Electrolysis of seawater enabling the production of Mg(OH)2 and mineral fixation of CO2

Abstract

A method of producing one or more hydroxide solids includes providing a catholyte comprising an electrolyte solution, contacting the catholyte with an electroactive mesh cathode to electrolytically generate hydroxide ions, thereby precipitating one or more hydroxide solid(s), and removing the one or more hydroxide solids from the surface of the mesh on which they may be deposited.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Application No. 63 / 256,888, filed October 18, 2021, the contents of which are incorporated herein by reference in their entirety.

[0002] Statement regarding government support This invention was made with Government support under Contract No. DE-FE0031705 awarded by the U.S. Department of Energy. The Government has certain rights in this invention. [Background technology]

[0003] Ocean carbon storage is a pathway to reduce atmospheric carbon concentrations. 2 CO 3 , HCO 3 - , and CO 3 2- It is a vast reservoir of carbon, about 38,000 gigatons, stored in dissolved form as seeds. 1 Carbon capture from the oceans by forming divalent metal carbonate solids from ocean waters may reduce the carbon storage capacity due to the decrease in pH caused by this process. However, increasing the pH of ocean waters may increase this storage capacity according to Henry's law (e.g., the relationship between seawater CO2 and pH). 2 (See Figure 1A for a plot of uptake.) Thus, adding alkaline substances such as metal hydroxides to seawater could increase the pH and restore carbon storage capacity.

[0004] Industrial use of brucite (Mg(OH) 2 Magnesium oxide is obtained naturally by hydration of MgO, produced by calcination of magnesium carbonate, or by precipitation from seawater by providing alkalinity. Seawater contains large amounts of Mg, especially in the form of chlorides and sulfates. 2+ions. Thus, seawater can be a source for brucite production. There is a need for an efficient method for producing brucite from marine water. Additionally, there is a need for a method for increasing the pH of marine water, particularly as part of a carbon capture process. Summary of the Invention [Means for solving the problem]

[0005] The present disclosure relates to hydroxide solids, particularly Mg(OH). 2 Methods for Producing Solids In some embodiments, the present disclosure provides a method for producing one or more hydroxide solids, comprising: providing a catholyte comprising an electrolyte solution; contacting the catholyte with an electroactive mesh cathode to electrolytically generate hydroxide ions, thereby precipitating one or more hydroxide solids; The present invention provides a method comprising:

[0006] In some embodiments, the electrolyte solution includes a divalent metal cation. In certain embodiments, the electrolyte solution includes Mg2+ ions, Ca2+ ions, or both Mg2+ ions and Ca2+ ions. In particularly preferred embodiments, the divalent cation includes Mg2+ ions.

[0007] In certain embodiments, the electrolyte solution comprises salt water or seawater. Preferably, the electrolyte solution comprises seawater.

[0008] In certain embodiments, the salt water or seawater comprises NaCl in the salt water or seawater at a concentration of about 1,000 ppm or more, about 2,000 ppm or more, about 3,000 ppm or more, about 4,000 ppm or more, about 5,000 ppm or more, about 6,000 ppm or more, about 7,000 ppm or more, about 8,000 ppm or more, about 9,000 ppm or more, about 10,000 ppm or more, about 15,000 ppm or more, about 20,000 ppm or more, about 25,000 ppm or more, or about 30,000 ppm or more, about 35,000 ppm or more, about 40,000 ppm or more, about 45,000 ppm or more, about 50,000 ppm or more, about 55,000 ppm or more, or about 60,000 ppm or more. Preferably, the NaCl concentration is greater than or equal to about 35,000 ppm.

[0009] In certain embodiments, the electrolyte solution has a Ca equivalent concentration or Mg equivalent concentration of about 2 ppm or more, about 10 ppm or more, about 50 ppm or more, about 100 ppm or more, about 200 ppm or more, about 300 ppm or more, about 400 ppm or more, about 500 ppm or more, about 600 ppm or more, about 700 ppm or more, about 800 ppm or more, about 900 ppm or more, about 1000 ppm or more, about 1100 ppm or more, about 1200 ppm or more, about 1300 ppm or more, about 1400 ppm or more, or about 1500 ppm or more. Preferably, the electrolyte solution has a Mg equivalent concentration of about 1000 ppm or more.

[0010] In some embodiments, the one or more hydroxide solids are Mg(OH), Ca(OH), 2 , or Mg(OH) 2 and Ca(OH) 2 Preferably, the one or more hydroxide solids are Mg(OH) 2 Includes.

[0011] In some embodiments, the electroactive mesh cathode comprises a rotating disk cathode, hi certain embodiments, the rotating disk cathode has an electroactive mesh disposed thereon.

[0012] In some embodiments, the method further comprises removing one or more hydroxide solids from the surface of the mesh. In certain embodiments, removing one or more hydroxide solids from the surface of the mesh comprises scraping the surface of the mesh.

[0013] In some embodiments where the cathode is a rotating disk cathode, removing one or more hydroxide solids from the surface of the screen comprises rotating the rotating disk cathode past a scraper.

[0014] In certain embodiments, the electroactive reticulated cathode comprises a metallic composition, a non-metallic composition, or a hybrid of a metallic composition and a non-metallic composition.

[0015] In some embodiments, the electroactive mesh cathode comprises stainless steel, titanium oxide, carbon nanotubes, one or more polymers, graphite, or a combination thereof. Preferably, the mesh cathode comprises stainless steel.

[0016] In some embodiments, the electroactive meshwork comprises pores having diameters ranging from about 0.1 μm to about 10,000 μm.

[0017] In some embodiments, the method includes forming an alkalized effluent having a pH greater than 9, and in other embodiments, a pH greater than 10.

[0018] In some embodiments, the anolyte comprises an acid. In certain embodiments, the acid has a pH of less than about 6.

[0019] In some embodiments, the method further includes providing a partition separating the catholyte and the anolyte, hi some embodiments, the partition comprises a polymer such as cellulose, polyvinyl chloride, an organic rubber, a polyolefin, polyethylene, polypropylene, or any combination thereof.

[0020] In another embodiment, the method further comprises circulating the anolyte through the neutralization pool. The neutralization pool may comprise mafic material, ultramafic material, calcium-rich fly ash, slag, or any combination thereof.

[0021] In some embodiments, the electrolytic generation of hydroxide ions is greater than 50 μA / cm 2 It is carried out at a higher current density. [Brief description of the drawings]

[0022] [Figure 1A] 1 shows a plot of seawater CO2 uptake capacity versus pH. [Figure 1B] A plot of the improvement in CO2 uptake capacity of seawater due to the dissolution of Mg(OH)2 is shown. [Diagram 2] FIG. 1 shows a schematic diagram of a brucite mineralization reactor according to various embodiments. [Figure 3A] 1 shows a plot of brucite formation and removal rate per liter of seawater as a function of current density. [Figure 3B] A scanning electron microscope (SEM) image of brucite precipitates formed on the cathode is shown. [Figure 3C] 1 shows the X-ray diffraction (XRD) pattern of the brucite precipitate formed on the cathode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The process according to the present disclosure uses brucite (Mg(OH)) to increase ocean alkalinity and promote the dissolution of atmospheric carbon dioxide. 2 ) precipitate. Such processes include, but are not limited to, those disclosed in International Application No. PCT / US22 / 35289, filed June 28, 2022, International Application No. PCT / US20 / 37629, filed June 12, 2020, and U.S. Application No. 17 / 722036, filed April 15, 2022, which are incorporated herein by reference in their entireties.

[0024] As shown in Figure 1A, increasing the pH of seawater increases the H 2 CO 3 , HCO 3 - and CO 3 2- According to the equilibrium constants describing the speciation of ions, and Henry's law, the carbon storage capacity of seawater increases. In particular, the dissolution of alkaline (e.g., calcium- and magnesium-rich) solids into the ocean surface favorably increases the pH and CO 2 Allows additional uptake of CO 2 Uptake (CO2 incorporated into the solid product per mass of the initial solid or liquid material) 2 or dissolved ions) is the mass of gas CO 2 It measures the efficiency of a material to sequester CO into stable solid or dissolved ions. 2 By promoting the uptake of anthropogenic gaseous CO 2 can be removed in an impactful way.

[0025] As shown in Figure 1B, brucite (Mg(OH) 2 ) may be added to seawater until equilibrium is reached, resulting in a pH of 9.1, compared to a typical seawater pH of 8.2, due to the presence of dissolved CO 2 This corresponds to an increase of about three times in the total amount of CO2 produced by the brucite dissolution. Industrial brucite can be obtained naturally, for example by hydration of MgO produced by calcining magnesium carbonate, or by precipitation from seawater with an alkaline supply. Figure 1B shows the CO2 reduction enhanced by the dissolution of brucite. 2 The absorption capacity is approximately 1.6 moles of atmospheric CO per mole of dissolved brucite. 2 Absorption can be promoted.

[0026] In this disclosure, metal hydroxide solids such as brucite may be produced by an electrochemical process using seawater containing about 55 mmol Mg per liter or other Mg-rich saltwater as a feedstock. In some embodiments, a membrane-less reactor may be used to produce the brucite precipitate. Advantages of such membrane-less reactors may include lower energy requirements, reduced maintenance and operating costs, and reduced production costs as scale increases.

[0027] In some embodiments, a method according to the present disclosure includes providing a catholyte comprising an electrolyte solution and contacting the catholyte with an electroactive mesh cathode to electrolytically generate hydroxide ions, thereby precipitating one or more hydroxide solids.

[0028] In some embodiments, the method further comprises removing the one or more hydroxide solids from the surface of the mesh on which they may accumulate.

[0029] CO 2 The mineral immobilization process can be accomplished by alkalizing a near-neutral Ca- and Mg-containing solution (e.g., seawater, alkali-metal-rich groundwater, industrial wastewater, or desalinated brine). In some embodiments, the method uses a single-chamber continuous stirred tank reactor (CSTR). Operating parameters such as voltage, current density, and hydraulic retention time ("HRT") are selected to minimize the hydroxylation energy intensity of the design.

[0030] Turning to FIG. 2, a membraneless reactor useful for implementing certain embodiments of the present invention is shown. The membraneless electrolysis reactor 200 was conceptualized to electrochemically precipitate hydroxide solids from the catholyte. In some embodiments, the hydroxide formation process can be advantageously accomplished by alkalizing a near-neutral Ca- and Mg-containing solution, such as seawater, alkali-metal-rich groundwater, industrial wastewater, or desalinated brine. The inventors used a single-chamber continuous stirred tank reactor (CSTR) to evaluate the feasibility of the conceptualized multi-chamber reactor. Operational parameters (e.g., voltage, current density, and hydraulic residence time ("HRT")) may also be selected to demonstrate the carbonation energy intensity of the design.

[0031] 2, the reactor 200 includes a reservoir 405 containing a catholyte, such as seawater, alkali metal-rich groundwater, industrial wastewater, desalinated brine, or the like. The reactor further includes an anolyte inlet 203 and an outlet 211. An electrode assembly 206 is in fluid contact with the aqueous separator reservoir 205 and includes a rotating disk cathode 207 and an anode 209 separated by a partition layer 208. The rotating disk cathode 207 (e.g., a 316L stainless steel mesh) may rotate about an axis 202 to pass product through a scraper 210 for removal and collection. The reactor may further include a neutralization pool 212. O 2 may be generated at the anode 209, and O 2 It may be released at outlet 213. 2 may be generated at the rotating disk cathode 207, and H 2 It may be discharged at outlet 214 .

[0032] In an embodiment including a rotating disk cathode, inducing precipitation of carbonate solids includes rotating a cylinder containing an electroactive mesh in the solution while drawing the solution onto the exterior surface of the mesh.

[0033] The electrolyte may be partitioned with a porous partition for the following reasons: (1) the neutralization reaction between the anolyte and catholyte is minimized, allowing a stable catholyte pH for effective mineral immobilization; (2) the separated electrolyte promotes higher energy efficiency of the reactor; and (3) the gas stream (H 2 and O 2 ) may need to be split and collected separately.

[0034] 2, an online pH monitoring system may be used, for example, to control the applied current so that the catholyte pH is constant or above 9. The anolyte, in some embodiments, may provide:

[0035] In some embodiments, the reactor includes a catholyte and an anolyte. The catholyte may be an electrolyte solution configured to flow around or through the cathode. The anolyte may be an electrolyte configured to flow around or through the anode. The catholyte may include an electrolyte solution.

[0036] In some embodiments, the electrolyte solution contains Mg 2+ , Ca 2+ , or Mg 2+ and Ca 2+ In a particularly preferred embodiment, the electrolyte solution contains a divalent metal cation, such as Mg 2+ Contains ions.

[0037] In some embodiments, the electrolyte solution comprises seawater or salt water. Preferably, the electrolyte is seawater. In some embodiments, the electrolyte solution has a NaCl concentration of about 1,000 ppm or more, about 2,000 ppm or more, about 3,000 ppm or more, about 4,000 ppm or more, about 5,000 ppm or more, about 6,000 ppm or more, about 7,000 ppm or more, about 8,000 ppm or more, about 9,000 ppm or more, about 10,000 ppm or more, about 15,000 ppm or more, about 20,000 ppm or more, about 25,000 ppm or more, or about 30,000 ppm or more, about 35,000 ppm or more, about 40,000 ppm or more, about 45,000 ppm or more, about 50,000 ppm or more, about 55,000 ppm or more, or about 60,000 ppm or more, or more, or any range or value therebetween. In a preferred embodiment, the electrolyte solution has a NaCl concentration of about 35,000 ppm or greater.

[0038] In some embodiments, the catholyte solution has a Ca equivalent or Mg equivalent concentration of about 2 ppm or more, about 10 ppm or more, about 50 ppm or more, about 100 ppm or more, about 200 ppm or more, about 300 ppm or more, about 400 ppm or more, about 500 ppm or more, about 600 ppm or more, about 700 ppm or more, about 800 ppm or more, about 900 ppm or more, about 1000 ppm or more, about 1100 ppm or more, about 1200 ppm or more, about 1300 ppm or more, about 1400 ppm or more, or about 1500 ppm or more. Preferably, the catholyte solution has a Mg equivalent concentration of about 1000 ppm or more. Ca equivalent and Mg equivalent refer to salts of Ca and Mg in the electrolyte solution. Preferably, the salts are chloride salts or sulfate salts.

[0039] In some embodiments, the anolyte comprises an acid. In some embodiments, the anolyte has a pH of less than about 7, less than about 6, less than about 4, less than about 3, less than about 2, or less than about 1. In certain embodiments, the anolyte has a pH of about 1 to about 6, about 1 to about 5, about 1 to about 4, about 1 to about 3, or about 1 to about 2.

[0040] In some embodiments, the one or more hydroxide solids are Mg(OH). 2 , Ca(OH) 2 , or Mg(OH) 2 and Ca(OH) 2 In a particularly preferred embodiment, the one or more hydroxide solids include Mg(OH) 2 (also referred to herein as brucite).

[0041] In some embodiments, the cathode 207 comprises an electroactive mesh. In some embodiments, the electroactive mesh comprises a metallic composition or a non-metallic composition, or a combination of metallic and non-metallic compositions. In some embodiments, the electroactive mesh comprises, consists essentially of, or consists of a metallic mesh or a carbon-based mesh. In some embodiments, the electroactive mesh comprises stainless steel, titanium oxide, carbon nanotubes, polymers, and / or graphite, or other hybrid compositions of these materials. Preferably, the electroactive mesh comprises stainless steel.

[0042] In some embodiments, the electroactive meshwork comprises pores having diameters ranging from about 0.01 μm to about 10,000 μm (e.g., about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 1000, 1500, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, or 10,000 μm, or any range therebetween).

[0043] In some embodiments, the cathode 207 (e.g., 316L stainless steel mesh) is an OER- (oxygen evolution reaction) selective anode (e.g., MnO 2 Together with the coating Pt), it produces alkaline and acidic properties.

[0044] In some embodiments, the method further comprises removing one or more hydroxide solids from the surface of the mesh. In a preferred embodiment, the one or more hydroxide solids are removed by a scraping process. The scraping process may use a metal brush, blade, or high pressure nozzle. In certain embodiments where the cathode is a rotating disk cathode, the one or more hydroxide solids from the surface of the mesh may be removed from the surface of the mesh by rotating the rotating disk cathode past a scraper.

[0045] In some embodiments, the reactor further includes a partition 208 that separates the anolyte from the catholyte. In some embodiments, the partition includes cellulose, polyvinyl chloride, organic rubber, polyolefin, polyethylene, polypropylene, any other suitable material, or a combination thereof. The partition separates the catholyte and anolyte to: (1) minimize neutralization reactions between the anolyte and catholyte, resulting in a stable catholyte pH required for brucite formation, (2) increase the energy efficiency of the reactor, and (3) allow the gas stream (H 2 and O 2 ) to facilitate collection.

[0046] A pH monitoring system may be used, for example, to control the applied current to achieve a constant cathode pH. For example, in some embodiments, the catholyte pH is maintained above 9, e.g., about 9.5-9.6. The stainless steel cathode may be covered with a hydrophobic mesh (e.g., a polypropylene (PP) mesh) as a hydroxide catalyst, thereby electrolytically generating hydroxide ions at the cathode. The catholyte may be a 200-2500 sulphuric acid (200-2500 sulphuric acid) solution. 2+ OH ions are electrolytically generated - Reacts with ions to form Mg(OH) 2 The operating parameters, including current density and hydraulic residence time (HRT), may be optimized. Within a reasonable HRT (e.g., seconds to minutes), Mg(OH) 2 The production of is promoted at high current densities. In some embodiments, the current density is 50 μA / cm 2 Ultra, 100μA / cm2 Ultra, 200μA / cm 2 Ultra, 300μA / cm 2 Ultra, 400μA / cm 2 or greater than 5000μA / cm 2 In addition, high current densities may also result in an alkalized effluent (e.g., a pH greater than about 9, or greater than about 10), which may increase the CO2 content of the anolyte source, such as seawater. 2 It can be advantageously used to improve recovery capacity.

[0047] In some embodiments, the PP covered stainless steel cathode may be rotated past a scraper (e.g., metal brush, blade, or high pressure nozzle) to remove the hydroxide, thereby regenerating the cathode for subsequent hydroxide generation as the wheel spins back into the liquid. In some embodiments, a nozzle sprayer may be used to forcefully strip off the precipitated hydroxide.

[0048] In some embodiments, the anolyte is circulated to a neutralization pool 212 containing calcium-rich fly ash, slag, or any combination thereof, and the acidity thus produced can be consumed to restore alkalinity. The Ca-rich fly ash and minerals advantageously reduce the amount of Ca in the anolyte. 2+ It may also be used to concentrate

[0049] As shown in Figures 3A-C, Mg(OH) 2The formation of a scale on the cathode surface allows for easy removal by a simple scraping process. Figure 3A shows the plot of brucite production rate and removal rate per liter of seawater as a function of current density. Higher current density results in lower concentration of brucite produced and higher removal rate. Figure 3B shows a scanning electron microscope (SEM) image of brucite precipitate formed on the cathode mesh. The formed brucite is thick, brittle, and has well-defined cracks, which helps to facilitate its ease of removal. Figure 3C shows the X-ray diffraction (XRD) plot of the formed precipitate. The XRD plot shows the formation of brucite as the same peaks are observed between the precipitate and the brucite.

[0050] As used herein, the singular terms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to an object may include plural objects unless the context clearly dictates otherwise.

[0051] As used herein, the term "set" refers to a collection of one or more objects. Thus, for example, a set of objects can include a single object or multiple objects.

[0052] As used herein, the terms "substantially" and "about" are used to describe and take into account slight variations. When used with an event or circumstance, the term can refer to instances where the event or circumstance occurs exactly as well as instances where the event or circumstance occurs approximately. For example, when used with a numerical value, the term can encompass a variation range of ±10% or less of the numerical value, such as ±5% or less, ±4% or less, ±3% or less, ±2% or less, ±1% or less, ±0.5% or less, ±0.1% or less, or ±0.05% or less.

[0053] As used herein, the term "size" refers to a characteristic dimension of an object. Thus, for example, the size of a circular object can refer to the diameter of the object. In the case of a non-circular object, the size of the non-circular object can refer to the diameter of the corresponding circular object, which exhibits or has a particular set of derivable or measurable characteristics that are substantially the same as those of the non-circular object. Alternatively, or relatedly, the size of a non-circular object can refer to the average of the object's various orthogonal dimensions. Thus, for example, the size of an object that is an ellipse can refer to the average of the object's major and minor axes. When referring to a collection of objects as having a particular size, it is contemplated that the objects may have a distribution of sizes around the particular size. Thus, as used herein, the size of a collection of objects can refer to a typical size of the distribution of sizes, such as the mean size, the median size, or the peak size.

[0054] Furthermore, amounts, ratios, and other numerical values ​​may be presented in the form of a range herein. It is to be understood that such range formats are used for convenience and brevity, and should be understood flexibly to include not only the numerical values ​​explicitly specified as the limits of the range, but also to include all individual numerical values ​​or subranges subsumed within the range, as if each numerical value and subrange were explicitly specified. For example, a ratio in the range of about 1 to about 200 should be understood to include not only the explicitly specified limits of about 1 and about 200, but also individual ratios such as about 2, about 3, and about 4, and subranges such as about 10 to about 50, about 20 to about 100.

[0055] Although the present disclosure has been described with reference to specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made and equivalents substituted without departing from the true spirit and scope of the present disclosure as defined by the appended claims. In addition, many modifications may be made to adapt a particular situation, material, composition, method, operation(s) to the objective, spirit and scope of the present disclosure. All such modifications are intended to be within the scope of the appended claims. In particular, although a particular method may be described with reference to certain operations performed in a particular order, it will be understood that these operations may be combined, sub-divided, or reordered to form equivalent methods without departing from the teachings of the present disclosure. Thus, unless otherwise indicated herein, the order and grouping of operations are not limitations of the present disclosure.

[0056] The embodiments illustratively described herein may be suitably implemented in the absence of any element(s), limitation(s) not specifically disclosed herein. Thus, for example, terms such as "comprising", "including", "containing" and the like are intended to be interpreted broadly without limitation. Furthermore, the terms and expressions employed herein are used as terms of description rather than limitation, and the use of such terms and expressions is not intended to exclude the features shown and described or equivalents of portions thereof, but is recognized to be capable of various modifications within the scope of the claimed technology. Furthermore, the term "consisting essentially of" is understood to include the specifically described elements and additional elements that do not materially affect the basic and novel characteristics of the claimed technology. The term "consisting of" is intended to exclude any elements not specified.

[0057] References 1.Renforth, P.;Henderson, G.Assessing Ocean Alkalinity for Carbon Sequestration. Rev.Geophys.2017,55(3),636-674.https: / / doi.org / 10.1002 / 2016RG000533. 2.Kheshgi, HS Sequestering Atmospheric Carbon Dioxide by increasing Ocean Alkalinity.Energy 1995,20(9),915-922.https: / / doi.org / 10.1016 / 0360-5442(95)00035-F.

[0058] Incorporation by Reference All publications and patents mentioned herein are herein 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.

[0059] Equivalent While specific embodiments of the subject invention have been described, 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 claims that follow. 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. 1. A process for producing one or more hydroxide solids, comprising: providing a catholyte comprising an electrolyte solution; and contacting said catholyte with an electroactive mesh cathode to electrolytically generate hydroxide ions, thereby precipitating said one or more hydroxide solids; The method comprising:

2. The method of claim 1 , wherein the electrolyte solution comprises a divalent metal cation.

3. The divalent cation is Mg ２＋ , Ca ２＋ , or Mg ２＋ and Ca ２＋ 3. The method of claim 2, wherein the ions of

4. The method of any one of claims 1 to 3, wherein the electrolyte solution comprises salt water or seawater.

5. The NaCl concentration in the saltwater or seawater is about 1,000 ppm or more, about 2,000 ppm or more, about 3,000 ppm or more, about 4,000 ppm or more, about 5,000 ppm or more, about 6,000 ppm or more, about 7,000 ppm or more, about 8,000 ppm or more, about 9,000 ppm or more, about 10,000 ppm or more, about 15,000 ppm or more, or 5. The method of claim 4, wherein the concentration of the soluble solids is about 100 ppm or more, about 20,000 ppm or more, about 25,000 ppm or more, or about 30,000 ppm or more, about 35,000 ppm or more, about 40,000 ppm or more, about 45,000 ppm or more, about 50,000 ppm or more, about 55,000 ppm or more, or about 60,000 ppm or more.

6. 4. The method of any one of claims 1 to 3, wherein the electrolyte solution has a Ca or Mg equivalent concentration of about 2 ppm or more, about 10 ppm or more, about 50 ppm or more, about 100 ppm or more, about 200 ppm or more, about 300 ppm or more, about 400 ppm or more, about 500 ppm or more, about 600 ppm or more, about 700 ppm or more, about 800 ppm or more, about 900 ppm or more, about 1000 ppm or more, about 1100 ppm or more, about 1200 ppm or more, about 1300 ppm or more, about 1400 ppm or more, or about 1500 ppm or more.

7. The one or more hydroxide solids are Mg(OH) ２ , Ca(OH) ２ , or Mg(OH) ２ and Ca(OH) ２ The method according to any one of claims 1 to 3, comprising both of the steps of:

8. 4. The method of any one of claims 1 to 3, wherein the electroactive mesh cathode comprises a rotating disk cathode having an electroactive mesh disposed thereon.

9. The method of any one of claims 1 to 3, further comprising removing the one or more hydroxide solids from the surface of the mesh.

10. 10. The method of claim 9, wherein removing the one or more hydroxide solids from the surface of the mesh comprises scraping the surface of the mesh or forcing a solution across the surface of the mesh.

11. 10. The method of claim 9, wherein removing the one or more hydroxide solids from the surface of the mesh comprises rotating the spinning disk cathode over a scraper, metal brush, or blade.

12. The method of any one of claims 1 to 3, wherein the mesh cathode comprises stainless steel, titanium oxide, carbon nanotubes, one or more polymers, graphite, or a combination thereof.

13. The method of any one of claims 1 to 3, wherein the electroactive meshwork is composed of pores having diameters ranging from about 0.1 μm to about 10,000 μm.

14. The method of any one of claims 1 to 3, further comprising forming an alkalized effluent having a pH greater than 9.

15. The method of any one of claims 1 to 3, wherein the anolyte comprises an acid.

16. 16. The method of claim 15, wherein the anolyte has a pH of less than about 6.

17. The method of any one of claims 1 to 3, further comprising providing a partition separating the catholyte and the anolyte.

18. The method of claim 17 , wherein the septum comprises a polymer.

19. 20. The method of claim 18, wherein the septum comprises cellulose, polyvinyl chloride, organic rubber, polyolefin, polyethylene, polypropylene, or any combination thereof.

20. The method of any one of claims 1 to 3, further comprising circulating the anolyte to a neutralization pool.

21. 21. The method of claim 20, wherein the neutralization pool comprises mafic material, ultramafic material, calcium-rich fly ash, slag, or any combination thereof.

22. Electrolytic generation of hydroxide ions is performed at 50 μA / cm ２ The method according to any one of claims 1 to 3, wherein the method is carried out at a current density of more than 23. An electrolysis reactor comprising: An electrode assembly disposed within the electrolysis reactor, the electrode assembly comprising: an anode; a cathode; an electrode assembly, the anode in communication with the cathode; a catholyte chamber in communication with the cathode; an anolyte inlet and an anolyte outlet communicating with the anode; an electrolysis reactor comprising: Including, the system.

24. The system of claim 23, wherein the system is configured to produce one or more hydroxide solids.

25. The system of claim 23, further comprising a neutralization pool containing an alkaline material and coupled to the anolyte outlet.

26. The system of claim 23, wherein the cathode comprises an electroactive mesh.

27. ​​A system described in any one of claims 23 to 25, wherein the cathode comprises stainless steel, titanium oxide, carbon nanotubes, graphite, or a combination thereof, or one or more polymers.

28. A system described in any one of claims 23 to 25, wherein a partition layer is disposed between the anode and cathode.

29. The system of any one of claims 23 to 25, further comprising an H 2 outlet in fluid communication with the cathode and an O 2 outlet in fluid communication with the anode.

30. The system of any one of claims 23 to 25, further comprising a hydroxide ion production and precipitation zone.

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