Electrochemical seawater desalination with hydrogen depolarization

Abstract

A three-compartment electrochemical desalination system, and process of using same, is described, wherein a feed including brackish water or seawater can be introduced and fresh water can be produced. The electrochemical desalination system can be coupled to a carbon dioxide-capturing apparatus, which can scrub carbon dioxide from any air source, and an acid-base neutralizer, which can release the scrubbed carbon dioxide as a pure gas stream. The overall process thus results in the simultaneous separation of CO2 from an air source (i.e., carbon capture) and the production of fresh water from brine (i.e., desalination).

Description

ELECTROCHEMICAL SEAWATER DESALINATION WITH HYDROGEN DEPOLARIZATIONGOVERNMENT SUPPORT CLAUSE

[0001] This invention was made with government support under grant AR0001711 awarded by the Department of Energy. The government has certain rights in the invention.CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 626,243, filed January 29, 2024, the contents of which are incorporated herein by reference in their entirety.FIELD

[0003] The present disclosure relates to an innovative electrochemical desalination system and process of using same to desalinate seawater as well as produce acids and hydroxides.BACKGROUND

[0004] Fresh water scarcity continues to be one of the most prominent issues facing civilization at the global level. Water requirements are especially high in arid and semi-arid regions where renewable and traditional water resources and rainfall are scarce. The lack of fresh water in such areas contributes to poor health, low nutrition, and poverty, as well as hindering efforts to improve living standards and achieve sustainable development. One of the most effective methods to alleviate water shortage is through seawater desalination.

[0005] Desalination technologies are well known and can be classified based on their salt separation mechanism into thermal desalination and membrane desalination. The most frequently applied desalination techniques are reverse osmosis (RO), multi-stage flash (MSF), multiple-effect distillation (MED), electro-dialysis (ED), and vapor compression (VP). Thermal desalination is based on the principle of heating saline water using external means to saturation temperature to convert liquid water to vapor by evaporation, and then condensing this vapor to obtain fresh water without salt. The remaining heated saline water increases in saline content and is often discarded. Membrane desalination utilizes a membrane to separate the salt from the water. In general, thermaldesalination is more energy intensive than membrane desalination. Thermal desalination, however, can process water with higher salt concentrations than membrane desalination, while also producing better water quality. Among all of these desalination techniques, RO and MSF are the most commonly used.

[0006] Rapid globalization and the constantly increasing human population, especially in large cities, have increased the requirements to improve desalination processes and minimize the energy requirements and adverse impacts. Disadvantageously, all of the above-described desalination techniques require significant amounts of energy to produce fresh water. The need for desalination processes that are compact and scalable, with lower operating costs, higher efficiency and lower energy consumption continues to drive the development of different types of desalination processes.

[0007] Towards that end, the present invention relates to an electrochemical desalination system to remove the salt ions from water, and process of using same. Advantageously, the electrochemical desalination system described herein can remove ions from seawater using low voltage and can utilize renewable energy.

[0008] In addition to the global challenges of reliably supplying fresh water, our world is also facing challenges related to increasing carbon emissions. Accordingly, the present invention further integrates the electrochemical desalination system with carbon capture technology for the energy efficient capture of carbon dioxide while simultaneously desalinating seawater or brackish water to produce fresh water.SUMMARY

[0009] In some aspect, an electrochemical desalination system comprising a flow unit is described, said system comprising: a first compartment comprising: a first inlet configured to receive a first flow of a water source comprising salt; an anode; and at least one first outlet, wherein the water source is in electrical and fluid communication with the anode, wherein the anode is configured to oxidate hydrogen gas to generate hydrogen ions in the first compartment, and wherein the at least one first outlet isconfigured to remove an acid solution comprising the generated hydrogen ions from the first compartment; a third compartment comprising: a third inlet configured to receive a third flow of the water source comprising salt; a cathode; and at least one third outlet, wherein the water source is in electrical and fluid communication with the cathode, wherein the cathode is configured to generate a hydrogen gas and a hydroxide, and wherein the at least one third outlet is configured to remove the generated hydrogen gas and / or a base solution comprising the generated hydroxide from the third compartment; a second compartment positioned between and in fluid communication with the first compartment and the third compartment, wherein the first compartment is separated from the second compartment with one or more anion exchange membranes (AEM) and the second compartment is separated from the third compartment with one or more cation exchange membranes (CEM); wherein the second compartment comprises: a second inlet configured to receive a second flow of the water source comprising salt; and an outlet configured to remove fresh water from the second compartment.

[0010] In some other aspects, a desalination method is described, said method comprising: providing a electrochemical desalination system as described herein; flowing the water source comprising salt into each of the first, second and third compartments; generating a hydrogen gas stream and hydroxide ions on the cathode in the third compartment; and directing a stream comprising hydrogen gas into a fourth compartment, wherein the fourth compartment comprises a fourth inlet configured to receive a stream comprising the hydrogen gas, wherein the fourth compartment is positioned in proximity to the first compartment with the anode positioned therebetween, and wherein the hydrogen gas present in the stream is the generated hydrogen gas and / or a hydrogen gasprovided from an external source; generating hydrogen ions on the anode into the first compartment, wherein as hydrogen ions are generated in the first compartment, anions in the second compartment flow through the AEM to the first compartment and as hydroxide ions are generated in the third compartment, cations in the second compartment flow through the CEM to the third compartment, and wherein the water flown out of the second compartment is fresh water.

[0011] In some aspects, a system is described, said system comprising; one or more electrochemical desalination systems configured to produce an acid solution, a base solution, and fresh water; one or more carbon dioxide capturing apparatuses that is in fluid communication with the one or more electrochemical desalination systems and that are configured to capture a carbon dioxide from a gas source and convert the carbon dioxide to a bicarbonate solution, carbonate solution, or a combination thereof; and one or more neutralizers that is in fluid communication with the one or more electrochemical desalination systems and the one or more carbon dioxide capturing apparatuses.

[0012] In some other aspects, a system is described, said system comprising: one or more electrochemical desalination systems configured to produce an acid solution, a base solution, and fresh water; one or more carbon dioxide capturing apparatuses that is in fluid communication with the one or more electrochemical desalination systems and that are configured to capture a carbon dioxide from a gas source and convert the carbon dioxide to a bicarbonate solution, carbonate solution, or a combination thereof; and one or more neutralizers that is in fluid communication with the one or more electrochemical desalination systems and the one or more carbon dioxide capturing apparatuses, wherein the one or more electrochemical desalination systems comprise: a first compartment comprising an anode, wherein the anode is configured to oxidate hydrogen gas to generate an acid solution comprising hydrogen ions in the first compartment;a third compartment comprising a cathode, wherein the cathode is configured to generate a hydrogen gas and a base solution comprising hydroxide ions; a second compartment positioned between and in fluid communication with the first compartment and the third compartment, wherein the first compartment is separated from the second compartment with one or more anion exchange membranes (AEM) and the second compartment is separated from the third compartment with one or more cation exchange membranes (CEM).

[0013] In still other aspects, a method of simultaneously desalinating brackish water or seawater and directly capturing carbon dioxide from a gas source is described, wherein the method comprises: providing one or more of the electrochemical desalination systems, wherein the one or more electrochemical desalination systems are configured to produce an acid solution, a base solution, and fresh water; electrochemically generating a hydrogen gas and a base solution comprising hydroxide ions on the cathode in the third compartment; flowing a stream comprising a generated hydrogen gas, a hydrogen gas provided by an external source, or a combination thereof, to the fourth compartment, such that an acid solution comprising electrochemically generated hydrogen ions are formed on the anode in the first compartment; and directing a portion of base solution comprising the generated hydroxide ions to one or more carbon dioxide capturing apparatuses configured to capture a carbon dioxide from a gas source by converting the carbon dioxide to a bicarbonate solution, carbonate solution, or a combination thereof, wherein as hydrogen ions are generated in the first compartment, anions in the second compartment flow through the AEM into to the first compartment and as hydroxide ions are generated in the third compartment, cations in the second compartment flow through the CEM into the third compartment, and fresh water is generated in the second compartment.

[0014] In yet another aspect, a method of simultaneously desalinating brackish water or seawater and directly capturing carbon dioxide from a gas source is described, wherein the method comprises: providing one or more of the electrochemical desalination systems;electrochemically generating a hydrogen gas and a base solution comprising hydroxide ions on the cathode in the third compartment; flowing a stream comprising a generated hydrogen gas, a hydrogen gas provided by an external source, or a combination thereof, to the fourth compartment, such that an acid solution comprising electrochemically generated hydrogen ions are formed on the anode in the first compartment; and directing a portion of base solution comprising the generated hydroxide ions to one or more carbon dioxide capturing apparatuses configured to capture a carbon dioxide from a gas source by converting the carbon dioxide to a bicarbonate solution, carbonate solution, or a combination thereof, wherein as hydrogen ions are generated in the first compartment, anions in the second compartment flow through the AEM into to the first compartment and as hydroxide ions are generated in the third compartment, cations in the second compartment flow through the CEM into the third compartment, and fresh water is generated in the second compartment, and wherein the one or more electrochemical desalination systems comprise: a first compartment comprising an anode, wherein the anode is configured to oxidate hydrogen gas to generate an acid solution comprising hydrogen ions in the first compartment; a third compartment comprising a cathode, wherein the cathode is configured to generate a hydrogen gas and a base solution comprising hydroxide ions; a second compartment positioned between and in fluid communication with the first compartment and the third compartment, wherein the first compartment is separated from the second compartment with one or more anion exchange membranes (AEM) and the second compartment is separated from the third compartment with one or more cation exchange membranes (CEM).

[0015] Other aspects, features and advantages of the invention will be more fully apparent from the ensuing disclosure and appended claims.BRIEF DESCRIPTION OF THE FIGURES

[0016] Figure 1 . Overview of proposed system for electrochemically integrated carbon capture and desalination (EICCD). Figure 1A is an embodiment of an electrochemical desalination system. Figure IB is an embodiment of an air contactor. Figure 1C is an embodiment of a neutralizer.

[0017] Figure 2. Figure 2A illustrates proposed and Figure 2B illustrates conventional salt splitting. The oxygen evolution reaction on the anode in Figure 2B is replaced by hydrogen oxidation in Figure 2A. Fh circulation in Figure 2A closes the mass balance and saves energy for acid-base electrosynthesis and desalination.

[0018] Figure 3A. Preliminary study of acid-base electrosynthesis from desalination of brine using synthetic seawater. Composition of the synthetic water used as the brine feeding.

[0019] Figure 3B. Output salinity (•) from the second compartment and voltage (■) of the desalination operation.

[0020] Figure 4. Proposed intermittent operation of EICCD with off-peak electricity.

[0021] Figure 5A. Capture efficiency % (■) and output solution pH (•) of different air flow rate.

[0022] Figure 5B. Capture efficiency % (■)and output solution pH (•) of different liquid flow rate.

[0023] Figure 5C. Capture efficiency % (B)and output solution pH (•) of different NaOH concentration.

[0024] Figure 6A. An embodiment of a desalination system with liquid looping only.

[0025] Figure 6B. An embodiment of a desalination system with hydrogen looping and liquid looping.DETAILED DESCRIPTION OF THE DISCLOSURE

[0026] Although the claimed subject matter will be described in terms of certain embodiments, other embodiments, including embodiments that do not provide all of the benefits and features set forth herein, are within the scope of this disclosure as well. Various structural and parameter changes may be made without departing from the scope of this disclosure.Definitions

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control. Preferred methods and materials are described below, although methods and materials similar or equivalent to those described herein can be used in practice or testing of the present disclosure. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and not intended to be limiting.

[0028] ‘ ‘About” and “approximately” are used to provide flexibility to a numerical range endpoint by providing that a given value may be “slightly above” or “slightly below” the endpoint without affecting the desired result, for example, + / - 5%.

[0029] The phrase “in one embodiment” or “in some embodiments” as used herein does not necessarily refer to the same embodiment, though it may. Furthermore, the phrase “in another embodiment” as used herein does not necessarily refer to a different embodiment, although it may. Thus, as described below, various embodiments of the invention may be readily combined, without departing from the scope or spirit of the invention.

[0030] The terms “comprise(s),” “include(s),” “having,” “has,” “can,” “contain(s),” and variants thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that do not preclude the possibility of additional acts or structures. The singular forms “a,” “and” and “the” include plural references unless the context clearly dictates otherwise. The present disclosure also contemplates other embodiments “comprising,” “consisting of” and “consisting essentially of,” the embodiments or elements presented herein, whether explicitly set forth or not.

[0031] For the recitation of numeric ranges herein, each intervening number there between with the same degree of precision is explicitly contemplated. For example, for the range of 6-9, the numbers 7 and 8 are contemplated in addition to 6 and 9, and for the range 6.0-7.0, the number 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 are explicitly contemplated.

[0032] As used herein, a “system” refers to a plurality of real and / or abstract elements operating together for a common purpose. In some embodiments, a “system” is an integrated assemblage of hardware and / or software elements. In some embodiments, each component of the system interacts with one or more other elements and / or is related to one or more other elements. In some embodiments, a system refers to a combination of components and software for controlling and directing methods.

[0033] As used herein, “brackish water” describes water that has more salinity than freshwater, but less salinity than seawater. Brackish water is often used to describe water that is found in a transitional area between freshwater and seawater, for example, an estuary.

[0034] As used herein, the term “substantially free,” when used in the context of a composition or component of a composition that is substantially absent, is intended to refer to an amount that is less then about 2 % by weight, e.g., less than about 1% by weight, less than about 0.5 % by weight, less than about 0.1 % by weight, less than about 0.05 % by weight, or less than about 0.01 % by weight of the stated material, based on the total weight of the composition.

[0035] As used herein, “seawater” is known to be water from a sea or ocean. On average the salinity of seawater is about 3.5%, or about 35,000 ppm of “salt” (mostly sodium chloride).

[0036] As used herein, “fresh water” comprises less than 1,000 ppm of salt or has a salinity less than about 0.1%.Electrochemical Desalination

[0037] Broadly, the present invention relates to an innovative electrochemical desalination system, and process of using same, that can be implemented regardless of the salinity of the water (e.g., seawater or brackish water) to produce purified, potable water which is substantially free of contamination. In some embodiments, the electrochemical desalination system can be used to further produce commodity acids and hydroxides.

[0038] A conventional salt splitting electrochemical cell is illustrated in Figure 2B, wherein an oxygen evolution reaction occurs at the anode. In the present disclosure, hydrogen oxidation occurs at the anode (see, e.g., Figure 2A). By circulating the H2(g) in Figure 2A from a catholyte to a gas diffusion electrode in contact with the anolyte, the mass balance can be closed and energy saved for acid-base electrosynthesis and desalination.

[0039] One embodiment of an electrochemical desalination system is shown in Figure 1A. In Figure 1A, the electrochemical desalination system comprises three liquid compartments: a first compartment and a second compartment separated by an anion exchange membrane (AEM) and the second compartment and a third compartment separated by a cation exchange membrane (CEM); and a gas compartment configured to receive hydrogen gas (not shown in Figure 1A) that is separated from the first compartment by a gas diffusion electrode (GDE). Seawater can be introduced to the three liquid compartments and a voltage can be applied between the anode (+)(i.e., GDE) in contact with the anolyte in the first compartment and a cathode (-) in contact with the catholyte in the third compartment. In the first compartment, hydrogen gas from a fourth compartment (not shown) is oxidized at the GDE to produce H+in the first compartment and anions in the liquid in the second compartment including, but not limited to, chlorides, sulfates, nitrates, phosphates, citrates, formates, lactates, tartrates, malates, fumarates, oxalates, succinates, gluconates, ascorbates, and acetates, or mixtures thereof, will pass through the AEM to the anolyte in the first compartment. Accordingly, the anolyte withdrawn from the first compartment will be acidic and have a higher salinity, relative to the liquid in the second compartment. In the third compartment, the seawater will be reduced at the cathode to H2 and OH". Cations in the liquid in the second compartment including, but not limited to, Li+, Na+, K+, Mg2+, Ca2+, and NH4+, will pass through the CEM to the catholyte in the third compartment. Accordingly, the catholyte will be alkalic and have higher salinity, relative to the liquid in the second compartment. In the second compartment, as the ions are removed to the first or third compartment, the salinity of the seawater will decrease, and fresh water can be removed therefrom.

[0040] Advantageously, energy-efficient electrosynthesis of acids and bases is achieved using the three-compartment electrochemical cell coupled with hydrogen looping between the hydrogen evolution reaction (HER) on the cathode and hydrogen oxidation reaction (HOR) on the anode. The half reactions are:Cathode: 2 H2O + 2 e' H2+ 2 OH’, E° = -0.83 V vs. SHE at pH = 14 (Rl)Anode: H22H++ 2 e , E° = 0 V vs. SHE at pH = 0 (R2)This is accompanied with the removal of cations (e.g., Na+) and anions (e.g., Cl-) in the brine or seawater feed via electrical field-driven migration through the cation-exchange membrane (CEM) and anion-exchange membrane (AEM), respectively, and the deionized feed becomes a freshwater product. The theoretical voltage of the electrochemical reactions is 0.83 V.

[0041] In some embodiments, the electrochemical desalination system further comprises at least one first inlet that extends into the first compartment, at least one second inlet that extends into the second compartment, and at least one third inlet that extends into the third compartment. A stream of seawater can be introduced to each of compartments via the respective inlets. In some embodiments, it should be appreciated that the electrochemical desalination system further comprises at least one outlet configured to remove an acid solution stream comprising generated hydrogen ions from the first compartment, at least one outlet configured to remove a water streamfrom the second compartment, and one or more outlets configured to remove the generated hydrogen gas stream and / or a base solution stream comprising generated hydroxide from the third compartment. In some embodiments, the electrochemical desalination system comprises a fourth inlet configured to receive a stream of hydrogen gas in the gas compartment. In still further embodiments, while the disclosed above inlets and outlets are not shown in Figure 1A, the skilled practitioner can understand that inlet and outlet can be positioned anywhere within the compartment to allow inflow and outflow of respective streams as described. Further, in some embodiments, the generated in the third compartment hydrogen gas and the base solution can be removed from the same outlet, while in other embodiments, the generated hydrogen gas stream and the base solution can be removed from separate outlets.

[0042] In some embodiments, a pH of the acid solution present in, or withdrawn from, the first compartment is about 0<pH<7, including exemplary values of about 0, about 0.5, about 1, about1.5, about 2, about 2.5, about 3, about 3.5, about 4, about 4.5, about 5, about 5.5, about 6, about6.5, and about 7. It is understood that at any point of, the first compartment can comprise a solution having a pH value that falls within any two foregoing values. In some embodiments, a pH of the base solution present in, or withdrawn from, the third compartment can have a pH of about 7<pH<14, including exemplary values of about 7, about 7.5, about 8, about 8.5, about 9, about 9.5, about 10, about 10.5, about 11, about 11.5, about 12, about 12.5, about 13, about 13.5, and about 14. It is understood that at any point of, the third compartment can comprise a solution having a pH value that falls within any two foregoing values.

[0043] In some embodiments, the withdrawn anolyte and withdrawn catholyte can be mixed and the H+and OH" will form saline H2O, but there is no contamination so it can be returned directly to the sea.

[0044] In some embodiments, the H2 generated at the cathode in the third compartment is separated from the catholyte and introduced to a H2 recirculation loop for introduction to the fourth compartment for oxidation at the GDE. In some embodiments, the hydrogen gas stream comprises a hydrogen gas supplied from any external source, such as a hydrogen tank, externally generated hydrogen, and the like. In still other embodiments, the hydrogen gas stream can comprise both the hydrogen generated in the third compartment and the hydrogen gas received from the external source. In still further embodiments, disclosed are implementations where an operator can switch the supply of the hydrogen gas stream as desired.

[0045] It is also understood that any known in the art cation exchange membranes and anion exchange membranes can be used. In such embodiments, any known and commercially available cation exchange membranes and anion exchange membranes can be used. It should be appreciated that the cation and anion exchange membranes can have any desired thickness.

[0046] In some embodiments, the polymeric cation-exchange membranes comprise -SO r, -COO" , -PO32’, -PO3IT, or -C6H4O- cation exchange functional groups. The polymers for the preparation of cation-exchange membranes can be perfluorinated ionomers such as NAFION (a perfluorosulfonic -based membrane), FLEMION, and NEOSEPTA-F, partially fluorinated polymers, non-fluorinated hydrocarbon polymers, non-fluorinated polymers with aromatic backbone, or acid-base blends. It will be appreciated that in some embodiments, depending on the need to restrict or allow migration of a specific cation or an anion species between the electrolytes, a cation exchange membrane that is more restrictive and thus allows migration of one species of cations while restricting the migration of another species of cations may be used as, e.g., a cation exchange membrane that allows migration of potassium ions into the cathode electrolyte while restricting migration of other cations into the cathode electrolyte, may be used. Such restrictive cation exchange membranes are commercially available and can be selected by one ordinarily skilled in the art. Some exemplary and commercially available membranes, such as Nation ®N 117, CMI-7000, CMH-PP Ralex, EMION PF1-HLF8-15-X, CEM-Type I and CEM-Type II, etc., can be used.

[0047] Anion exchange membranes (AEM) are conventionally known in the art. In some embodiments, the polymeric anion-exchange membranes comprise -NH3+, -NRH2+, -NRiH", - NR3+, or -SR2- anion exchange functional groups. The polymers for the preparation of anion- exchange membranes can be perfluorinated ionomers such as NAFION (a perfluorosulfonic-based membrane), FLEMION, and NEOSEPTA-F, partially fluorinated polymers, non-fluorinated hydrocarbon polymers, non-fluorinated polymers with aromatic backbone, or acid-base blends. It will be appreciated that in some embodiments, depending on the need to restrict or allow migration of a specific cation or an anion species between the electrolytes, an anion exchange membrane that is more restrictive and thus allows migration of one species of anions while restricting the migration of another species of anions may be used as, e.g., an anion exchange membrane that allows migration of chloride ions into the anode electrolyte while restricting migration of other anions into the anode electrolyte, may be used. Such restrictive anion exchange membranes arecommercially available and can be selected by one ordinarily skilled in the art. In still further embodiments, any known and commercially available anion exchange membranes can be used. For example, and without limitations, Sustainion® 37-50, PiperlON TP-85, Fumasep FAPQ-375, PBI, Neosepta ACN, etc.

[0048] In still further embodiments, each of the cathode and anode are electrically connected to a power source. In some embodiments, the power source can provide a desired current to achieve the electrochemical reaction to desalinate seawater. In certain embodiments, the current can have a current density from about 50 mA / cm2to about 500 mA / cm2, including exemplary ranges of about 50 mA / cm2to about 75 mA / cm2, about 75 mA / cm2to about 100 mA / cm2, about 100 mA / cm2to about 125 mA / cm2, about 125 mA / cm2to about 150 mA / cm2, about 150 mA / cm2to about 175 mA / cm2, about 175 mA / cm2to about 200 mA / cm2, about 200 mA / cm2to about 225 mA / cm2, about 225 mA / cm2to about 250 mA / cm2, about 250 mA / cm2to about 275 mA / cm2, about 275 mA / cm2to about 300 mA / cm2, about 300 mA / cm2to about 325 mA / cm2, about 325 mA / cm2to about 350 mA / cm2, about 350 mA / cm2to about 375 mA / cm2, about 375 mA / cm2to about 400 mA / cm2, about 400 mA / cm2to about 425 mA / cm2, about 425 mA / cm2to about 450 mA / cm2, about 450 mA / cm2to about 475 mA / cm2, and about 475 mA / cm2to about 500 mA / cm2. In some embodiments, the power source is configured to provide a desired voltage between the cathode and anode material. In such embodiments, the provided voltage can be from about 0.5 V to about 10 V, including exemplary values of about 1 V, about 1.5 V, about 2 V, about 2.5 V, about 3 V, about 3.5 V, about 4 V, about 4.5 V, about 5 V, about 5.5 V, about 6 V, about 6.5 V, about 7 V, about 7.5 V, about 8 V, about 8.5 V, about 9 V, and about 9.5 V. It is understood that any voltage having a value between any two foregoing values can be used to achieve the desired outcome.

[0049] In still further embodiments, any known in the art cathode and anode materials can be used in the disclosed system. For example, the cathode can comprise a Pt group metal or their alloys based electrode, a Ni-and its alloys-based electrode, a NiFe-based electrode, a NiTi-based electrode, a steel-based electrode, other transition metal electrodes (e.g., comprising at least one of Fe, Co, Ni, Cu, Pt), transition metal sulfates-based electrode, such as for example, and without limitations, molybdenum sulfide, tungsten sulfide, transition metal phosphide-based electrode, for example, and without limitations cobalt phosphide, Fe-based catalysts, carbon-based materials, or any combination thereof. In still further embodiments, any cathode materials capable of inducing electrochemical desalination can be used.

[0050] In still further embodiments, any anodes known in the art and suitable for the desired operation can be utilized. In certain embodiments, the anode can comprise a gas diffusion electrode having a first side, in contact with the contents of the fourth compartment, and a second side, in contact with the contents of the first compartment. Yet in further embodiments, the anode further comprises a hydrogen oxidation catalyst layer. It is understood that the gas diffusion layer assists with maintaining a stable gas-liquid interface. It is further understood that other configurations capable of maintaining a stable gas-liquid interface other than the disclosed herein gas diffusion layer can be used. In some embodiments, the anode comprises a carbon-based gas diffusion layer, a Pt / carbon-based gas diffusion layer, an ultra-low Pt loading anode, a NAFION-coated Pt / C anode, a carbon-free Pt anode, a Pt-group metal (PGM) free anode, a fluorocarbon-based gas diffusion layer, a hydrophobic material comprising a plurality of pores, or any combination thereof. It is understood that any hydrophobic material can be utilized. In some embodiments, the gas diffusion layer can be made from the materials that are not inherently hydrophobic but can comprise a hydrophobic coating that provides the desired utility. In gas diffusion, the gas diffusion layer comprises a carbon-based paper, a carbon-based textile, a modified carbon-based paper, a modified carbon-based textile, micro-porous PTFE membrane, mesoporous PTFE membrane, macro-porous PTFE membrane, or a combination thereof. It is understood that the term “modified” as used herein refers to the disposed desired coatings on the surfaces or any other modification of the surfaces to introduce the desired surface properties. For example, the surface can be chemically, electrochemically, physically, and / or plasma modified to increase roughness, introduce the desired chemical moieties, and the like.

[0051] In still further embodiments, the hydrogen oxidation catalyst layer comprises one or more Pt group metal (PGM) or alloys thereof-based catalysts, PGM-free catalysts, and any combination thereof. In still further exemplary and unlimiting embodiments, the hydrogen oxidation catalyst layer comprises one or more of Pt / C, Pd and its alloys, Au and its alloys, Ru and its alloys, transition metal oxides and their alloys, transition metal carbides and nitrides, metal-organic frameworks, carbon-supported metal atoms, hydrogenase, hydrogenase mimic compounds, hydrogenase, or any combinations thereof.

[0052] In still further embodiments, to collect the current through both electrodes, current collectors are used for both anode and cathode. In some embodiments, the current collector can be presented as a bipolar plate, or a wire, or a plate, or any combination thereof. For example andwithout limitations, the current collector / bipolar plates can be made of graphite (plain or porous), titanium, gold or gold-coated metal plates, etc.

[0053] In still further embodiments, the electrochemical desalination system can be constructed by any known in the art methods. For example, and without limitations, each compartment can be any vessel configured to receive and retain disclosed above streams. It is understood that all materials that are used to form the electro-synthesizer unit are chemically and physically compatible with the electrolytes used in the unit as well as output streams formed in the unit compartments. In still further embodiments, each of the compartments can have any width that can accommodate the desired flow rate of the described above streams, as understood by the person skilled in the art. In some embodiments, all compartments can have the same width, while in other embodiments, some of the compartments can have the same width, and some of them can have a different width. It is understood that the desired flow rate and coulombic efficiency of the cell can determine the width of the compartment. In yet still further embodiments, the width of the compartment can be changed in the cell by introducing (or removing) additional plates, gaskets, membranes, and the like (e.g., is adjustable).

[0054] In some embodiments, the first compartment, the second compartment, the third compartment and the fourth compartment can, independently of one another, have a width of about 0.01 mm to about 500 mm, including exemplary values of about 0.05 mm, about 0.1 mm, about 0.5 mm, about 1 mm, about 5 mm, about 10 mm, about 15 mm, about 20 mm, about 25 mm, about 50 mm, about 75 mm, about 100 mm, about 125 mm, about 150 mm, about 175 mm, about 200 mm, about 250 mm, about 300 mm, about 350 mm, about 400 mm, and about 450 mm. It is understood that each compartment can, independently of the others, also have any width value that falls within any of the disclosed above values. For example, and without limitations, the width of each compartment can, independently of the others, be about 0.01 mm to about 50 mm, about 1 mm to about 10 mm, or about 5 mm to about 100 mm, and so on.

[0055] In some embodiments, the second compartment can have a width of about 0.01 mm to about 500 mm. In some embodiments, the third compartment can have a width of about 0.01 mm to about 500 mm.

[0056] In still further embodiments, each of the cathode and anode are electrically connected to a power source. In still further embodiments, the power source can provide a desired current to achieve the electrochemical reaction to produce the hydroxide ions and hydrogen in the thirdcompartment and the hydrogen ions in the first compartment at desired efficiencies, all while producing fresh water in the second compartment. In some embodiments, the current can have a current density from about 50 mA / cm2to about 500 mA / cm2, including exemplary values of about 75 mA / cm2, about 100 mA / cm2, about 125 mA / cm2, about 150 mA / cm2, about 175 mA / cm2, about 200 mA / cm2, about 225 mA / cm2, about 250 mA / cm2, about 275 mA / cm2, about 300 mA / cm2, about 325 mA / cm2, about 350 mA / cm2, about 375 mA / cm2, about 400 mA / cm2, about 425 mA / cm2, about 450 mA / cm2, and about 475 mA / cm2. In yet still further embodiments, the current density can have any value between any two foregoing values. In still further embodiments, the power source is configured to provide a desired voltage between the cathode and anode material. In such embodiments, the provided voltage can be from about 0.5 V to about 10 V, including exemplary values of about 1 V, about 1.5 V, about 2 V, about 2.5 V, about 3 V, about 3.5 V, about 4 V, about 4.5 V, about 5 V, about 5.5 V, about 6 V, about 6.5 V, about 7 V, about 7.5 V, about 8 V, about 8.5 V, about 9 V, and about 9.5 V. It is understood that any voltage having a value between any two foregoing values can be used to achieve the desired outcome.

[0057] In some embodiments, the generated hydroxide comprises one or more of sodium hydroxide, lithium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, ammonium hydroxide, amine-based bases, or any combination thereof.

[0058] In some embodiments, the electrochemical desalination system disclosed herein has a coulombic efficiency of greater than about 80%, about 85%, about 90%, about 95%, and 100%. In still other embodiments, the electrochemical desalination system disclosed herein exhibits a coulombic efficiency of substantially 100%.

[0059] Accordingly, in some embodiments, an electrochemical desalination system is described comprising a flow unit comprising: a first compartment comprising: a first inlet configured to receive a first flow of a water source comprising salt; an anode; and at least one first outlet, wherein the water source is in electrical and fluid communication with the anode, wherein the anode is configured to oxidate hydrogen gas to generate hydrogen ions in the first compartment, and wherein the at least one first outlet isconfigured to remove an acid solution comprising the generated hydrogen ions from the first compartment; a third compartment comprising: a third inlet configured to receive a third flow of the water source comprising salt; a cathode; and at least one third outlet, wherein the water source is in electrical and fluid communication with the cathode, wherein the cathode is configured to generate a hydrogen gas and a hydroxide, and wherein the at least one third outlet is configured to remove the generated hydrogen gas and / or a base solution comprising the generated hydroxide from the third compartment; a second compartment positioned between and in fluid communication with the first compartment and the third compartment, wherein the first compartment is separated from the second compartment with one or more anion exchange membranes (AEM) and the second compartment is separated from the third compartment with one or more cation exchange membranes (CEM); wherein the second compartment comprises: a second inlet configured to receive a second flow of the water source comprising salt; and an outlet configured to remove fresh water from the second compartment.In some embodiments, the electrochemical desalination can further comprise a fourth compartment comprising a fourth inlet configured to receive a stream comprising the hydrogen gas, wherein the fourth compartment is in positioned in proximity to the anode and the first compartment such that hydrogen ions are generated in the first compartment. In some embodiments, the stream comprising the hydrogen gas is directly fed from the third compailment to the fourth compartment. In some embodiments, the hydrogen gas is provided from an external source. In some embodiments, the generated in the third compailment hydrogen gas and the base solution comprising the generated hydroxide are removed from the same outlet. In some embodiments, the generated hydrogen gas stream and the base solution comprising the generated hydroxide are removed from separate outlets. In some embodiments, the anode comprises a gas diffusion layer. In some embodiments, the anode further comprises a hydrogen oxidation catalyst layer. In someembodiments, the gas diffusion layer comprises a carbon-based gas diffusion layer, a Pt / carbon- bascd gas diffusion layer, an ultra-low Pt loading anode, a NAFION-coatcd Pt / C anode, a carbon- free Pt anode, a Pt-group metal (PGM) free anode, a fluorocarbon-based gas diffusion layer, a hydrophobic material comprising a plurality of pores, or any combination thereof. In some embodiments, the hydrogen oxidation catalyst layer comprises one or more Pt group metal (PGM) or alloys thereof-based catalysts, PGM-free catalysts, and any combination thereof. In some embodiments, the cathode comprises a Pt group metal or their alloys based electrode, a Ni-and its alloys-based electrode, a NiFe-based electrode, a NiTi-based electrode, a steel-based electrode, ottransition metal sulfates-based electrode, transition metal phosphide-based electrode, Fe-based catalysts, carbon-based materials, or any combination thereof. In some embodiments, the cation and / or anion exchange membranes are polymer reinforced, wherein the polymer is inert to the water source comprising salt, the acid solution comprising the generated hydrogen ions, and the base solution comprising the generated hydroxide.

[0060] In some other embodiments of the first aspect, a desalination method is described comprising: providing an electrochemical desalination system; flowing the water source comprising salt into each of the first, second and third compartments; generating a hydrogen gas stream and hydroxide ions on the cathode in the third compartment; directing a stream comprising hydrogen gas into a fourth compartment, wherein the fourth compartment comprises a fourth inlet configured to receive a stream comprising the hydrogen gas, wherein the fourth compartment is positioned in proximity to the first compartment with the anode positioned therebetween, and wherein the hydrogen gas present in the stream is the generated hydrogen gas and / or a hydrogen gas provided from an external source; and generating hydrogen ions on the anode into the first compartment, wherein as hydrogen ions are generated in the first compartment, anions in the second compartment flow through the AEM to the first compailment and as hydroxide ions arc generated in the third compartment, cations in the second compartment flow through theCEM to the third compartment, and wherein the water flown out of the second compartment is fresh water.In some embodiments, the electrochemical desalination system comprises a flow unit comprising: a first compartment comprising: a first inlet configured to receive a first flow of a water source comprising salt; an anode; and at least one first outlet, wherein the water source is in electrical and fluid communication with the anode, wherein the anode is configured to oxidate hydrogen gas to generate hydrogen ions in the first compartment, and wherein the at least one first outlet is configured to remove an acid solution comprising the generated hydrogen ions from the first compartment; a third compartment comprising: a third inlet configured to receive a third flow of the water source comprising salt; a cathode; and at least one third outlet, wherein the water source is in electrical and fluid communication with the cathode, wherein the cathode is configured to generate a hydrogen gas and a hydroxide, and wherein the at least one third outlet is configured to remove the generated hydrogen gas and / or a base solution comprising the generated hydroxide from the third compartment; a second compartment positioned between and in fluid communication with the first compartment and the third compartment, wherein the first compartment is separated from the second compartment with one or more anion exchange membranes (AEM) and the second compartment is separated from the third compartment with one or more cation exchange membranes (CEM); wherein the second compartment comprises: a second inlet configured to receive a second flow of the water source comprising salt; and an outlet configured to remove fresh water from the second compartment.In some embodiments, the anions comprise chlorides, sulfates, nitrates, phosphates, citrates, formates, lactates, tartrates, malates, fumarates, oxalates, succinates, gluconates, ascorbates, acetates, or mixtures thereof. In some embodiments, the generated hydroxide comprises one or more of sodium hydroxide, lithium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, ammonium hydroxide, amine-based bases, or any combination thereof. In some embodiments, the cations comprise Li+, Na+, K+, Mg2+, Ca2+, and NH4+, or any combination thereof.Electrochemically Integrated Carbon Capture and Desalination (EICCD)

[0061] Carbon capture, utilization, and storage (CCUS) is a promising solution to the global challenges associated with the excessive emission of carbon dioxide (CO2). Unfortunately, significant technical barriers are still present for the development of energy-efficient methods to capture CO2, especially the dilute CO2 from air (-400 ppm). Existing carbon capture technologies typically rely on molecular adsorbents, mostly amine-based polymers, to selectively interact with CO2 in flue gas or air to achieve chemical separation. Unfortunately, this methodology is highly energy intensive because the CO2 has to be liberated and the sorbents regenerated, using temperature changes, varying pressures and / or vapor swing cycles. Moreover, typical molecular adsorbents suffer from thermal / oxidative or hydrothermal degradation during such swing cycles.

[0062] Electrochemical methods have also been developed for carbon capture. Prior art CO2 capture systems typically rely on electrochemical generation of nucleophiles that attack CO2 at the electrophilic carbon atom, forming a CO2 adduct. Then, CO2 is released in pure form via a subsequent electrochemical step. Although reversible redox pairs are superior to the thermochemical sorbents in terms of energy consumption due to relatively weak binding to CO2, the sluggish capture kinetics and high cost of such molecular sorbents are largely limiting the practical application of such strategies. On the other hand, electrochemical pumps have also been reported for CO2 capture using molten carbonate or aqueous alkaline fuel cells, but unfortunately, both also face major disadvantages.

[0063] Broadly, a second aspect relates to an EICCD which comprises a electrochemical desalination system of the first aspect, which has the capability to produce acid (e.g., HC1) and base (e.g., NaOH) from a brine or seawater (NaCl) stream while simultaneously generating fresh water (see, e.g., Figure 1A). In the EICCD system, at least a portion of the electrosynthesizedhydroxide ions from the third compartment are introduced to a contactor for CO2 capture from flue gas or air (see, e.g., Figure IB) to produce carbonates and bicarbonatcs. The carbonatc / bicarbonatc solution derived from the air contactor is then neutralized in a neutralizer, e.g., a continuously stirred-tank reactor (CSTR), upon combination with the electrosynthesized hydrogen ions (H+) (see, e.g., Figure 1C) from the first compartment. The reaction in the CSTR releases the captured CO2 as a pure gas stream and generates a stream of brackish water that can be discharged. The overall process thus results in simultaneous separation of CO2 (i.e., carbon capture in Figure IB) and production of fresh water from brine / seawater (i.e., desalination in Figure 1A).

[0064] As disclosed, at least a portion of the hydroxide-containing solution formed in the third compartment is withdrawn from the electrochemical desalination system and is fed by a line to one or more carbon dioxide-capturing apparatuses. It is understood that any known in the art capturing apparatuses can be used. For example and without limitations, any commercial carbon dioxide contactors can be utilized. In some embodiments, the contactor for CO2 capture from flue gas or air is a cross-flow air contactor. In some embodiments, the contactor is a 3M™ Liqui-Cel™ Membrane Contactor. In some embodiments, the contactor comprises the system described in copending International Patent Application No. PCT / US2023 / 071488, filed on August 2, 2023, in the name of Chao Wang and Yulin LIU and entitled “Efficient Liquid- Air Contactor in Parallel Flow Configuration,” which is hereby incorporated by reference herein in its entirety. Briefly, the at least one contactor disclosed in the PCT / US2023 / 071488 application comprises an air contactor membrane module that comprises a housing and a plurality of membranes within said housing. The plurality of membranes comprising modified polypropylene creates a barrier separating a gas phase from a liquid phase. The polypropylene material of the membranes comprises pores such that specific molecules in the gas phase can diffuse through the membrane and into the liquid phase to react with the liquid phase. The surface of the membranes is designed to be substantially hydrophobic, effectively preventing water molecules from entering the gas phase. However, this specific contactor is exemplary, and any other known contactor can be used for the desired purpose.

[0065] The captured carbon dioxide reacts with the hydroxide-containing solution to form a bicarbonate solution, carbonate solution, or a combination thereof. In still further embodiments, the one or more carbon dioxide capturing apparatuses captures CO2 and generates a gas that comprises less than about 200 ppm of carbon dioxide, less than about 100 ppm of carbon dioxide,less than about 50 ppm of carbon dioxide, or less than about 10 ppm of carbon dioxide. In yet still further embodiments, the generated gas is substantially free of carbon dioxide.

[0066] It is understood that carbon dioxide can be captured from any gas. For example, and without limitations, the gas, directed towards one or more carbon dioxide-capturing apparatuses, can comprise ambient air, industrial gas source, substantially high concentration carbon dioxide, or any combination thereof. In some embodiments, the gas source is the ambient air. In some embodiments, the gas source is the industrial gas source. In some embodiments, the gas source is a substantially high concentration of carbon dioxide. It is understood that the ambient air includes indoor and outdoor air. It is understood that industrial gas sources include any waste gas stream, any gas stream that is a by-product of any manufacturing processes, or a by-product of any industrial processes. In some embodiments, the gas source is obtained from various industrial sources that release carbon dioxide, including carbon dioxide from combustion gases of fossil- fueled power plants, e.g., conventional coal, oil and gas power plants, or IGCC (Integrated Gasification Combined Cycle) power plants that generate power by burning syngas; cement manufacturing plants that convert limestone to lime; ore processing plants; fermentation plants; and the like. In some embodiments, the gas source may comprise other gases, e.g., nitrogen, oxides of nitrogen (nitrous oxide, nitric oxide), sulfur and sulfur gases (sulfur dioxide, hydrogen sulfide), and vaporized materials. In some embodiments, the gas source is scrubbed or otherwise treated to remove at least a portion of gases other than carbon dioxide prior to flowing into the carbon dioxide-capturing apparatus. Yet, in other embodiments, the gas source is untreated prior to being flown into the carbon dioxide-capturing apparatus.

[0067] As disclosed, the EICCD system can further comprise one or more neutralizers. As can be seen in Figures 1 A-1C, the one or more neutralizers (e.g., in Figure 1C) are in fluid communication with the one or more carbon dioxide gas capturing apparatuses and one or more electrochemical desalination systems. In some embodiments, the first compartment of the one or more electrochemical desalination systems is in fluid communication with the one or more neutralizers. In such embodiments, at least a portion of the acid (H+) solution formed in the first compartment is withdrawn from the electrochemical desalination system and fed into the one or more neutralizers. It is understood that this step is aimed to neutralize at least a portion of the base solution removed from the at least one carbon dioxide-capturing apparatuses and then fed into the one or more neutralizers, wherein the base solution comprises at least one of hydroxides,bicarbonates, carbonates, or any combination thereof. In still further embodiments, if desired, the one or more neutralizers can comprise mixing means. Upon combination of at least a portion of the acid solution from the electrochemical desalination system with at least a portion of the base solution removed from the at least one carbon dioxide-capturing apparatuses, salt and pure carbon dioxide are formed. The pure carbon dioxide can be collected and used for any desired purpose. The salt can also be collected and used for any desired purpose.

[0068] In some embodiments, the one or more neutralizers comprise a continuously stirred-tank reactor.

[0069] In some embodiments, the EICCD system is a batch operation. In some embodiments, the EICCD system operates continuously. In yet still further embodiments, the EICCD system utilizes an energy source configured to operate continuously or on demand. For example, as depicted in Figure 4, in some embodiments, the electrochemical desalination systems can utilize off-peak periods when the energy is cheap. In such exemplary and unlimiting embodiments, the electrochemical desalination systems can be stopped when energy is expensive and operate only when energy is cheap. In some embodiments, the generated acids / bases can be utilized immediately, while in other embodiments, the generated acids / bases can be collected for further desired applications. In some embodiments, other parts of the system, for example, the carbon capturing apparatus and / or the one or more neutralizers, operate continuously without inteiTuptions.

[0070] In some embodiments, once in operation, the EICCD system is a recirculated-in-a-loop system that requires only a gas source feed and a seawater / brackish water feed. The seawater / brackish water can be captured when the electrochemical desalination system is in operation, and the output is fresh water and an acid and base solution that will be consumed in the neutralizer and the contactor, respectively. The CO2 in the air can be continuously captured, and the output is a pure CO2 product and salt water. In some embodiments, during the whole process, no additional chemicals are added or consumed. In some embodiments, during the whole process, a small amount of NaCl(aq) is fed into the first and third compartments at the beginning to provide initial ionic conductivity, and thereafter no additional chemicals are added or consumed.

[0071] In some embodiments, if desired, the EICCD system can further comprise a heat exchanger. In some embodiments, the heat exchanger comprises a recirculation-based system. This heat exchanger can be beneficial if the various parts of the EICCD system operate at differentenergy consumptions. For example, the one or more carbon dioxide capturing devices operate endothermically, while the one or more neutralizers operate exothermically, thus, the heat exchanger can reduce the energy usage associated with the operation of the overall EICCD system disclosed herein.

[0072] Advantageously, compared to existing carbon capture technologies, the EICCD technology takes advantage of the ambient-condition acid-base reactions to capture and release CO2, which is believed to have faster kinetics because of the barrierless reactions, be more energy-efficient because high-temperature calcination and / or pressure-swing processes are avoided, and more scalable because of the continuous flowing operations. The robust acid-base chemistries also enable the integration with electrochemical desalination, generating fresh water as a valuable byproduct to leverage the costs and improve value proposition of carbon capture systems. The whole process is fully powered by electricity and can accommodate renewable but intermittent energy sources such as solar and wind via system engineering.Alternative desalination systems

[0073] In a third aspect, alternative electrochemical desalination systems are described. Referring to Figures 6A and 6B, the alternative desalination systems are illustrated, each comprising a first compartment, a second compartment, a third compartment, an AEM, a CEM, an anode (+) and a cathode (-), arranged analogous to the electrochemical desalination system of Figure 1A, but the electrochemical desalination systems of the third aspect include the looping of all of the liquid from the first compartment to the third compartment and all of the liquid from the third compartment to the first compartment. The liquid looping results in the neutralization of the acids and bases inside the electrochemical cell, reducing the energy consumption for desalination. In some embodiments, the liquid looping occurs continuously.

[0074] In one embodiment of the third aspect, as illustrated in Figure 6A and hereinafter referred to scheme 2, the electrochemical desalination system is arranged for the oxidation of water at an anode in the first compartment and the reduction of water at the cathode in the third compartment, according to the chemical equations shown. Brackish water or seawater is introduced to three liquid compartments and a voltage can be applied between the anode (+) in contact with the anolyte in the first compartment and a cathode (-) in contact with the catholyte in the third compartment. As oxidation occurs, protons are generated in the anolyte in the first compartment and anions inthe liquid in the second compartment including, but not limited to, chlorides, sulfates, nitrates, phosphates, citrates, formates, lactates, tartrates, malates, fumarates, oxalates, succinates, gluconates, ascorbates, and acetates, or mixtures thereof, will pass through the AEM to the anolyte in the first compartment. As reduction occurs, hydroxides are generated in the catholyte in the third compartment and cations in the liquid in the second compartment including, but not limited to, Li+, Na+, K+, Mg2+, Ca2+, and NtU+, will pass through the CEM to the catholyte in the third compartment. In the second compartment, as the ions are removed to the first or third compartment, the salinity of the seawater will decrease, and fresh water can be removed therefrom.

[0075] In some embodiments, the electrochemical desalination system of scheme 2 includes means to safely collect the generated oxygen gas from the first compartment. In some embodiments, the electrochemical desalination system of scheme 2 includes means to safely collect the generated hydrogen gas from the third compartment. In some embodiments, the collected oxygen gas is packaged for commercial use. In some embodiments, the collected hydrogen gas is packaged for commercial use. In some embodiments, the collected hydrogen gas and the collected oxygen gas are reacted to produce water and energy that can be harnessed to operate the electrochemical desalination system. In some embodiments, the anode for the electrochemical desalination system of scheme 2 include dimensionally stable anodes (DSA) such as platinized titanium anodes and mixed metal oxide (MMO) coated anodes, e.g., Ir-Ru-Ox, as readily understood by the person skilled in the ail.

[0076] In some embodiments, the electrochemical desalination system of scheme 2 further comprises at least one first inlet that extends into the first compartment, at least one second inlet that extends into the second compartment, and at least one third inlet that extends into the third compartment. A stream of seawater can be introduced to each of compartments via the respective inlets. In some embodiments, it should be appreciated that the electrochemical desalination system of scheme 2 further comprises one or more outlets configured to remove an acid solution stream comprising generated hydrogen ions and / or the generated oxygen gas stream from the first compartment, at least one outlet configured to remove a water stream from the second compartment, and one or more outlets configured to remove the generated hydrogen gas stream and / or a base solution stream comprising generated hydroxide from the third compartment. In still further embodiments, while the disclosed above inlets and outlets are not shown in Figure 6A, the skilled practitioner can understand that inlet and outlet can be positioned anywhere within thecompartment to allow inflow and outflow of respective streams as described. Tn some embodiments, the generated in the third compartment hydrogen gas and the base solution can be removed from the same outlet, while in other embodiments, the generated hydrogen gas stream and the base solution can be removed from separate outlets. In some embodiments, the generated in the first compartment oxygen gas and the acid solution can be removed from the same outlet, while in other embodiments, the generated oxygen gas stream and the acid solution can be removed from separate outlets. As previously described, the electrochemical desalination system of scheme 2 includes the looping of all of the liquid from the first compartment to the third compartment and all of the liquid from the third compartment to the first compartment.

[0077] It should be appreciated that the materials of the cathode, AEM and CEM of the electrochemical desalination systems of the third aspect can be the same as the cathode, AEM and CEM of the electrochemical desalination systems of the first aspect, as described herein.

[0078] Accordingly, in some embodiments of the third apsect, an electrochemical desalination system as depicted in scheme 2 is described comprising a flow unit comprising: a first compartment comprising: a first inlet configured to receive a first flow of a water source comprising salt; an anode; and at least one first outlet, wherein the water source is in electrical and fluid communication with the anode, wherein the anode is configured to oxidate water to generate hydrogen ions and oxygen gas in the first compartment, and wherein the at least one first outlet is configured to remove the generated oxygen gas and / or acid solution comprising the generated hydrogen ions from the first compartment; a third compartment comprising: a third inlet configured to receive a third flow of the water source comprising salt; a cathode; and at least one third outlet, wherein the water source is in electrical and fluid communication with the cathode, wherein the cathode is configured to generate a hydrogen gas and a hydroxide, and wherein the at least one third outlet is configured to remove thegenerated hydrogen gas and / or a base solution comprising the generated hydroxide from the third compartment; a second compartment positioned between and in fluid communication with the first compartment and the third compartment, wherein the first compartment is separated from the second compartment with one or more anion exchange membranes (AEM) and the second compartment is separated from the third compartment with one or more cation exchange membranes (CEM); wherein the second compartment comprises: a second inlet configured to receive a second flow of the water source comprising salt; and an outlet configured to remove fresh water from the second compartment, and wherein the acid solution from the first compartment is in fluid communication with the third compartment and the base solution from the third compartment is in fluid communication with the first compartment.In some embodiments, the acid solution and the base solution are recirculated through the first compartment and the third compartment. In some embodiments, the recirculation is continuous.

[0079] In some other embodiments of the third aspect, a desalination method using the electrochemical desalination system of scheme 2 is described comprising: providing the electrochemical desalination system of scheme 2; flowing the water source comprising salt into each of the first, second and third compartments; generating a hydrogen gas stream and hydroxide ions on the cathode in the third compartment; and generating an oxygen gas stream and hydrogen ions on the anode into the first compartment, wherein as hydrogen ions are generated in the first compartment, anions in the second compartment flow through the AEM to the first compailment and as hydroxide ions are generated in the third compartment, cations in the second compartment flow through the CEM to the third compartment, wherein a catholyte comprising the hydroxide ions is in fluid communication with the first compartment, and an anolyte comprising the hydrogen ions isin fluid communication with the first compartment, and wherein the water flown out of the second compartment is fresh water.

[0080] In another embodiment of the third aspect, as illustrated in Figure 6B and hereinafter referred to scheme 3, the electrochemical desalination system is arranged for the oxidation of hydrogen gas at an anode and the reduction of water at the cathode in the third compartment, according to the chemical equations shown. In addition to the liquid looping between the first compartment and the third compartment, there is an additional hydrogen gas loop between the third compartment and the first compailment. Brackish water or seawater is introduced to three liquid compartments and a voltage can be applied between the anode (+) in contact with the anolyte in the first compartment and a cathode (-) in contact with the catholyte in the third compartment. As reduction occurs, hydroxides and hydrogen gas are generated in the catholyte in the third compartment and cations in the liquid in the second compartment including, but not limited to, Li+, Na+, K+, Mg2+, Ca2+, and NH4+, will pass through the CEM to the catholyte in the third compartment. The hydrogen gas is directed to a fourth compartment (not shown) which is separated from the first compartment by a gas diffusion electrode (GDE), similar to the electrochemical desalination system of the first aspect. As oxidation occurs at the GDE, protons are generated in the anolyte in the first compartment and anions in the liquid in the second compartment including, but not limited to, chlorides, sulfates, nitrates, phosphates, citrates, formates, lactates, tartrates, malates, fumarates, oxalates, succinates, gluconates, ascorbates, and acetates, or mixtures thereof, will pass through the AEM to the anolyte in the first compartment. In the second compartment, as the ions are removed to the first or third compartment, the salinity of the seawater will decrease, and fresh water can be removed therefrom.

[0081] In some embodiments, the electrochemical desalination system of the third scheme further comprises at least one first inlet that extends into the first compartment, at least one second inlet that extends into the second compartment, and at least one third inlet that extends into the third compartment. A stream of seawater can be introduced to each of compartments via the respective inlets. In some embodiments, it should be appreciated that the electrochemical desalination system further comprises at least one outlet configured to remove an acid solution stream comprising generated hydrogen ions from the first compartment, at least one outlet configured to remove a water stream from the second compailment, and one or more outlets configured to remove the generated hydrogen gas stream and / or a base solution stream comprisinggenerated hydroxide from the third compartment. In some embodiments, the electrochemical desalination system comprises a fourth inlet configured to receive a stream of hydrogen gas in the fourth compartment. In still further embodiments, while the disclosed above inlets and outlets are not shown in Figure 6B, the skilled practitioner can understand that inlet and outlet can be positioned anywhere within the compartment to allow inflow and outflow of respective streams as described. Further, in some embodiments, the generated in the third compailment hydrogen gas and the base solution can be removed from the same outlet, while in other embodiments, the generated hydrogen gas stream and the base solution can be removed from separate outlets. As previously described, the electrochemical desalination system of scheme 3 includes the looping of all of the liquid from the first compartment to the third compartment and all of the liquid from the third compartment to the first compailment.

[0082] It should be appreciated that the materials of the anode, cathode, AEM and CEM of the electrochemical desalination systems of the third aspect can be the same as the anode, cathode, AEM and CEM of the electrochemical desalination systems of the first aspect, as described herein.

[0083] Accordingly, in some embodiments of the third aspect, an electrochemical desalination system as depicted in scheme 3 is described comprising a flow unit comprising: a first compartment comprising: a first inlet configured to receive a first flow of a water source comprising salt; an anode; and at least one first outlet, wherein the water source is in electrical and fluid communication with the anode, wherein the anode is configured to oxidate hydrogen gas to generate hydrogen ions in the first compartment, and wherein the at least one first outlet is configured to remove an acid solution comprising the generated hydrogen ions from the first compartment; a third compartment comprising: a third inlet configured to receive a third flow of the water source comprising salt; a cathode; and at least one third outlet, wherein the water source is in electrical and fluid communication with the cathode, wherein the cathode is configured to generate a hydrogen gas and ahydroxide, and wherein the at least one third outlet is configured to remove the generated hydrogen gas and / or a base solution comprising the generated hydroxide from the third compartment; a second compartment positioned between and in fluid communication with the first compartment and the third compartment, wherein the first compartment is separated from the second compartment with one or more anion exchange membranes (AEM) and the second compartment is separated from the third compartment with one or more cation exchange membranes (CEM); wherein the second compartment comprises: a second inlet configured to receive a second flow of the water source comprising salt; and an outlet configured to remove fresh water from the second compartment, and wherein the acid solution from the first compartment is in fluid communication with the third compartment and the base solution from the third compartment is in fluid communication with the first compartment.In some embodiments, the electrochemical desalination system of scheme 3 further comprises a fourth compartment comprising a fourth inlet configured to receive a stream comprising the hydrogen gas, wherein the fourth compartment is positioned in proximity to the anode and the first compailment such that hydrogen ions are generated in the first compartment. In some embodiments, the stream comprising the hydrogen gas is directly fed from the third compartment to the fourth compartment. In some embodiments, the acid solution and the base solution are recirculated through the first compartment and the third compartment. In some embodiments, the recirculation is continuous.

[0084] In some other embodiments of the third aspect, a desalination method using the electrochemical desalination system of scheme 3 is described comprising: providing the electrochemical desalination system of scheme 3; flowing the water source comprising salt into each of the first, second and third compartments; generating a hydrogen gas stream and hydroxide ions on the cathode in the third compartment; and generating hydrogen ions on the anode into the first compartment,wherein as hydrogen ions are generated in the first compartment, anions in the second compartment flow through the AEM to the first compartment and as hydroxide ions arc generated in the third compartment, cations in the second compartment flow through the CEM to the third compartment, wherein a catholyte comprising the hydroxide ions is in fluid communication with the first compartment, and an anolyte comprising the hydrogen ions is in fluid communication with the first compartment, and wherein the water flown out of the second compartment is fresh water.In some embodiments, the electrochemical desalination system of scheme 3 further comprises a fourth compartment comprising a fourth inlet configured to receive a stream comprising the hydrogen gas, wherein the fourth compartment is positioned in proximity to the anode and the first compartment such that the hydrogen ions are generated in the first compartment. In some embodiments, the stream comprising the hydrogen gas is directly fed from the third compartment to the fourth compartment.Computer program product

[0085] The present subject matter described in the first, second or third aspect may be a system, a method, and / or a computer program product. In some embodiments, the computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present subject matter.

[0086] In some embodiments, the computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a RAM, a ROM, an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such asradio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (c.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire.

[0087] In some embodiments, computer readable program instructions described herein can be downloaded to respective computing / processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and / or a wireless network, or Near Field Communication. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and / or edge servers. A network adapter card or network interface in each computing / processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing / processing device.

[0088] In some embodiments, computer readable program instructions for carrying out operations of the present subject matter may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++, Javascript or the like, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present subject matter.

[0089] In some embodiments, the computer readable program instructions may be provided to a processor of a computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks. In some embodiments, the computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and / or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function / act specified in the flowchart and / or block diagram block or blocks.

[0090] In some embodiments, the computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0091] In light of the present disclosure and the general level of skill in the art, those of skill can appreciate that the following examples are intended to be exemplary only and that numerous changes, modifications, and alterations can be employed without departing from the scope of the presently disclosed subject matter. The synthetic descriptions and specific examples that follow are only intended for the purposes of illustration, and are not to be construed as limiting in any manner to make compounds of the disclosure by other methods.EXAMPLE 1

[0092] In a preliminary study of the electrosynthesis / desalination, synthetic seawater with a salinity of 36% was used as the brine feeding (see, Figure 3A). A volume (~50 ml) of this solution was recirculated through the second compartment of a 1-cm2electrochemical desalination system (wherein each compartment has a thick flow chamber (10 mm) for each flow stream) for continuous desalination. The cathode and anode were fed with 1 M NaCl at the beginning to provide initial ionic conductivity. When a current density of 80 mA / cm2was applied, the salinityof the output water stream from the second compartment continuously decreased, reaching nearly zero within -2 hours (sec, Figure 3B). Faradaic efficiencies (FEs) of >90% were consistently obtained from the measured pH of acidic catholyte and alkaline anolyte. Voltage of the electrosynthesizer started at 2.8-3.0 V for the initial period until the feed salinity dropped to -15%, after which the voltage began to increase due to the reduced conductivity of the desalted water in the second compartment. About 10 V was recorded when the output water reached zero salinity (<l%0).EXAMPLE 2

[0093] A 5-cm2electrochemical desalination system with serpentine flow field and ultrathin flow chambers (1.0 mm) was also prepared. The electrochemical cell can be operated at 1.3 V with 500 mA current. The outlet streams of acid and base reached the steady state of pH 0.8 and 13.6, respectively, within only about 300 sec. The overall current efficiency of the 5-cm2flow cell system was over 95%.EXAMPLE 3

[0094] Figure 5 shows the preliminary results of carbon capture from air using a 3M™ Liqui- Cel™ Membrane Contactor. The experimental conditions were 35 L / min of air and 100 mL / h of 0.2 M NaOH. Among the various parameters, air flow rate showed the greatest influence on carbon capture efficiency (CCE). About 50% CCE was achieved at 20 L / min of air (Figure 5 A) and 100 mL / h of 0.2 M NaOH (Figures 5B and 5C). This indicates that the air / liquid contact time is the main parameter governing the efficiencies of carbon capture.

Claims

CLAIMSWhat is claimed is:

1. An electrochemical desalination system comprising a flow unit comprising: a first compartment comprising: a first inlet configured to receive a first flow of a water source comprising salt; an anode; and at least one first outlet, wherein the water source is in electrical and fluid communication with the anode, wherein the anode is configured to oxidate hydrogen gas to generate hydrogen ions in the first compartment, and wherein the at least one first outlet is configured to remove an acid solution comprising the generated hydrogen ions from the first compartment; a third compartment comprising: a third inlet configured to receive a third flow of the water source comprising salt; a cathode; and at least one third outlet, wherein the water source is in electrical and fluid communication with the cathode, wherein the cathode is configured to generate a hydrogen gas and a hydroxide, and wherein the at least one third outlet is configured to remove the generated hydrogen gas and / or a base solution comprising the generated hydroxide from the third compartment; a second compartment positioned between and in fluid communication with the first compartment and the third compartment, wherein the first compartment is separated from the second compartment with one or more anion exchange membranes (AEM) and the second compartment is separated from the third compartment with one or more cation exchange membranes (CEM);wherein the second compartment comprises: a second inlet configured to receive a second flow of the water source comprising salt; and an outlet configured to remove fresh water from the second compartment.

2. The electrochemical desalination system of claim 1, further comprising a fourth compailment comprising a fourth inlet configured to receive a stream comprising the hydrogen gas, wherein the fourth compartment is in positioned in proximity to the anode and the first compartment such that hydrogen ions are generated in the first compartment.

3. The electrochemical desalination system of claim 2, wherein the stream comprising the hydrogen gas is directly fed from the third compartment to the fourth compartment.

4. The electrochemical desalination system of claim 1, wherein the hydrogen gas is provided from an external source.

5. The electrochemical desalination system of any of the preceding claims, wherein the generated in the third compartment hydrogen gas and the base solution comprising the generated hydroxide is removed from the same outlet or wherein the generated hydrogen gas stream and the base solution comprising the generated hydroxide are removed from separate outlets.

6. The electrochemical desalination system of any of the preceding claims, wherein the anode comprises a gas diffusion layer.

7. The electrochemical desalination system of claim 6, wherein the anode further comprises a hydrogen oxidation catalyst layer.

8. The electrochemical desalination system of claim 6, wherein the gas diffusion layer comprises a carbon-based gas diffusion layer, a Pt / carbon-based gas diffusion layer, an ultra-low Pt loading anode, a NAFION-coated Pt / C anode, a carbon-free Pt anode, a Pt-group metal (PGM) freeanode, a fluorocarbon-based gas diffusion layer, a hydrophobic material comprising a plurality of pores, or any combination thereof.

9. The electrochemical desalination system of claim 7, wherein the hydrogen oxidation catalyst layer comprises one or more Pt group metal (PGM) or alloys thereof-based catalysts, PGM-free catalysts, and any combination thereof.

10. The electrochemical desalination system of any of the preceding claims, wherein the cathode comprises a Pt group metal or their alloys based electrode, a Ni-and its alloys-based electrode, a NiFe-based electrode, a NiTi-based electrode, a steel-based electrode, ottransition metal sulfates- based electrode, transition metal phosphide-based electrode, Fe-based catalysts, carbon-based materials, or any combination thereof.

11. The electrochemical desalination system of any of the preceding claims, wherein the cation and / or anion exchange membranes are polymer reinforced, wherein the polymer is inert to the water source comprising salt, the acid solution comprising the generated hydrogen ions, and the base solution comprising the generated hydroxide.

12. A desalination method comprising: providing the electrochemical desalination system of claim 1; flowing the water source comprising salt into each of the first, second and third compartments; generating a hydrogen gas stream and hydroxide ions on the cathode in the third compartment; and directing a stream comprising hydrogen gas into a fourth compailment, wherein the fourth compartment comprises a fourth inlet configured to receive a stream comprising the hydrogen gas, wherein the fourth compartment is positioned in proximity to the first compartment with the anode positioned therebetween, and wherein the hydrogen gas present in the stream is the generated hydrogen gas and / or a hydrogen gas provided from an external source; generating hydrogen ions on the anode into the first compartment,wherein as hydrogen ions are generated in the first compartment, anions in the second compartment flow through the AEM to the first compartment and as hydroxide ions arc generated in the third compartment, cations in the second compartment flow through the CEM to the third compartment, and wherein the water flown out of the second compartment is fresh water.

13. The method of claim 12, wherein the anions comprise chlorides, sulfates, nitrates, phosphates, citrates, formates, lactates, tartrates, malates, fumarates, oxalates, succinates, gluconates, ascorbates, acetates, or mixtures thereof.

14. The method of claims 12 or 13, wherein the generated hydroxide comprises one or more of sodium hydroxide, lithium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, ammonium hydroxide, amine-based bases, or any combination thereof.

15. The method of any of claims 12-14, wherein the cations comprise Li+, Na+, K+, Mg2+, Ca2+, and NH4+, or any combination thereof.

16. A system comprising: one or more electrochemical desalination systems configured to produce an acid solution, a base solution, and fresh water; one or more carbon dioxide capturing apparatuses that is in fluid communication with the one or more electrochemical desalination systems and that are configured to capture a carbon dioxide from a gas source and convert the carbon dioxide to a bicarbonate solution, carbonate solution, or a combination thereof; and one or more neutralizers that is in fluid communication with the one or more electrochemical desalination systems and the one or more carbon dioxide capturing apparatuses.

17. The system of claim 16, wherein the one or more electrochemical desalination systems comprise:a first compartment comprising an anode, wherein the anode is configured to oxidate hydrogen gas to generate an acid solution comprising hydrogen ions in the first compartment; a third compartment comprising a cathode, wherein the cathode is configured to generate a hydrogen gas and a base solution comprising hydroxide ions; a second compartment positioned between and in fluid communication with the first compartment and the third compartment, wherein the first compartment is separated from the second compartment with one or more anion exchange membranes (AEM) and the second compartment is separated from the third compartment with one or more cation exchange membranes (CEM).

18. The system of claim 16, wherein the one or more electrochemical desalination system comprises a flow unit comprising: a first compartment comprising: a first inlet configured to receive a first flow of a water source comprising salt; an anode; and at least one first outlet, wherein the water source is in electrical and fluid communication with the anode, wherein the anode is configured to oxidate hydrogen gas to generate an acid solution comprising hydrogen ions in the first compartment, and wherein the at least one first outlet is configured to remove an acid solution comprising the generated hydrogen ions from the first compartment; a third compartment comprising: a third inlet configured to receive a third flow of the water source comprising salt; a cathode; and at least one third outlet, wherein the water source is in electrical and fluid communication with the cathode, wherein the cathode is configured to generate a hydrogen gas and a basesolution comprising hydroxide ions, and wherein the at least one third outlet is configured to remove the generated hydrogen gas and / or a base solution comprising the generated hydroxide from the third compartment; a second compartment positioned between and in fluid communication with the first compartment and the third compartment, wherein the first compartment is separated from the second compartment with one or more anion exchange membranes (AEM) and the second compartment is separated from the third compartment with one or more cation exchange membranes (CEM); wherein the second compartment comprises: a second inlet configured to receive a second flow of the water source comprising salt; and an outlet configured to remove fresh water from the second compartment.

19. The system of claims 17 or 18, further comprising a fourth compartment comprising a fourth inlet configured to receive a stream comprising the hydrogen gas, wherein the fourth compartment is in positioned in proximity to the anode and the first compartment such that hydrogen ions are generated in the first compartment.

20. The system of claim 19, wherein the stream comprising the hydrogen gas is directly fed from the third compartment to the fourth compartment.

21. The system of claim 16, wherein the hydrogen gas is provided from an external source.

22. The system of any of claims 16-21, wherein the generated in the third compartment hydrogen gas and the base solution comprising the generated hydroxide is removed from the same outlet or wherein the generated hydrogen gas stream and the base solution comprising the generated hydroxide arc removed from separate outlets.

23. The system of any of claims 16-22, wherein the anode comprises a gas diffusion layer.

24. The system of claim 23, wherein the anode further comprises a hydrogen oxidation catalyst layer.

25. The system of claim 23, wherein the gas diffusion layer comprises a carbon-based gas diffusion layer, a Pt / carbon-based gas diffusion layer, an ultra-low Pt loading anode, a NAFION- coated Pt / C anode, a carbon-free Pt anode, a Pt-group metal (PGM) free anode, a fluorocarbon- based gas diffusion layer, a hydrophobic material comprising a plurality of pores, or any combination thereof.

26. The system of claim 24, wherein the hydrogen oxidation catalyst layer comprises one or more Pt group metal (PGM) or alloys thereof-based catalysts, PGM-free catalysts, and any combination thereof.

27. The system of any of claims 16-26, wherein the cathode comprises a Pt group metal or their alloys based electrode, a Ni-and its alloys-based electrode, a NiFe-based electrode, a NiTi-based electrode, a steel-based electrode, ottransition metal sulfates-based electrode, transition metal phosphide-based electrode, Fe-based catalysts, carbon-based materials, or any combination thereof.

28. The system of any of claims 16-27, wherein the cation and / or anion exchange membranes are polymer reinforced, wherein the polymer is inert to the water source comprising salt, the acid solution comprising the generated hydrogen ions, and the se solution comprising the generated hydroxide.

29. The system of any one of claims 16-28, wherein at least a portion of the base solution formed in the third compartment is fed to the one or more carbon dioxide capturing apparatuses configured to capture the carbon dioxide such that the carbon dioxide is converted to the bicarbonate solution, carbonate solution, or a combination thereof by reacting the carbon dioxide from the source with the at least a portion of the base solution.

30. The system of any of claims 16-29, wherein the one or more neutralizers are in fluid communication with the one or more carbon dioxide capturing apparatuses and at least the first compartment of the one or more electrochemical desalination systems.

31. The system of any of claims 29-30, wherein at least a portion of the acid solution is fed into the one or more neutralizers and is reacted with the bicarbonate solution, carbonate solution, or a combination thereof to form a salt and a substantially high concentration carbon dioxide.

32. The system of claim 31, wherein the substantially high concentration of carbon dioxide is collected.

33. The system of any one of claims 16-32, wherein the one or more electrochemical desalination systems operate at a voltage of about 0.5 V to about 10.0 V.

34. The system of any one of claims 16-33, wherein the one or more electrochemical desalination systems generate the acid solution, the base solution, and fresh water in a batch or in a continuous operation.

35. The system of any one of claims 16-34, wherein the one or more electrochemical desalination systems generate the acid solution, the base solution, and fresh water utilizing an energy source configured to operate continuously or in the off-peak period, wherein the energy source is a conventional power grid or a renewable energy source.

36. The system of any one of claims 16-35, wherein one or more carbon dioxide capturing apparatuses comprise at least one air contactor.

37. The system of any one of claims 16-36, wherein the one or more carbon dioxide capturing apparatuses captures carbon dioxide such that a gas comprising less than about 200 ppm of carbon dioxide is generated.

38. The system of claim 37, wherein the generated gas is substantially free of carbon dioxide.

39. The system of any one of claims 16-38, wherein the gas source is an ambient air, industrial gas source, or any combination thereof.

40. A method of simultaneously desalinating brackish water or seawater and directly capturing carbon dioxide from a gas source, wherein the method comprises: providing one or more of the electrochemical desalination systems of any one of claims 16-39; electrochemically generating a hydrogen gas and a base solution comprising hydroxide ions on the cathode in the third compartment; flowing a stream comprising a generated hydrogen gas, a hydrogen gas provided by an external source, or a combination thereof, to the fourth compartment, such that an acid solution comprising electrochemically generated hydrogen ions are formed on the anode in the first compartment; and directing a portion of base solution comprising the generated hydroxide ions to one or more carbon dioxide capturing apparatuses configured to capture a carbon dioxide from a gas source by converting the carbon dioxide to a bicarbonate solution, carbonate solution, or a combination thereof, wherein as hydrogen ions are generated in the first compartment, anions in the second compartment flow through the AEM into to the first compartment and as hydroxide ions are generated in the third compartment, cations in the second compartment flow through the CEM into the third compartment, and fresh water is generated in the second compartment.

41. The method of claim 40, further comprising directing the bicarbonate solution, carbonate solution, or a combination thereof to one or more neutralizers that is in fluid communication with the one or more carbon dioxide capturing apparatuses.

42. The method of claim 41, wherein the one or more neutralizers are in fluid communication with at least the first compartment of the one or more electrochemical desalination systems.

43. The method of claims 41 or 42, wherein a portion of an acid solution comprising the generated hydrogen ions is fed into the one or more neutralizers and is reacted with the bicarbonate solution, carbonate solution, or a combination thereof, to form a salt and a substantially high concentration carbon dioxide.

44. The method of claim 43, wherein the substantially high concentration of carbon dioxide is collected.

45. The method of any one of claims 40-44, wherein the one or more electrochemical desalination systems generate the hydrogen ions in the first compartment and the hydroxide ions in the third compartment utilizing an energy source configured to operate continuously or in an off-peak period, wherein the energy source is a conventional power grid or a renewable energy source.

46. The method of any one of claims 40-45, wherein one or more carbon dioxide capturing apparatuses comprise at least one air contactor.

47. The method of any one of claims 40-46, wherein the one or more carbon dioxide capturing apparatuses captures carbon dioxide such that a gas comprising less than about 200 ppm of carbon dioxide is generated.

48. The method of claim 47, wherein the generated gas is substantially free of carbon dioxide.

49. The method of any one of claims 40-48, wherein the gas source is an ambient air, industrial gas source, or any combination thereof50. The method of any one of claims 40-49, wherein the method is carried out at room temperature.

51. The method of any one of claims 40-50, wherein the method exhibits coulombic efficiency of about 90% to 100%.

2. A electrochemical desalination system comprising a flow unit comprising: a first compartment comprising: a first inlet configured to receive a first flow of a water source comprising salt; an anode; and at least one first outlet, wherein the water source is in electrical and fluid communication with the anode, wherein the anode is configured to oxidate water to generate hydrogen ions and oxygen gas in the first compartment, and wherein the at least one first outlet is configured to remove the generated oxygen gas and / or acid solution comprising the generated hydrogen ions from the first compartment; a third compartment comprising: a third inlet configured to receive a third flow of the water source comprising salt; a cathode; and at least one third outlet, wherein the water source is in electrical and fluid communication with the cathode, wherein the cathode is configured to generate a hydrogen gas and a hydroxide, and wherein the at least one third outlet is configured to remove the generated hydrogen gas and / or a base solution comprising the generated hydroxide from the third compartment; a second compartment positioned between and in fluid communication with the first compartment and the third compartment, wherein the first compartment is separated from the second compartment with one or more anion exchange membranes (AEM) and the second compartment is separated from the third compartment with one or more cation exchange membranes (CEM); wherein the second compartment comprises: a second inlet configured to receive a second flow of the water source comprising salt; and an outlet configured to remove fresh water from the second compartment, andwherein the acid solution from the first compartment is in fluid communication with the third compartment and the base solution from the third compartment is in fluid communication with the first compartment.

53. The system of claim 52, wherein the acid solution and the base solution are recirculated through the first compartment and the third compartment.

54. The system of claims 52 or 53, wherein the recirculation is continuous.

55. A desalination method comprising: providing the electrochemical desalination system of any of claims 52 to 54; flowing the water source comprising salt into each of the first, second and third compartments; generating a hydrogen gas stream and hydroxide ions on the cathode in the third compartment; and generating an oxygen gas stream and hydrogen ions on the anode into the first compartment, wherein as hydrogen ions are generated in the first compartment, anions in the second compartment flow through the AEM to the first compailment and as hydroxide ions are generated in the third compartment, cations in the second compartment flow through the CEM to the third compartment, wherein a catholyte comprising the hydroxide ions is in fluid communication with the first compartment, and an anolyte comprising the hydrogen ions is in fluid communication with the first compartment, and wherein the water flown out of the second compartment is fresh water.

56. An electrochemical desalination system comprising a flow unit comprising: a first compailment comprising: a first inlet configured to receive a first flow of a water source comprising salt; an anode; and at least one first outlet,wherein the water source is in electrical and fluid communication with the anode, wherein the anode is configured to oxidate hydrogen gas to generate hydrogen ions in the first compartment, and wherein the at least one first outlet is configured to remove an acid solution comprising the generated hydrogen ions from the first compartment; a third compartment comprising: a third inlet configured to receive a third flow of the water source comprising salt; a cathode; and at least one third outlet, wherein the water source is in electrical and fluid communication with the cathode, wherein the cathode is configured to generate a hydrogen gas and a hydroxide, and wherein the at least one third outlet is configured to remove the generated hydrogen gas and / or a base solution comprising the generated hydroxide from the third compartment; a second compartment positioned between and in fluid communication with the first compartment and the third compartment, wherein the first compartment is separated from the second compartment with one or more anion exchange membranes (AEM) and the second compartment is separated from the third compartment with one or more cation exchange membranes (CEM); wherein the second compartment comprises: a second inlet configured to receive a second flow of the water source comprising salt; and an outlet configured to remove fresh water from the second compartment, and wherein the acid solution from the first compartment is in fluid communication with the third compartment and the base solution from the third compartment is in fluid communication with the first compartment.

57. The system of claim 56, further comprising a fourth compartment comprising a fourth inlet configured to receive a stream comprising the hydrogen gas, wherein the fourth compartment is positioned in proximity to the anode and the first compartment such that hydrogen ions are generated in the first compartment.

58. The system of claim 57, wherein the stream comprising the hydrogen gas is directly fed from the third compartment to the fourth compartment.

59. The system of any of claims 56 to 58, wherein the acid solution and the base solution are recirculated through the first compartment and the third compartment.

60. The system of claim 59, wherein the recirculation is continuous.

61. A desalination method comprising: providing the electrochemical desalination system of any of claims 56 to 60; flowing the water source comprising salt into each of the first, second and third compartments; generating a hydrogen gas stream and hydroxide ions on the cathode in the third compartment; and generating hydrogen ions on the anode into the first compartment, wherein as hydrogen ions are generated in the first compartment, anions in the second compartment flow through the AEM to the first compartment and as hydroxide ions are generated in the third compartment, cations in the second compartment flow through the CEM to the third compartment, wherein a catholyte comprising the hydroxide ions is in fluid communication with the first compartment, and an anolyte comprising the hydrogen ions is in fluid communication with the first compartment, and wherein the water flown out of the second compartment is fresh water.

62. The method of claim 61, wherein the system further comprises a fourth compartment comprising a fourth inlet configured to receive a stream comprising the hydrogen gas, wherein the fourth compartment is positioned in proximity to the anode and the first compartment such that the hydrogen ions are generated in the first compartment.

63. The method of claim 62, wherein the stream comprising the hydrogen gas is directly fed from the third compartment to the fourth compartment.

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