Valuable Metal Ions Research Articles

Separation of Co(II), Mn(II), and Ni(II) by solvent extraction with Cyanex 272 and D2EHPA from the sulfuric acid leaching solution of spent lithium-ion batteries

Spent lithium-ion batteries contain valuable metals such as cobalt, lithium, manganese and nickel. Smelting reduction of spent LIBs at high temperature results in metallic alloys. Therefore, it is necessary to recover the valuable metal ions present in the sulfuric acid leaching solutions of the metallic alloys. In this work, solvent extraction experiments were performed to separate the three metal ions, Co(II), Mn(II) and Ni(II) present in the leaching solutions of the metallic alloys. Synthetic sulfate solutions were prepared and commercial organophosphorous extractants were employed. First, both Co(II) and Mn(II) were completely extracted in one stage by using 40% saponified 0.3 M Cyanex 272, leaving Ni(II) in the raffinate. The small amount of Ni(II) co-extracted into Cyanex 272 was removed by two stages of cross-current scrubbing using pure CoSO4 solution. The effect of pH and CoSO4 concentration of the scrubbing solution on the scrubbing of Ni(II) was investigated. The Co(II) and Mn(II) present in the scrubbed Cyanex 272 were completely stripped by 0.05 M H2SO4 solution. Batch simulation experiments for the three stage of counter-current extraction with 1 M D2EHPA verified that Mn(II) and Co(II) were completely separated by selective extraction of Mn(II) into D2EHPA, leaving Co(II) in the raffinate. By consecutive extraction with Cyanex 272 and D2EHPA, pure solutions of Co(II), Mn(II) and Ni(II) with purity higher than 99.9% can be recovered from the starting solutions. A process was proposed for the treatment of sulfuric acid leaching solutions of spent LIBs containing Co(II), Mn(II) and Ni(II) by solvent extraction.

Highly efficient Mn2+, Mg2+, and NH4+ recovery from electrolytic manganese residue via leaching, solvent extraction, coprecipitation, and atmospheric oxidation

Electrolytic manganese residue (EMR), a solid waste generated during electrolytic manganese production, exhibits substantial leaching toxicity owing to its elevated levels of soluble Mn2+ and NH4+. The leaching and recovery of valuable metal ions and NH4+ from EMR are key to the hazard-free treatment and resource utilization of EMR. In this study, two-stage countercurrent leaching with water was used to leach Mn2+, Mg2+, and NH4+ from EMR. Subsequently, two-stage countercurrent extraction was conducted using α-hydroxy-2-ethylhexyl phosphinic acid (α-H-2-EHA) as an extractant to enrich Mn2+, and Mg2+, and NH4+ were recovered via coprecipitation. Based on the calculations for a single leaching-extraction process, the recoveries of Mn2+, Mg2+, and NH4+ ions exceeded 80%, 99%, and 90%, respectively. In addition, high-purity Mn3O4 with an Mn content of 71.61% and struvite were produced. This process represents a win-win strategy that facilitates the hazard-free treatment of EMR while simultaneously recovering valuable Mn2+, Mg2+, and NH4+ resources from waste. Thus, this study provides a novel approach to the hazard-free and resourceful management of solid waste. Environmental implicationElectrolytic manganese residue (EMR), a solid waste generated during electrolytic manganese production, poses significant environmental risks due to its soluble heavy metals and ammonia nitrogen content. Efforts have been made to address this issue, but there has been no mature industrial application due to cost or processing capacity constraints. In this work, solvent extraction was first used to enrich Mn2+ from EMR leachate, and a novel α‑hydroxy‑2‑ethylhexyl phosphinic acid was used as extractant. High purity Mn3O4 and struvite was synthesized through this process. The win‑win strategy offers a novel approach for the hazard‑free and resourceful utilization of solid waste.

Recovery of valuable metals from cathode materials of spent ternary lithium‐ion battery using natural product as reducing reagent

AbstractIn recent years, ternary lithium‐ion batteries (LIBs) have been vigorously promoted in the field of new energy vehicles for their excellent overall performance, and the rapid growth of battery production and sales has brought about a proliferation of spent LIBs. The recycling of cathode materials of spent ternary LIBs, which are rich in many valuable metal elements, will bring multiple environmental and economic benefits. In this paper, a systematic study of the key influencing factors in the wet leaching and recycling process was carried out. A natural product tea polyphenol was innovatively used as the reducing reagent, and a sulphuric acid–tea polyphenol leaching system was constructed for the reductive acid leaching of cathode materials of spent ternary LIBs. Under the optimum leaching conditions, the leaching efficiencies of lithium, nickel, cobalt, and manganese were 99.54%, 98.88%, 99.37%, and 98.45%, respectively. After leaching, a stepwise precipitation method was used to separate and recover the valuable metal ions from the leachate. In summary, an innovatively complete recycling process route for cathode materials of spent ternary LIBs was constructed, which provides a solid theoretical basis and technical support for the efficient and clean recycling of spent LIBs.

Recovery of Strategic Metals from Waste Printed Circuit Boards with Deep Eutectic Solvents and Ionic Liquids

The recycling of metals from waste printed circuit boards (WPCBs) has been presented as a solid–liquid extraction process using two deep eutectic solvents (DESs) and four ionic liquids (ILs). The extraction and separation of Cu(II), Ag(I), and other metals, such as Al(III), Fe(II), and Zn(II), from the solid WPCBs (after the physical, mechanical, and thermal pre-treatments) with different solvents are demonstrated. Two popular DESs were used to recover valuable metal ions: (1) choline chloride + malonic acid, 1:1, and (2) choline chloride + ethylene glycol, 1:2. The extraction efficiencies of DES 1 after two extraction and two stripping stages were only 15.7 wt% for Cu(II) and 17.6 wt% for Ag(I). The obtained results were compared with those obtained with four newly synthetized ILs as follows: didecyldimethylammonium propionate ([N10,10,1,1][C2H5COO]), didecylmethylammonium hydrogen sulphate ([N10,10,1,H][HSO4]), didecyldimethylammonium dihydrogen phosphate ([N10,10,1,1][H2PO4]), and tetrabutylphosphonium dihydrogen phosphate ([P4,4,4,4][H2PO4]). Various additives, such as didecyldimethyl ammonium chloride surfactant, DDACl; hydrogen peroxide, H2O2; trichloroisocyanuric acid, TCCA; and glycine or pentapotassium bis(peroxymonosulphate) bis(sulphate), PHM, were used with ILs during the extraction process. The solvent concentration, quantity of additivities, extraction temperature, pH, and solid/liquid, as well as organic/water ratios, and the selectivity and distribution ratios were described for all of the systems. The utilization of DESs and the new ILs with different additives presented in this work can serve as potential alternative extractants. This will help to compare these extractants, additives, extraction efficiency, temperature, and time of extraction with those of others with different formulas and procedures. The metal ion content in aqueous and stripped organic solutions was determined by the ICP-MS or ICP-OES methods. The obtained results all show that solvent extraction can successfully replace traditional hydrometallurgical and pyrometallurgical methods in new technologies for the extraction of metal ions from a secondary electronic waste, WPCBs.

Biosorption of Technologically Valuable Metal Ions on Algae Wastes: Laboratory Studies and Applicability

In the context of a circular economy that recommends the most efficient use of wastes, algae wastes have a huge potential for valorization. In this study, algae wastes obtained after the alkaline extraction of active compounds from two types of marine algae (green algae—Ulva sp. and red algae—Callithamnion sp.) were used as biosorbents to remove metal ions from aqueous effluents. The efficiency of these biosorbents was tested for Zn(II), Cu(II), and Co(II) ions, considered technologically valuable metal ions. The batch monocomponent experiments performed under optimal conditions (pH = 5.0; 4.0 g biosorbent/L; 22 ± 1 °C) showed that more than 75% of the metal ions were removed when their initial concentration was less than 1.25 mmol/L. The experimental data were well described by the pseudo-second-order kinetic model and Langmuir isotherm model. The high values obtained for the maximum biosorption capacity (qmax: Cu(II) (0.52 mmol/g) > Zn(II) (0.41 mmol/g) > Co(II) (0.39 mmol/g) for G-AWB, and qmax: Cu(II) (1.78 mmol/g) > Zn(II) (1.72 mmol/g) > Co(II) (1.66 mmol/g) for R-AWB) show the potential use of these biosorbents to remove such technologically valuable metal ions from industrial wastewater. This possibility was tested using industrial wastewater samples obtained from the metal coating industry. The quantitative removal (>91%) of Zn(II), Cu(II), and Co(II) ions was obtained when their initial concentration was adjusted to 50 mg/L. In addition, the rapid and efficient desorption of these metal ions from loaded biosorbents by simple treatment with small volumes of HNO3 (10−1 mol/L) further emphasizes the possibility of their recovery and reuse in the technological circuit. The results included in this study indicate that algae wastes have the potential to be used in industrial effluent decontamination processes and open new perspectives for the implementation of circular economy principles.

Recovery of metal ion resources from waste lithium batteries by in situ electro-leaching coupled with electrochemically switched ion exchange

A new green pathway of in situ electro-leaching coupled with electrochemically switched ion exchange (EL-ESIX) technology was developed for the separation and recovery of valuable metal ions from waste lithium batteries. By using the in situ electro-leaching, the leaching rates of Li+ and Co2+ from the prepared LiCoO2 film electrodes reached 100 % and 93.30 %, respectively, under the combined effect of the acidic microenvironment formed by the anodic electrolytic water and electrostatic repulsion. Subsequently, the Li+ in the electrolyte was further extracted by an electrochemically switched ion exchange (ESIX) process using LiMn2O4 as the film electrode, and Li+ was further enriched in the eluate by a cyclic adsorption and desorption process. The results indicate that the in situ electro-leaching has significant advantages over powder leaching, and for the recycling of waste lithium batteries, the final lithium recovery rate reached 94.51 % by using this in situ EL-ESIX technology.

Liquid membrane coupled electrodialysis system for highly-efficient lithium recovery from fly ash acid leaching solution

Recovering lithium (Li) from high Li-bearing coal fly ash (CFA) is a challenging task due to CFA's complexity and minor content of Li. Acid leaching is a common treatment, but it faces the difficulties of complex leaching solution and selective separation of Li+. This work evaluated a liquid membrane coupled with the electrodialysis (LME) system to separate Li+ from the CFA leach liquor. The liquid membrane (LM) performs as an ion carrier to selectively transport Li+, while the electric field can drive the ion migration. The results show that the LM TBP+[HOEmim][NTf2] (v/v, 5:5) exhibits the best recognition and releasing ability toward Li+. The selective migration of Li+ can be achieved in acidic environment in the presence of concentrated Al3+. The Al/Li ratio decreases from 30 of the feed to 0.55 in the receiving solution after 12 h at 3 V. The practical application in the CFA leach liquor indicates that the system has preferential selectivity for transmembrane transport of Li+, while other multivalent ions were mostly hindered. This work presents a new idea for Li recovery from the solid waste residues, and offers a deep insight into the separation of valuable metal ions from complex solutions.

Performance scrutiny of spent lithium-ion batteries cathode material as a catalyst for oxidation of benzyl alcohol

The widespread use of Li-ion batteries (LIBs) in energy storage devices has resulted in the generation of additional waste which contains valuable metal ions and these metal ions are well known for their catalytic activities. The recovered black mass of cathode material was exposed to pretreatment with final calcination for 2 h at 800 0C. After the calcination, the material was subjected to structural characterization (XRD, FE-SEM, EDAX, and XPS). In the present work, we have used spent LIBs cathode material as a catalyst for the oxidation reaction of benzyl alcohol to benzoic acid. The catalytic activity of this recovered cathode material was found to be highly efficient showing 100% conversion of benzyl alcohol with >99% selectivity of benzoic acid with lower catalyst loading of even 2%.

Efficient separation and coprecipitation for simplified cathode recycling

Hydrometallurgical recycling of spent lithium-ion batteries is among the most promising recovery approaches. The current hydrometallurgical method for battery recycling faces challenges such as complex separation and precipitation processes, and environmental concerns from the use of caustic inorganic acid and hazardous hydrogen peroxide. Our proposed modified method, namely polyol-metallurgy, uses citric acid in ethylene glycol as dual-function green solution to overcome these obstacles. This bifunctional solution leaches valuable metal ions from cathode materials (e.g., LiCoO2), and then acts as chelating agents to selectivxely precipitate cobalt through an esterification reaction, without the need for additional precipitation agents. The leaching efficiency of cobalt and lithium reaches 99.55 % and 97.65 %, respectively, and more than 96 % of cobalt could be directly self-precipitated and recovered. The unique characteristics of the dual-function solution also avoids impurities from Al foils and PVDF/carbon black films, enabling the simple separation process. Therefore, the process can be completed in one-pot system with efficient leaching, separation and coprecipitation, making it more efficient and feasible for operation than existing alternatives.

Bifunctional hydrophobic deep eutectic solvents for selective recovery of Sm and Co from waste SmCo permanent magnets

The application of hydrophobic deep eutectic solvent (HDES) to single-use separation of valuable metal ions in waste samarium-cobalt permanent magnets has been a significant challenge. Trioctylphosphine oxide and 3-benzoyl-1,1,1-trifluoroacetone were combined to prepare a bifunctional HDES that was investigated for green, efficient and safe recovery Sm and Co. Firstly, internal hydrogen bond interaction was verified by DSC, TGA, NMR, FT-IR and molecular dynamics study. Then, a various of optimization experiments were carried out to discovery extraction behaviors on different metal ions. The findings indicated that the acidity has a significant impact on the effectiveness of the extraction process. The maximum extraction capacities were measured as 98.8 g/L Sm(III), 64.8 g/L Co(II), 52.4 g/L, Fe(III) and 75.1 g/L Cu(II), respectively. After that, combined with UV–vis, FT-IR and XPS, the neutral complex extraction mechanism was proposed. Finally, the competitive extraction experiments at different acidity provided the theoretical underpinnings for a three-stage separation strategy that, through acidity control and the use of various stripping agents, was able to efficiently recover 97.8% Sm(III), 99.1% Co(II), 99.5% Fe(III) and 95.6% Cu(II). The whole recycling process has no need additional organic solvents, enabling cleaner and sustainable engineering production.

Rapid extraction of valuable metals from spent LiNixCoyMn1-x-yO2 cathodes based on synergistic effects between organic acids

The slow rate of organic acid leaching is the main factor hindering the ecological recycling of spent lithium-ion battery (LIB) cathode materials. Here, a mixed green reagent system of ascorbic acid and acetic acid is proposed to leach valuable metal ions from the spent LIBs cathode materials rapidly. In 10 min, 94.93% Li, 95.09% Ni, 97.62% Co, and 96.98% Mn were leached, according to the optimization results. Kinetic studies and material characterization technologies like XRD, SEM, XPS, UV–vis, and FTIR show that the “diffusion” and “stratification” effects of acetic acid contribute to the dual-function leaching agent ascorbic acid quickly extract metal ions from spent LiNi0.5Co0.3Mn0.2O2 (NCM532) materials at a mild temperature. In addition, the density-functional theory (DFT) calculations of spent NCM532 structural surfaces and leaching agents show that the fast leaching of valuable metal ions is due to the synergy between ascorbic acid and acetic acid. These results provided an approachable thinking for developing advanced and environmentally friendly strategies for recycling spent LIB cathode materials.

Seawater bittern recovery system for CO2, SOx and NOx removal using microbubble scrubber

In salt production, a considerable amount of seawater bittern is discharged, which contains valuable metal ions such as K+ and Mg2+. These metal ions react with sulfate and carbonate ions and can be used to isolate air pollutants. Here, this work developed a seawater bittern recovery process using a novel microbubble scrubber with the aim of CO2, SOx, and NOx reduction. The low equipment cost and compactness of the microbubble scrubber makes it highly compatible to industrial applications. In addition, it removes air pollutants using only distilled water, which is environmentally and economically desirable. To design the proposed system, a process model is developed based on the experimental results for the developed microbubble scrubber. The suggested process comprises the following four procedures: (1) metal ion separation for KOH and Mg(OH)2 production, (2) CO2 capture using the produced KOH, (3) SOx and NOx capture using the microbubble scrubber, and (4) sulfurization and carbonation using the generated Mg(OH)2. The experimental results show that 98 % and 99 % of the CO2 and SOx can be captured and utilized as CaCO3 and CaSO4, respectively. Finally, the payback period (PBP) of the proposed process is determined to be 0.5 y, confirming its economic feasibility.

State-of-the-Art of Polymer/Fullerene C60 Nanocomposite Membranes for Water Treatment: Conceptions, Structural Diversity and Topographies.

To secure existing water resources is one of the imposing challenges to attain sustainability and ecofriendly world. Subsequently, several advanced technologies have been developed for water treatment. The most successful methodology considered so far is the development of water filtration membranes for desalination, ion permeation, and microbes handling. Various types of membranes have been industrialized including nanofiltration, microfiltration, reverse osmosis, and ultrafiltration membranes. Among polymeric nanocomposites, nanocarbon (fullerene, graphene, and carbon nanotubes)-reinforced nanomaterials have gained research attention owing to notable properties/applications. Here, fullerene has gained important stance amid carbonaceous nanofillers due to zero dimensionality, high surface areas, and exceptional physical properties such as optical, electrical, thermal, mechanical, and other characteristics. Accordingly, a very important application of polymer/fullerene C60 nanocomposites has been observed in the membrane sector. This review is basically focused on talented applications of polymer/fullerene nanocomposite membranes in water treatment. The polymer/fullerene nanostructures bring about numerous revolutions in the field of high-performance membranes because of better permeation, water flux, selectivity, and separation performance. The purpose of this pioneering review is to highlight and summarize current advances in the field of water purification/treatment using polymer and fullerene-based nanocomposite membranes. Particular emphasis is placed on the development of fullerene embedded into a variety of polymer membranes (Nafion, polysulfone, polyamide, polystyrene, etc.) and effects on the enhanced properties and performance of the resulting water treatment membranes. Polymer/fullerene nanocomposite membranes have been developed using solution casting, phase inversion, electrospinning, solid phase synthesis, and other facile methods. The structural diversity of polymer/fullerene nanocomposites facilitates membrane separation processes, especially for valuable or toxic metal ions, salts, and microorganisms. Current challenges and opportunities for future research have also been discussed. Future research on these innovative membrane materials may overwhelm design and performance-related challenging factors.

Utilization of desalination wastewater for SOx, NOx, and CO2 reduction using NH3: Novel process designs and economic assessment

Many countries discharge considerable amounts of desalination wastewater directly into the ocean, which cause environmental pollution, destruction of ecosystems, and economic losses. Desalination wastewater contains valuable metal ions such as Na+, Ca2+, and Mg2+, which react with carbonate and sulfate ions; therefore, it has the high potential to reduce the NOx, SOx, and CO2. Thus, this study designed process for the utilization of desalination wastewater to capture and utilize NOx, SOx, and CO2 using NH3. A process model was developed, which was composed of following three steps: (1) metal ion separation in desalination wastewater based on pH swing processes for separating Ca2+ and Mg2+ as Ca(OH)2 and Mg(OH)2, respectively; (2) NOx capture and SOx capture and utilization using generated Mg(OH)2, and (3) CO2 capture and utilization using NH3. Subsequently, to demonstrate the economic validity of the suggested process, an economic assessment was conducted and total annualized costs (TACs) of the conventional and proposed processes were compared. As a result, ~96 % of NOx was captured, the SOx capture efficiency was 99 %, and ~94.7 % of CO2 was captured. Thus, a reduction of 11.2 % in the TAC was achieved using the proposed process, indicating its high economic feasibility.

Sustainable electrochemical process for recovery of metal ions in synthetic mining wastewater and their utilization in photocathodic CO2 reduction into formic acid

The recovery and utilization of metal ions from mining and industrial wastewater are highly desirable to turn waste into wealth. Herein, polyaniline decorated date seed-derived activated carbon (PANI-DSAC) has been successfully used as an electrode for the capacitive deionization of Fe2+ and Cu2+ ions in synthetic mining wastewater. Symmetrical assembly of the PANI-DSAC CDI electrodes recovered 99% of the Fe2+ and Cu2+ ions from synthetic mining wastewater via several redox reactions. The mechanism of redox reactions and electrosorption of multiple metal ions has been demonstrated. In addition, the recovered metal ions by PANI-DSAC were then successfully converted to CuFe2O4/CFs-DSAC via the thermochemical conversion process. Further, CuFe2O4/CFs-DSAC was successfully used as a photocathode to reduce CO2 into formic acid. The results demonstrate that recovered valuable metal ions from mining wastewater can be utilized to fabricate high-performing functional electrocatalytic materials for energy conversion and storage applications.

The Use of Polymer Inclusion Membranes for the Removal of Metal Ions from Aqueous Solutions-The Latest Achievements and Potential Industrial Applications: A Review.

The growing demand for environmentally friendly and economical methods of removing toxic metal ions from polluted waters and for the recovery of valuable noble metal ions from various types of waste, which are often treated as their secondary source, has resulted in increased interest in techniques based on the utilization of polymer inclusion membranes (PIMs). PIMs are characterized by many advantages (e.g., the possibility of simultaneous extraction and back extraction, excellent stability and high reusability), and can be adapted to the properties of the removed target analyte by appropriate selection of carriers, polymers and plasticizers used for their formulation. However, the selectivity and efficiency of the membrane process depends on many factors (e.g., membrane composition, nature of removed metal ions, composition of aqueous feed solution, etc.), and new membranes are systematically designed to improve these parameters. Numerous studies aimed at improving PIM technology may contribute to the wider use of these methods in the future on an industrial scale, e.g., in wastewater treatment. This review describes the latest achievements related to the removal of various metal ions by PIMs over the past 3 years, with particular emphasis on solutions with potential industrial application.

Designing Metal-Chelator-like Traps by Encoding Amino Acids in Zirconium-Based Metal–Organic Frameworks

Metal chelators and porous sorbents are two of the forefront technologies applied for the recovery and separation of hazardous and/or valuable metal ions from aqueous solutions (i.e., polluted water sources, metal-rich mining wastewaters, acid leachates, and so forth). The transfer of the metal coordination functions of metal chelators to chemically stable host materials had only limited success so far. Here, we report the installation of natural acids (i.e., malic acid, mercaptosuccinic acid, succinic acid, fumaric acid, and citric acid) and amino acids (i.e., histidine, cysteine, and asparagine) within a porous zirconium-based trimesate metal–organic framework (MOF), namely, MOF-808. Applying this strategy, we were able to produce a pore environment spatially decorated with multiple functional groups usually found in commercial chelator molecules. The chemical stability of the amino acid molecules installed by the solvent-assisted ligand exchange has been studied to delimitate the applicability window of these materials. The adsorption affinity of MOF-808@(amino)acids in static and column-bed configurations can be fine-tuned as a function of the amino acid residues installed in the framework. MOF-808(amino)acid columns can be applied efficiently both for water remediation of heavy metals and for the separation of metal ions with different acidities. For instance, the initial trends for the dispersion of rare-earth elements have been identified. Electron paramagnetic resonance and inelastic neutron scattering spectroscopy reveal that MOF-808@(amino)acids stabilize metal centers as isolated and clustered species in a coordination fashion that involves both the amine and thiol functionals and that affects the vibrational freedom of some of the chemical groups of the amino acid molecules. The metal-ion stabilization within amino acid-decorated MOFs opens the avenue for application for pseudo biocatalysis purposes in the near future.

Comprehensive extraction of valuable metals from waste ternary lithium batteries via roasting and leaching: Thermodynamic and kinetic studies

Considering the existing problems in the extraction of waste ternary materials, a method of reduction roasting - sulfuric acid leaching is proposed in this paper. The waste ternary battery material is mixed with carbon powder, reduced and roasted in an argon atmosphere to destroy the original crystal lattice of the ternary material, adjust the valuable metal ions to a valence state suitable for leaching, and reduce the difficulty of leaching. Moreover, recycling waste lithium batteries were systematically studied from the thermodynamic and kinetic aspects. Thermodynamic calculations indicate that the theoretical temperature for reduction roasting is 500–650 °C, and the roasting products are composed of lithium carbonate, nickel, cobalt, nickel oxide and manganese oxide, which has been confirmed by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy analysis. The activation energy for the reduction roasting of the cathode material was calculated as 134.7 kJ/mol by thermogravimetry–differential scanning calorimetry and Kissinger formula. The roasted electrode materials were subjected to an acid leaching process. The effects of roasting and leaching conditions on the metal extraction from waste ternary batteries were investigated based on thermodynamic calculations, and the following optimal conditions were identified: 10% carbon content, 600 °C roasting temperature, 120 min roasting time, 2 mol/L sulfuric acid concentration, 85 °C leaching temperature, 10:1 liquid-to-solid ratio and 60 min leaching time. The extraction of lithium, nickel, cobalt, and manganese reached 98.3%, 97.2%, 98.8%, 96.1%, respectively, under the optimal conditions. The kinetic analysis of the acid leaching process adopted the shrinking core model and Arrhenius formula. The activation energies of lithium, nickel, cobalt, and manganese leaching were 23.9 kJ/mol, 25.2 kJ/mol, 23.0 kJ/mol, and 27.6 kJ/mol, respectively, which indicates that acid leaching is an internal diffusion control process. This study provides an economical and efficient process route and lays a theoretical and technological foundation for the extraction of cathode materials from waste ternary batteries.

Aminopolycarboxylic Acids-Functionalized Chitosan-Based Composite Cryogels as Valuable Heavy Metal Ions Sorbents: Fixed-Bed Column Studies and Theoretical Analysis.

Over the years, a large number of sorption experiments using the aminopolycarboxylic acid (APCA)-functionalized adsorbents were carried out in batch conditions, but prospective research should also be directed towards column studies to check their industrial/commercial feasibility. In this context, sorption studies of five-component heavy metal ion (HMI) solutions containing Zn2+, Pb2+, Cd2+, Ni2+, and Co2+ in equimolar concentrations were assessed in fixed-bed columns using some APCA-functionalized chitosan-clinoptilolite (CS-CPL) cryogel sorbents in comparison to unmodified composite materials. The overall sorption tendency of the APCA-functionalized composite sorbents followed the sequence Co2+ < Zn2+ < Cd2+ ≤ Pb2+ < Ni2+, meaning that Co2+ ions had the lowest affinity for the sorbent’s functional groups, whereas the Ni2+ ions were strongly and preferentially adsorbed. To get more insights into the application of the composite microbeads into continuous flow set-up, the kinetic data were described by Thomas and Yoon–Nelson models. A maximum theoretical HMI sorption capacity of 145.55 mg/g and a 50% breakthrough time of 121.5 min were estimated for the column containing CSEDTA-CPL cryogel sorbents; both values were much higher than those obtained for the column filled with pristine CS-CPL sorbents. In addition, desorption of HMIs from the composite microbeads in dynamic conditions was successfully achieved using 0.1 M HCl aqueous solution. Moreover, a theoretical analysis of APCA structures attached to composite adsorbents and their spatial structures within the complex combinations with transition metals was systematically performed. Starting from the most stable conformer of EDTA, coordinative combinations with HMIs can be obtained with an energy consumption of only 1 kcal/mole, which is enough to shift the spatial structure into a favorable conformation for HMI chelation.

Cu(II) and Au(III) recovery with electrospun lignosulfonate CO2-activated carbon fiber

The objectives of this study were twofold: developing lignosulfonate activated carbon fibers (LACFs) and determining the corresponding metal recovery mechanisms with batch experiments and non-linear modeling. LACFs were developed through electrospinning, followed by CO2-based physical activation. Physical and chemical characterizations revealed that the LACF sample that was activated for 60 min exhibited a higher specific surface area (376.54 m2/g), larger total pore volume (0.30 cm3/g), higher micropore ratio (32%), and more acidic and sulfur functional groups than did the other samples. Cu(II) and Au(III) adsorption behaviors on the LACF could be described with the Freundlich and Langmuir model, respectively. Both systems consist of physisorption and chemisorption, and the mechanisms include electrostatic forces, Van der Walls forces, cation exchange, surface complexation. In particular, Au(III) adsorption was faster, and LACF-Au bonds were stronger due to the additional microprecipitation. Furthermore, the LACF sample could regenerate after three adsorption-desorption cycles. Overall, this study provides the foundation for developing physically activated lignosulfonate carbon and its application in recovering valuable metal ions.