Electrolytic nitrogen removal from water

Abstract

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

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 333,605, filed on April 22, 2022, the disclosure of which is incorporated herein by reference in its entirety. Background Art

[0003] Nitrogen is a common component of agricultural fertilizers, manure, and organic waste in sewage and industrial effluents. It is an essential element for plant life. However, when water contains too much nitrogen, it can cause plant and algae growth and consume oxygen in the water at a rate that the ecosystem cannot sustain, causing serious ecological impacts, including toxic algal blooms, die-offs of native aquatic species, and loss of biodiversity (eutrophication). Simple particle removal processes, such as filtration, will remove particles and reduce total nitrogen concentrations; however, these processes will not reduce the concentration of water-soluble forms of nitrogen. Although there are a variety of methods to remove soluble nitrogen from water, these methods are expensive, complex, and difficult to control. Summary of the invention

[0004] The present invention provides an apparatus for removing nitrogen from water. The apparatus comprises an electrolytic cell, the electrolytic cell comprising an anode, a cathode and two or more bipolar plates positioned between the anode and the cathode.

[0005] The present invention provides a device for removing nitrogen from water. The device includes an electrolytic cell, the electrolytic cell includes an anode plate including titanium, wherein the anode plate includes a catalyst coating including TiO2, RuO2 and IrO2. The electrolytic cell includes a cathode plate including titanium. The electrolytic cell also includes two or more bipolar electrode plates positioned between the anode and the cathode. The main surfaces of the anode plate, the cathode plate and the bipolar plate are parallel to each other. Each bipolar plate includes a catalyst coating on one main surface facing the cathode plate. The catalyst coating includes TiO2, RuO2 and IrO2. The other main surface of each bipolar plate has no catalyst coating, or includes another catalyst coating having a different composition from the catalyst coating on the main surface facing the cathode plate.

[0006] The present invention provides a device for removing nitrogen from water. The device includes a first electrolytic cell, which includes a first anode plate including titanium, wherein the first anode plate includes a catalyst coating including TiO2, RuO2 and IrO2. The first electrolytic cell includes a first cathode plate including titanium. The first electrolytic cell also includes two or more first bipolar plates positioned between the first anode plate and the first cathode plate. The main surfaces of the first anode plate, the first cathode plate and the first bipolar plate are parallel to each other. Each first bipolar plate includes a catalyst coating on one main surface facing the first cathode plate. The catalyst coating includes TiO2, RuO2 and IrO2. The other main surface of each first bipolar plate has no catalyst coating, or includes another catalyst coating having a different composition from the catalyst coating on the main surface facing the first cathode plate. The device also includes a second electrolytic cell, which includes the first cathode plate, two or more second bipolar plates and a second anode plate, wherein the second anode plate includes a catalyst coating. The second bipolar plate is located between the first cathode plate and the second anode plate. The main surfaces of the first cathode plate, the second bipolar plate and the second anode plate are parallel to each other. Each second bipolar plate comprises a catalyst coating on one of its main faces facing the first cathode plate. The other main face of each second bipolar plate has no catalyst coating or comprises another catalyst coating having a different composition than the catalyst coating on the main face facing the first cathode plate.

[0007] The present invention provides a device for removing nitrogen from water. The device includes a first electrolytic cell, which includes a first anode plate including titanium, wherein the first anode plate includes a catalyst coating including TiO2, RuO2 and IrO2. The first electrolytic cell includes a first cathode plate including titanium. The first electrolytic cell also includes two or more first bipolar plates positioned between the first anode plate and the first cathode plate. The main surfaces of the first anode plate, the first cathode plate and the first bipolar plate are parallel to each other. Each first bipolar plate includes a catalyst coating on one main surface facing the first cathode plate. The catalyst coating includes TiO2, RuO2 and IrO2. The other main surface of each first bipolar plate has no catalyst coating, or includes another catalyst coating having a different composition from the catalyst coating on the main surface facing the first cathode plate. The device also includes a second electrolytic cell, which includes the first anode plate, two or more second bipolar plates, and a second cathode plate. The second bipolar plate is located between the first anode plate and the second cathode plate. The main surfaces of the first anode plate, the second bipolar plate and the second cathode plate are parallel to each other. Each second bipolar plate comprises a catalyst coating on one of its main faces facing the second cathode plate.The other main face of each second bipolar plate has no catalyst coating or comprises another catalyst coating having a different composition than the catalyst coating on the main face facing the second cathode plate.

[0008] The present invention provides a method for removing nitrogen from water. The method comprises immersing an electrolytic cell of the apparatus for removing nitrogen from water described herein into nitrogen-containing water. The method also comprises applying an electric potential between an anode and a cathode of the electrolytic cell to form nitrogen gas and to form product water having a nitrogen concentration lower than that of the nitrogen-containing water.

[0009] The present invention provides a method for removing nitrogen from water. The method includes immersing an electrolytic cell in nitrogen-containing water, wherein the water includes ammonia and / or ammonium ions, and the water also includes chloride ions. The electrolytic cell includes an anode plate including titanium, wherein the anode plate includes a catalyst 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 positioned between the anode and the cathode. The main surfaces of the anode plate, the cathode plate and the bipolar plate are parallel to each other. Each bipolar plate includes a catalyst coating on one main surface facing the cathode plate. The catalyst coating includes TiO2, RuO2 and IrO2. The other main surface of each bipolar plate does not have a catalyst coating or includes another catalyst coating having a different composition from the catalyst coating on the main surface facing the cathode plate. The method also includes applying an electric potential between the anode plate and the cathode plate of the electrolytic cell to form nitrogen gas and form product water having a nitrogen concentration lower than the nitrogen concentration of the nitrogen-containing water.

[0010] The apparatus for removing nitrogen from water and methods of use of the present invention have various advantages over other apparatus and methods of use thereof. For example, in various aspects, the two or more bipolar plates of the electrolytic cell of the present invention can be capable of achieving efficient conversion of ammonium and / or ammonia to nitrogen by forming chlorine and / or hypochlorite from chlorides in the water, for example by generating a chlorine and / or hypochlorite concentration that is two to three times higher than an electrolytic cell without bipolar plates or with only one bipolar plate, thereby achieving a higher treatment rate. In various aspects, the present invention can remove nitrates and / or nitrites from water, for example by reducing them to ammonia and / or ammonium, and then reacting the ammonia and / or ammonium with the hypochlorite generated in the electrolytic cell. In various aspects, the present invention employs a pH control system that prevents acidic conditions that increase the risk of producing toxic substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The drawings generally illustrate various aspects of the invention by way of example and not by way of limitation.

[0012] Figure 1 An electrolytic cell according to various aspects of the invention is shown.

[0013] Figure 2 Two electrolytic cells according to various aspects of the invention are shown.

[0014] Figure 3 Two electrolytic cells according to various aspects of the invention are shown.

[0015] Figure 4 A plurality of electrolytic cells according to various aspects of the invention are shown.

[0016] Figure 5A Shown are side views of a plurality of electrolytic cells according to various aspects of the present invention.

[0017] Figure 5B Shown are elevation views of a plurality of electrolytic cells in accordance with various aspects of the present invention.

[0018] Figure 5C Shown are top views of a plurality of electrolytic cells according to various aspects of the present invention.

[0019] Figure 5D Shown are front, side and top views of a plurality of electrolytic cells showing various aspects of the present invention.

[0020] Figure 6 Three arrays of ten electrolytic cells are shown in accordance with various aspects of the present invention.

[0021] Figure 7 Shown are close-ups of 10 electrolytic cells according to various aspects of the invention.

[0022] Figure 8 Chlorine concentration versus time during electrolysis using an electrolysis cell having two bipolar plates according to various aspects of the present invention is shown.

[0023] Fig. 9 The dependence of the pH value on the charge used during electrolysis using an electrolysis cell having two bipolar plates is shown.

[0024] Fig.10 The ammonia concentration is shown as a function of the charge used during electrolysis using an electrolysis cell having two bipolar plates. DETAILED DESCRIPTION

[0025] Reference will now be made in detail to certain aspects of the disclosed subject matter, examples of which are partially illustrated in the accompanying drawings.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.

[0026] Reference will now be made in detail to certain aspects 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.

[0027] In this document, values ​​expressed in range format should be interpreted in a flexible manner to include not only the values ​​explicitly listed as the limits of the range, but also all individual values ​​or sub-ranges contained within the range, as if each value and sub-range were explicitly listed. 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 values ​​(e.g., 1%, 2%, 3% and 4%) and sub-ranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. Unless otherwise specified, the expression "about X to Y" has the same meaning as "about X to about Y". Similarly, unless otherwise specified, the expression "about X, Y or about Z" has the same meaning as "about X, about Y or about Z".

[0028] In this document, unless the context clearly dictates otherwise, no article modifier includes one or more than one. Unless otherwise specified, the term "or" means a non-exclusive "or". The expression "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 but not otherwise defined are for descriptive purposes only and not for limiting purposes. Any section headings used are intended to aid in reading the document and should not be construed as limiting; information related to the section heading may appear within or outside that particular section.

[0029] In the methods described herein, unless the 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 the claim language explicitly states that they must be performed separately. For example, a claimed action of performing X and a claimed action of performing Y may be performed simultaneously in a single operation, and the resulting process will fall within the literal scope of the claimed process.

[0030] The term "about" as used herein may allow for a certain degree of variation in numerical values ​​or ranges, for example, within 10%, within 5%, or within 1% of a specified numerical value or specified range limit, and includes the exact specified numerical value or range. The term "substantially" as used herein refers to most or most, 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 of or essentially free of" may mean free of or containing a very small amount such that the amount of the material present does not affect the material properties of the composition including the material, such that about 0 wt% (weight percent) to about 5 wt% of the composition is the material, or about 0 wt% to about 1 wt%, or about 5 wt% or less, 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 about 0.001 wt% or less, or about 0 wt%.

[0031] In various aspects, the salt with a positively charged counterion can include any suitable positively charged counterion. For example, the counterion can be ammonium (NH4 + ), or such as sodium (Na + ), potassium (K + ) or lithium (Li + In some aspects, the counterion can have a positive charge greater than +1, which in some aspects can be complexed into multiple ionizable groups, such as Zn 2+ 、A1 3+ , or such as Ca 2+ or Mg 2+ of alkaline earth metals.

[0032] Unless otherwise stated, all references to nitrogen, chloride, chlorine, ammonia and ammonium concentrations are concentrations in which these substances are dissolved in elemental or non-elemental (e.g., as compounds or ions comprising the material). Unless otherwise stated, all concentrations given herein are by weight.

[0033] As used herein, "total nitrogen" refers to the sum of nitrate nitrogen (NO3), nitrite nitrogen (NO2), ammonia-nitrogen (NH3), and organically bound nitrogen. Total nitrogen can be measured by adding total Kjeldahl nitrogen (TKN), nitrate nitrogen, and nitrite nitrogen. Nitrate nitrogen and nitrite nitrogen can be measured by US-EPA 353.2, Revision 2.0: Determination of Nitrite-Nitrate Nitrogen by Automated Colorimetry. Total Kjeldahl nitrogen (TKN) is the sum of ammonia-nitrogen plus organically bound nitrogen, but does not include nitrate nitrogen or nitrite nitrogen. TKN can be measured by US-EPA 351.2, Revision 2.0: Determination of Total Kjeldahl Nitrogen by Semi-Automated Colorimetry.

[0034] Device for removing nitrogen from water

[0035] Various aspects of the invention provide an electrolytic cell, or multiple electrolytic cells, for removing nitrogen from water. Various aspects of the invention provide an apparatus for removing nitrogen from water, wherein the apparatus comprises or is the electrolytic cell or multiple electrolytic cells. The electrolytic cell may comprise an anode, a cathode, and two or more bipolar electrodes positioned between the anode and the cathode.

[0036] Anode, cathode and bipolar electrode can independently have any suitable physical form, such as rod, screen or plate. Anode, cathode and bipolar electrode can respectively have the form of plate, wherein each plate in these plates is arranged parallel to each other. Anode plate, cathode plate and bipolar plate can independently have any suitable thickness, such as 0.1mm to 50mm, 1mm to 30mm, or less than or equal to 50mm and greater than or equal to 0.1mm, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40 or 45mm. Anode plate, cathode plate and bipolar plate can have different thickness or the same thickness.

[0037] Anode, cathode and bipolar electrode may not be in physical contact with each other.Except that the electrolytic cell is immersed in an optional aqueous liquid and an optional potential applied between the anode and cathode, the anode, cathode and bipolar electrode may not be electrically connected to each other.The electrolytic cell may include a gap between the anode and bipolar electrode (e.g., the nearest one of the two or more bipolar electrodes) and a gap between the cathode and bipolar electrode (e.g., the nearest one of the two or more electrodes).These gaps may have any suitable size individually, such as 0.1mm to 20mm, 0.1mm to 5mm, or less than or equal to 20mm and greater than or equal to 0.1mm, 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 18mm. The electrolytic cell can include a gap between the bipolar electrodes, for example, from 0.1 mm to 20 mm, from 0.1 mm to 5 mm, or a gap 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.

[0038] One or more of the anode plate, cathode plate and bipolar plate can be held in place by any suitable means so that the gap between the anode and the bipolar plate, the gap between the bipolar plate and / or the gap between the bipolar plate and the cathode is maintained. In various aspects, one or more non-conductive connectors can hold one or more of the anode, cathode and bipolar plate together and / or in place. For example, the electrolytic 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 can be made of any suitable material, such as plastic, or a conductive material (such as metal such as stainless steel) coated or otherwise covered with a non-conductive material (such as rubber or plastic). The non-conductive rod can be a threaded rod, and one or more nuts can be screwed onto the threaded rod to prevent the anode, cathode and bipolar plate from sliding longitudinally along the rod. The one or more non-conductive rods can connect the anode, cathode and bipolar plate and maintain the gap between the anode, cathode and bipolar plate, and can hold multiple electrolytic cells together by passing through multiple electrolytic cells.

[0039] The electrolytic cell may include two or more bipolar electrodes. The electrolytic cell may include two bipolar electrodes. The electrolytic cell may include three bipolar electrodes. The electrolytic cell may include three or more bipolar electrodes.

[0040] The anode of the electrolytic cell can be made of any suitable material, such as titanium, stainless steel, graphite, conductive carbon material or a combination thereof. The anode can include titanium. The anode can include a catalyst coating, such as a coating on both main surfaces of the anode plate. The anode can be titanium with a catalyst coated thereon. The catalyst coating can be any suitable catalyst coating. The catalyst coating can include one or more transition metal oxides. The catalyst coating can include TiO2, RuO2, IrO2 or a combination thereof (e.g., an alloy thereof). The catalyst coating can include TiO2, RuO2, IrO2, such as TiO2:RuO2:IrO2 in a ratio of (50-90):(10-50):(0.1-20) or (60-80):(20-30):(1-6). The catalyst coating can include TiO2:RuO2:IrO2 in a ratio of 70:27:3. The catalyst coating can include Cu / Co (e.g., an alloy of copper and cobalt). The catalyst coating can include Cu / Ni (e.g., an alloy of copper and nickel).

[0041] The cathode of the electrolytic cell can be made of any suitable material, such as titanium, stainless steel, or a combination thereof. The cathode can include titanium, or can be titanium. The cathode can be free of a coating, such as a catalyst coating. The cathode can include a catalyst coating, such as a catalyst coating including Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or a combination thereof (e.g., an alloy thereof).

[0042] The bipolar electrode may include titanium, stainless steel, or a combination thereof. The bipolar electrode may include titanium. The bipolar electrode may not have a coating, such as a catalyst coating. The bipolar electrode may include a catalyst coating. The bipolar electrode may be a titanium electrode having a catalyst coating thereon. The bipolar electrode may include a catalyst coating on both main surfaces of the bipolar plate. The bipolar electrode may include a catalyst coating on one main surface of each bipolar plate (e.g., the main surface facing the cathode), and the other surface of each bipolar plate (e.g., the main surface facing the anode) may not have a catalyst coating or may include a catalyst coating having a different composition from the catalyst coating on the other main surface. The catalyst coating may be any suitable catalyst coating. The catalyst coating may include one or more transition metal oxides. The catalyst coating may include TiO2, RuO2, IrO2, Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or a combination thereof (e.g., an alloy thereof). The catalyst coating may include TiO2, RuO2, IrO2, for example, TiO2:RuO2:IrO2 in a ratio of (50-90):(10-50):(0.1-20) or (60-80):(20-30):(1-6). The catalyst coating may include TiO2:RuO2:IrO2 in a ratio of 70:27:3. The catalyst coating may include Cu / Co. The catalyst coating may include Cu / Ni. The bipolar plate may include one coating (e.g., TiO2, RuO2, IrO2, or a combination thereof) on the major surface facing the cathode and a different coating (e.g., Cu, Ag, Co, Ni, Fe, Mo, or a combination thereof, such as Cu / Co and / or Cu / Ni) on the major surface facing the anode.

[0043] The electrolytic cell can have a high sustained Faradaic efficiency for producing chlorine from chloride ions when an electric potential is applied between the anode and cathode while the electrolytic cell is immersed in water including chloride ions, for example, a Faradaic efficiency for producing chlorine gas from chloride ions of 50% to 100%, 70% to 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%.

[0044] When an electric potential is applied between the anode and cathode while the electrolytic cell is immersed in water comprising chloride and ammonium ions and / or ammonia, the electrolytic cell can effectively remove ammonium ions and / or ammonia from the water in the form of nitrogen. For example, chloride and ammonium ions and / or ammonia can react to form nitrogen. For example, chlorine can form hypochlorite (e.g., by oxidation of chloride at the anode and hydrolysis of the resulting chlorine), which reacts with ammonium ions and / or ammonia to form nitrogen.

[0045] The device may include a single electrolytic cell. The device may include a plurality of electrolytic cells. For example, the device may include 2 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 device may include 2 to 1,000 electrolytic cells.

[0046] The device may include at least two electrolytic cells. The anode, cathode and 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 device may also include a second electrolytic cell including a first cathode, two or more second bipolar electrodes, and a second anode, wherein the second bipolar electrode is located between the first cathode and the second anode. In various aspects, the device also includes a third electrolytic cell including a second anode, two or more third bipolar electrodes and a second cathode.

[0047] The anode, cathode and bipolar electrode can be a first anode, a first cathode and a first bipolar electrode, and the electrolytic cell can be a first electrolytic cell. The device can also include a second electrolytic cell, which includes a first anode, two or more second bipolar electrodes, and a second cathode. The second bipolar electrode is located between the first anode and the second cathode. In various aspects, the device also includes a third electrolytic cell, which includes a second cathode, two or more third bipolar electrodes and a second anode.

[0048] In various aspects, the device also includes a pH control system for raising and / or maintaining the pH of the water in which the electrolytic cell is immersed. For example, the pH control system can add a base to the water and optionally measure the pH of the water. The pH control system can prevent the pH from falling too low, thereby avoiding a significant risk of forming toxic substances. For example, the pH system can raise or maintain the pH of the water in which the electrolytic cell is immersed to 4 to 12, 5 to 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.

[0049] Figure 1 An electrolytic cell 100 is shown. The electrolytic cell comprises an anode plate 110. The electrolytic cell comprises a cathode plate 120. The anode plate comprises a catalyst coating. The electrolytic cell comprises two bipolar plates 130 positioned between the anode plate 110 and the cathode plate 120. The two bipolar plates 130 each comprise a catalyst coating on one of their main faces 140 facing the cathode plate 120.

[0050] Figure 2Two electrolytic cells are shown, including a first electrolytic cell 200 and a second electrolytic cell 201. The first electrolytic cell 200 includes a first cathode plate 220, a first anode plate 210, and two first bipolar plates 230 positioned between the first cathode plate 220 and the first anode plate 210. The first anode plate 210 includes a catalyst coating. The two first bipolar plates 230 include a catalyst coating on one main face 240 thereof facing the first cathode plate 220. The second electrolytic cell 201 includes 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 catalyst coating on one main face 270 thereof facing the second cathode plate 250.

[0051] Figure 3 Two electrolytic cells are shown, including a first electrolytic cell 300 and a second electrolytic cell 301. The first electrolytic cell 300 includes a first anode plate 310, a first cathode plate 320, and two first bipolar plates 330 positioned between the first anode plate 310 and the first cathode plate 320. The first anode plate 310 includes a catalyst coating. The two first bipolar plates 330 include a catalyst coating on one main surface 340 thereof facing the first cathode plate 320. The second electrolytic cell 301 includes a first cathode plate 320, a second anode plate 350, and two second bipolar plates 360. The second bipolar plate 360 ​​is located between the first cathode plate 320 and the second anode plate 350. The second anode plate 350 includes a catalyst coating. The second bipolar plates 330 each include a catalyst coating on one main surface 370 thereof facing the first cathode plate 320.

[0052] Figure 4 A plurality of electrolytic cells 400 are shown. Each electrolytic cell comprises an anode 410, a cathode 420 and two bipolar plates 430. The anode 410 comprises a catalyst coating. Each bipolar plate comprises a catalyst coating on its major face 440 facing the cathode 420 nearest to it. Figure 4 Ten electrolytic cells are shown.

[0053] Methods for removing nitrogen from water

[0054] In various aspects, the present invention provides a method for removing nitrogen from water. The method includes immersing an electrolytic cell or multiple electrolytic cells described herein into nitrogen-containing water. The water may include nitrogen in the form of ammonia and / or ammonium. The water may also include chloride ions. The electrolytic cell may be partially or completely submerged / immersed in the water. The method may include applying an electric potential between an anode and a cathode of the electrolytic cell to form nitrogen gas and form product water having a nitrogen concentration lower than the nitrogen concentration in the nitrogen-containing water.

[0055] The potential may be a unipolar potential that produces a DC current in the electrolytic cell. The potential may be of alternating polarity such that the potential produces an AC current in the electrolytic cell. The method comprises operating the electrolytic cell and applying a sufficient potential between the anode and the cathode so that the electrolytic cell has any suitable density, such as 0.001-0.1 A / cm 2 , 0.02-0.04A / cm 2 , or 0.001A / cm 2 or less, or less 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 or smaller.

[0056] The nitrogen-containing water may include chloride ions and ammonium ions and / or ammonia. The nitrogen-containing water may have any suitable concentration of ammonia and / or ammonium ions, such as 50 ppm to 5,000 ppm, 150 ppm to 400 ppm, or 50 ppm or more, or less than, 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 can have any suitable concentration of chloride ions, for example, from 50 ppm to 40,000 ppm, from 200 ppm to 10,000 ppm, or 50 ppm or greater, or less than, 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 40,000 ppm or less. The method can also include adding chloride ions to the nitrogen-containing water (e.g., by adding a chloride salt, such as sodium chloride and / or potassium chloride), for example, adding sufficient chloride ions to achieve a chloride ion concentration of 50 ppm to 40,000 ppm, 200 ppm to 10,000 ppm, or 50 ppm or greater, or less than, 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 40,000 ppm or less.

[0057] The nitrogen-containing water may have any suitable pH, such as a pH of 4 to 12, 5 to 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 adding one or more bases to the nitrogen-containing water to adjust the pH of the water, such as by raising or maintaining 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 of 4 to 12, 5 to 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.

[0058] The product water may have any suitable total nitrogen concentration, dissolved nitrogen concentration, or combination thereof, from 0 ppm to 2 ppm, or from 0 ppm to about 1 ppm, or about 0 ppm, or less than, equal to, or greater than 0.001 ppm, 0.0012, 0.0014, 0.0016, 0.0018, 0.0020, 0.0022, 0.0024, 0.0026, 0.0028, 0.00 30, 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 less.

[0059] The product water can have any suitable amount of ammonia and / or ammonium ions removed from the nitrogenous water, for example, 80% to 100%, or 99% to 100%, or 80% to 100%, 99-100%, or 80% or more, or less than, equal to, or greater than 81%, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.9, 99.99, or 99.999% or less.

[0060] The product water can reduce the total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof to any suitable percentage of the total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof of the nitrogen-containing water, for example, 0% to 70%, or about 0% to 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 of the nitrogen-containing water.

[0061] The method can generate any suitable concentration of hypochlorite from chloride in nitrogen-containing water, such as 100 ppm to 20,000 ppm, or 2000 ppm to 2,500 ppm or greater, or less than, 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 20,000 ppm or less. The method is not limited to any particular mechanism for removing nitrogen from water in the form of ammonia using an electrolytic cell. Removing nitrogen as nitrogen gas can include converting ammonia and / or ammonium in water into nitrogen gas using an electrolytic cell. Passing the water through an electrolytic denitrification stage can generate hypochlorite in the water (e.g., by oxidation of chloride ions to chlorine at the anode, which is hydrolyzed to form hypochlorite), which can react with ammonia and / or ammonium in the water to form nitrogen gas, which can be released into the environment. This reaction can be described as NH4 + +1.5HOCl→0.5N2+1.5H2O+2.5H + +1.5Cl - Passing water through an electrolytic denitrification stage can generate chlorine in the water, which can react with ammonia and / or ammonium in the water to form nitrogen, which can be released into the environment. The reaction can be described as 2NH4 + +3Cl2→N2+6Cl - +8H + .

[0062] The product water can 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 50 ppm or greater, or less than, 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 40,000 ppm or less.

[0063] The product water can have any suitable pH, for example, a pH of 4 to 12, 5 to 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.

[0064] The method can make the Faradaic efficiency of generating chlorine gas from chloride ions in nitrogen-containing water be 50% to 100%, 70% to 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%.

[0065] The method may include circulating and / or stirring and / or shearing the nitrogen-containing water in which the electrolytic cell is immersed, which may help remove air bubbles on the anode, cathode and / or bipolar electrodes and may increase contact between the water and the anode, cathode and bipolar electrodes.

[0066] The electrolytic cell may be a flow cell, and the method may include flowing the nitrogen-containing water continuously through the cell at a rate that allows the desired degree of nitrogen removal to be achieved. Optionally, the water may be recirculated after leaving the cell so as to flow continuously 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 water after it has been recirculated through the cell one or more times.

[0067] The method can process the nitrogen-containing water into product water at any suitable rate. For example, the method can process the nitrogen-containing water into product water at a rate of 1 gallon per minute (GPM) to 1,000,000 GPM, or 10 GPM to 100,000 GPM, or 100 GPM to 5,000 GPM.

[0068] The method may remove nitrogen in the form of ammonia and / or ammonium from the nitrogen-containing water at any suitable rate, for example, from 0.01 kWh / kg (per kg of nitrogen removed) to 200 kWh / kg, 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 releasing the nitrogen to the atmosphere.

[0069] In various aspects, the method can remove nitrate (NO3-) and / or nitrite (NO2-) from nitrogenous water. The method is not limited to any specific mechanism using an electrolytic cell to remove nitrate and / or nitrite. In various aspects, nitrate and / or nitrite can be reduced (e.g., at the cathode) to form ammonia and / or ammonium. Then, ammonia and / or ammonium can react with the hypochlorite generated in the electrolytic cell (e.g., chlorine is formed by oxidation of chloride ions at the anode, and chlorine is hydrolyzed to form hypochlorite) to form nitrogen. In various aspects, nitrate and / or nitrite are removed without generating nitrous oxide, or the nitrogen generated is more than nitrous oxide.

[0070] The method may include immersing a single electrolytic cell in nitrogen-containing water. The method may include immersing a plurality of electrolytic cells in nitrogen-containing water.

[0071] Example

[0072] Various aspects of the invention may be better understood with reference to the following examples which are provided by way of illustration.The invention is not limited to the examples given herein.

[0073] In these examples, an apparatus comprising a plurality of electrolytic cells was used. The apparatus comprises an anode section, a cathode section and a bipolar section. These sections are fastened together and insulated by 30 mm nylon rods. The anode section and the cathode section are connected by 165 mm x 382 mm x 6.4 mm ASTM Grade 1 titanium plates and have vertical 165 mm x 600 mm x 6.4 mm ASTM Grade 1 titanium plates. e 1 Titanium busbar for connection to power supply.

[0074] The anode section consists of 5 titanium plates with dimensions of 410mm X 660mm X 2mm, and the effective anode surface area of ​​each section is 2.5m 2 The cathode section consists of 6 titanium plates with dimensions of 410mm X 660mm X 2mm, and the effective cathode surface area of ​​each section is 2.5m 2 The bipolar section consists of 20 titanium plates, each with an effective surface area of ​​10m2 (5m2 anode surface and 5m 2 The anode includes a catalyst coating of TiO2:RuO2:IrO2 in a ratio of 70:27:3. The bipolar plate also includes a catalyst coating on a major face facing the nearest cathode plate, while the other major face of the bipolar plate does not have a catalyst coating.

[0075] The device includes 10 electrolytic cells. Figure 5A -D shows a side view, a front view, a top view, and a combined side / front / top view of the device. Figure 6 A front view is shown showing three arrays of 10 electrolytic cells. Figure 7 A close-up of the side of the device is shown.

[0076] Example 1. Yield of chlorine generation in an electrolytic cell with two bipolar electrodes

[0077] Figure 8 The results obtained by using the electrolytic cell to electrolyze a solution having a chloride concentration of 6 g / L are shown. The conditions included I=16 Amp, E=14 V and pH=7.3. Figure 8 The linear variation of the chlorine concentration as a function of the electrolysis time is shown, with a slope of 43 ppm Cl2 / min; this value corresponds to 80% of the value obtained from the Faraday equation. The results confirm that the use of two bipolar plates allows the amount of chlorine generated to be increased threefold compared to an electrode of equal size using only one bipolar plate, maintaining an efficiency of 80%, which is the maximum efficiency reported by other authors for electrochemical chlorine production. This efficiency value is achieved due to the current density in the cell being lower than the diffusion current density of 6 g / L chloride ions and the hydrodynamic conditions, which would not be possible in an electrolyzer without bipolar plates or in an electrolyzer with only one bipolar plate.

[0078] Example 2. Changing the pH of water during the ammonia breakpoint reaction by electrochemical means

[0079] Fig. 9 Results obtained from electrolysis of water including chloride and ammonia ions in an electrolytic cell are shown. The conditions included an initial NH3 of 57.9 ppm, chloride ions of 6 g / L, I=3 Amp, and E=7.6 V. Fig. 9 The linear decrease of the pH value of water as a function of the charge used for the electrolysis of aqueous ammonia is shown. Fig.10 Shown in Fig. 9 The results show a correlation between the decrease in the pH of the water and the decrease in the ammonia concentration during the electrolysis process, indicating that the breakpoint reaction of ammonia in the in situ electrochemical generation of chlorine leads to a decrease in pH, which favors the formation of undesirable products such as chlorate or chloramines, which can be prevented by implementing a pH control tank coupled to the electrolysis cell.

[0080] The terms and expressions used are used only as descriptive and not limiting terms, and the use of these terms and expressions is not intended to exclude any equivalents of the features shown and described or parts thereof, and it should be recognized that various modifications can be made within the scope of the various aspects of the present invention. Therefore, it should be understood that although the present invention has been specifically disclosed through specific aspects and optional features, those of ordinary skill in the art may modify and change the concepts disclosed herein, and such modifications and changes should be considered within the scope of the present invention.

[0081] Exemplary Aspects

[0082] The following exemplary aspects are provided, and their numbering should not be construed as designating a level of importance:

[0083] Aspect 1 provides a device for removing nitrogen from water, the device comprising:

[0084] An electrolytic cell comprising

[0085] anode;

[0086] cathode; and

[0087] Two or more bipolar electrodes are positioned between the anode and cathode.

[0088] Aspect 2 provides the device of aspect 1, wherein the anode, cathode and bipolar electrode are each in the shape of a plate and arranged parallel to each other.

[0089] Aspect 3 provides the device of any of aspects 1-2, wherein the anode plate, cathode plate, and bipolar plate each independently have a thickness of about 0.1 mm to 50 mm.

[0090] Aspect 4 provides the device of any of aspects 1-3, wherein the anode plate, cathode plate, and bipolar plate each independently have a thickness of about 1 mm to 30 mm.

[0091] Aspect 5 provides the device of any of aspects 1-4, wherein the anode plate, cathode plate, and bipolar plate have approximately the same thickness.

[0092] Aspect 6 provides the apparatus of any of Aspects 1-5, wherein the anode, cathode, and bipolar electrodes are not in physical contact with each other, and wherein the anode, cathode, and bipolar electrodes are not electrically connected to each other except for an optional aqueous liquid in which the electrolytic cell is immersed and an optional potential applied between the anode and cathode.

[0093] Aspect 7 provides the apparatus of any of aspects 1-6, wherein the electrolytic cell comprises a gap between the anode and the bipolar electrode and a gap between the bipolar electrode and the cathode, the gaps being each independently 0.1 mm to 20 mm.

[0094] Aspect 8 provides the apparatus of aspect 7, wherein the gap between the anode and the bipolar electrode and the gap between the bipolar electrode and the cathode of the electrolytic cell are each independently 0.1 mm to 5 mm.

[0095] Aspect 9 provides the device of any of aspects 1-7, wherein the electrolytic cell comprises a gap between the bipolar electrodes, the gap being from 0.1 mm to 20 mm.

[0096] Aspect 10 provides the device of aspect 9, wherein the gap between the bipolar electrodes is 0.1 mm to 5 mm.

[0097] Aspect 11 provides the apparatus of any of aspects 1-10, wherein the electrolytic cell comprises a non-conductive connector that physically connects the anode, bipolar plate, and cathode together and maintains gaps between the anode and bipolar plate, between the bipolar plates, and between the bipolar plate and the cathode.

[0098] Aspect 12 provides the device of any of aspects 1-11, comprising two of said bipolar electrodes positioned between the anode and the cathode.

[0099] Aspect 13 provides the device of any of aspects 1-12, comprising three or more of said bipolar electrodes positioned between the anode and the cathode.

[0100] Aspect 14 provides the device of any of aspects 1-13, wherein the anode comprises titanium, stainless steel, graphite, a conductive carbon material, or a combination thereof.

[0101] Aspect 15 provides the device of any of aspects 1-14, wherein the anode comprises Ti.

[0102] Aspect 16 provides the device of any of aspects 1-15, wherein the anode comprises a catalyst coating.

[0103] Aspect 17 provides the device of aspect 16, wherein the anode comprises a catalyst coating on both major faces of the anode.

[0104] Aspect 18 provides the device of any of aspects 16-17, wherein the catalyst coating comprises one or more transition metal oxides.

[0105] Aspect 19 provides the device of any of Aspects 16-18, wherein the catalyst coating comprises TiO2, RuO2, IrO2, or a combination thereof.

[0106] Aspect 20 provides the device of any one of aspects 16-19, wherein the catalyst coating comprises TiO2, RuO2, IrO2.

[0107] Aspect 21 provides the device of any of aspects 16-20, wherein the catalyst coating comprises 70:27:3 TiO2:RuO2:IrO2.

[0108] Aspect 22 provides the device of any of aspects 1-21, wherein the cathode comprises titanium, stainless steel, or a combination thereof.

[0109] Aspect 23 provides the device of any of aspects 1-22, wherein the cathode comprises Ti.

[0110] Aspect 24 provides the device of any of aspects 1-23, wherein the cathode is uncoated.

[0111] Aspect 25 provides the device of any of Aspects 1-24, wherein the cathode is free of a catalyst coating, or the cathode includes a catalyst coating, such as a catalyst coating comprising Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or a combination thereof (e.g., an alloy thereof).

[0112] Aspect 26 provides the device of any of aspects 1-25, wherein the bipolar electrode comprises titanium, stainless steel, or a combination thereof.

[0113] Aspect 27 provides the device of any of aspects 1-26, wherein the bipolar electrode comprises Ti.

[0114] Aspect 28 provides the device of any of aspects 1-27, wherein the bipolar electrode is uncoated.

[0115] Aspect 29 provides the device of any of aspects 1-28, wherein the bipolar electrode is free of a catalyst coating.

[0116] Aspect 30 provides the device of any of aspects 1-29, wherein the bipolar electrode comprises a catalyst coating.

[0117] Aspect 31 provides the apparatus of aspect 30, wherein the bipolar electrode comprises a catalyst coating on both major faces of each bipolar plate.

[0118] Aspect 32 provides an apparatus of aspect 30, wherein the bipolar electrode includes a catalyst coating on one major surface of each bipolar plate (e.g., the surface facing the cathode nearest the cathode), and wherein the other major surface of each bipolar plate (e.g., the surface facing the anode nearest the anode) is free of a catalyst coating or includes a catalyst coating having a different composition than the catalyst coating on the opposite surface.

[0119] Aspect 33 provides the device of any of aspects 30-32, wherein the catalyst coating comprises one or more transition metal oxides.

[0120] Aspect 34 provides the device of any of Aspects 30-33, wherein the catalyst coating comprises TiO2, Ruc2, IrO2, Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or a combination thereof.

[0121] Aspect 35 provides the device of any of Aspects 30-34, wherein the catalyst coating comprises TiO2:RuO2:IrO2. In various aspects, the bipolar electrode comprises a catalyst coating comprising TiO2:RuO2:IrO2 on a major face of the bipolar electrode facing the cathode nearest thereto, and has no catalyst coating on the opposite major face, or comprises a catalyst coating comprising Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or a combination thereof on the opposite major face.

[0122] Aspect 36 provides the device of any of aspects 30-35, wherein the catalyst coating comprises 70:27:3 TiO2:RuO2:IrO2.

[0123] Aspect 37 provides the apparatus of any of aspects 1-36, wherein the electrolytic cell has a sustained Faradaic efficiency of 50% to 100% for generating chlorine gas from chloride ions when a potential is applied between the anode and cathode while the electrolytic cell is immersed in water comprising chloride ions.

[0124] Aspect 38 provides the apparatus of any of aspects 1-37, wherein the electrolytic cell has a sustained Faradaic efficiency of 70% to 90% for producing chlorine gas from chloride ions when a potential is applied between the anode and cathode while the electrolytic cell is immersed in water comprising chloride ions.

[0125] Aspect 39 provides the apparatus of any of aspects 1-38, wherein when a potential is applied between the anode and cathode while the electrolytic cell is immersed in water comprising chloride ions and ammonium ions, the electrolytic cell is effective to remove ammonium ions from the water in the form of nitrogen gas.

[0126] Aspect 40 provides the apparatus of any of aspects 1-39, wherein the apparatus comprises a plurality of electrolytic cells.

[0127] Aspect 41 provides the apparatus of any of aspects 1-40, wherein the apparatus comprises 2 to 1,000 electrolytic cells.

[0128] Aspect 42 provides the device of any of Aspects 1-41, wherein the anode, cathode and bipolar electrode are a first anode, a first cathode and a first bipolar electrode, wherein the device further comprises a second electrolytic cell comprising a first cathode, two or more second bipolar electrodes and a second anode, wherein the second bipolar electrode is located between the first cathode and the second anode.

[0129] Aspect 43 provides the apparatus of aspect 42, wherein the apparatus further comprises a third electrolytic cell comprising a second anode, two or more third bipolar electrodes, and a second cathode.

[0130] Aspect 44 provides the device of any of Aspects 1-43, wherein the anode, cathode and bipolar electrode are a first anode, a first cathode and a first bipolar electrode, wherein the device further comprises a second electrolytic cell comprising a first anode, two or more second bipolar electrodes and a second cathode, wherein the second bipolar electrode is located between the first anode and the second cathode.

[0131] Aspect 45 provides the apparatus of aspect 44, wherein the apparatus further comprises a third electrolytic cell comprising a second cathode, two or more third bipolar electrodes, and a second anode.

[0132] Aspect 46 provides the apparatus of any of aspects 1-45, further comprising a pH control system for raising and / or maintaining the pH of water in which the electrolytic cell is immersed.

[0133] Aspect 47 provides the apparatus of aspect 46, wherein the pH control system adds a base to the water and optionally measures the pH of the water.

[0134] Aspect 48 provides an apparatus for removing nitrogen from water, the apparatus comprising:

[0135] An electrolytic cell, the electrolytic cell comprising:

[0136] An anode plate comprising titanium, wherein the anode plate comprises a catalyst coating comprising TiO2, RuO2 and IrO2;

[0137] a cathode plate comprising titanium; and

[0138] Two or more bipolar electrode plates are positioned between an anode and a cathode, wherein the major faces of the anode, cathode and bipolar plates are parallel to each other, wherein each bipolar plate includes a catalyst coating on one major face thereof facing the cathode plate, the catalyst coating including TiO2, RuO2 and IrO2, and wherein the other major face of each bipolar plate is free of the catalyst coating or includes another catalyst coating having a different composition than the catalyst coating on the major face facing the cathode plate.

[0139] Aspect 49 provides an apparatus for removing nitrogen from water, the apparatus comprising:

[0140] A first electrolytic cell, the first electrolytic cell comprising:

[0141] a first anode plate comprising titanium, wherein the first anode plate comprises a catalyst coating comprising TiO2, RuO2 and IrO2;

[0142] a first cathode plate comprising titanium; and

[0143] two or more first bipolar plates positioned between a first anode plate and a first cathode plate, wherein major faces of the first anode plate, the first cathode plate, and the first bipolar plate are parallel to each other, wherein each first bipolar plate comprises a catalyst coating on one major face thereof facing the first cathode plate, the catalyst coating comprising TiO2, RuO2, and IrO2, and wherein another major face of each first bipolar plate is free of the catalyst coating or comprises another catalyst coating having a different composition than the catalyst coating on the major face facing the first cathode plate; and

[0144] A second electrolytic cell, the second electrolytic cell comprising:

[0145] the first cathode plate,

[0146] two or more second bipolar plates, and

[0147] A second anode plate including a catalyst coating thereon, wherein the second bipolar plate is located between the first cathode plate and the second anode plate, wherein major surfaces of the first cathode plate, the second bipolar plate and the second anode plate are parallel to each other, wherein each second bipolar plate includes a catalyst coating on one major surface thereof facing the first cathode plate, and wherein the other major surface of each second bipolar plate has no catalyst coating or includes another catalyst coating having a different composition from the catalyst coating on the major surface facing the first cathode plate.

[0148] Aspect 50 provides an apparatus for removing nitrogen from water, the apparatus comprising:

[0149] A first electrolytic cell, the first electrolytic cell comprising:

[0150] a first anode plate comprising titanium, the first anode plate comprising a catalyst coating comprising TiO2, RuO2, and IrO2;

[0151] a first cathode plate comprising titanium; and

[0152] two or more first bipolar plates defined between a first anode plate and a first cathode plate, wherein major faces of the first anode plate, the first cathode plate, and the first bipolar plate are parallel to each other, wherein each first bipolar plate comprises a catalyst coating on one major face thereof facing the first cathode plate, the catalyst coating comprising TiO2, RuO2, and IrO2, and wherein another major face of each first bipolar plate is free of the catalyst coating or comprises another catalyst coating having a different composition than the catalyst coating on the major face facing the first cathode plate; and

[0153] A second electrolytic cell, the second electrolytic cell comprising:

[0154] the first anode plate,

[0155] two or more second bipolar plates, and

[0156] A second cathode plate, wherein the second bipolar plate is located between the first anode plate and the second cathode plate, wherein the main surfaces of the first anode plate, the second bipolar plate and the second cathode plate are parallel to each other, wherein each second bipolar plate includes a catalyst coating on one main surface thereof facing the second cathode plate, and wherein the other main surface of each second bipolar plate has no catalyst coating or includes another catalyst coating having a different composition from the catalyst coating on the main surface facing the second cathode plate.

[0157] Aspect 51 provides a method for removing nitrogen from water, the method comprising:

[0158] immersing the electrolytic cell of any one of aspects 1-48 or the plurality of electrolytic cells of any one of aspects 49-50 in nitrogen-containing water; and

[0159] An electric potential is applied between the anode and cathode of the electrolytic cell to form nitrogen gas and to form product water having a nitrogen concentration lower than that of the nitrogen-containing water.

[0160] Aspect 52 provides the method of aspect 51, wherein the electrical potential produces a DC current in the electrolytic cell.

[0161] Aspect 53 provides the method of any of aspects 51-52, wherein the electrical potential produces an AC current in the electrolytic cell.

[0162] Aspect 54 provides the method of any one of aspects 51-53, wherein the nitrogen-containing water comprises chloride ions and ammonium ions.

[0163] Aspect 55 provides the method of any of aspects 51-54, wherein the nitrogen-containing water has an ammonia and / or ammonium ion concentration of 50 ppm to 5,000 ppm.

[0164] Aspect 56 provides the method of any of aspects 51-55, wherein the nitrogen-containing water has an ammonia and / or ammonium ion concentration of 150 ppm to 400 ppm.

[0165] Aspect 57 provides the method of any of aspects 51-56, wherein the nitrogen-containing water has a chloride concentration of 50 ppm to 40,000 ppm.

[0166] Aspect 58 provides the method of any of aspects 51-57, wherein the nitrogen-containing water has a chloride concentration of 200 ppm to 10,000 ppm.

[0167] Aspect 59 provides the method of any one of aspects 51-58, further comprising adding chloride ions to the nitrogen-containing water.

[0168] Aspect 60 provides the method of aspect 59, wherein adding chloride ions comprises adding sodium chloride, potassium chloride, or a combination thereof.

[0169] Aspect 61 provides the method of any one of aspects 51-60, wherein the nitrogen-containing water has a pH of 4 to 12.

[0170] Aspect 62 provides the method of any one of aspects 51-61, wherein the nitrogen-containing water has a pH of 5 to 8.

[0171] Aspect 63 provides the method of any one of aspects 51-62, further comprising adding one or more bases to the nitrogen-containing water to adjust the pH of the water.

[0172] Aspect 64 provides the method of any of aspects 51-63, wherein the product water has an ammonia and / or ammonium ion concentration of 0 ppm to 2 ppm.

[0173] Aspect 65 provides the method of any of aspects 51-64, wherein the product water has a total nitrogen concentration, a dissolved nitrogen concentration, or a combination thereof, of 0 ppm to 2 ppm.

[0174] Aspect 66 provides the method of any of aspects 51-65, wherein the method removes 80% to 100% of the ammonia and / or ammonium from the nitrogen-containing water.

[0175] Aspect 67 provides the method of any of aspects 51-66, wherein the method removes 99% to 100% of the ammonia and / or ammonium from the nitrogen-containing water.

[0176] Aspect 68 provides the method of any of aspects 51-67, wherein the method reduces the total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof to 0% to 70% of the total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof of the nitrogen-containing water.

[0177] Aspect 69 provides the method of any of aspects 51-68, wherein the method reduces the total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof to 0% to 30% of the total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof of the nitrogen-containing water.

[0178] Aspect 70 provides the method of any of aspects 51-69, wherein the method further comprises contacting the product water with a galvanic cell to form galvanic treated water.

[0179] Aspect 71 provides the method of any of Aspects 51-70, wherein the galvanic cell comprises a cathode comprising copper and an anode comprising aluminum, wherein the method optionally comprises adding hydrogen peroxide to the product water before or during contact of the product water with the galvanic cell.

[0180] Aspect 72 provides the method of any of aspects 51-71, wherein the method generates 100 ppm to 20,000 ppm of hypochlorite from chloride in nitrogen-containing water.

[0181] Aspect 73 provides the method of any of aspects 51-72, wherein the method produces 2000 ppm to 2,500 ppm of hypochlorite from chloride in water.

[0182] Aspect 74 provides the method of any of aspects 51-73, wherein the product water has a chloride concentration of 1 ppm to 40,000 ppm.

[0183] Aspect 75 provides the method of any of aspects 51-74, wherein the product water has a chloride concentration of 50 ppm to 10,000 ppm.

[0184] Aspect 76 provides the method of any of aspects 51-75, wherein the product water has a pH of 4 to 12.

[0185] Aspect 77 provides the method of any of aspects 51-76, wherein the product water has a pH of 5 to 8.

[0186] Aspect 78 provides the method of any of aspects 51-77, wherein the method provides a sustained Faradaic efficiency of 50% to 100% for the production of chlorine gas from chloride ions in nitrogen-containing water.

[0187] Aspect 79 provides the apparatus of any of aspects 51-78, wherein the method provides a sustained Faradaic efficiency of 70% to 90% for the production of chlorine gas from chloride ions.

[0188] Aspect 80 provides the method of any of aspects 51-79, wherein the method comprises circulating and / or stirring and / or shearing the nitrogen-containing water in which the electrolytic cell is immersed.

[0189] Aspect 81 provides the method of any of aspects 51-80, wherein the method comprises flowing nitrogen-containing water through the tank.

[0190] Aspect 82 provides the method of any of aspects 51-81, wherein the method processes nitrogen-containing water into product water at a rate of 1 GPM to 1,000,000 GPM.

[0191] Aspect 83 provides the method of any of aspects 51-82, wherein the method processes nitrogen-containing water into product water at a rate of 100 GPM to 5,000 GPM.

[0192] Aspect 84 provides the method of any one of aspects 51-83, wherein the method removes nitrogen in the form of ammonia and / or ammonium from nitrogen-containing water at a rate of 0.01 kWh / kg (per 1 kg of nitrogen removed) to 200 kWh / kg.

[0193] Aspect 85 provides the method of any one of aspects 51-84, wherein the method removes nitrogen in the form of ammonia and / or ammonium from the nitrogen-containing water at a rate of 30 kWh / kg to 50 kWh / kg.

[0194] Aspect 86 provides the method of any of aspects 51-85, further comprising releasing the nitrogen into the atmosphere.

[0195] Aspect 87 provides the method of any one of aspects 51-86, comprising: 2The electrolytic cell is operated at a current density of .

[0196] Aspect 88 provides the method of any one of aspects 51-87, comprising heating the mixture at 0.02-0.04 A / cm 2 The electrolytic cell is operated at a current density of .

[0197] Aspect 89 provides the method of any of aspects 51-88, wherein the method comprises immersing a plurality of electrolytic cells in nitrogen-containing water.

[0198] Aspect 90 provides a method for removing nitrogen from water, the method comprising:

[0199] The electrolytic cell is immersed in nitrogen-containing water, wherein the water includes ammonia and / or ammonium ions, and the water also includes chloride ions, wherein the electrolytic cell comprises:

[0200] An anode plate comprising titanium, wherein the anode plate comprises a catalyst coating comprising TiO2, RuO2 and IrO2;

[0201] a cathode plate comprising titanium; and

[0202] Two or more bipolar electrode plates are positioned between the anode and cathode, wherein

[0203] The major faces of the anode, cathode and bipolar plates are parallel to each other, wherein each bipolar plate comprises a catalyst coating on one major face thereof facing the cathode plate, the catalyst coating comprising TiO2, RuO2 and IrO2, and wherein the other major face of each bipolar plate is free of the catalyst coating or comprises another catalyst coating having a different composition than the catalyst coating on the major face facing the cathode plate;

[0204] An electrical potential is applied between the anode plate and the cathode plate of the electrolytic cell to form nitrogen gas and to form product water having a nitrogen concentration lower than that of the nitrogen-containing water.

[0205] Aspect 91 provides a method for removing nitrogen from water, the method comprising:

[0206] The electrolytic cell is immersed in nitrogen-containing water, wherein the water includes ammonia and / or ammonium ions, and the water also includes chloride ions, wherein the electrolytic cell comprises:

[0207] An anode plate comprising titanium, wherein the anode plate comprises a catalyst coating comprising TiO2, RuO2 and IrO2;

[0208] a cathode plate comprising titanium, wherein the cathode plate comprises a catalyst coating comprising Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni, or a combination thereof, or wherein the cathode plate is free of a catalyst coating; and

[0209] Two or more bipolar electrode plates positioned between an anode and a cathode, wherein major faces of the anode, cathode and bipolar plates are parallel to each other, wherein each bipolar plate comprises a catalyst coating on one major face thereof facing the cathode plate, the catalyst coating comprising TiO2, RuO2 and IrO2, and wherein the other major face of each bipolar plate is free of the catalyst coating or comprises another catalyst coating comprising Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni or a combination thereof;

[0210] An electrical potential is applied between the anode and cathode plates of the electrolytic cell to form nitrogen gas and to form product water having a lower nitrogen concentration than the nitrogen-containing water.

[0211] Aspect 92 provides an apparatus or method according to any one or any combination of aspects 1-91, optionally configured so that all elements or options recited are available for use or selection.

Claims

1. A device for removing nitrogen from water, the device comprising: An electrolytic cell, comprising: anode; cathode; and Two or more bipolar electrodes are positioned between the anode and cathode.

2. The device according to 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 gaps is independently 0.1 mm to 20 mm, and wherein the electrolytic cell comprises a gap between the bipolar electrodes of 0.1 mm to 20 mm.

3. The device according to claim 1, wherein: The electrolytic cell includes a non-conductive connector that physically connects the anode, bipolar plates, and cathode to each other and maintains gaps between the anode and bipolar plates, between the bipolar plates, and between the bipolar plates and the cathode.

4. The device of claim 1, comprising two or more of said bipolar electrodes positioned between an anode and a cathode.

5. The device according to claim 1, wherein: The anode includes titanium, stainless steel, graphite, a conductive carbon material, or a combination thereof, and wherein the anode includes a catalyst coating.

6. The device according to claim 5, wherein: The catalyst coating includes TiO2, RuO2, IrO2 or a combination thereof.

7. The device according to claim 1, wherein: The cathode includes titanium, stainless steel, or a combination thereof.

8. The device according to claim 1, wherein: The bipolar electrodes include titanium, stainless steel, or a combination thereof.

9. The device according to claim 1, wherein: The bipolar electrode includes a catalyst coating, which includes TiO2, RuO2, IrO2, Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni or a combination thereof.

10. The device according to claim 9, wherein: The bipolar electrode includes a catalyst coating on both main surfaces of each of the bipolar plates, wherein the catalyst coating on the main surface of the bipolar plate facing the cathode includes TiO2, RuO2, IrO2 or a combination thereof, and wherein the catalyst coating on the main surface of the bipolar plate facing the anode includes Cu, Ag, Co, Ni, Fe, Mo, Cu / Co, Cu / Ni or a combination thereof.

11. The device according to claim 9, wherein: The bipolar electrode includes a catalyst coating on one major face of each of the bipolar plates, wherein the other major face of each of the bipolar plates is free of a catalyst coating.

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

13. An apparatus for removing nitrogen from water, the apparatus comprising: An electrolytic cell, comprising: An anode plate comprising titanium, wherein the anode plate comprises TiO2, RuO2, Catalyst coating of IrO2; a cathode plate comprising titanium; and Two or more bipolar electrode plates are positioned between an anode and a cathode, wherein the major faces of the anode, cathode and bipolar plates are parallel to each other, wherein each bipolar plate includes a catalyst coating on one major face thereof facing the cathode plate, the catalyst coating including TiO2, RuO2, IrO2, and wherein the other major face of each bipolar plate has no catalyst coating or includes another catalyst coating having a different composition from the catalyst coating on the major face facing the cathode plate.

14. A method for removing nitrogen from water, the method comprising: Immersing the electrolytic cell according to claim 1 in nitrogen-containing water; as well as An electric potential is applied between the anode and cathode of the electrolytic cell to form nitrogen gas and to form product water having a nitrogen concentration lower than that of the nitrogen-containing water.

15. The method according to claim 14, wherein: The concentration of ammonia and / or ammonium ions in the nitrogen-containing water is 50 ppm to 5,000 ppm, wherein the concentration of ammonia and / or ammonium ions in the product water is 0 ppm to 2 ppm.

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

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

18. The method according to claim 14, wherein: The chloride concentration of the nitrogen-containing water is 50 ppm to 40,000 ppm, and wherein the method generates 100 ppm to 20,000 ppm of hypochlorite from the chloride in the nitrogen-containing water.

19. The method of claim 14, further comprising releasing the nitrogen into the atmosphere.

20. A method for removing nitrogen from water, the method comprising: immersing an electrolytic cell in nitrogen-containing water, wherein the water comprises ammonia and / or ammonium ions, and the water further comprises chloride ions, wherein the electrolytic cell comprises: An anode plate comprising titanium, wherein the anode plate comprises TiO2, RuO2, Catalyst coating of IrO2; a cathode plate comprising titanium; and Two or more bipolar electrode plates positioned between an anode and a cathode, wherein the major faces of the anode, cathode and bipolar plates are parallel to each other, wherein each bipolar plate comprises a catalyst coating on one major face thereof facing the cathode plate, the catalyst coating comprising TiO2, RuO2, IrO2, and wherein the other major face of each bipolar plate is free of catalyst coating or comprises another catalyst coating having a different composition than the catalyst coating on the major face facing the cathode plate, An electrical potential is applied between the anode plate and the cathode plate of the electrolytic cell to form nitrogen gas and to form product water having a nitrogen concentration lower than that of the nitrogen-containing water.

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