Mitigation of chloride ion oxidation during brine electrolysis for hydrogen production and carbon dioxide mineralization

Abstract

The present disclosure relates to a method for sequestering CO2, comprising: a first cathode chamber, conducting a first alkaline process; a first anode chamber, conducting a first acidic process; and dechlorinating a solution by contacting the solution with a dechlorinating agent. Also provided herein is a system comprising a first cathode chamber and a first anode chamber. Provided herein is a method for sequestering CO2, the method comprising an alkaline process, an acidic process, and a dechlorination process, wherein CO2 is recovered by an alkaline solution in the alkaline process, and free chlorine species produced in the acidic process are removed or reduced by the dechlorination process.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Application No. 63 / 442,292, filed January 31, 2023, and U.S. Provisional Application No. 63 / 442,295, filed January 31, 2023, the contents of each of which are incorporated herein in their entirety.

[0002] Government Funding Statement This invention was made with government support under DE-AR0001551 awarded by the U.S. Department of Energy. The government has certain rights in this invention. [Background technology]

[0003] Efficient and cost-effective means of sequestering CO2, such as through mineralization, are highly desirable as a key element in combating global climate change. Alkaline solutions react with CO2 sources to produce CO3 that can be isolated. 2- Although it is known to produce species, which are stable solids, large-scale CO2 sequestration using highly concentrated (e.g., industrially produced) alkaline solutions presents several challenges, including the cost of the alkalinizing reagent. For example, wastewater from oil and gas processing (known as "produced water") contains mineral concentrations that are higher than those found in seawater and are affected by the relative concentrations of sediments at the well site. These produced water streams offer a unique opportunity to sequester large amounts of CO2 on a volumetric basis, with the increase in CO2 sequestered per volume of treated water being proportional to the increase in mineral concentration. However, treating these waters also presents challenges to the electrolysis process described above, such as: 1) high pH gradients in the anode-cathode cell; 2) high rates / extent of chlorine oxide generation; 3) high current densities; and / or 4) precipitation of undesirable minerals (e.g., NaCl). Alternatively, alkaline solutions can be used to electrolyze water and the resulting H2O4. + (acid) and OH -The (basic) species can be efficiently prepared by separating them into acidic and basic solutions. However, the chlorine evolution reaction (ClER) is - Solutions containing ions, such as naturally occurring brine or seawater, are convenient. The undesirable ClER, which occurs in competition with the desirable oxygen evolution reaction (OER), prevents the use of such processes for large-scale CO2 capture, and more generally for seawater electrolysis for hydrogen production. Thus, there is a need for electrolysis systems for CO2 capture that mitigate the undesirable generation of free chlorine species and chlorine gas. Summary of the Invention [Means for solving the problem]

[0004] In certain aspects, provided herein are methods for sequestering CO, the methods including an alkaline process, an acidic process, and a dechlorination process, wherein the alkaline process recovers CO with an alkaline solution, and the dechlorination process removes or reduces free chlorine species produced in the acidic process. In certain embodiments, an anode that is unfavorable to the production of free chlorine species may be used.

[0005] In some aspects, provided herein are methods for sequestering CO using a high Total Dissolved Solids (TDS) salt solution, the methods including at least one of an alkaline process, an acidic process, a dechlorination process, and a deacidification process, wherein the alkaline process contacts a CO source with the alkaline solution, and the dechlorination process removes or reduces free chlorine species produced in the acidic process. In certain embodiments, a selective anode that prevents the production of free chlorine species may be used.

[0006] In certain embodiments, provided herein are methods of sequestering CO2, comprising: (a) conducting an alkaline process in a first cathode chamber, the process comprising: (i) alkalizing a first solution by contacting the first solution with a cathode disposed within the cathode chamber, thereby forming an alkaline solution and H2, wherein the first solution comprises water and divalent alkaline earth ions; (ii) contacting the alkaline solution with a source of CO2, thereby forming a carbonated solution containing a mixture of ionic compounds, wherein the ionic compounds are CO3 2- containing, (b) conducting an acidic process in the first anode chamber, the process comprising: (i) acidifying a second solution containing chloride ions by contacting the second solution with an anode disposed within the anode chamber, thereby forming an acidic solution; (ii) deacidifying the acidic solution by contacting the acidic solution with a deacidifying agent, thereby forming a deacidified solution; and (c) dechlorinating the acidic or deacidified solution by contacting the acidic or deacidified solution with a dechlorinating agent; in this case, the cathode chamber and the anode chamber are in ionic communication; The acidic process and the alkaline process may be carried out simultaneously or sequentially.

[0007] In some embodiments, provided herein are methods of sequestering CO2, comprising: (a) conducting a first alkaline process in a first cathode chamber, the process comprising: (i) alkalizing a first solution by contacting the first solution with a cathode disposed in the first cathode chamber, thereby forming an alkaline solution and producing H2, wherein the first solution comprises water and divalent alkaline earth ions; (ii) contacting the alkaline solution with a source of CO, thereby - and / or CO3 2- forming a carbonate solution containing a mixture of salts comprising: (iii) from the carbonate solution, OH - and / or CO3 2- precipitating a salt comprising (b) conducting a first acidic process in the first anode chamber, the first acidic process comprising: (i) acidifying a second solution containing chloride ions by contacting the second solution with an anode disposed in the first anode chamber, thereby forming an acidic solution; and (ii) deacidifying the acidic solution by contacting the acidic solution with a deacidifying agent, thereby forming a deacidified solution; and (c) dechlorinating the acidic or deacidified solution by contacting the acidic or deacidified solution with a dechlorinating agent; in this case, the first cathode chamber and the first anode chamber are in ionic communication; the first solution and the second solution are aqueous solutions having greater than about 8 parts per thousand (ppt) of completely dissolved solids; The first acidic process and the first alkaline process may be carried out simultaneously or sequentially.

[0008] In certain embodiments, provided herein is a system for sequestering CO2, comprising: (a) a first cathode chamber comprising: a first cathode; a first cathode gas outlet; a first solution inlet; and a first alkaline solution outlet; In this case, the first cathode is disposed within the first cathode chamber and connected to a power source; and (b) a first anode chamber comprising: a first anode; a first anode gas outlet; a second solution inlet; and a first acid solution outlet; In this case, the anode is disposed inside the anode chamber and connected to a power source; In this case, the first cathode chamber and the first anode chamber are in ionic communication. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 shows a simplified block flow diagram illustrating brine electrolysis as a carbon removal route.

[0010] [Figure 2] 1 shows the acid neutralization capacity (mol H+ / kg solute) of various exemplary deoxidizers of the present disclosure, established based on their chemical composition. Generally, as the acid neutralization capacity increases, less solute (by mass) is used.

[0011] [Figure 3] 1 shows the dechlorination capacity (mol Cl / kg solute) of various dechlorinating agents of the present disclosure, established based on their chemical composition. Generally, as the dechlorination capacity increases, less solute (mass) is used.

[0012] [Figure 4] 1 shows a schematic cross-sectional view of an exemplary flow-through single compartment electrolyzer.

[0013] [Figure 5] The pH of each effluent recorded at various times from the system shown in Figure 4 is shown.

[0014] [Figure 6] 5 shows the chemical composition of the solids precipitated from the cathode chamber of the system shown in FIG.

[0015] [Figure 7] Inorganic carbon (IC, e.g., HCO3 -, CO3 2+) concentrations over time are shown by continuously bubbling the catholyte and cathode chamber with a 400 ppm CO2 gas mixture.

[0016] [Figure 8] Chlorine concentration over time in the anolyte and (inset) an exemplary Mn oxide coated anode are shown.

[0017] [Figure 9] Results of exemplary continuous stirred reactor experiments using acidified seawater (initial pH = 2) with forsterite-olivine at various solid / liquid ratios (50, 125, 250 g / L) and a hydraulic residence time of 10 minutes are shown.

[0018] [Figure 10] FIG. 1 is a schematic diagram illustrating an exemplary carbon fixation and sequestration process described herein.

[0019] [Figure 11] FIG. 1 is a schematic diagram illustrating an exemplary carbon fixation and sequestration process described herein.

[0020] [Figure 12] FIG. 1 is a schematic diagram illustrating an exemplary carbon fixation and sequestration process described herein.

[0021] [Figure 13] The pH of each effluent recorded at various times from the system shown in Figure 4 is shown.

[0022] [Figure 14] 5 shows a photograph of the solids precipitated from the cathode chamber of the system shown in FIG.

[0023] [Figure 15] 5 shows the X-ray diffraction pattern and chemical composition of the solid precipitated from the cathode chamber of the system shown in FIG.

[0024] [Figure 16] 5 shows a scanning electron image of solids precipitated from the cathode chamber of the system shown in FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0025] Electrochemical brine alkalinization is a transformative approach for CO2 removal and / or hydrogen production. For example, carbon fixation via seawater electrolysis can address (i) the ocean-atmosphere equilibrium of gas-phase and dissolved CO2 (approximately 2 mM dissolved inorganic carbon, DIC), and (ii) the abundance of divalent alkali cations in seawater (55 mM Mg 2+ and 10.5 mM Ca 2+ ) can be utilized. These attributes can be utilized to electrochemically form carbonate and hydroxide minerals (e.g., Ca, Mg carbonates, hydroxides, and their variants), which consume dissolved CO2 and absorb additional atmospheric CO2 in the form of carbonates / bicarbonates. Electro-alkalinization does not require expensive alkaline additives (e.g., NaOH), but instead utilizes hydroxide ions (OH - This can be achieved by electrochemical pH swing of brine near a flow-through electrode surface, which generates ions that promote heterogeneous and homogeneous nucleation and growth of carbonate and hydroxide mineral precipitates. However, brine electrolysis typically involves oxidation of chloride ions and the formation of free chlorine species (Cl, ClO) at the anode. - Chlorine oxidation involves the formation of CO2, CO3, and HClO. Unless these species can be collected prior to discharge of the electrolyzer effluent, chlorine oxidation is generally harmful and should be suppressed. Provided herein are methods and systems for immobilizing CO2 as solid and aqueous carbonate and bicarbonate species while simultaneously inhibiting the chloride ion oxidation reaction via 1) upstream strategies, e.g., the use of oxygen evolution reaction (OER)-selective anodes, and / or 2) downstream strategies, e.g., chlorine capture processes. An exemplary simplified flow diagram is shown in Figure 1, with detailed strategies established on the catholyte (alkaline) and anolyte (acidic) sides, respectively.

[0026] CO2 capture using alkaline solutions Alkalinization of saltwater (e.g., seawater) involves the local generation of alkalinity (OH) at the cathode as a result of the hydrogen evolution reaction (HER): -can be induced with reasonable overpotentials (≦0.5 V) resulting in: 2H2O (l) +2e - →H 2(g) +2OH (aq) - (1)

[0027] This reaction not only produces hydrogen that can be collected as a clean fuel, but also produces alkalinity, which can then react with air or concentrated CO2 (400 ppm to 100%): CO2+OH - →HCO3 - (2) CO2+2OH - →CO3 2- +H2O (3)

[0028] Alternatively, multivalent cations (e.g., Ca 2+ , Mg 2+ If the alkali (OH - ions) combine with CO2, overcoming the obstacle to the precipitation of Ca- and Mg-based minerals. The basic reaction of calcium and magnesium ions is: Ca 2+ +CO2+2OH - →CaCO3+H2O (4) Mg 2+ +CO2+2OH - →MgCO3+H2O (5)

[0029] In most cases, CO2 is trapped in solid carbonate and / or hydroxycarbonate forms. However, since the precipitation of calcium and magnesium carbonates can be kinetically limited at low DIC concentrations (<10 mM), alkalinity can also precipitate hydroxides according to the following reaction: Ca 2+ +2OH - →Ca(OH)2+H2O (6) Mg 2+ +2OH- →Mg(OH)2+H2O (7) Its dissolution in water (e.g., seawater) also reduces atmospheric or concentrated CO2 (400 ppm to 100%) by HCO3 - / CO3 2- ions (as shown in Reactions 2-3). Strategies and conditions (e.g., direct hydroxide carbonation) for the formation of calcium and magnesium carbonates and hydroxycarbonates, such as calcite (CaCO), aragonite (CaCO), nesquehonite (MgCO 3 3H 2 O), and hydromagnesite (Mg 5 (CO 3 ) 4 (OH) 2 4H 2 O), can also be utilized, resulting in solid CO 2 mineralization. In other embodiments, carbon can be introduced into the atmosphere as dissolved (i.e., HCO 3 - / CO3 2- The alkalinity (OH) required per mole of CO2 captured and mineralized in the form of - These conditions can be achieved by equilibrating the alkalinized brine with air (i.e., 400 ppm CO2) or a concentrated CO2 stream (400 ppm to 100%), resulting in two extreme cases: (1) solid carbonate / hydroxycarbonate formation (i.e., 100% solid CO2 sequestration), and (2) aqueous CO2 sequestration. According to the former, 1 mole of CO2 produces 2 moles of hydroxyl ions (OH - ) to produce 1 mol of CaCO3, MgCO3, or other alkali metal (Na, K, etc.) carbonates and bicarbonates. In the latter case, every mole of hydroxide ion (OH-) leads to the absorption of 1-2 mol of CO2, resulting in the production of aqueous HCO3 - / CO3 2- CO2 sequestration can be carried out by using liquid-phase, gas-phase, or mixed-phase reactors for carbonation, or by placing the alkaline products (solid and solution) in soil and / or oceans to reduce atmospheric CO2. In either case, the product of CO2 sequestration should fall within the two extremes and result in a combination of solid and aqueous carbonate species.

[0030] Treatment of anode products Meanwhile, acid is produced at the anode from the oxygen evolution reaction (OER): H2O → 1 / 2O2 + 2H + +2e - (8)

[0031] In the case of salt water electrolysis (containing NaCl), the chlorine evolution reaction (ClER) occurs: 2Cl - -2e - →Cl2 (9) competes with OER at the anode. OER is thermodynamically favored (i.e., begins at a lower potential), but ClER is kinetically faster due to the fewer electron transfers involved. At large scale, Cl evolution and the formation of free chlorine species (Cl, ClO) - The formation of HClO, etc. is generally harmful and should be suppressed.

[0032] In certain embodiments, the anode is manganese oxide-based (MnO x ) anode. In certain such embodiments, ClER efficiencies of less than 20% and OER efficiencies of at least 80% are achieved to inhibit chlorine evolution. Generally, the manganese oxide can be doped or functionalized with oxides of other transition metals (e.g., Mo, W, Fe, Co, Cr, Ru, Ir, etc.) to improve selectivity and durability. Furthermore, the manganese oxide-based (MnOx-) catalysts can be directly coated (e.g., by electroplating, sol-gel coating, chemical / physical vapor deposition, calcination, etc.) onto conductive substrates (e.g., metal, metal oxide, or carbon-based) to promote anode stability and conductivity, or can be mixed with or coated onto other catalysts (e.g., pure or doped Ru oxide and Ir oxide).

[0033] Modifications to the System of the Present Disclosure Naturally enhanced aeration of the catholyte can be achieved by dumping the catholyte and produced hydroxide into the ocean or soil, ensuring effective mixing and CO2 equilibration. When released into the ocean, the catholyte can act as an alkalizing agent for seawater, promoting atmospheric CO2 reduction and countering ocean acidification. In certain embodiments, carbonation of the catholyte can be achieved using atmospheric or more concentrated CO2 streams in a separate carbonation unit or alkaline process chamber. Example results, as shown in Figures 5a-b, demonstrate that aeration of the catholyte and precipitate results in CO2 mineralization, both as solid and aqueous species, even at CO2 concentrations as low as 400 ppm (atmospheric).

[0034] Aqueous electrochemical processes and systems for carbon fixation and sequestration Several strategies can be implemented to better utilize the mineral content of the feedstream. In certain embodiments, to limit bottlenecks associated with high pH gradients, the cell can be operated at a low conversion rate per pass, recycling the partially demineralized product to the inlet. Because magnesium is largely removed in the first pass, the recycle ratio should be calculated based on the calcium to magnesium ratio. The calcium and magnesium hydroxides produced can then be exposed to carbon dioxide, converted to mineral carbonates, and the carbon dioxide sequestered. In various embodiments, this sequestration occurs in an air condenser, through a slurry or suspension separated from the product liquid, or directly through or within the product liquid.

[0035] In certain embodiments, the anolyte stream may also be neutralized before further use or disposal. In certain embodiments, an ion exchange resin is used to neutralize the resulting high pH anolyte stream. A high sodium content feed stream can be used to regenerate the resin. Free chlorine species (e.g., dissolved chlorine gas, hypochlorous acid, and chlorate ions) are minimized by electrode selection (e.g., oxygen-selective anodes) and then removed by separation. Free chlorine species reduce the capacity of the ion exchange resin.

[0036] In certain embodiments, reverse osmosis (RO) or nanofiltration (aqueous solution having a pH of about 7) at the inlet of the system provides a calcium- and magnesium-rich stream to the catholyte half of the cell and a sodium-rich stream to the ion exchange resin. Reverse osmosis and nanofiltration cannot operate at pH > 8 and high mineral concentrations because mineral scaling occurs on the membrane surface. The effect of this additional process is to reduce the amount of regenerant required for the ion exchange system, as well as potentially reducing the physical footprint of the cell.

[0037] In certain embodiments, brucite (e.g., [Mg(OH)2]) is recycled and alkalinity (e.g., OH) for calcium carbonate precipitation is added. - In certain such embodiments, the cathode may operate at a lower pH (<11), which can increase cell efficiency (e.g., by generating protons at a slower rate at the anode, recycle flows can be reduced and the physical components of the cell are less susceptible to corrosion).

[0038] In certain embodiments, the ion-selective RO permeate is fed to the electrochemical cell, and the retentate is used solely as the ion exchange regenerant. In certain such embodiments, a separate feed to the anode is used to implement a recycle stream of neutralized anolyte. In certain embodiments, the recycle rate is proportional to the rate necessary to limit the proton concentration to no more than 0.1 M or a pH below 1, thereby allowing for the desired per-pass conversion of minerals while maintaining cell efficiency.

[0039] In certain embodiments, a second electrolytic cell is used in series. The use of multiple sequential electrolytic cells produces relatively pure magnesium hydroxide in the first cell and relatively pure calcium hydroxide in the second cell, generally allowing for separation of the precipitated solids based on their pH-based solubility (i.e., by solubility gradient separation). The increased purity of the MgOH and CaOH by-products in such embodiments provides benefits, such as the production of potentially saleable products (i.e., commercial grade). In further embodiments, a process (RO or NF) to remove excess chloride ions is employed to minimize the amount of sodium chloride that co-precipitates with the product stream. In yet further embodiments, the anolyte stream is neutralized and recycled.

[0040] In certain embodiments, the free chlorine species produced by the disclosed method are used as a commercial biocide. In other embodiments, the recycled anolyte stream is dechlorinated using a dechlorinating agent prior to recycling. In yet further embodiments, the dechlorinating agent is selected from biochar, activated carbon, iron, and lignite. In certain embodiments, chlorine gas produced at the anode is converted to HCl by reaction with hydrogen (H). In further embodiments, the free chlorine species are reduced using UV light. In yet further embodiments, an oxygen-selective electrode is used that favors the chlorine evolution reaction and the oxygen evolution reaction.

[0041] In certain embodiments, provided herein are methods of sequestering CO2, comprising: (a) conducting a first alkaline process in a first cathode chamber, the process comprising: (i) alkalizing a first solution by contacting the first solution with a cathode disposed in the first cathode chamber, thereby forming an alkaline solution and producing H2, wherein the first solution comprises water and divalent alkaline earth ions; (ii) contacting the alkaline solution with a source of CO, thereby - and / or CO3 2-forming a carbonate solution containing a mixture of salts comprising: (iii) from the carbonate solution, OH - and / or CO3 2- precipitating a salt comprising (b) conducting a first acidic process in the first anode chamber, the first acidic process comprising: (i) acidifying a second solution containing chloride ions by contacting the second solution with an anode disposed in the first anode chamber, thereby forming an acidic solution; and (ii) deacidifying the acidic solution by contacting the acidic solution with a deacidifying agent, thereby forming a deacidified solution; and (c) dechlorinating the acidic or deacidified solution by contacting the acidic or deacidified solution with a dechlorinating agent; in this case, the first cathode chamber and the first anode chamber are in ionic communication; the first solution and the second solution are aqueous solutions having greater than about 8 parts per thousand (ppt) of completely dissolved solids; The first acidic process and the first alkaline process may be carried out simultaneously or sequentially.

[0042] In certain embodiments, the first and second solutions each comprise Mg and Ca. In further embodiments, the first and second solutions further comprise Na.

[0043] In some embodiments, the methods of the present disclosure further comprise: - and / or CO3 2- and isolating the salt comprising:

[0044] In certain embodiments, the disclosed methods include a solution containing an amount of fully dissolved solid matter representing the total dissolved species in the solution. Dissolved species may include inorganic and organic substances, such as, but not limited to, neutral species, molecular ions, polyatomic ions, or monatomic ions, or combinations thereof. In certain embodiments, the fully dissolved solid matter comprises magnesium. In some embodiments, the fully dissolved solid matter comprises calcium. In certain embodiments, the fully dissolved solid matter comprises magnesium and calcium. In certain embodiments, the first solution and the second solution each contain greater than about 10 parts per thousand (ppt) of fully dissolved solid matter (e.g., calcium and / or magnesium). In some embodiments, the first solution and the second solution each contain greater than about 15 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium). In certain embodiments, the first solution and the second solution each contain greater than about 20 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium). In some embodiments, the first solution and the second solution each contain greater than about 25 ppt of fully dissolved solids (e.g., calcium and / or magnesium). In certain embodiments, the first solution and the second solution each contain greater than about 30 ppt of fully dissolved solids (e.g., calcium and / or magnesium). In some embodiments, the first solution and the second solution each contain greater than about 35 ppt of fully dissolved solids (e.g., calcium and / or magnesium). In certain embodiments, the first solution and the second solution each contain greater than about 40 ppt of fully dissolved solids (e.g., calcium and / or magnesium). In some embodiments, the first solution and the second solution each contain greater than about 55 ppt of fully dissolved solids (e.g., calcium and / or magnesium). In certain embodiments, the first solution and the second solution each contain greater than about 70 ppt of fully dissolved solids (e.g., calcium and / or magnesium). In some embodiments, the first solution and the second solution each contain greater than about 85 ppt of completely dissolved solid matter (eg, calcium and / or magnesium).In certain embodiments, the first solution and the second solution each contain greater than about 100 ppt of fully dissolved solids (e.g., calcium and / or magnesium). In some embodiments, the first solution and the second solution each contain greater than about 150 ppt of fully dissolved solids (e.g., calcium and / or magnesium). In certain embodiments, the first solution and the second solution each contain greater than about 200 ppt of fully dissolved solids (e.g., calcium and / or magnesium). In some embodiments, the first solution and the second solution each contain greater than about 225 ppt of fully dissolved solids (e.g., calcium and / or magnesium). In certain embodiments, the first solution and the second solution each contain greater than about 250 ppt of fully dissolved solids (e.g., calcium and / or magnesium). In some embodiments, the first solution and the second solution each contain greater than about 500 ppt of fully dissolved solids (e.g., calcium and / or magnesium).

[0045] In certain embodiments, the first alkaline process and the first acidic process are carried out simultaneously.

[0046] In some embodiments, the anode conducts the chlorine evolution reaction (ClER) at a current of 0.001 to 100,000 A / m 2 At a current density of 1000 keV, the anode reduces to a faradaic efficiency of less than 25%. In certain embodiments, the anode is selective for the oxygen evolution reaction (OER). In further embodiments, the anode has a selectivity for the OER of greater than about 85%. In some embodiments, the anode has a selectivity for the OER of greater than about 95%. In certain embodiments, the anode has a selectivity for the OER of greater than about 98%.

[0047] In certain embodiments, the anode comprises a Group 6, Group 7, or Group 8 element. In further embodiments, the anode comprises a Group 6 element. In other embodiments, the anode comprises a Group 7 element. In some embodiments, the anode comprises a Group 8 element. In preferred embodiments, the Group 7 element is manganese. In certain embodiments, the anode comprises manganese oxide. In some embodiments, the anode further comprises a transition metal additive. In certain preferred embodiments, the anode comprises manganese oxide coated on a transition metal core. In some such embodiments, the transition metal core comprises titanium.

[0048] In some embodiments, the deoxidizing agent is selected from ion exchange resin, periclase, lime, lime kiln dust, forsterite, olivine, larnite, serpentine, basalt, stainless steel slag, peridotite, lizardite (serpentine), slag ladle, blast furnace slag, diopside, air-cooled blast furnace slag, wollastonite, converter slag, brownmillerite, co-mingled electric arc furnace slag, cement kiln dust, talc, electric arc furnace slag, Class C fly ash, recycled Class C fly ash, anorthite, trona rich fly ash, anorthite, gabbro, anorthosite, albite, and Class F fly ash. In certain preferred embodiments, the deoxidizing agent comprises Mg, Fe, Si, and O.

[0049] In certain preferred embodiments, the acid scavenger is an ion exchange resin.

[0050] In some embodiments, the dechlorinating agent is selected from hydrogen sulfide, sulfur dioxide, sulfite, copper slag, ferroolivine, ferro-silicate, magnetite, antigotite, periclase, lime, lime kiln dust, forsterite, olivine, larnite, serpentine, basalt, stainless steel slag, peridotite, lizardite, slag ladle, blast furnace slag, diopside, air-cooled blast furnace slag, wollastonite, converter slag, brownmillerite, co-mingled electric arc furnace slag, cement kiln dust, talc, electric arc furnace slag, Class C fly ash, recycled Class C fly ash, anorthite, trona rich fly ash, anorthite, gabbro, anorthosite, albite, and Class F fly ash. In certain preferred embodiments, the dechlorinating agent comprises Mg, Fe, Si, and O.

[0051] In certain preferred embodiments, the acid scavenger is a chlorine scavenger.

[0052] In some embodiments, the CO2 source comprises about 400 ppm to about 100% CO2. In certain preferred embodiments, the CO2 source comprises about 400 ppm CO2. In certain embodiments, the CO2 source is ambient air. In some embodiments, the CO2 source has the same CO2 concentration as ambient air. In other embodiments, the CO2 source has a higher CO2 concentration than ambient air, such as a gaseous effluent from an industrial process. In certain embodiments, the industrial process is selected from oil and gas production, power generation, cement production, or steel production. In some embodiments, a gaseous effluent from the industrial process is condensed, and the condensed stream is the CO2 source. In certain embodiments, the CO2 source is condensed CO2 from a direct air capture process. In some embodiments, the CO2 is nearly pure or pure CO2. In further embodiments, the CO2 source comprises greater than 90% CO2.

[0053] In certain embodiments, the first solution is an aqueous solution produced as a by-product of oil and gas extraction.

[0054] In some embodiments, the second solution is an aqueous solution produced as a by-product of oil and gas extraction.

[0055] In certain embodiments, the first solution and the second solution are derived from the same source solution.

[0056] In some embodiments, the first alkaline process and the first acidic process are carried out in a space separated by a semipermeable barrier. In certain such embodiments, the semipermeable barrier is a semipermeable membrane. In certain embodiments, the semipermeable barrier is a semipermeable membrane (e.g., a membrane made of an ion exchange material (e.g., Nafion), a hydrophilic ceramic membrane or plate (e.g., aluminum oxide, zirconium oxide, silicon dioxide, asbestos, hydrous aluminum phyllosilicate, clay, or any combination thereof), a polymer (e.g., cellulose, polyvinyl chloride, organic rubber, polyolefin, polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, epoxy resin, silicone, or any combination thereof), or a ceramic-polymer composite). In certain embodiments, the semipermeable membrane comprises polystyrene, polysulfone, polyethersulfone, polyacrylonitrile, cellulose, polyvinyl chloride, organic rubber, polyolefin, polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, epoxy resin, silicone, or a combination thereof).

[0057] In some embodiments, the alkaline solution has a pH of about 7 to about 14. In further embodiments, the alkaline solution has a pH of about 10 to about 11. In yet further preferred embodiments, the alkaline solution has a pH of about 10.5.

[0058] In certain embodiments, the acidic solution has a pH of about 0.1 to about 7. In further embodiments, the acidic solution has a pH of about 0.5 to 3.5. In yet further preferred embodiments, the acidic solution has a pH of about 1.

[0059] In some embodiments, the first acidic process and the first alkaline process are carried out at a pass conversion rate of from about 5 to about 95. In some embodiments, the first acidic process and the first alkaline process are carried out at a single pass conversion rate of from about 5 to about 95.

[0060] In certain embodiments, the methods of the present disclosure further include separating sodium from a feedstock solution to form the first and second solutions.

[0061] In some embodiments, separating sodium from the first and second solutions comprises nanofiltration or reverse osmosis. In certain embodiments, separating sodium from the first and second solutions comprises nanofiltration. In other embodiments, separating sodium from the first and second solutions comprises reverse osmosis. In certain embodiments, separating sodium from the first and second solutions comprises nanofiltration, which removes divalent ions (e.g., Mg 2+ and / or Ca 2+ ) and selectively enrich monovalent ions (e.g., Na + In some such embodiments, the nanofiltration produces a retentate having a higher ratio of divalent ions to monovalent ions (e.g., Mg) than the first and second solutions prior to nanofiltration. 2+ and / or Ca 2+ Na + (High ratio to ). As will be appreciated by those skilled in the art, nanofiltration and reverse osmosis have different ion selectivities based on the properties of the NF or RO membrane. For a detailed discussion of reverse osmosis and nanofiltration for ion separation, see, e.g., Mulder, M., Basic Principles of Membrane Technology, 2nd ed.; Springer Dordrecht, 1996, and Baker, RW, Membrane Technology and Applications, Wiley, 2004, the contents of which are incorporated herein by reference in their entireties.

[0062] In certain embodiments, separation of sodium from the feed solution produces an aqueous permeate solution and an aqueous retentate solution, and the aqueous permeate solution is used for the first solution and the second solution.

[0063] In some embodiments, deacidifying the acidic solution comprises contacting the acidic solution with an ion exchange resin. In further embodiments, the ion exchange resin is an anion exchange resin. In certain embodiments, the ion exchange resin is DuPont's Amberlite™ IRA weakly basic anion exchange resin. In other embodiments, the ion exchange resin is DuPont's Amberlite™ IRA strongly basic anion exchange resin. In certain embodiments, the ion exchange resin is a polystyrene-based microporous strongly basic anion exchange resin (e.g., Purolite™). In certain embodiments, the ion exchange resin comprises polystyrene, polysulfone, polyethersulfone, polyacrylonitrile, polytetrafluoroethylene, nylon, or polyethylene, or a combination thereof. In certain embodiments, deacidifying the acidic solution comprises contacting the acidic solution with two or more ion exchange resins, for example, a combination of two or more of the examples provided above.

[0064] In certain embodiments, the methods of the present disclosure further comprise regenerating the ion exchange resin with the aqueous retentate solution.

[0065] In some embodiments, the methods of the present disclosure further comprise adding Mg(OH) to the first solution before or during the first alkaline process.

[0066] In certain embodiments, the method of the present disclosure further comprises recirculating the deacidification solution by combining the deacidification solution with the second solution.

[0067] In some embodiments, the methods of the present disclosure further comprise conducting a second alkaline process in sequence with the first alkaline process.

[0068] In certain embodiments, the methods of the present disclosure further comprise conducting a second acidic process in sequence with the first acidic process.

[0069] In some preferred embodiments, primarily Mg(OH)2 is produced in the first alkaline process. In certain preferred embodiments, primarily Ca(OH)2 is produced in the second alkaline process. In some embodiments, the Mg(OH)2 produced in the first alkaline process and the Ca(OH)2 produced in the second alkaline process are greater than 70% pure. The Mg(OH)2 produced in the first alkaline process and the Ca(OH)2 produced in the second alkaline process are greater than about 70% pure. In certain embodiments, the Mg(OH)2 produced in the first alkaline process and the Ca(OH)2 produced in the second alkaline process are greater than about 80% pure. The Mg(OH)2 produced in the first alkaline process and the Ca(OH)2 produced in the second alkaline process are about 70% to about 100% pure.

[0070] In certain embodiments, the methods of the present disclosure further comprise separating chloride ions in situ from the Ca(OH) and Mg(OH).

[0071] In certain embodiments, provided herein is a system for sequestering CO2, comprising: (a) a first cathode chamber comprising: a first cathode; a first cathode gas outlet; a first solution inlet; and a first alkaline solution outlet; In this case, the first cathode is disposed within the first cathode chamber and connected to a power source; and (b) a first anode chamber comprising: a first anode; a first anode gas outlet; a second solution inlet; and a first acid solution outlet; In this case, the anode is disposed inside the anode chamber and connected to a power source; In this case, the first cathode chamber and the first anode chamber are in ionic communication.

[0072] In certain embodiments, the system of the present disclosure further comprises a dechlorination chamber comprising: chlorinated solution inlet, dechlorination solution outlet, Dechlorinators, In this case, the dechlorinating agent is disposed inside the dechlorinating chamber, and the chlorinated solution inlet is connected to the first acidic solution outlet.

[0073] In certain embodiments, the system of the present disclosure further comprises a deoxidation chamber comprising: Acid solution inlet, deacidification solution outlet, Deoxidizer, In this case, the deoxidizer is disposed inside the deoxidation chamber, and the acid solution inlet of the deoxidation chamber is connected to the dechlorination solution outlet.

[0074] In some embodiments, the alkaline process chamber and the acidic process chamber are separated by a separator. In certain embodiments, the separator is a semipermeable barrier, such as a semipermeable membrane (e.g., a membrane made of an ion exchange material (e.g., Nafion), a hydrophilic ceramic membrane or plate (e.g., aluminum oxide, zirconium oxide, silicon dioxide, asbestos, hydrous aluminum phyllosilicate, clay, or any combination thereof), a polymer (e.g., cellulose, polyvinyl chloride, organic rubber, polyolefin, polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, epoxy resin, silicone, or any combination thereof), or a ceramic-polymer composite). In certain embodiments, the semipermeable membrane comprises polystyrene, polysulfone, polyethersulfone, polyacrylonitrile, cellulose, polyvinyl chloride, organic rubber, polyolefin, polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, epoxy resin, silicone, or a combination thereof).

[0075] In some embodiments, the semipermeable membrane comprises polyvinylidene fluoride (PVDF). In further embodiments, the semipermeable membrane comprising PVDF has undergone a hydrophilic treatment. In yet further embodiments, the semipermeable membrane comprising PVDF has a hydrophilic coating and / or surface. In certain embodiments, the semipermeable membrane is a proton exchange ceramic membrane.

[0076] In certain embodiments, the system of the present disclosure further comprises a second cathode chamber comprising: a second cathode, a second cathode gas outlet; a first alkaline solution inlet; and a second alkaline solution outlet; In this case, the second cathode is disposed within the second cathode chamber and is connected to a power source.

[0077] In some embodiments, the system of the present disclosure further includes an ion exchange resin disposed within the deacidification chamber. In further embodiments, the ion exchange resin is an anion exchange resin. In certain embodiments, the ion exchange resin is DuPont's Amberlite™ IRA weakly basic anion exchange resin. In other embodiments, the ion exchange resin is DuPont's Amberlite™ IRA strongly basic anion exchange resin. In certain embodiments, the ion exchange resin is a polystyrene-based microporous strongly basic anion exchange resin (e.g., Purolite™). In certain embodiments, the ion exchange resin comprises polystyrene, polysulfone, polyethersulfone, polyacrylonitrile, polytetrafluoroethylene, nylon, or polyethylene, or a combination thereof. In certain embodiments, deacidifying the acidic solution includes contacting the acidic solution with two or more ion exchange resins, such as a combination of two or more of the examples provided above.

[0078] definition Unless otherwise defined herein, scientific and technical terms used in this application shall have the meanings commonly understood by those of ordinary skill in the art. Generally, the nomenclature used in connection with, and techniques of, chemistry, chemical engineering, electrical engineering, and civil engineering described herein is that which is well known and commonly used in the art.

[0079] The methods and techniques of the present disclosure are generally carried out according to conventional methods well known in the art and as described in various general and more specific references cited and described throughout the specification, unless otherwise indicated.

[0080] Chemical terms used herein, unless otherwise defined herein, are used according to conventional usage in the art, such as in "The McGraw-Hill Dictionary of Chemical Terms," ​​Parker S., Ed., McGraw-Hill, San Francisco, CA (1985).

[0081] All publications, patents, and published patent applications mentioned herein are specifically incorporated herein by reference. In case of conflict, the present specification, including specific definitions thereof, will control.

[0082] As used herein, the term "optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances in which the event or circumstance occurs and instances in which it does not occur. For example, "optionally substituted alkyl" refers to the alkyl being optionally substituted, as well as the alkyl being unsubstituted.

[0083] As used herein, the terms "olivine" and "peridotite" can refer to at least one olivine containing Mg, Fe, and SiO4, as well as any of the various members of the "olivine group," which includes olivine, teflonite, monticellite, larnite, and ferromanganese. The olivine species can further contain other elements, such as Mg, Fe, Mn, Al, Ti, Ca, Cr, Ni, and Co. Olivine can also be found in mafic and ultramafic igneous rocks.

[0084] As used herein, the terms "deacidifying," "deacidify," and "deacidification" refer to a process that results in an increase in the pH of an aqueous solution.

[0085] As used herein, "deoxidizing composition" refers to a composition that deoxidizes a substrate. Deoxidizing compositions include alkaline rocks and minerals containing carbonates, hydroxides, oxides, and / or silicates. As a non-limiting example, peridotite may be used as a deoxidizing composition in certain embodiments to deoxidize low pH solutions.

[0086] As used herein, "free chlorine species" may refer to any compound that contains or can generate chlorine atoms with oxidation states greater than or equal to 0. As non-limiting examples, free chlorine species of the present disclosure include Cl, ClO, - , and HClO.

[0087] As used herein, the terms "dechlorinate" and "dechlorination" refer to a process of removing Cl-containing compounds or ions from a substrate, e.g., an aqueous solution. In a preferred embodiment, as a non-limiting example, dechlorination involves removing free chlorine species (e.g., Cl, ClO) using a dechlorination composition. - , HClO, etc.) to chloride (Cl - ) by chemical conversion into

[0088] As used herein, the term "dechlorinating composition" refers to a composition that promotes the chemical conversion of free chlorine species to chlorides.

[0089] As used herein, the term "deacidifying and dechlorinating composition" refers to a composition that advantageously deacidifies (e.g., induces an increase in the pH of) and dechlorinates (e.g., promotes the chemical conversion of free chlorine species to chlorides) an aqueous solution.

[0090] As used herein, the term "reducing species" refers to a chemical species that interacts with another chemical species and transfers at least one valence electron to the chemical species, thereby reducing the chemical species. Reducing species may include, but are not limited to, low-valent metal species.

[0091] As used herein, the term "low valent metal species" refers to a chemical species that exists in a formal oxidation number that is less than (i.e., lower than) at least one of the most common naturally occurring non-zero oxidation states. As a non-limiting example, low valent metal species described herein include Fe 0 , Fe 2+ , Mn 0 , Mn 3+ , Mn 4+ , Ni 0 , Ni + , and Ni 3+ may be mentioned.

[0092] As used herein, the term "alkalinizing" refers to the process of increasing the pH of a given solution, for example, alkalizing a first solution to prepare an alkaline solution with a higher pH.

[0093] As used herein, the term "acidifying" or "acidification" refers to the process of lowering the pH of a given solution. The given solution may be at any starting pH before undergoing acidification; for example, the solution may already have a pH below 7 before the step of acidifying the solution is performed.

[0094] As used herein, the term "ionic communication" refers to the ability of ions to flow freely between two objects or regions of objects, e.g., between the cathode and anode chambers of an electrochemical cell, according to a local chemical gradient. Non-limiting examples of such gradients include the flow of ions from an area of ​​high potential to an area of ​​low potential, from a high ion concentration to a low ion concentration, and from a high chemical potential to a low chemical potential. In certain embodiments, two objects or regions may be physically separated (e.g., not in fluid communication) by a semipermeable barrier, yet still be in ionic communication, e.g., by ion diffusion or transport through the barrier. [Example]

[0095] The present invention will now be generally described, but the present invention will be more readily understood by reference to the following examples, which are included solely for the purpose of illustrating certain aspects and embodiments of the invention and are not intended to be limiting thereof.

[0096] Example 1: Exemplary Deoxidizers [Table 1-1] [Table 1-2]

[0097] Example 2: Results of an Exemplary CO2 Removal System An exemplary two-chamber flow-through reactor (e.g., Figure 4) was used, with a porous diaphragm used to separate the anolyte and catholyte. Seawater (prepared using Instant Ocean® salt) was used to pass through the anolyte and catholyte chambers. 316 stainless steel mesh was used as the cathode, and MnOx-coated titanium was used as the anode. In this setup, the flow rates of the catholyte and anolyte were the same and controlled by a peristaltic pump. By applying a voltage to the electrode pair, the pH of the catholyte was maintained above 10, while the pH of the anolyte was below 2 (Figure 5).

[0098] Regarding anolyte treatment, the use of manganese oxide-coated anodes (Figure 8, inset) significantly reduced chlorine oxidation during the electrolysis process by approximately 99% (Figure 8). The remaining free chlorine species (<100 ppm) can be easily dechlorinated using the aforementioned approaches or commercially available reagents (e.g., activated carbon, SO2, sulfite, etc.), ensuring that oxidized chlorine species are not generated during the large-scale carbon removal process. Furthermore, Figure 9 shows exemplary results using peridotite (forsterite) to neutralize anolyte acidity. It should be noted that over 99% of the acidity (H+) was neutralized even at a low solids loading (50 g / L) with a 10-minute hydraulic residence time.

[0099] Example 3: Results of an exemplary hydroxide production system An exemplary two-chamber flow-through reactor (e.g., Figure 4) was used, with a porous diaphragm used to separate the anolyte and catholyte. Product water (760 mM Ca, 130 mM Mg, 2.5 M Na, 4 M Cl, traces of Fe, Mn, Sr, etc.) was used to pass through the anolyte and catholyte chambers. A 316 stainless steel mesh was used as the cathode, and Pt-coated titanium was used as the anode. In this setup, the flow rates of the catholyte and anolyte were the same and controlled by a peristaltic pump. By applying a voltage to the electrode pair, the pH of the catholyte was maintained above 9, while the pH of the anolyte was below 2 (Figure 5).

[0100] After approximately 2 hours of electrolysis, precipitation at the cathode was identified as a thick layer of Ca+Mg hydroxide (Figure 6), which was later identified as primarily portlandite and blue light (Figures 7-8). The cell efficiency in producing Ca+Mg hydroxide reached 90 (±20)%. Portlandite formed even when the bulk effluent pH was below 10, due to the high Ca concentration (800 mM), and the pH near the cathode surface satisfied the conditions for Ca(OH)2 precipitation.

[0101] Incorporation by Reference All publications and patents mentioned herein are incorporated by reference in their entirety as if each individual publication or patent was specifically and individually indicated to be incorporated by reference. In case of conflict, the present application, including definitions herein, will control.

[0102] equivalent While specific embodiments of the subject disclosure have been discussed, the above specification is illustrative and not restrictive. Many variations of the invention will become apparent to those skilled in the art upon review of this specification and the following claims. The full scope of the invention should be determined by reference to the claims, along with their full scope of equivalents, and the specification, along with such variations.

Claims

1. CO ２ 1. A method for isolating a (a) in a first cathode chamber; (i) alkalizing the first solution by contacting the first solution with a cathode disposed within the cathode chamber, thereby producing an alkaline solution and H ２ wherein the first solution comprises water and divalent alkaline earth ions; (ii) dissolving the alkaline solution in CO ２ a source of ionic compounds, thereby forming a carbonate solution containing a mixture of ionic compounds, said ionic compounds being CO ３ ２－ said contacting comprising: carrying out an alkaline process, including (b) in the first anode chamber; (i) acidifying a second solution containing chloride ions by contacting the second solution with an anode disposed within the anode chamber, thereby forming an acidic solution; and (ii) deacidifying the acidic solution by contacting the acidic solution with a deacidifying agent, thereby forming a deacidified solution; performing an acidic process, including (c) dechlorinating the acidic solution or the deacidified solution by contacting the acidic solution or the deacidified solution with a dechlorinating agent; Including, the cathode chamber and the anode chamber are in ionic communication; The acidic process and the alkaline process are carried out simultaneously or sequentially. The method.

2. 10. The method according to any of the preceding claims, wherein the alkaline process and the acidic process are carried out simultaneously.

3. The anode mitigates the chlorine evolution reaction (ClER) (e.g., the anode mitigates the ClER at a rate of 0.001 to 100,000 A / m ２ 4. The method of claim 1, wherein the current density is reduced to a faradaic efficiency of less than 10%.

4. 10. The method of any preceding claim, wherein the anode comprises a group 6, 7, or 8 element.

5. The method of claim 4 wherein the anode comprises a Group 7 element.

6. 6. The method of claim 5, wherein the Group 7 element is manganese.

7. The method of claim 6 , wherein the anode comprises manganese oxide.

8. The method of any one of claims 4 to 7, wherein the anode further comprises a transition metal additive (eg, one or more transition metal additives or species).

9. The method of claim 8 , wherein the anode comprises manganese oxide coated on a transition metal substrate.

10. The method of claim 9 , wherein the transition metal substrate comprises titanium (e.g., titanium coated with a mixed metal oxide (MMO) layer).

11. 10. The method of any preceding claim, wherein the deoxidizer is selected from periclase, lime, lime kiln dust, forsterite, olivine, larnite, serpentine, basalt, stainless steel slag, peridotite, lizardite (serpentine), slag ladle, blast furnace slag, diopside, air-cooled blast furnace slag, wollastonite, converter slag, brownmillerite, co-mingled electric arc furnace slag, cement kiln dust, talc, electric arc furnace slag, Class C fly ash, recycled Class C fly ash, anorthite, trona rich fly ash, anorthite, gabbro, anorthosite, albite, and Class F fly ash.

12. 10. The method of any preceding claim, wherein the dechlorinating agent is selected from hydrogen sulfide, sulfur dioxide, sulfite, copper slag, ferroolivine, ferro-silicate, magnetite, antigotite, periclase, lime, lime kiln dust, forsterite, olivine, larnite, serpentine, basalt, stainless steel slag, peridotite, lizardite, slag ladle, blast furnace slag, diopside, air-cooled blast furnace slag, wollastonite, converter slag, brownmillerite, co-mingled electric arc furnace slag, cement kiln dust, talc, electric arc furnace slag, Class C fly ash, recycled Class C fly ash, anorthite, trona rich fly ash, anorthite, gabbro, anorthosite, albite, and Class F fly ash.

13. The method according to any one of claims 1 to 12, wherein the acid scavenger is the dechlorinator.

14. The CO ２ The source is from about 400 ppm to about 100% CO ２ 10. A method according to any preceding claim, comprising:

15. The CO ２ 10. A method according to any preceding claim, wherein the source is ambient air.

16. The CO ２ The source may be ambient air, e.g., flue gas from an industrial process, or concentrated CO from a direct air capture process. ２ Higher CO ２ The method according to any one of claims 1 to 10, wherein the concentration is

17. 10. The method of any preceding claim, wherein the first solution is selected from seawater, desalinated brine, industrial brine, and natural brine.

18. 10. The method of any preceding claim, wherein the second solution is selected from seawater, desalinated brine, industrial brine, and natural brine.

19. 10. The method of any preceding claim, wherein the first solution and the second solution are derived from the same source solution.

20. 10. The method according to any of the preceding claims, wherein the alkaline process and the acidic process are carried out in a space separated by a semi-permeable barrier.

21. 21. The method of claim 20, wherein the semi-permeable barrier is a semi-permeable membrane.

22. 10. The method of any preceding claim, wherein the alkaline solution has a pH of about 7 to about 14.

23. 23. The method of claim 22, wherein the alkaline solution has a pH of about 10 to about 11.

24. 24. The method of claim 23, wherein the alkaline solution has a pH of about 10.

5.

25. 10. The method of any preceding claim, wherein the acidic solution has a pH of about 0.1 to about 7.

26. 26. The method of claim 25, wherein the acidic solution has a pH of about 0.5 to about 1.

5.

27. 27. The method of claim 26, wherein the acidic solution has a pH of about 1.

28. CO ２ 1. A system for the isolation of (a) cathode, Cathode gas outlet, a first solution inlet; and Alkaline solution outlet, a cathode chamber comprising: (b) anode, Anode gas outlet, a second solution inlet; and acidic solution outlet, an anode chamber comprising: Including, The system wherein the cathode chamber and the anode chamber are in ionic communication.

29. moreover, Acid solution inlet, deacidification solution outlet, Deoxidizer, a deoxidation chamber comprising:

29. The system of claim 28, wherein the deoxidizer is disposed inside the deoxidizer chamber, and the acid solution inlet of the deoxidizer chamber is connected to the acid solution outlet.

30. moreover, chlorinated solution inlet, dechlorination solution outlet, Dechlorinators, a dechlorination chamber comprising:

30. The system of claim 28 or 29, wherein the dechlorinating agent is disposed inside the dechlorinating chamber, and the chlorinating solution inlet is connected to the deacidifying solution outlet, if present, or to the acidic solution outlet.

31. 31. The system of any one of claims 28 to 30, wherein the alkaline process chamber and the acidic process chamber are separated by a separator.

32. 32. The system of claim 31, wherein the separator is a semi-permeable barrier, e.g., a semi-permeable membrane (e.g., a membrane made of an ion exchange material (e.g., Nafion), a hydrophilic ceramic membrane or plate (e.g., aluminum oxide, zirconium oxide, silicon dioxide, asbestos, hydrous aluminum phyllosilicate, clay, or any combination thereof), a polymer (e.g., cellulose, polyvinyl chloride, organic rubber, polyolefin, polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, epoxy resin, silicone, or any combination thereof), or a ceramic-polymer composite).

33. CO ２ 1. A method for isolating a (a) in a first cathode chamber; (i) alkalizing the first solution by contacting the first solution with a cathode disposed in the first cathode chamber, thereby forming an alkaline solution and generating H ２ wherein the first solution comprises water and divalent alkaline earth ions; (ii) Adding the alkaline solution to CO ２ source of OH － and / or CO ３ ２－ forming a carbonate solution containing a mixture of salts comprising: (iii) from the carbonate solution, － and / or CO ３ ２－ precipitating a salt comprising performing a first alkaline process, comprising: (b) in the first anode chamber; (i) acidifying a second solution containing chloride ions by contacting the second solution with an anode disposed in the first anode chamber, thereby forming an acidic solution; and (ii) deacidifying the acidic solution by contacting the acidic solution with a deacidifying agent, thereby forming a deacidified solution; performing a first acidic process comprising: (c) dechlorinating the acidic solution or the deacidified solution by contacting the acidic solution or the deacidified solution with a dechlorinating agent; Including, the first cathode chamber and the first anode chamber are in ionic communication; the first solution and the second solution are aqueous solutions having greater than about 8 parts per thousand (ppt) of completely dissolved solids; The method, wherein the first acidic process and the first alkaline process are carried out simultaneously or sequentially.

34. 34. The method of claim 33, wherein the first solution and the second solution each contain Mg and Ca.

35. 35. The method of claim 34, wherein the first solution and the second solution further comprise Na.

36. Furthermore, OH － and / or CO ３ ２－ 36. The method of any one of claims 33 to 35, comprising isolating a salt comprising from the carbonate solution.

37. 37. The method of any one of claims 33-36, wherein the first solution and the second solution each contain greater than about 10 parts per thousand (ppt) of totally dissolved solid material (e.g., calcium and / or magnesium).

38. 38. The method of any one of claims 33-37, wherein the first solution and the second solution each contain greater than about 15 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium).

39. 39. The method of any one of claims 33-38, wherein the first solution and the second solution each contain greater than about 20 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium).

40. 40. The method of any one of claims 33-39, wherein the first solution and the second solution each contain greater than about 25 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium).

41. 41. The method of any one of claims 33-40, wherein the first solution and the second solution each contain greater than about 30 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium).

42. 42. The method of any one of claims 33-41, wherein the first solution and the second solution each contain greater than about 35 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium).

43. 43. The method of any one of claims 33-42, wherein the first solution and the second solution each contain greater than about 40 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium).

44. 44. The method of any one of claims 33-43, wherein the first solution and the second solution each contain greater than about 55 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium).

45. 45. The method of any one of claims 33-44, wherein the first solution and the second solution each contain greater than about 70 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium).

46. 46. ​​The method of any one of claims 33-45, wherein the first solution and the second solution each contain greater than about 85 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium).

47. 47. The method of any one of claims 33-46, wherein the first solution and the second solution each contain greater than about 100 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium).

48. 48. The method of any one of claims 33-47, wherein the first solution and the second solution each contain greater than about 150 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium).

49. 49. The method of any one of claims 33-48, wherein the first solution and the second solution each contain greater than about 200 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium).

50. 50. The method of any one of claims 33-49, wherein the first solution and the second solution each contain greater than about 225 ppt of totally dissolved solid matter (e.g., calcium and / or magnesium).

51. 51. The method of any one of claims 33-50, wherein the first solution and the second solution each contain greater than about 250 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium).

52. 52. The method of any one of claims 33-51, wherein the first solution and the second solution each contain greater than about 500 ppt of fully dissolved solid matter (e.g., calcium and / or magnesium).

53. 53. The method of any one of claims 33 to 52, wherein the first alkaline process and the first acidic process are carried out simultaneously.

54. The anode conducts the chlorine evolution reaction (ClER) at a current of 0.001 to 100,000 A / m ２ 54. The method of any one of claims 33 to 53, wherein the faradaic efficiency is reduced to less than 25% at a current density of

55. 55. The method of any one of claims 33 to 54, wherein the anode comprises a Group 6, 7, or 8 element.

56. 56. The method of claim 55, wherein the anode comprises a Group 7 element.

57. 57. The method of claim 56, wherein the Group 7 element is manganese.

58. 56. The method of claim 55, wherein the anode comprises manganese oxide.

59. The method of any one of claims 55 to 58, wherein the anode further comprises a transition metal additive.

60. 56. The method of claim 55, wherein the anode comprises manganese oxide coated on a transition metal core.

61. 61. The method of claim 60, wherein the transition metal core comprises titanium.

62. 62. The method of any one of claims 33 to 61, wherein the deoxidizing agent is selected from ion exchange resin, periclase, lime, lime kiln dust, forsterite, olivine, larnite, serpentine, basalt, stainless steel slag, peridotite, lizardite, slag ladle, blast furnace slag, diopside, air-cooled blast furnace slag, wollastonite, converter slag, brownmillerite, co-mingled electric arc furnace slag, cement kiln dust, talc, electric arc furnace slag, Class C fly ash, recycled Class C fly ash, anorthite, trona rich fly ash, anorthite, gabbro, anorthosite, albite, and Class F fly ash.

63. 63. The method of claim 62, wherein the acid scavenger is an ion exchange resin.

64. 64. The method of any one of claims 33 to 63, wherein the dechlorinating agent is selected from hydrogen sulfide, sulfur dioxide, sulfite, copper slag, ferroolivine, ferro-silicate, magnetite, antigotite, periclase, lime, lime kiln dust, forsterite, olivine, larnite, serpentine, basalt, stainless steel slag, peridotite, lizardite, slag ladle, blast furnace slag, diopside, air-cooled blast furnace slag, wollastonite, converter slag, brownmillerite, co-mingled electric arc furnace slag, cement kiln dust, talc, electric arc furnace slag, Class C fly ash, recycled Class C fly ash, anorthite, trona rich fly ash, anorthite, gabbro, anorthosite, albite, and Class F fly ash.

65. The method of any one of claims 33 to 64, wherein the acid scavenger is the chlorine scavenger.

66. The CO ２ The source is from about 400 ppm to about 100%, preferably 400 ppm CO ２ 66. The method of any one of claims 33 to 65, comprising:

67. The CO ２ The method of any one of claims 33 to 36, wherein the source is ambient air.

68. The CO ２ The sources include ambient air, gaseous emissions from industrial processes (e.g., oil and gas production, power generation, cement production, or steel production), and concentrated CO from direct air capture processes. ２ Higher CO ２ Concentration (e.g., near-pure or pure CO ２ 68. The method of any one of claims 33 to 67, comprising:

69. 69. The method of any one of claims 33 to 68, wherein the first solution is an aqueous solution produced as a by-product of oil and gas extraction.

70. 70. The method of any one of claims 33 to 69, wherein the second solution is an aqueous solution produced as a by-product of oil and gas extraction.

71. 71. The method of any one of claims 33 to 70, wherein the first solution and the second solution are derived from the same source solution.

72. 72. The method of any one of claims 33 to 71, wherein the first alkaline process and the first acidic process are carried out in a space separated by a semi-permeable barrier.

73. 73. The method of claim 72, wherein the semi-permeable barrier is a semi-permeable membrane.

74. 75. The method of any one of claims 33 to 74, wherein the alkaline solution has a pH of from about 7 to about 14.

75. 75. The method of claim 74, wherein the alkaline solution has a pH of about 10 to about 11.

76. 76. The method of claim 75, wherein the alkaline solution has a pH of about 10.

5.

77. 77. The method of any one of claims 33 to 76, wherein the acidic solution has a pH of from about 0.1 to about 7.

78. 78. The method of claim 77, wherein the acidic solution has a pH of about 0.5 to about 3.

5.

79. 79. The method of claim 78, wherein the acidic solution has a pH of about 1.

80. 80. The method of any one of claims 33 to 79, wherein the first acidic process and the first alkaline process are conducted at a pass conversion rate of from about 5 to about 95.

81. 81. The method of any one of claims 33 to 80, further comprising forming the first solution and the second solution by separating sodium from a source solution.

82. 82. The method of claim 81, wherein separating sodium from the first solution and the second solution comprises nanofiltration or reverse osmosis.

83. 83. The method of claim 82, wherein separating sodium from the feed solution produces a permeate solution and a retentate solution, and the permeate solution is used for the first solution and the second solution.

84. 84. The method of claim 83, wherein deacidifying the acidic solution comprises contacting the acidic solution with an ion exchange resin.

85. 85. The method of claim 84, further comprising regenerating the ion exchange resin with the aqueous retentate solution.

86. Additionally, the first solution may contain Mg(OH) ２ 86. The method of any one of claims 33 to 85, comprising adding

87. 87. The method of any one of claims 33 to 86, further comprising recirculating the deacidification solution by combining the deacidification solution with the second solution.

88. 88. The method of any one of claims 33 to 87, further comprising conducting a second alkaline process in sequence with the first alkaline process.

89. 90. The method of claim 88, further comprising conducting a second acidic process in sequence with the first acidic process.

90. Mainly Mg(OH) ２ 89. The method of claim 88, wherein:

91. Mainly Ca(OH) ２ 91. The method of claim 90, wherein:

92. The Mg(OH) produced in the first alkaline process ２ and the Ca(OH) produced in the second alkaline process. ２ 92. The method of claim 91, wherein said soluble soluble cellulose is of greater than 70% purity.

93. Furthermore, the Ca(OH) ２ and the Mg(OH) ２ 93. The method of any one of claims 89 to 92, comprising in situ separating chloride ions from the

94. CO ２ 1. A system for the isolation of (a) a first cathode; a first cathode gas outlet; a first solution inlet; and a first alkaline solution outlet; a first cathode chamber comprising: (b) a first anode; a first anode gas outlet; a second solution inlet; and a first acid solution outlet; a first anode chamber comprising: wherein the first cathode chamber and the first anode chamber are in ionic communication.

95. moreover, chlorinated solution inlet, dechlorination solution outlet, Dechlorinators, a dechlorination chamber comprising:

95. The system of claim 94, wherein the dechlorinating agent is disposed within the dechlorinating chamber and the chlorinated solution inlet is connected to the first acidic solution outlet.

96. moreover, Acid solution inlet, deacidification solution outlet, Deoxidizer, a deoxidation chamber comprising:

96. The system of claim 95, wherein the deoxidizer is disposed within the deoxidation chamber, and the acid solution inlet of the deoxidation chamber is connected to the dechlorination solution outlet.

97. 97. The system of any one of claims 94 to 96, wherein the alkaline process chamber and the acidic process chamber are separated by a separator.

98. 98. The system of claim 97, wherein the separator is a semi-permeable barrier, e.g., a semi-permeable membrane.

99. moreover, a second cathode, a second cathode gas outlet; a first alkaline solution inlet; and a second alkaline solution outlet; a second cathode chamber comprising:

99. The system of any one of claims 94 to 98, wherein the second cathode is disposed within the second cathode chamber and connected to a power source.

100. Further included is an ion exchange resin disposed within the deoxidation chamber. A system according to any one of claims 96 to 99.

101. The method of any one of claims 1 to 27 and 33 to 93, wherein the deoxidizer comprises Mg, Fe, Si, and O.

102. 102. The method of any one of claims 1 to 27, 33 to 93, and 101, wherein the deoxidizer is olivine.

103. The method according to any one of claims 1 to 27 and 33 to 93, wherein the acid scavenger is an ion exchange resin.

104. 104. The method of claim 103, wherein the ion exchange resin is an anion exchange resin.

105. 105. The method of claim 104, wherein the anion exchange resin comprises polystyrene, polysulfone, polyethersulfone, polyacrylonitrile, polytetrafluoroethylene, nylon, or polyethylene, or a combination thereof.

106. 94. The method of any one of claims 1 to 27 and 33 to 93, wherein the dechlorinating agent comprises Mg, Fe, Si, and O.

107. 107. The method of any one of claims 1 to 27, 33 to 93, and 101 to 106, wherein the first alkaline process and the first acidic process are carried out in a space separated by a semi-permeable barrier.

108. 108. The method of claim 107, wherein the semi-permeable barrier is a semi-permeable membrane.

109. 109. The method of claim 108, wherein the semipermeable membrane comprises an ion exchange material (e.g., Nafion), a hydrophilic ceramic membrane or plate (e.g., aluminum oxide, zirconium oxide, silicon dioxide, asbestos, hydrous aluminum phyllosilicate, clay, or any combination thereof), a polymer (e.g., polystyrene, polysulfone, polyethersulfone, polyacrylonitrile, cellulose, polyvinyl chloride, organic rubber, polyolefin, polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, epoxy resin, silicone, or any combination thereof), or a ceramic-polymer composite.

110. 109. The method of claim 108, wherein the semipermeable membrane comprises polyvinylidene fluoride (PVDF).

111. 111. The method of claim 110, wherein the semipermeable membrane further comprises a hydrophilic coating.

112. 109. The method of claim 108, wherein the semi-permeable membrane comprises a proton exchange ceramic membrane.

113. The system of any one of claims 28 to 32 and 93 to 100, wherein the deoxidizer comprises Mg, Fe, Si, and O.

114. 114. The system of any one of claims 28-32, 93-100, and 113, wherein the deoxidizer is olivine.

115. The system according to any one of claims 28 to 32 and 93 to 100, wherein the acid scavenger is an ion exchange resin.

116. 116. The system of claim 115, wherein the ion exchange resin is an anion exchange resin.

117. 117. The system of claim 116, wherein the anion exchange resin comprises polystyrene, polysulfone, polyethersulfone, polyacrylonitrile, polytetrafluoroethylene, nylon, or polyethylene, or a combination thereof.

118. The system of any one of claims 28 to 32 and 93 to 100, wherein the dechlorinating agent comprises Mg, Fe, Si, and O.

119. 119. The system of any one of claims 28-32, 93-100, and 113-118, wherein the alkaline process chamber and the acidic process chamber are separated by a semi-permeable barrier.

120. 120. The system of claim 119, wherein the semi-permeable barrier is a semi-permeable membrane.

121. 121. The system of claim 120, wherein the semipermeable membrane comprises an ion exchange material (e.g., Nafion), a hydrophilic ceramic membrane or plate (e.g., aluminum oxide, zirconium oxide, silicon dioxide, asbestos, hydrous aluminum phyllosilicate, clay, or any combination thereof), a polymer (e.g., polystyrene, polysulfone, polyethersulfone, polyacrylonitrile, cellulose, polyvinyl chloride, organic rubber, polyolefin, polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, epoxy resin, silicone, or any combination thereof), or a ceramic-polymer composite.

122. 121. The system of claim 120, wherein the semi-permeable membrane comprises polyvinylidene fluoride (PVDF).

123. 123. The system of claim 122, wherein the semi-permeable membrane further comprises a hydrophilic coating.

124. 121. The system of claim 120, wherein the semi-permeable membrane comprises a proton exchange ceramic membrane.

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