with another catalytic coating having a different composition than the catalytic coating on the major surface facing the cathode plate; the immersion step comprising: and applying an electrical potential between the anode plate and the cathode plate of the electrolytic cell to generate nitrogen gas and produce a product water having a lower concentration of nitrogen than the nitrogen-containing water.

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