Selective manganese extraction and recovery from aqueous solutions using NANO-titanate absorbents

Abstract

Selective manganese extraction and recovery from aqueous solutions containing manganese ions via adsorption on nano-titanate materials may use alkali or alkaline-earth or transition metal titanates having the chemical formulas X2TiO2 or YTiO2 (where X is an element with a valence of 1+ and Y is an element with a valence of 2+) at the nano-crystalline domain range that preferentially adsorb manganese cations from aqueous solutions with different pH. Recovery of the adsorbed manganese cations includes washing the manganese-saturated adsorbent with a flow of an aqueous acidic solution, which can be polished to obtain a concentrated solution of a manganese salt that can be crystalized to obtain manganese chloride, manganese nitrite, manganese sulfate or a carboxylic acid salt of manganese. The polishing can also be accomplished by precipitating from the solution a manganese oxide solid, like MnO2, by oxidation of the original cation present in the recovery acidic brine.

Description

Attorney Docket No.: 5317.002WO1 SELECTIVE MANGANESE EXTRACTION AND RECOVERY FROM AQUEOUS SOLUTIONS USING NANO-TITANATE ABSORBENTS BACKGROUND

[0001] Manganese ranks as one of the most prevalent transition metals in the Earth’s crust, following iron and titanium. It is widely distributed across the globe, appearing in various geological formations such as rocks, soils, and even bodies of water. Typically, manganese is encountered in association with other chemical elements within mineral compounds. Examples of these minerals include pyrolusite (MnO2), rhodochrosite (MnCO3), romanechite ((Ba,H2O)2(Mn4+,Mn3+)5O10), manganite (MnO(OH)), and hausmannite (Mn3O4).

[0002] Manganese, functioning both as an element and alloying agent, possesses diverse industrial applications. In the realm of steel production, manganese assumes a pivotal role. It imparts corrosion resistance, enhances strength and hardness, all while avoiding brittleness. Additionally, manganese serves as a deoxidizer, preventing rust formation and minimizing material shrinkage, thereby contributing to the preservation of steel’s integrity and longevity.

[0003] The incorporation of manganese into steel piping offers several advantages, particularly within the domain of martensitic steel, a variety of steel known for its ability to be strengthened through heat treatment. These advantages include improved hardenability, whereby manganese facilitates more efficient quenching during heat treatment, resulting in a harder and stronger material, making it especially pertinent for applications demanding high strength and wear resistance.

[0004] Furthermore, the inclusion of manganese contributes to overall strength by increasing tensile and yield strength. This makes the steel more suitable for demanding applications, such as pipelines that must endure high pressure and external stresses. Additionally, manganese enhances the toughness and ductility of martensitic steel, mitigating its brittleness and making it less prone to fracturing or cracking under impact or sudden loading conditions, thereby ensuring the integrity of steel piping systems.

[0005] Moreover, manganese can improve the corrosion resistance of steel, particularly in specific environmental conditions. Although martensitic steel is not as inherently corrosion- resistant as certain stainless-steel variants, the addition of manganese enhances its resistance to certain forms of corrosion, making it suitable for various applications, including those in corrosive environments.

[0006] Manganese also enhances the workability of steel during the manufacturing process, aiding in hot working, forging, and machining, which simplifies the fabrication of steel pipingAttorney Docket No.: 5317.002WO1 components for manufacturers. Additionally, its cost-effectiveness and abundant availability make manganese an attractive option for improving steel properties without significantly increasing production costs.

[0007] Furthermore, manganese is compatible with heat treatment processes, such as quenching and tempering, often used with martensitic steel, helping achieve desired mechanical properties while maintaining dimensional stability. Lastly, manganese contributes to enhanced wear resistance, a critical factor for applications where steel piping is subjected to abrasion, erosion, or sliding wear, particularly in industries like mining and oil and gas where abrasive materials encounter the piping infrastructure.

[0008] The benefits of incorporating manganese into martensitic steel piping vary depending on the desired properties and intended applications. Careful consideration of alloy composition, including manganese content and other alloying elements, is crucial to achieve the desired balance of properties for a specific use. Manganese steel, also known as Hadfield steel or mangalloy, is a type of steel alloy with a relatively high manganese content, typically ranging from 11% to 15%. These alloys are renowned for their exceptional toughness, wear resistance, and work-hardening properties, making them suitable for a range of applications.

[0009] Manganese steel with around 13–14% manganese content is commonly used for railway tracks due to its high strength, wear resistance, and ability to withstand heavy loads. Railway tracks endure constant wear and impact from trains, and manganese steel helps extend their lifespan.

[0010] For safes, manganese steel with approximately 12–14% manganese is employed, as it offers extreme strength and resistance to drilling, cutting, and impact. The high manganese content provides enhanced durability and security, making it challenging for burglars to breach the safe.

[0011] Rifle barrels made from manganese steel, typically containing 12–14% manganese, exhibit excellent wear resistance and strength, crucial properties for firearm barrels that must withstand high pressure and friction during firing.

[0012] In correctional facilities, prison bars made from manganese steel, usually with 11–14% manganese content, are chosen for their exceptional strength and toughness, capable of withstanding vandalism attempts or escape efforts, providing enhanced security.

[0013] Additionally, manganese is added to aluminum alloys used in can production, typically around 1.5%, to improve their resistance to corrosion. This is essential for preserving the contents of aluminum cans, such as beverages, by preventing can corrosion and preserving product quality.Attorney Docket No.: 5317.002WO1

[0014] In all these applications, manganese steel alloys are selected for their specific properties, surpassing those of regular steel with lower manganese content. These properties include high strength, wear resistance, toughness, and corrosion resistance, depending on the application’s requirements. Manganese steel’s unique ability to work-harden, becoming harder and tougher through use, makes it particularly valuable in applications where prolonged wear or impact resistance is crucial.

[0015] Manganese is a vital micro-nutrient essential for both plant growth and photosynthesis, significantly influencing crop quality and yield. Although plants require manganese in smaller quantities compared to macronutrients like nitrogen, phosphorus, and potassium, its role in various physiological processes is indispensable.

[0016] Manganese plays a crucial part in photosynthesis, contributing to crop quality and yield through several key mechanisms: (1) Photosynthesis: Manganese is integral to the photosynthetic process, where plants convert sunlight into energy (sugars) and oxygen. It serves essential functions within photosynthesis, including oxygen evolution and participation in the electron transport chain. (2) Enzyme Activation: Manganese acts as a cofactor for various enzymes involved in plant metabolism, facilitating processes such as polyamine synthesis and the detoxification of reactive oxygen species (ROS) generated during photosynthesis. (3) Nutrient Uptake and Transport: Manganese aids in the efficient uptake and distribution of essential nutrients like iron and phosphorus within the plant, ensuring their availability in tissues, particularly in the leaves where photosynthesis occurs. (4) Chlorophyll Production: Manganese contributes to the synthesis of chlorophyll, the pigment responsible for capturing light energy during photosynthesis. (5) Stress Tolerance: Adequate manganese levels enhance a plant’s ability to withstand environmental stressors like intense light, drought, and diseases, resulting in healthier and higher-yielding crops.

[0017] In summary, as a micro-nutrient, manganese is indispensable for optimizing the photosynthetic machinery in plants. It plays a critical role in energy production, oxygen generation, and the formation of organic compounds necessary for plant growth and crop quality. Ensuring plants have sufficient access to manganese, whether through soil amendments or fertilization, leads to improved photosynthetic activity, enhanced stress tolerance, and ultimately, higher-quality and more productive agricultural yields.

[0018] Manganese plays a significant role in the production of batteries, particularly in batteries that use alkaline metals and dry-cell batteries. In alkaline batteries, manganese dioxide (MnO2) is a crucial component in alkaline batteries, commonly used in various consumer electronics such as remote controls, flashlights, toys, and portable devices. Manganese dioxideAttorney Docket No.: 5317.002WO1 serves as the cathode material, which is one of the two electrodes in a battery where reduction (gain of electrons) occurs during discharge. During the discharge process of an alkaline battery, the manganese dioxide undergoes an electrochemical reaction in which it acts as an oxidizing agent. It reacts with zinc (the anode material) and potassium hydroxide (the electrolyte) to produce electricity, water, and zinc oxide. This reaction generates electrical energy that powers the device. Alkaline batteries are known for their relatively high energy density, meaning they can provide a significant amount of electrical energy for their size and weight. Manganese dioxide contributes to this energy density due to its ability to efficiently participate in the electrochemical reactions. Furthermore, alkaline batteries have a long shelf life, partly because manganese dioxide is a stable compound that does not readily self-discharge, allowing these batteries to be stored for extended periods without significant loss of power.

[0019] Dry-cell batteries, such as zinc-carbon batteries, are commonly employed in applications like flashlights, radios, and clocks. In zinc-carbon dry-cell batteries, manganese dioxide serves as a depolarizer, helping maintain a balance of chemical reactions within the battery to ensure efficient energy production. Manganese dioxide plays a vital role in improving the performance of zinc-carbon batteries by preventing the accumulation of hydrogen gas at the anode. Hydrogen gas buildup can interfere with battery operation, and manganese dioxide helps mitigate this issue. Zinc-carbon dry-cell batteries are known for their cost-effectiveness, making them a popular choice for everyday devices. Manganese’s availability and relatively low cost contribute to the affordability of these batteries.

[0020] As described above, manganese is a critical component in the cathode materials of alkaline batteries, where it facilitates the electrochemical reactions that produce electrical energy. Additionally, in dry-cell batteries like zinc-carbon batteries, manganese dioxide acts as a depolarizer, helping to maintain efficient battery performance. Its availability, stability, and effectiveness in these battery types make manganese an essential element in the production of various portable power sources used in everyday consumer electronics.

[0021] The demand for manganese is poised for continual growth over time. Among the prevalent methods employed for its extraction, mining predominantly stands out as the primary means to procure the ores containing manganese. It is a recognized fact that mining operations exert a notable environmental footprint due to the necessity of rock extraction, coupled with the inadvertent release of byproducts into nearby water bodies such as streams, rivers, or lakes. This, in turn, has the potential to disrupt both local ecosystems and the well-being of inhabitants in proximity, potentially resulting in detrimental health consequences.Attorney Docket No.: 5317.002WO1

[0022] Manganese is an essential nutrient for living organisms; however, an excessive accumulation of it can yield adverse health effects. Extensive research has been conducted to delineate the repercussions of manganese excess on living organisms. Elevated manganese levels have been linked to oxidative stress in vital organs such as gills, kidneys, liver, and the brain, as well as disruptions to the immune system and testicular apoptosis. Moreover, it can impact dopamine regulation, giving rise to neurotoxicity and hepatoxicity, locomotor deficiencies, inflammatory intestinal damage, mitochondrial dysfunction, genotoxicity, and other deleterious effects. For humans, a failure to maintain the requisite manganese balance in the body can give rise to a myriad of issues, including memory impairment, attention deficits, mobility limitations, and developmental and learning challenges in infants, as reported by the World Health Organization.

[0023] Human activities, such as mining and industrial steelmaking, can release manganese into water systems, thereby impacting the ecosystem (as indicated in a WHO report). Various methods for removing manganese from water sources have been investigated. These methods include biological oxidation, sorption, catalytic oxidation, and ion exchange. Biological oxidation / removal operates through three possible mechanisms. The first involves intracellular oxidation of manganese due to metabolic pathways in manganese-oxidizing organisms, where manganese (II) serves as an electron donor and oxygen as an acceptor. The second method entails extracellular adsorption by manganese-oxidizing organisms, as the ion adsorbs to negatively charged surfaces. The third mechanism utilizes biopolymers produced by microorganisms to catalyze the oxidation of manganese (II).

[0024] Catalytic oxidation and sorption rely on the ion attaching to a surface, typically manganese oxides, and can be facilitated by chemicals like chlorine and oxygen. However, it's worth noting that catalytic oxidation may produce halogenated disinfection by-products, some of which are known carcinogens and genotoxic substances. In solution, manganese typically exists in the 2+ charge state, making ion exchange a viable process for its removal. In this method, a monovalent cation like sodium or a proton is released from a cationic ion exchange medium, allowing for the removal of manganese (II). Other cations such as iron, magnesium, and calcium may compete with manganese cations for removal.

[0025] Organic compounds have been explored as manganese removal agents from water sources, with varying degrees of success. Certain organic compounds, such as rice husk ash, peanut husks, walnut shells, sugarcane bagasse, orange peel, tea waste, and canola flower, among others, do not appear to effectively recover the metal (as observed in the study on Mn adsorption via agricultural waste adsorbents). However, a few adsorbents have shownAttorney Docket No.: 5317.002WO1 manganese adsorption / removal rates exceeding 90%, with rice husk ash and peanut husks achieving 100% removal when manganese concentrations are 8 mg / L and 3.8 mg / L, respectively, under specific conditions. Most reactions occur within close-to-neutral pH ranges (6–8), with a few taking place under acidic conditions (4–5), and temperatures ranging from 23–30°C, with some occurring between 34–45°C, but none exceeding the boiling point.

[0026] Another study focusing on activated carbon revealed a manganese adsorption capacity of approximately 2.5 mg / g, with a preference for adsorbing iron at a higher capacity of 3.6 mg / g. This preference may be attributed to differences in electronegativity and ionic radius between the two compounds in relation to the adsorbent. Iron (II) possesses a higher electronegativity than manganese (II), making it more attractive to the adsorbent’s surface. Additionally, the smaller ionic radius of iron compared to manganese allows iron to penetrate the micropores of the adsorbent more easily. This experiment was conducted in batch form, as described in the study on the removal of manganese and iron using granular activated carbon.

[0027] A study involving steel slag demonstrated manganese adsorption rates exceeding 95%. This was particularly evident when enough adsorbent was available, and a basic pH was maintained, as the latter condition appeared to mitigate interference from competing hydrogen ions on the adsorbent surface. SUMMARY

[0028] The extraction and retrieval of manganese from water sources is a crucial task due to its significant impact on both the environment and industry. This disclosure presents a practical method for adsorbing manganese from aqueous sources onto nano titanium-based adsorbents, effectively removing it from the water. Furthermore, the separated manganese can be reclaimed from the adsorbent and concentrated for future use and the adsorbent can be reused many times. Additionally, while manganese is a vital trace element necessary for various biological processes, an excess of manganese in water bodies can pose significant environmental risks. The described systems and techniques not only offer economic benefits but also contribute to sustainable resource management. These efforts help reduce environmental pollution and promote responsible and economically viable handling of this essential metal, thereby fostering a more environmentally conscious and financially sustainable future.

[0029] The present disclosure describes methods of selective manganese extraction and recovery from aqueous solutions using nano-titanate selective adsorbents applied to natural waters, processed waters, or wastewaters containing manganese cations. The selective nano-Attorney Docket No.: 5317.002WO1 titanate adsorbents have the chemical formulas X2TiO2or YTiO2where X is an element with a valence of 1+ and Y is an element with a valence of 2+. Mixtures of these materials also can be used for the selective extraction of manganese.

[0030] In another embodiment of the present disclosure, the selected adsorbent can simultaneously adsorb a second cation from the solution if it is present and desired.

[0031] In another embodiment of the present disclosure, the method for extracting manganese from a aqueous solution comprises the following steps: (1) contacting the activated adsorbent material with a solution containing the manganese cations, whereby manganese cations undergo a selective adsorption on the surface of the adsorbent until all adsorption sites are saturated with the manganese cation (water is depleted of manganese); (2) contacting the manganese saturated adsorbent with an acidic solution of hydrochloric, nitric, sulfuric or carboxylic acids where the manganese cation is separated from the adsorbent and the adsorbent is regenerated; (3) separating the released manganese ions from the acidic solution as crystalized salts of manganese or oxidizing and precipitating manganese oxides. Examples of the manganese adsorbent materials include, but are not limited to, titanic acids, metatitanic acid (H2TiO3), lithium titanate (Li2TiO3), sodium titanium oxide (Na2TiO3), potassium titanate (K2TiO3), cesium titanate (Cs2TiO3), rubidium titanate (Rb2TiO3), magnesium titanium oxide (MgTiO3), calcium titanate (CaTiO3), strontium titanate (SrTiO3), barium titanate (BaTiO3), iron (II) titanate (FeTiO3), manganese (II) titanate (MnTiO3), cobalt titanate (CoTiO3), copper titanate (CuTiO3), nickel (II) titanate (NiTiO3), and zinc titanate (ZnTiO3), and mixtures thereof.

[0032] In some examples, the disclosure describes a technique for extracting manganese from an aqueous solution having a first concentration of manganese. The technique may include preparing a nano-titanate selective adsorbent, contacting the aqueous solution with the nano- titanate selective adsorbent, adsorbing, by the nano-titanate selective adsorbent, a mass of manganese from the aqueous solution to produce a loaded adsorbent and an effluent having a second concentration of manganese that is less than the first concentration of manganese, and recovering at least a portion of the mass of manganese from the loaded adsorbent.

[0033] In some examples, the disclosure describes a system for extracting manganese from an aqueous solution having a first concentration of manganese. The system includes an aqueous solution source containing the aqueous solution and an adsorption vessel having an effluent channel. The adsorption vessel defines an inlet fluidly coupled to the aqueous solution source and an outlet fluidly coupled to the effluent channel. Adsorption vessel includes a nano-titanate selective adsorbent configured to adsorb a mass of manganese from the aqueous solution toAttorney Docket No.: 5317.002WO1 generate a loaded adsorbent and an effluent having a second concentration of manganese that is less than the first concentration of manganese. The effluent channel is configured to direct the effluent to a collection vessel.

[0034] In some examples, the disclosure describes an adsorbent for extracting manganese from an aqueous solution, which includes a nano-titanate selective adsorbent powder having an average crystalline domain size less than 100 nanometers and which has been shaped to form larger particles suitable for column bed adsorption and including at least one of X2TiO2or YTiO2, where X is an element with a valence of 1+ and Y is an element with a valence of 2+, which defines a plurality of hydroxyl nests on a surface of particles of the powder. The plurality of hydroxyl nests are configured to selectively bind with manganese from an aqueous solution.

[0035] Other principal features and advantages of the present disclosure are going to become apparent to those skilled in the art upon review of the presented drawings, detailed descriptions, examples, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The disclosure can be understood in consideration of the following detailed description of various embodiments in connection with the accompanying drawings.

[0037] FIGS. 1A and 1B are schematic diagrams illustrating manganese adsorption and recovery from the titanate adsorbents, respectively, in neutral and anionic systems.

[0038] FIG. 2 is a conceptual diagram illustrating an example batch system for adsorptive removal and recovery of manganese from an aqueous solution.

[0039] FIG. 3. is a conceptual diagram illustrating an example continuous system for adsorptive removal and recovery of manganese from an aqueous solution.

[0040] FIG. 4 is a graph illustrating an XRD pattern depicting the structure of the Li2TiO3material of Example 2 before calcination.

[0041] FIG. 5 is a graph illustrating an XRD pattern depicting the structure of the Li2TiO3material of Example 2 after calcination.

[0042] FIG. 6 is a graph illustrating an XRD pattern depicting the structure of the Na2TiO3material of Example 3 before calcination.

[0043] FIG. 7 is a graph illustrating an XRD pattern depicting the structure of the Na2TiO3material of Example 3 after calcination.

[0044] FIG. 8 is a graph illustrating an XRD pattern depicting the structure of the BaTiO3material of Example 4 before calcination.Attorney Docket No.: 5317.002WO1

[0045] FIG. 9 is a graph illustrating an XRD pattern depicting the structure of the BaTiO3material of Example 4 after calcination.

[0046] FIG. 10 is a graph illustrating an XRD pattern depicting the structure of the SrTiO3material of Example 5 before calcination.

[0047] FIG. 11 is a graph illustrating an XRD pattern depicting the structure of the SrTiO3material of Example 5 after calcination.

[0048] FIG.12 is a graph illustrating a percentage of manganese uptake as a function of time in the continuous Setup mode of Example 8.

[0049] FIG.13 is a graph illustrating an infrared spectrum depicting the IR-vibration modes of the TiO2material of Example 1.

[0050] FIG. 14 is a graph illustrating an infrared spectrum depicting the structure of the Li2TiO3material of Example 2 after calcination.

[0051] FIG.15 is a graph illustrating an infrared spectrum depicting the IR-vibration modes of the BaTiO3material of Example 4 as prepared.

[0052] FIG.16 is a graph illustrating an infrared spectrum depicting the IR-vibration modes of the SrTiO3material of Example 5 as prepared. DETAILED DESCRIPTION

[0053] For purposes of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nonetheless be understood that no limitation of the scope of the disclosure is intended by the illustration and description of certain embodiments of the disclosure. In addition, any alterations and / or modifications of the illustrated and / or described embodiment(s) are contemplated as being within the scope of the present disclosure. Further, any other applications of the principles of the disclosure, as illustrated and / or described herein, as would normally occur to one skilled in the art to which the disclosure pertains, are contemplated as being within the scope of the present disclosure.

[0054] System and techniques for the selective extraction and recovery of manganese cations from aqueous solutions containing manganese are provided. The example systems and methods can be used to selectively extract and recover manganese cations from different water samples such as natural and processed waters, natural brines, synthetic brines, salted waters, and man-made wastewaters. The systems and methods utilize titanate-based materials in the nano-crystalline domain sizes. These materials may be selected and altered to produce an enriched surface containing hydroxyls nests capable of interacting selectively with manganeseAttorney Docket No.: 5317.002WO1 ions (Mn2+) and bind these manganese ions (Mn2+) on the surface of the adsorbent relative to any other cation present in the water sample forming a reversible colored complex. For example, white titanates become pale yellow when the manganese ions are adsorbed on their surface. The concentration of manganese that can be processed with the selective adsorbents ranges from approximately 1 parts-per-million (ppm) to 10,000 ppm. In a typical adsorption process of the present disclosure the sample water may contain a manganese ion concentration in the range from 5 ppm to 1,000 ppm. Hence, adsorbents may be selected to have a greater selectivity for manganese and greater loading capacity compared to adsorbents for other processes, such as for adsorption of manganese in municipal water supplies in which the concentration of manganese may be less than 1 ppm.

[0055] The adsorbent material is composed of nano-titanate adsorbents having chemical formulas X2TiO2or YTiO2where X is an element with a valence of +1 and Y is an element with a valence of +2. Examples of the manganese adsorbent materials may include, but are not limited to, H2TiO3, Li2TiO3, Na2TiO3, K2TiO3, Cs2TiO3, Rb2TiO3, MgTiO3, CaTiO3, SrTiO3, BaTiO3, FeTiO3, MnTiO3, CoTiO3, CuTiO3, NiTiO3, ZnTiO3and mixtures thereof. Mixtures of these materials also can be used for the selective extraction of manganese. The adsorbent material may be selected and presented (e.g., formed) to be in the nanometer range in order to have an enriched surface having hydroxyl nests capable of interacting with the manganese ions forming a colored superficial complex and separating them from the rest of the other cations present in the sourced water.

[0056] FIGS. 1A and 1B are schematic diagrams illustrating manganese adsorption and recovery from the titanate adsorbents, respectively, in neutral and anionic systems. As illustrated in FIG.1A, a nano-titanate adsorbent material 102A (white color) defines a surface that includes a plurality of hydroxyl nests as –OH groups. As illustrated by adsorption interaction 104A, a manganese (II) cation is adsorbed by the hydroxyl nests to produce a loaded adsorbent 106A (pale yellow color). After adsorption, as illustrated by adsorbent regeneration 108A, the loaded adsorbent may be contacted with a proton donor, such as an acidic solution to produce a regenerated adsorbent 110A (white color) and desorb the manganese.

[0057] The system illustrated in FIG. 1B, may be substantially the same as the system illustrated in FIG.1A except that the surface of absorbent may be anionic. The anionic nano- titanate adsorbent material 102B (white color) defines a surface that includes a plurality of hydroxyl nests as –O–groups. As illustrated by adsorption interaction 104B, a manganese (II) cation is adsorbed by the hydroxyl nests to produce a loaded adsorbent 106B (pale yellow color). After adsorption, as illustrated by adsorbent regeneration 108B, the loaded adsorbentAttorney Docket No.: 5317.002WO1 may be contacted with a proton donor, such as an acidic solution to produce a regenerated adsorbent 110B (white color) and desorb the manganese.

[0058] The selected adsorbent of the present disclosure (or mixture of adsorbents) which is white colored before entering into contact with a source water having manganese ions is exposed to the water sample containing manganese ions having a pH within a range from approximately 2 to approximately 10, such as within a range of 3 to 9, wherein the material adsorbs preferentially manganese on its surface within the engineered hydroxyl nest on the surface of the nano adsorbent until the water source is depleted from manganese ions, the adsorbent is loaded or saturated with manganese ions forming a pale yellow colored complex with the surface hydroxyl nests, or both. The saturated (loaded) adsorbent may be contacted with an acidic solution having a pH within a range from about 1 to about 6.9. Example acidic solutions may include one or more of hydrochloric acid, nitric acid, sulfuric acid, or carboxylic acid. When the saturated adsorbent is contacted with the acidic solution, manganese cations may be released from the adsorbent and the adsorbent is regenerated recovering the hydroxyl nests and its original white color. The manganese ions released from the adsorbent into the acidic solution may be separated by, for example, forming crystalline salts of the acid used for the recovery or the manganese cation, oxidizing the manganese ions to form insoluble manganese oxide which is separated from the solution, or combinations thereof.

[0059] The adsorbents presented in this disclosure can be prepared in many ways; however, the preparation methods that provide the production of homogeneous nano-crystalline domain sizes with high enriched hydroxyl nests are preferred for the selective adsorption of manganese as these adsorbents require a high surface area which cannot be provided by the methods that produce large crystals of the selected adsorbent materials. The methods presented here may include hydrothermal treatments, hydrothermal-calcination treatments, solid state treatments, or the like to produce the desired adsorbent in the nano-crystalline range. Hydrothermal treatments may include heating a mixture of the selected adsorbent material and water to produce a slurry or paste that may be subsequently formed. Optionally, the slurry or paste may be calcinated to remove water, volatile materials, or the like. Additionally, or alternatively, solid state treatments may be used to heat the adsorbent material to a fluid or near-fluid state such that molecules of the adsorbent material exhibits a selected molecule and / or particle configuration. The adsorbent can be presented any suitable form, including, but not limited to, powders, films, membranes, pellets, extrudates, composites, deposition onto matrix materials such as polymeric or ceramic scaffolds, combinations thereof, or other means of binding a nano-powder to at least a portion of a column or other adsorption vessel.Attorney Docket No.: 5317.002WO1

[0060] For the extraction of manganese there is a wide range of water pH that can be accommodated for the selective extraction. The method of the present disclosure can treat water samples having a preferred pH within a range from approximately 2 to approximately 10, such as within a range of approximately 3 to approximately 9. Temperature of the water sample can be anywhere within the freezing point and boiling point of the sample, which may depend upon the composition of the water sample, such as for example, the salinity of the water sample. In some examples, a temperature of the water sample may be within a range from approximately –21.1°C to approximately 108.7°C, such as from approximately 0°C to approximately 100°C or approximately 20°C to approximately 80°C. Pressure of the water can range from approximately 14.7 pounds per square inch (psi) to approximately 150 psi.

[0061] Manganese (Mn) extraction can be accomplished using various system configurations, such as, for example, a batch configuration as illustrated in FIG.2 or a continuous configuration as illustrated in FIG.3.

[0062] FIG. 2 is a conceptual diagram illustrating an example batch system for adsorptive removal and recovery of manganese from an aqueous solution. In FIG.2, system 200 includes a glass adsorption vessel 202 (hereinafter, column 202) positioned above an aqueous solution source 204 (hereinafter, feed tank 204). A pump 206 inside feed tank 204 drives the aqueous solution 201 upwards through column 202, and the outlet 208 is strategically placed at the top of the column. This setup promotes aqueous solution recirculation, as it allows effluent from column 202 to return to feed tank 204.

[0063] In some examples, system 200 may include an adsorbent regeneration unit 210. Adsorbent regeneration unit 210 may be configured to pass an acidic solution through column 202 in a counter flow direction to desorb manganese from a loaded adsorbent within column 202. For example, adsorbent regeneration unit 210 may include an input fluidly coupled to the output of column 202 (the adsorption vessel) and an output fluidly coupled to the input of column 202, such that adsorbent regeneration unit 210 is configured to pass an acidic solution through at least a portion of column 202 to desorb at least a portion of the mass of manganese from the loaded adsorbent into a loaded acidic solution.

[0064] Additionally, system 200 may include an optional polishing unit 212. Polishing unit 212 may be configured to receive the manganese loaded acidic solution from regeneration unit 210 and remove the manganese from the loaded acidic solution. For example, polishing unit 212 may be configured to receive at least a portion of the loaded acidic solution from adsorbent regeneration unit 201 and at least one of crystalize, oxidize, and precipitate the at least portionAttorney Docket No.: 5317.002WO1 of the mass of manganese or a compound comprising the at least portion of the mass of manganese.

[0065] FIG. 3. is a conceptual diagram illustrating an example continuous system 300 for adsorptive removal and recovery of manganese from an aqueous solution. System 300 may be substantially similar to system 200 described above in reference to FIG. 2, except for the differences described herein. For example, system 300 includes a column 302, an aqueous solution source 304 containing an aqueous solution 301, a pump 306 configured to move aqueous solution through column 302, as well as an optional adsorbent regeneration unit 310 and polishing unit 312.

[0066] In FIG. 3, pump 306 responsible for aqueous solution 301 movement is located externally to feed tank 304 and is controlled by a separate controller 307. Additionally, the outlet connected to the top of column 302 directs aqueous solution 301 to a collection vessel 305, ensuring that all aqueous solution 301 passing through column 302 remains fresh solution.

[0067] In some examples, a flow rate of batch system 200 and continuous system 300 may differ. For example, with the batch mode setup (system 200) having a higher flow rate compared to the continuous mode (system 300). As can be obvious for those skilled in the art, there are other modifications that can be adopted and they are embraced within the scope of this disclosure to present the adsorbent to the aqueous solution for the extraction and recovery of manganese ions from different water sources.

[0068] The examples presented below are a way to demonstrate embodiments in which the present disclosure can be carried out and in no way, they limit the scope of the disclosure. For those skilled in the art, it will become apparent that some modifications can be made, and those modifications are within the scope of the present disclosure.

[0069] EXAMPLE 1: Preparation of extruded nano-TiO2adsorbent.

[0070] Titanium dioxide (TiO2) nano powder (≥99.5%) was obtained from sigma-Aldrich and used for the preparation of the adsorbent. The powder was mixed with distilled water until it reached a paste-like consistency, then the material was then shaped to the desired cylinder like shape and calcinated in an oven at a temperature of 550℃ for 6 hours.

[0071] EXAMPLE 2: Preparation of extruded nano-Li2TiO3adsorbent.

[0072] Lithium hydroxide (LiOH with a purity of at least 98%) and Titanium dioxide (TiO2with a purity of at least 99.5%) nano powder were both sourced from sigma-Aldrich. The synthesis process began with the dissolution of 6.48 grams of LiOH in 180 mL of distilled water. Subsequently, 9.9 grams of TiO2were carefully introduced into the LiOH solution.Attorney Docket No.: 5317.002WO1 This mixture was then transferred to a 300cc PARR reactor and subjected to a 48-hour treatment at a temperature of 120℃, with continuous stirring at 300 RPM.

[0073] After the 48-hour period elapsed and the reactor had cooled down, the produced slurry was subjected to filtration. The resulting solid material was shaped into the desired cylindrical form and subsequently underwent calcination in an oven, maintained at a temperature of 550℃, for a duration of 6 hours.

[0074] To evaluate the resulting material, its structural characteristics and textural properties were assessed using XRD (X-ray Diffraction) techniques, as depicted in FIG. 4 and FIG. 5. Furthermore, BET (Brunauer-Emmett-Teller) analysis was performed to determine specific surface area properties. The analysis revealed that the material had a surface area of 7.75 m2 / g. Additionally, BJH (Barrett-Joyner-Halenda) desorption analysis was performed to determine a micropore area of 1.72 m2 / g and an average pore size of 201.3 Å.

[0075] EXAMPLE 3: Preparation of extruded nano-Na2TiO3adsorbent.

[0076] Sodium hydroxide (NaOH with a purity level exceeding 98%) and Titanium dioxide (TiO2with a purity of at least 99.5%) nano powder were procured from sigma-Aldrich for this experimental process. The synthesis procedure commenced with the dissolution of 10.9 grams of NaOH in 180 mL of distilled water. Subsequently, a measured quantity of 9.9 grams of TiO2was slowly introduced into the NaOH solution. This resulting solution was carefully transferred into a 300cc PARR reactor, where it underwent continuous treatment for a duration of 72 hours.

[0077] The treatment occurred at an elevated temperature of 160 ℃, with the solution being agitated at a speed of 300 rotations per minute (rpm). Following the completion of the 72-hour period and after the reactor had cooled down, the mixture was subjected to filtration. The solid material obtained through this process was shaped into the desired cylindrical form and then subjected to calcination in an oven, maintained at a temperature of 700℃, for a period of 6 hours.

[0078] To evaluate the structural changes that occurred during this process, X-Ray Diffraction (XRD) patterns were generated for both the sodium titanate material before and after the calcination step. These XRD patterns are presented in FIGS.6 and 7, respectively, providing insights into the material’s structural transformation.

[0079] EXAMPLE 4: Preparation of extruded nano-BaTiO3.

[0080] For this experiment, high-purity Barium hydroxide (Ba(OH)2with a minimum purity of 98%) and Titanium dioxide (TiO2with a minimum purity of 99.5%) nano powder were sourced from sigma-Aldrich. The synthesis process began by adding 46.9 grams of Ba(OH)2Attorney Docket No.: 5317.002WO1 to 200 mL of distilled water, allowing for thorough mixing. Subsequently, 9.9 grams of TiO2were slowly introduced into the solution. This resulting solution was then transferred to a 300cc PARR reactor, where it underwent a controlled treatment for a duration of 48 hours.

[0081] During this treatment, the solution was maintained at a temperature of 120 ℃, with continuous agitation at a speed of 300 rotations per minute (rpm). Following the completion of the 48-hour period and after the reactor had cooled down, the product was subjected to filtration. The solid material obtained through this process was then carefully shaped into the desired cylindrical form and underwent calcination in an oven, which was maintained at a temperature of 550℃, for a duration of 6 hours.

[0082] To assess the structural changes that occurred during the experiment, X-ray Diffraction (XRD) patterns were generated for both the barium titanate material before and after the calcination step. These XRD patterns are presented in FIGS. 8 and 9, respectively. Interestingly, the XRD patterns reveal that there is no discernible structural difference between the calcinated and non-calcinated materials, in contrast to what was observed with the sodium and lithium titanate materials in previous experiments.

[0083] EXAMPLE 5: Preparation of extruded nano-SrTiO3.

[0084] In this experiment, the synthesis process involved dissolving 30.5 grams of Strontium hydroxide (Sr(OH)2) in 180 mL of distilled water. Subsequently, 9.9 grams of TiO2nano powder were meticulously introduced into the mixture. The resulting slurry was then carefully transferred into a PARR reactor, where it underwent a controlled treatment for a period of 48 hours.

[0085] During this treatment, the slurry was subjected to a temperature of 160 ℃, and continuous agitation was maintained at a speed of 300 rotations per minute (rpm). After the 48-hour treatment had elapsed, and the reactor had cooled down, the product was subjected to a filtration process. The solid material obtained through this filtration was then shaped into the desired form and subsequently underwent a calcination process in an oven, where it was exposed to a temperature of 550℃ for a duration of 6 hours.

[0086] To evaluate the structural characteristics of the resulting material, X-ray Diffraction (XRD) patterns were generated for both the calcinated and non-calcinated samples. They are shown in FIGS. 10 and 11, respectively. Interestingly, the XRD analysis revealed that there was no observable structural difference between the calcinated and non-calcinated materials, a contrast to what was observed in previous experiments involving sodium and lithium titanate materials.Attorney Docket No.: 5317.002WO1

[0087] EXAMPLE 6: Testing the nano-TiO2for selective adsorption of manganese in BATCH MODE.

[0088] The manganese removal testing was conducted using the experimental setup depicted in FIG. 2. Prior to the manganese (Mn) adsorption process, the absorbent material may be activated, for example, by protonation to enhance the selectivity of the adsorbent material, e.g., the hydroxyl nests, for manganese. In some examples, activation of the adsorbent’s surface may be completed using an acid solution. In this context, a 1-liter natural brine solution having the composition shown in Table 1 and containing 18 parts per million (ppm) of Mn was continuously passed through the adsorbent material at a consistent flow rate for a duration of 24 hours. Following this initial adsorption step, an acidic solution was subsequently passed through the material for an additional 24-hour period. This second step aimed to remove the Mn that had been trapped on the absorbent material.

[0089] The results of the adsorption process are presented in Table 1, with all values expressed in milligrams (mg). The adsorption efficiency was determined to be 44%, signifying the percentage of Mn effectively captured by the absorbent material. Furthermore, the recovery rate was found to be 37%, indicating the proportion of the initially adsorbed Mn that was successfully removed during the subsequent treatment with the acidic solution. Ca Mg B K Na Mn Initial Brine 4179 112 42 5325 30427 18 Final Brine 3925 103 38 5035 29442 10 Recovered 51.3 1.25 0.95 48 273 6.6 Table 1. Manganese uptake testing for 1L natural brine solution and TiO2 absorbent material of Example 1 (values in milligrams).

[0090] EXAMPLE 7: Testing the nano-H2TiO3for selective adsorption of manganese at near neutral pH in BATCH MODE.

[0091] In the batch setup mode, as illustrated in FIG.2, a comprehensive series of experiments were conducted to investigate the manganese removal capabilities of H2TiO3material. Three distinct tests were carried out, each using 10 grams of the H2TiO3material. The first test served as a baseline, conducted without any additives, and it was conducted at room temperature. In the second experiment, the setup mirrored the first one, but with the temperature elevated to nearly 80°C. The third test, conducted at room temperature, involved the introduction of scale inhibitors in a concentration of 100 ppm each into the brine, the used scale inhibitors were commercial Scaletrol (available from Scaletrol Inc., Suwanee, Georgia) and ProSolv (available from Veolia North America, Boston, Massachusetts) (which are mixtures of carboxylic acidsAttorney Docket No.: 5317.002WO1 and alcohols like thioglycolic acid, acetic acid, 1,2-benzisothiazol-3(2H)-one, 2- butoxyethanol, ethylene glycol). It’s important to note that in all three tests, the pH of the brine was carefully controlled and maintained above 6.5 by adding sodium carbonate powder (Na2CO3with a minimum purity of 99.5%).

[0092] The experiments revealed that H2TiO3exhibited a remarkable capacity to remove all the manganese present in the source water, which typically contained 20–22 milligrams of manganese. Subsequent treatment with an acid wash demonstrated the ability to remove and recover more than half of the previously adsorbed manganese from the adsorbent material. These experiments were conducted over varying time durations, ranging from 24 to 40 hours, yet a notable observation was that most of the manganese removal occurred within the first 2 hours. Interestingly, alterations in temperature and the presence of inhibitors did not appear to significantly impact the material’s ability to adsorb manganese.

[0093] Data documenting manganese adsorption under different conditions, encompassing room temperature and 80℃ experiments, as well as experiments conducted with and without inhibitors, have been recorded and presented in Tables 2, 3, and 4. All values are expressed in milligrams, and the volume of all solutions used was standardized at 1 liter. Furthermore, any potential evaporation effects were duly considered in the data analysis. Importantly, the pH levels in all the conducted experiments consistently fell within the range of 6.50 to 7.20, ensuring the consistency and reliability of the experimental conditions. Ca Mg B K Na Mn Initial 3868 89.6 54.7 4576 25567 21.1 After 3954 84.1 49.8 4690 26323 3.75 Final 3606 79.8 42.4 4339 24363 2.16Table 2. Manganese adsorption without scale inhibitors at room temperature. Adsorption: 90%. Ca Mg B K Na MnTable 3. Manganese adsorption without scale inhibitors at 80℃. Adsorption: 99%Attorney Docket No.: 5317.002WO1 Ca Mg B K Na Mn Initial 4179 96.4 51.6 4910 27173 22.5 Final 3925 91.7 41.6 4668 26111 0.81 Recovered 51.3 0.57 1.51 8.47 188 17.9 Table 4. Manganese adsorption and recovery with inhibitors at room temperature. Adsorption: 96%. Recovery: 80%

[0094] EXAMPLE 8: Testing the nano-H2TiO3for selective adsorption of manganese CONTINOUS MODE.

[0095] In the continuous mode, as depicted in FIG. 3, a systematic evaluation of manganese removal using H2TiO3material was conducted with a meticulous approach. A total volume of 500 milliliters (mL) of natural brine water was passed through a 10-gram portion of the H2TiO3material, with the distinct characteristic of not including any scale inhibitors in the setup. This operation was performed at room temperature.

[0096] To ensure optimal conditions for manganese adsorption, the pH of the brine was adjusted upward to surpass a value of 7 by introducing a few drops of a 12.5% sodium hydroxide (NaOH) solution. It was anticipated that the initial brine solution contained 8.2 milligrams (mg) of manganese. As the brine passed through the column continuously, the H2TiO3adsorbent exhibited an impressive uptake capacity, successfully capturing 6.9 mg of manganese, corresponding to an 80% intake efficiency.

[0097] Furthermore, the role of pH in manganese uptake was explored, revealing its significance in the process. A previous experiment, in which the pH of the brine was not adjusted in any manner, yielded slightly lower results. However, even in that scenario, it was evident that manganese could still be effectively absorbed by the adsorbent material.

[0098] FIG. 12 provides a graphical representation of the manganese uptake as a function of time, offering valuable insights into the dynamic behavior of the adsorption process over time.

[0099] FIG. 12 illustrates a general decrease in the uptake of manganese from the original solution over time. This is indicative of saturation of the adsorption sites for manganese on the surface of the adsorbent. It is expected that at some point there is not more adsorption capacity, and the adsorbent is saturated; thus, in practical terms, the column needs to be regenerated and the adsorbed manganese recovered from the column in order for the adsorbent in the column to be active for manganese adsorption once more. For example, the column may be switched from the brine to the recovery by regenerating it with the acid solution after the uptake drops to 75% (around 80 minutes) and the acid solution with manganese is obtained. Additionally,Attorney Docket No.: 5317.002WO1 FIG.12 illustrates a first region between about zero minute and about 40 minutes having a first removal rate of manganese between 100% and 90% of the manganese present in the solution that is going through the absorbent. There is a second region starting at around 45 minutes where the uptake of manganese from the solution is around 75%. Finally, after 110 minutes the uptake drops to 40% indicating the saturation with manganese of most of the adsorption sites within the adsorbent in the column. The different removal rates during each of these time periods may be indicative of certain hydroxyl nests being more active in early adsorption and second hydroxyl nests being more active in secondary adsorption. For example, early adsorption may have a first arrangement of adsorbed manganese on the surface of the adsorbent, whereas secondary adsorption may have a second, more closely packed arrangement of manganese on the surface of the adsorbent. Additionally, different titanates or titanates prepared by different methods may behave differently with respect to adsorption over time.

[0100] EXAMPLE 9: Testing the nano-Na2TiO3for selective adsorption of manganese at neutral pH.

[0101] The experimental procedure in this instance closely resembled the batch experiment conducted earlier (set up shown in FIG.2), involving the use of both H2TiO3material and TiO2material. Specifically, the investigation involved the passage of a 300 mL sample of a natural brine solution through a bed of 3 grams of Na2TiO3solid. Prior to this adsorption step, the Na2TiO3material had undergone a sequential treatment involving an acid wash followed by a basic wash. These operations were conducted at room temperature and, notably, did not involve the addition of any supplementary additives.

[0102] After the adsorption process, another acid wash was implemented to facilitate the removal of manganese ions from the adsorbent material. It's important to mention that any potential effects of evaporation during the experimental procedures were meticulously considered when analyzing and presenting the results.

[0103] While the Na2TiO3material demonstrated effective manganese adsorption capabilities, it was observed that the extent of manganese uptake was not as high when compared to the performance of other tested solid materials in previous experiments indicating some room for improvement of the adsorbent surface.Attorney Docket No.: 5317.002WO1 Ca Mg K Na Mn Initial 37.6 1379 8581 6.71Final 1733 42.6 1382 8535 4.52 Recovered 7.83 1.25 2.57 15.6 1.73 Table 6. Adsorption and recovery of Mn from the material. All values are in mg. Adsorption: 33%. Recovery: 26%

[0104] EXAMPLE 10: Testing the nano-H2TiO3for selective adsorption of manganese at near neutral pH in BATCH MODE with high Mn concentration.

[0105] In the illustrated batch mode configuration, depicted in FIG. 2, 5 grams of H2TiO3material were employed to assess the manganese removal efficacy of the adsorbent under heightened manganese concentrations in the source brine. The experimental procedure closely resembled preceding instances. A one-liter synthetic brine solution, containing 101 milligrams of manganese, was prepared, and subsequently passed through the 5 grams of adsorbent over an approximate duration of 72 hours. Subsequently, an acidic solution was introduced to elute the manganese from the column. The column demonstrated an absorption capacity of 18.2% for manganese in the solution (equivalent to 18.3 milligrams), with 14.4% of manganese successfully recovered after the acid wash (equivalent to 14.2 milligrams). This experiment indicates that the H2TiO3 has an estimated adsorption capacity, in the tested conditions, of about 4 mg of Mn per gram of adsorbent. Ca Mg Na Mn Initial 1152 965 6238 101 After 1171 952 6239 82.7 27.0 7.72 71.6 14.2Table 5. Manganese adsorption and recovery in a synthetic brine at 100 milligrams of Mn. All values are in milligrams. Adsorption: 18.2%. Recovery: 14.4%

[0106] The X-ray powder diffraction analysis of the prepared materials may be carried out using a Bruker D8 Advance ECO diffractometer equipped with a Cu Kα source (λ = 1.54178 Å, kV = 40, mA = 25) and a LYNXEYE XE detector. The samples were loaded into a 25 mm PMMA sample holder. The scan can be done in the range of 3–90° of 2θ degrees using a 0.05° step and a counting time of 1° per min to obtain the diffractogram for each prepared material.

[0107] Regarding the size of the nanocrystalline domain sizes shown in Table 7, the sizes may be considered to relate to an “average three-dimensional size” as there is no apparentAttorney Docket No.: 5317.002WO1 preferential orientation of the oxides in the X-ray diffraction pattern and all the crystalline planes of the oxide structures correspond to values of less than 50 nm.

[0108] The size of the nanocrystalline domain size is calculated using the Scherrer equation. The dimension is an average of the different crystalline planes which in all the planes are lower than 50 nm; thus, there is not a visible preferential growth of the crystals in the X-ray diffraction pattern. The conventional factor of 0.9 is used as implemented in the software.

[0109] A surface area may be determined using gas absorption using the BET (Brunauer, Emmett and Teller) method (e.g., using the ISO 9277:2022 standard). The BET method may use nitrogen gas. Within the measurement of the absorption of a gas on the adsorbents it is possible to determine the pore size and pore volume by applying the Barrett-Joyner-Halenda (BJH) Pore Size and Volume Analysis. The nitrogen adsorption–desorption measurements of the samples may be performed at 77 K on a Micromeritics Tristar 3000 analyzer.Table 7. Average crystalline domain sizes for the materials prepared in the examples.

[0110] FIGS. 13 through 16 are example graphs illustrating the structure of various titanate adsorbent materials of Examples 1, 2, 4, and 5, respectively. A Shimadzu’s IRAffinity-1S spectrometer may be used to investigate functional groups in solid oxide samples as the ones tested in the prepared examples by using the KBr technique. About 5 mg of each sample is mixed with 100 mg of KBr and homogenized and transferred to the sample holder which was then inserted into the apparatus. The expert analyst software applied a pre-designed algorithm to measure the wavelengths of the samples in the region of interest (400 to 4000 cm-1).Attorney Docket No.: 5317.002WO1

[0111] The stretching vibration modes of the hydroxyl groups of the materials of the present invention can be observed in the mid-infrared region between 3600 and 3000 cm-1and the bending vibration mode of the hydroxyl groups of the materials of the present invention can be observed in the mid-infrared region around 1400 and 1500 cm-1.

[0112] While the foregoing is directed to various embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

[0113] In accordance with the present disclosure, a plurality of patent applications pertaining to the extraction and recovery of manganese are herein disclosed. The scope of these applications encompasses a range of metals, notably including manganese, and primarily focuses on the recovery processes applied to both batteries and ores. The techniques described therein exhibit considerable variability, showcasing diverse methodologies tailored for the extraction and recovery of several elements including manganese.

[0114] Other techniques fail to provide the desired selectivity for manganese, lack a practical ability to recover manganese particularly at scale, utilize materials that may not be desirable either for their expense in procurement and / or disposal or potential impact on the environment. A concise summary of certain methodologies is provided below.

[0115] Patent application number CA3186731A1 describes a solvent extraction method for the separation and recovery of nickel, cobalt, manganese, and zinc. Specifically, the invention pertains to a solvent extraction method designed to facilitate the individual recovery of four distinct valuable metals, each as a monotype metal, from a feedstock comprising nickel, cobalt, manganese, and zinc. The method encompasses a sequence of operational steps as follows: (1) A first solvent extraction step, wherein the initial feedstock is differentially partitioned into a primary aqueous phase solution, enriched with nickel and cobalt, and a secondary aqueous phase solution, comprising nickel, cobalt, manganese, and zinc. (2) A second solvent extraction step dedicated to the isolation and reclamation of nickel (Ni) and cobalt (Co). (3) A third solvent extraction step tailored for the retrieval of zinc (Zn). (4) A fourth solvent extraction step engineered to effectively segregate and recover manganese (Mn) and cobalt (Co).

[0116] Patent application number US20220166079A1 describes a process for the separation of manganese and lithium, as well as a solution preparation process prior to extraction for the comprehensive recovery of cobalt, nickel, manganese, and lithium elements from ternary battery waste materials. The separation of cobalt and nickel ions is achieved through a hydrolysis technique following the removal of impurities from the solution. Meanwhile,Attorney Docket No.: 5317.002WO1 manganese, lithium, and other ions within the impurity-depleted solution are excluded from undergoing an extraction step. This procedure facilitates the effective separation and elimination of a substantial majority of manganese ions via a wet method prior to the extraction process. This pre-emptive action serves to prevent the introduction of manganese ions into the extraction system. Additionally, the nickel ions are exempted from the complete extraction and full back-extraction steps, with nickel hydroxide being precipitated directly following the removal of relevant impurities through the extraction process.

[0117] In accordance with the patent application number US20120046159A1, there is provided a method for the reclamation of cobalt and manganese from a depleted cobalt-manganese- bromine (CMB) catalyst. The method encompasses a sequence of steps, which consist of: (a) a continuous leaching process employing sulfuric acid to treat the spent CMB catalyst, (b) the separation of the resultant leachate into a solution and a residue, (c) an extraction procedure using a suitable solvent on the solution, and (d) a subsequent washing operation of the extracted material with water. This method, as disclosed therein, facilitates the retrieval of high-purity cobalt and manganese from a spent CMB catalyst, all the while minimizing the presence of impurities. The disclosure encompasses a method for the production of a CMB liquid catalyst, which is derived from the aforementioned extract containing cobalt and manganese, as obtained through the recovery process.

[0118] The patent US4680098A outlines a method to recover cobalt and manganese catalyst metals from trimellitic anhydride process residue through electrodialysis. The process involves using an electrodialyzer with a specific separation stack. The residue is first extracted with water, and the resulting solution is employed as a diluting solution in the electrodialyzer. The electrodialyzer consists of an anode channel and repeating units with three channels, labeled A, B, and C. These channels are equipped with various permeation membranes to facilitate metal separation. An anolyte is introduced to the anode channel, and the diluting solution is fed into the A channels. Simultaneously, an electrolyte is supplied to the B channels, and a catholyte is provided to the C channels. The result is a solution rich in cobalt and manganese, free from contaminants and organic materials, obtained from the B channels. Additionally, this process enables the recovery of these metals as aqueous acetate salts from a solution containing aromatic compounds, offering a more efficient alternative to traditional carbonate precipitation methods.

[0119] The patent US4309390A outlines A method for the retrieval and isolation of cobalt and manganese metal oxidation catalysts from the byproducts of trimellitic acid production, as well as the selective separation of the reclaimed cobalt from the reclaimed manganese, is disclosedAttorney Docket No.: 5317.002WO1 therein. This process entails the dissolution of the aforementioned byproducts in an aqueous medium. Subsequently, the dissolved cobalt is rendered as metallic cobalt through displacement by the addition of manganese metal to the solution, which is appropriately adjusted to a pH level of 6. The utilization of magnetic means for the separation of the metallic cobalt from the cobalt-depleted solution further characterizes this technique.

[0120] The patent US3894927A outlines a method for the extraction of metallic constituents from seabed nodular mineral deposits. The method involves the interaction of said nodular mineral deposits with a fused bath comprising alkali metal halides and / or alkaline earth metal halides, resulting in the formation of halides corresponding to the manganese, copper, cobalt, and nickel elements contained within the mineral deposits. Subsequently, the aforesaid halides are separated from the reaction mixture, for instance, by means of vaporization. The amalgamated halides can subsequently be isolated into their individual constituents, typically achieved through dissolution in water and subsequent extraction. It is advantageous that the mineral deposits undergo an initial dehydration process, and in certain embodiments, the mineral deposits can be exposed to a reducing agent to reduce the manganese to its divalent state.

[0121] Patent application number US20230332269A1 describes a method for the reclamation of nickel, cobalt, and manganese from a liquid feedstock containing said nickel, cobalt, and manganese, said method comprising the following steps: (1) Imposing a primary extraction process upon the liquid feedstock to yield an aqueous phase denominated as “Phase 1” and an organic phase designated as “Phase 1.” (2) Subsequently, implementing a secondary extraction process on the “Phase 1” aqueous portion to produce an organic phase labeled as “Phase 2” and an “Aqueous Phase 2” possessing a pH level within the range of 5 to 7.5. In a further embodiment of the method, a purification and reverse extraction procedure is sequentially conducted on the “Phase 2” organic component to generate a solution encompassing nickel, cobalt, and manganese. Notably, the extractant “A” utilized in the secondary extraction step comprises a carboxylic acid extractant, thereby enabling the efficient recovery of these valuable metals.

[0122] The patent US9057117B2 outlines a method for the selective extraction of manganese and zinc from geothermal brines. The method comprises a series of sequential steps, including the elimination of silica and iron impurities from the geothermal brine, the oxidation of manganese and zinc species to yield corresponding precipitates, the retrieval of said manganese and zinc precipitates, the dissolution of these precipitates, the purification of manganese andAttorney Docket No.: 5317.002WO1 zinc components, followed by the formation and recovery of manganese precipitate, and the final recovery of zinc using electrochemical techniques.

[0123] The patent US9057117B2 pertains to a method for the discerning retrieval of manganese and zinc from geothermal brines. This process encompasses several sequential steps that collectively facilitate the extraction and purification of these essential metals. Initially, silica and iron contaminants are effectively separated from the geothermal brine. Subsequently, the manganese and zinc present in the brine are subjected to oxidation, leading to the formation of respective precipitates. These manganese and zinc precipitates are then meticulously recovered. Following this recovery, the precipitates are solubilized to enable further processing, during which the manganese and zinc are purified. The purified manganese is subsequently induced to precipitate once more, while the final step in the process involves the electrochemical retrieval of zinc.

[0124] The patent US9057117B2 pertains to a method for the retrieval of manganese products derived from a manganese-containing ore and / or manganese-containing concentrate. The method encompasses a series of sequential steps, including but not limited to the following: (1) initiating a leaching process, during which the ore and / or concentrate is exposed to sulfur dioxide (SO2) to generate a pregnant leach solution. (2) The ensuing phase involves the treatment of the pregnant leach solution through one or more purification procedures, resulting in the production of a purified pregnant leach solution. (3) Subsequently, a fraction of the purified pregnant leach solution is directed toward an electrowinning operation to yield manganese metal, while another portion is subjected to a crystallization process, leading to the formation of a manganese salt.

[0125] The following clauses illustrated example subject matter described herein.

[0126] Clause 1: A method of extracting manganese from an aqueous solution, wherein the method comprises: preparing a nano-titanate selective adsorbent; contacting the aqueous solution with the nano-titanate selective adsorbent, wherein the aqueous solution comprises a first concentration of manganese; adsorbing, by the nano-titanate selective adsorbent, a mass of manganese from the aqueous solution to produce a loaded adsorbent and an effluent, wherein the effluent comprises a second concentration of manganese, wherein the second concentration of manganese is less than the first concentration of manganese; and recovering at least a portion of the mass of manganese from the loaded adsorbent.

[0127] Clause 2: The method of clause 1, wherein the nano-titanate selective adsorbent comprises at least one of X2TiO2or YTiO2where X is an element with a valence of +1 and Y is an element with a valence of +2, and wherein preparing the nano-titanate selective adsorbentAttorney Docket No.: 5317.002WO1 comprises at least one of hydrothermal treatment and calcination of the nano-titanate selective adsorbent.

[0128] Clause 3: The method of clause 1 or 2, wherein preparing the nano-titanate selective adsorbent comprises activating a surface of the nano-titanate selective adsorbent to produce a plurality of hydroxyl nests on the surface, wherein the plurality of hydroxyl nests selectively bind with manganese from the aqueous solution.

[0129] Clause 4: The method of any one of clauses 1 through 3, wherein the nano-titanate selective adsorbent comprises at least one of titanic acid, metatitanic acid (H2TiO3), lithium titanate (Li2TiO3), sodium titanium oxide (Na2TiO3), potassium titanate (K2TiO3), cesium titanate (Cs2TiO3), rubidium titanate (Rb2TiO3), magnesium titanium oxide (MgTiO3), calcium titanate (CaTiO3), strontium titanate (SrTiO3), barium titanate (BaTiO3), iron (II) titanate (FeTiO3), manganese (II) titanate (MnTiO3), cobalt titanate (CoTiO3), copper titanate (CuTiO3), nickel (II) titanate (NiTiO3), and zinc titanate (ZnTiO3).

[0130] Clause 5: The method of any one of clauses 1 through 4, wherein preparing the nano- titanate selective adsorbent comprises loading the nano-titanate selective adsorbent into a vessel configured to receive the aqueous solution and output the effluent.

[0131] Clause 6: The method of any one of clauses 1 through 5, wherein a pH of the aqueous solution is within a range from approximately 2 to approximately 10, wherein the first concentration of manganese is within a range from approximately 1 parts-per-million (ppm) to approximately 1,000 ppm, and wherein the aqueous solution comprises at least one of natural water, processed water, brine water, salted water, and wastewater.

[0132] Clause 7: The method of any one of clauses 1 through 6, wherein recovering at least the portion of the mass of manganese comprises contacting the loaded adsorbent with an acidic aqueous solution comprising at least one of hydrochloric, nitric, sulfuric or carboxylic acids to produce a regenerated adsorbent and a loaded acidic solution.

[0133] Clause 8: The method of clause 7, wherein recovering at least the portion of the mass of manganese comprises polishing the loaded acidic solution by at least one of crystalizing, oxidizing, and precipitating the at least portion of the mass of manganese or a compound comprising the at least portion of the mass of manganese.

[0134] Clause 9: The method of any one of clauses 1 through 8, wherein contacting the aqueous solution with the nano-titanate selective adsorbent, comprises recirculating a volume of the aqueous solution through a vessel containing the nano-titanate selective adsorbent.

[0135] Clause 10: The method of any one of clauses 1 through 9, wherein contacting the aqueous solution with the nano-titanate selective adsorbent, comprises: continuously flowingAttorney Docket No.: 5317.002WO1 a volume of the aqueous solution from a first tank through a vessel containing the nano-titanate selective adsorbent; and collecting the effluent in a second tank.

[0136] Clause 11: A system for extracting manganese from an aqueous solution, comprising: an aqueous solution source containing an aqueous solution, wherein the aqueous solution comprises a first concentration of manganese; an adsorption vessel defining an inlet and an outlet, wherein the inlet is fluidly coupled to the aqueous solution source, wherein the adsorption vessel comprises a nano-titanate selective adsorbent configured to adsorb a mass of manganese from the aqueous solution to generate a loaded adsorbent and an effluent, wherein the effluent comprises a second concentration of manganese, wherein the second concentration of manganese is less than the first concentration of manganese; and an effluent channel fluidly coupled to the outlet of the adsorption vessel and configured to direct the effluent to a collection vessel.

[0137] Clause 12: The system of clause 11, further comprising an adsorbent regeneration unit comprising an input fluidly coupled to the output of the adsorption vessel and an output fluidly coupled to the input of the adsorption vessel, wherein the adsorbent regeneration unit is configured to pass an acidic solution through at least a portion of the adsorption vessel to desorb at least a portion of the mass of manganese from the loaded adsorbent into a loaded acidic solution.

[0138] Clause 13: The system of clause 12, further comprising polishing unit fluidly coupled to the adsorbent regeneration unit and configured to receive at least a portion of the loaded acidic solution and at least one of crystalize, oxidize, and precipitate the at least portion of the mass of manganese or a compound comprising the at least portion of the mass of manganese.

[0139] Clause 14: The system of any one of clauses 11 through 13, wherein the nano-titanate selective adsorbent comprises: at least one of X2TiO2or YTiO2where X is an element with a valence of 1+ and Y is an element with a valence of 2+; and a plurality of hydroxyl nests on a surface of the nano-titanate selective adsorbent configured to selectively bind with manganese from the aqueous solution.

[0140] Clause 15: The system of any one of clauses 11 through 14, wherein the nano-titanate selective adsorbent comprises at least one of titanic acid, metatitanic acid (H2TiO3), lithium titanate (Li2TiO3), sodium titanium oxide (Na2TiO3), potassium titanate (K2TiO3), cesium titanate (Cs2TiO3), rubidium titanate (Rb2TiO3), magnesium titanium oxide (MgTiO3), calcium titanate (CaTiO3), strontium titanate (SrTiO3), barium titanate (BaTiO3), iron (II) titanate (FeTiO3), manganese (II) titanate (MnTiO3), cobalt titanate (CoTiO3), copper titanate (CuTiO3), nickel (II) titanate (NiTiO3), and zinc titanate (ZnTiO3).Attorney Docket No.: 5317.002WO1

[0141] Clause 16: The system of any one of clauses 11 through 15, wherein a pH of the aqueous solution is within a range from approximately 2 to approximately 10, wherein the first concentration of manganese is within a range from approximately 5 parts-per-million (ppm) to approximately 1,000 ppm, and wherein the aqueous solution comprises at least one of natural water, processed water, brine water, salted water, and wastewater.

[0142] Clause 17: The system of any one of clauses 11 through 16, wherein the aqueous solution source comprises a first tank, wherein the collection vessel comprises the first tank, and wherein the system further comprises a pump configured to recirculate the aqueous solution from the first tank through the adsorption vessel.

[0143] Clause 18: The system of any one of clauses 11 through 17, further comprising a second adsorption vessel defining a second inlet and a second outlet, wherein the second inlet is fluidly coupled to the effluent channel, wherein the second adsorption vessel comprises a second nano- titanate selective adsorbent configured to adsorb a second mass of manganese from the effluent to generate a second loaded adsorbent and a second effluent, wherein the second effluent comprises a third concentration of manganese, wherein the third concentration of manganese is less than the second concentration of manganese; and a second effluent channel fluidly coupled to the second outlet of the second adsorption vessel and configured to direct the second effluent to a second collection vessel.

[0144] Clause 19: An adsorbent for extracting manganese from an aqueous solution, comprising a nano-titanate selective adsorbent powder having a particle size less than 100 nanometers comprising: at least one of X2TiO2or YTiO2, where X is an element with a valence of 1+ and Y is an element with a valence of 2+; and a plurality of hydroxyl nests on a surface of particles of the powder, wherein the plurality of hydroxyl nests are configured to selectively bind with manganese from an aqueous solution.

[0145] Clause 20: The absorbent of clause 19, wherein the nano-titanate selective adsorbent comprises at least one of titanic acid, metatitanic acid (H2TiO3), lithium titanate (Li2TiO3), sodium titanium oxide (Na2TiO3), potassium titanate (K2TiO3), cesium titanate (Cs2TiO3), rubidium titanate (Rb2TiO3), magnesium titanium oxide (MgTiO3), calcium titanate (CaTiO3), strontium titanate (SrTiO3), barium titanate (BaTiO3), iron (II) titanate (FeTiO3), manganese (II) titanate (MnTiO3), cobalt titanate (CoTiO3), copper titanate (CuTiO3), nickel (II) titanate (NiTiO3), and zinc titanate (ZnTiO3).

[0146] As used herein with reference to a measured value, the terms about and approximately indicate that the stated value may vary due to errors in a measurement device or errors in a measurement procedure, such that an actual value (i.e., true value) may vary by a percentageAttorney Docket No.: 5317.002WO1 (e.g., 1%, 5%, or 10%) greater or less than the stated value. Therefore, a stated approximate value may include values that are up to 10% greater than or less than the stated approximate value.

[0147] While the disclosure has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the disclosure is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under the law. Furthermore, it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the disclosure, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and / or “a portion” is used the item may include a portion and / or the entire item unless specifically stated to the contrary.

Claims

Attorney Docket No.: 5317.002WO1 CLAIMS What is claimed is:

1. A method of extracting manganese from an aqueous solution, wherein the method comprises: preparing a nano-titanate selective adsorbent; contacting the aqueous solution with the nano-titanate selective adsorbent, wherein the aqueous solution comprises a first concentration of manganese; adsorbing, by the nano-titanate selective adsorbent, a mass of manganese from the aqueous solution to produce a loaded adsorbent and an effluent, wherein the effluent comprises a second concentration of manganese, wherein the second concentration of manganese is less than the first concentration of manganese; and recovering at least a portion of the mass of manganese from the loaded adsorbent.

2. The method of claim 1, wherein the nano-titanate selective adsorbent comprises at least one of X2TiO2or YTiO2where X is an element with a valence of +1 and Y is an element with a valence of +2, and wherein preparing the nano-titanate selective adsorbent comprises: at least one of hydrothermal treatment and calcination of the nano-titanate selective adsorbent; and activating a surface of the nano-titanate selective adsorbent to produce a plurality of hydroxyl nests on the surface, wherein the plurality of hydroxyl nests selectively bind with manganese from the aqueous solutionAttorney Docket No.: 5317.002WO1 3. The method of claim 1, wherein the nano-titanate selective adsorbent comprises at least one of titanic acid, metatitanic acid (H2TiO3), lithium titanate (Li2TiO3), sodium titanium oxide (Na2TiO3), potassium titanate (K2TiO3), cesium titanate (Cs2TiO3), rubidium titanate (Rb2TiO3), magnesium titanium oxide (MgTiO3), calcium titanate (CaTiO3), strontium titanate (SrTiO3), barium titanate (BaTiO3), iron (II) titanate (FeTiO3), manganese (II) titanate (MnTiO3), cobalt titanate (CoTiO3), copper titanate (CuTiO3), nickel (II) titanate (NiTiO3), and zinc titanate (ZnTiO3).

4. The method of claim 1, wherein a pH of the aqueous solution is within a range from approximately 2 to approximately 10, wherein the first concentration of manganese is within a range from approximately 1 parts-per-million (ppm) to approximately 1,000 ppm, and wherein the aqueous solution comprises at least one of natural water, processed water, brine water, salted water, and wastewater.

5. The method of claim 1, wherein recovering at least the portion of the mass of manganese comprises: contacting the loaded adsorbent with an acidic aqueous solution comprising at least one of hydrochloric, nitric, sulfuric or carboxylic acids to produce a regenerated adsorbent and a loaded acidic solution; and polishing the loaded acidic solution by at least one of crystalizing, oxidizing, and precipitating the at least portion of the mass of manganese or a compound comprising the at least portion of the mass of manganese.Attorney Docket No.: 5317.002WO1 6. A system for extracting manganese from an aqueous solution, comprising: an aqueous solution source containing an aqueous solution, wherein the aqueous solution comprises a first concentration of manganese; an adsorption vessel defining an inlet and an outlet, wherein the inlet is fluidly coupled to the aqueous solution source, wherein the adsorption vessel comprises a nano-titanate selective adsorbent configured to adsorb a mass of manganese from the aqueous solution to generate a loaded adsorbent and an effluent, wherein the effluent comprises a second concentration of manganese, wherein the second concentration of manganese is less than the first concentration of manganese; and an effluent channel fluidly coupled to the outlet of the adsorption vessel and configured to direct the effluent to a collection vessel.

7. The system of claim 6, further comprising: an adsorbent regeneration unit comprising an input fluidly coupled to the output of the adsorption vessel and an output fluidly coupled to the input of the adsorption vessel, wherein the adsorbent regeneration unit is configured to pass an acidic solution through at least a portion of the adsorption vessel to desorb at least a portion of the mass of manganese from the loaded adsorbent into a loaded acidic solution; and a polishing unit fluidly coupled to the adsorbent regeneration unit and configured to receive at least a portion of the loaded acidic solution and at least one of crystalize, oxidize, and precipitate the at least portion of the mass of manganese or a compound comprising the at least portion of the mass of manganese.Attorney Docket No.: 5317.002WO1 8. The system of claim 6, wherein the nano-titanate selective adsorbent comprises: at least one of X2TiO2or YTiO2where X is an element with a valence of 1+ and Y is an element with a valence of 2+; and a plurality of hydroxyl nests on a surface of the nano-titanate selective adsorbent configured to selectively bind with manganese from the aqueous solution.

9. The system of claim 6, wherein the nano-titanate selective adsorbent comprises at least one of titanic acid, metatitanic acid (H2TiO3), lithium titanate (Li2TiO3), sodium titanium oxide (Na2TiO3), potassium titanate (K2TiO3), cesium titanate (Cs2TiO3), rubidium titanate (Rb2TiO3), magnesium titanium oxide (MgTiO3), calcium titanate (CaTiO3), strontium titanate (SrTiO3), barium titanate (BaTiO3), iron (II) titanate (FeTiO3), manganese (II) titanate (MnTiO3), cobalt titanate (CoTiO3), copper titanate (CuTiO3), nickel (II) titanate (NiTiO3), and zinc titanate (ZnTiO3).

10. The system of claim 6, further comprising a second adsorption vessel defining a second inlet and a second outlet, wherein the second inlet is fluidly coupled to the effluent channel, wherein the second adsorption vessel comprises a second nano-titanate selective adsorbent configured to adsorb a second mass of manganese from the effluent to generate a second loaded adsorbent and a second effluent, wherein the second effluent comprises a third concentration of manganese, wherein the third concentration of manganese is less than the second concentration of manganese; and a second effluent channel fluidly coupled to the second outlet of the second adsorption vessel and configured to direct the second effluent to a second collection vessel.

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