Recovery Of Metals Research Articles

Design, spectroscopic analysis, DFT calculations, adsorption evaluation, molecular docking, comprehensive in silico and in vitro bioactivity studies of thiocarbohydrazide grafted dialdehyde cellulose nanobiosorbent

Heavy metals have attracted considerable attention lately because of their widespread occurrence in aquatic environments and potential biological toxicity to animals and human. The current investigation focused on synthesizing the DAC@TCH nanobiosorbent by coupling dialdehyde cellulose with thiocarbohydrazide ligand. Subsequent characterization of DAC@TCH was carried out utilizing various analytical methods such as elemental analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), and thermogravimetric analysis (TGA and DTA). DFT calculations were utilized to verify the molecular structure, analysis of frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP) and reactivity descriptor for all phases. In vitro experiments were conducted to evaluate the biological properties of the DAC@TCH nanobiosorbent. These findings revealed that the synthesized DAC@TCH nanobiosorbent has been observed to show effective antibacterial IZD value against E. Coli (28 mm) which is superior to the efficacy of standard drug amoxicillin used (5 mm). Furthermore, in silico antibacterial activities (molecular docking) of the DAC@TCH have indicated this to exhibit excellent efficacy with docking score of (−7.4237 kcal/mol) and (−7.1325 kcal/mol) for S. aureus and, E. coli, respectively. Meanwhile the binding energies (best docking scores) in kcal/mol for Amoxicillin are (−5.8090) and (−6.7442) for S. aureus and, E. coli, respectively. Drug-likeness rules like Lipinski’s, Veber’s and Egan’s were considered for a more comprehensive evaluation. The prepared DAC@TCH nanobiosorbent was investigated for its potential to adsorb metal ions (Ag+, Hg2+, and Cu2+) from diverse water samples. Optimal conditions including pH, temperature, DAC@TCH dosage, oscillation time, initial metal ion concentration, and interference from other ions were explored. The adsorption of Hg2+, Cu2+, and Ag+ ions by DAC@TCH followed pseudo-second-order kinetics and Langmuir isothermal model, achieving maximum adsorption capacities of 196 mg/g for Ag+, 190 mg/g for Hg2+, and 73 mg/g for Cu2+. The adsorption process was determined to be exothermic and spontaneous across varying temperatures. Additionally, over 95% of adsorbed metal ions were effectively desorbed using thiourea (5%) and 0.3 M HNO3 elution mixture. DAC@TCH nanobiosorbent demonstrated excellent reusability, retaining its adsorption capacity through five cycles without degradation. The study highlights the potential of DAC@TCH for efficient recovery of heavy metals from different water sources, considering its application versatility, reusability, and minimal interference. Furthermore, the plausible mechanism of Ag+, Hg2+, and Cu2+ adsorption onto DAC@TCH bionanosorbent is elucidated.

Functionalized Polyethylene Terephthalate Nanofiber Adsorbents for Prospective Metal Recovery from Spent Lithium-Ion Batteries

The lack of economically viable and environmentally friendly recycling processes to recover valuable metals from spent lithium-ion batteries (LIBs) has resulted in an environmental pollution and a high risk of metal resource shortage. Among various approaches, adsorption using electrospun nanofiber adsorbents has attracted research interest due to several distinctive properties. This study synthesized electrospun polyethylene terephthalate (PET) nanofiber adsorbent which was functionalized with Di-2-ethylhexyl phosphoric acid (DEHPA) to recover Ni, Co, or Mn metal ions. The pristine and modified electrospun nanofibers were characterized using Fourier Transform Infrared spectroscopy (FTIR)-Attenuated Total Reflection (ATR), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Thermogravimetric Analysis (TGA), and X-ray Diffraction (XRD). The adsorption kinetics and capacity of the modified PET-DEHPA nanofibers were obtained at optimum pH 4; 60 min of contact time and 100 mg/L initial metal concentration. The adsorption capacity of PET-DEHPA nanofibers for Ni, Co and Mn metal ions was 80 mg/g, 98 mg/g, and 118 mg/g, respectively. The selectivity of Mn over Ni and Co metal ions was also examined at pH 4 and showed that the recovery efficiencies were 5%; 11% and 58% for Ni, Co and Mn, respectively. Thus, indicating that the modified PET-DEHPA nanofiber was selective for Mn ions. The desorption and regeneration were also studied in solutions of nitric acid and Ni, Co and Mn ions, and results showed that PET-DEHPA nanofiber was able to withstand over 5 cycles, highlighting its potential in economic viability and sustainability. Overall, this study presents a new and promising approach for recycling Mn ions from solutions of spent LIBs.

Mechanism and Kinetics for Copper Leaching by Complexing with Lysine Bearing Two Amino Groups.

In order to overcome the environmental problems associated with ammonia volatilization during the ammonia leaching process, the leaching effects of copper by amino acids with various numbers and substitution positions of amino functional groups were systematically studied. The results showed that lysine had the best leaching efficiency for copper. When the concentration of lysine was 0.2 mol/L, the leaching temperature was 20 °C, the molar ratio of lysine to copper was 3.88, the stirring speed was 250 rpm, the pH was 10, and the leaching time was 14 h, the leaching rate of copper reached 99%. The leaching results of copper containing smelting slag showed that lysine has an excellent effect on selective leaching of copper. The leaching kinetic results indicated that the rate-limiting step of the leaching process is controlled by the interfacial chemical reaction, with an apparent activation energy of 64.8 kJ/mol. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses confirmed that COO- and -NH groups in lysine can form complexes with copper ions. Compared to conventional methods, this approach not only achieves environmentally benign disposal of heavy metal pollutants but also provides a novel strategy for the green recovery of valuable metals from secondary resources.

Anaerobic Bioremediation of Acid Mine Drainage Using Sulphate-Reducing Bacteria: Current Status, Challenges, and Future Directions

Biological reduction of sulphates has gradually replaced unit chemical processes for the treatment of acid mine drainage (AMD), which exerts a significant environmental impact due to its elevated acidity and high concentrations of heavy metals. Bioremediation is optimally suited for the treatment of AMD because it is cost-effective and efficient. Anaerobic bioremediation employing sulphate-reducing bacteria (SRB) presents a promising solution by facilitating the reduction of sulphate to sulphide. The formed can precipitate and immobilise heavy metals, assisting them in their removal from contaminated wastewater. This paper examines the current status of SRB-based bioremediation, with an emphasis on recent advances in microbial processes, reactor design, and AMD treatment efficiencies. Reviewed studies showed that SRB-based bioreactors can achieve up to 93.97% of sulphate reduction, with metal recovery rates of 95% for nickel, 98% for iron and copper, and 99% for zinc under optimised conditions. Furthermore, bioreactors that used glycerol and ethanol as a carbon source improved the efficiency of sulphate reduction, achieving a pH neutralisation from 2.8 to 7.5 within 14 days of hydraulic retention time. Despite the promising results achieved so far, several challenges remain. These include the need for optimal environmental conditions, the management of toxic hydrogen sulphide production, and the economic feasibility of large-scale applications. Future directions are proposed to address these challenges, focusing on the genetic engineering of SRB, integration with other treatment technologies, and the development of cost-effective and sustainable bioremediation strategies. Ultimately, this review provides valuable information to improve the efficiency and scalability of SRB-based remediation methods, contributing to more sustainable mining practices and environmental conservation. To ensure relevance and credibility, relevance and regency were used as criteria for the literature search. The literature sourced is directly related to the subject of the review, and the latest research, typically from the last 5 to 10 years, was prioritised.

Extraction of Copper from Printed Circuit Boards in an Alkaline Solution Using EDTA

With the rapid technological development in the 21st century, the increasing consumption of electronic devices has led to a rise in the generation of waste electrical and electronic equipment (WEEE) due to the disposal of equipment considered obsolete. A significant portion of these wastes contain printed circuit boards (PCBs), which serve as substrates for the connection of microchips, resistors, capacitors, and other components. These boards are composed of various materials, primarily metals such as copper. Thus, this study investigated the recovery of copper from PCB waste (WPCBs) from computers through alkaline leaching, using EDTA and hydrogen peroxide at temperatures of 40 °C, 60 °C, and 80 °C, with a concentration of 0.6 mol/L and varying particle sizes. Using a UV-VIS spectrophotometer, it was observed that the copper extraction process with EDTA at 0.6 mol/L and a temperature of 60 °C achieved a recovery rate of 78.6% for particles smaller than 0.177 mm after 180 min, following the Avrami kinetic model. The results highlight the potential of EDTA as a complexing agent in copper extraction, positioning it as a promising technique to reduce environmental contamination and recover strategic resources through urban mining through the recovery of metals from WEEE.

Treatment of Metallurgical Residues by Chemical Modification, Reduction, and Phase Modification for Metal Recovery and Slag Utilization

Advancing material efficiency in the steel and cement industry is essential for achieving climate goals. One approach to addressing this is to increase the provisioning of alternative reactive binder materials from residues, in this case, from the steel industry. Different mixtures of identified residues are evaluated for metal recovery and suitability as supplementary cementitious material. For this purpose, suitable combinations are modeled according to specified quality requirements from the cement industry. These mixtures are heated up to 1600 °C for a targeted reduction of predominantly transition metal oxides and a separation into a mineral fraction. Subsequently, controlled cooling of the molten material is implemented through water granulation. The produced granulate is crushed and sieved, and finally, the metallic and mineral fractions are magnetically separated. The chemical modification, reduction, and phase modification are tested to prevent landfilling and provide alternative secondary resources for the steel and cement industry. According to the results, it is possible to recover metals from metallurgical residues and simultaneously separate the modified mineral fraction as an alternative cement constituent. These findings will be further investigated through additional research to identify the variables that influence and impact/affect the reduction efficiency.

Proteomic Insights into the Adaptation of Acidithiobacillus ferridurans to Municipal Solid Waste Incineration Residues for Enhanced Bioleaching Efficiency.

Acidithiobacillus spp. have traditionally been utilized to extract metals from mineral ores through bioleaching. This process has recently expanded to include artificial ores, such as those derived from municipal solid waste incineration (MSWI) residues. Previous studies have indicated that microbial adaptation enhances bioleaching efficiency, prompting this study to identify proteins involved in the adaptation of A. ferridurans to MSWI residues. We employed data-independent acquisition-parallel accumulation serial fragmentation to determine the proteomic response of A. ferridurans DSM 583 to three distinct materials: bottom ash (BA), kettle ash (KA), and filter ash (FA), which represent typical MSWI residues. Our findings indicate that, irrespective of the residue type, a suite of membrane transporters, porins, efflux pumps, and specific electron and cation transfer proteins was notably upregulated. The upregulation of certain proteins involved in anaerobic pathways suggested the development of a spontaneous microaerobic environment, which minimally impacted the bioleaching efficiency. Additionally, the adaptation was most efficient at half the target FA concentration, marked by a significant increase in the detoxification and efflux systems required by microorganisms to tolerate high heavy metal concentrations. Given that metal recovery peaked at lower FA concentrations for most metals of interest, further adaptation at the level of protein expression may not be warranted for improved bioleaching outcomes.

Decatungstate‐Driven Photocatalytic Pathways for Sustainable and Cleaner Recovery of Precious Metals

The recovery of precious metals from waste streams is crucial for sustainable resource utilization but remains hindered by traditional methods involving high toxicity, energy consumption, and environmental pollution. Here, we present a photocatalytic strategy employing hydrothermally synthesized decatungstate ([W10O32]4‐) homogeneous ion catalysts to achieve simultaneous oxidation and reduction of precious metals under ambient conditions. This innovative approach integrates solvent‐controlled reaction pathways, enabling efficient dissolution and recovery of precious metals from diverse waste sources, including electronic waste (e‐waste), platinum membrane electrodes, and platinum‐containing catalysts. The decatungstate catalyst exhibits exceptional performance, with an apparent quantum yield of 0.027%—nearly double that of commercial TiO2 (0.014%)—and achieves recovery efficiency of 80–100% for platinum, surpassing 21 tested photocatalysts. The process adheres to a solid‐phase dissolution model and remains against ionic interference. Time‐dependent density functional theory (TD‐DFT) calculations corroborate experimental UV‐Vis spectra, while electron‐hole pair analyses elucidate atomic and molecular contributions to photocatalytic activity. Density functional theory (DFT) further validates the thermodynamic feasibility of the reaction pathways. By combining high efficiency, ambient operational conditions, and scalability, this work establishes decatungstates as a sustainable benchmark for green precious metal recovery, addressing the limitations of traditional methods and advancing innovation in resource circularity.

Decatungstate-Driven Photocatalytic Pathways for Sustainable and Cleaner Recovery of Precious Metals.

The recovery of precious metals from waste streams is crucial for sustainable resource utilization but remains hindered by traditional methods involving high toxicity, energy consumption, and environmental pollution. Here, we present a photocatalytic strategy employing hydrothermally synthesized decatungstate ([W10O32]4-) homogeneous ion catalysts to achieve simultaneous oxidation and reduction of precious metals under ambient conditions. This innovative approach integrates solvent-controlled reaction pathways, enabling efficient dissolution and recovery of precious metals from diverse waste sources, including electronic waste (e-waste), platinum membrane electrodes, and platinum-containing catalysts. The decatungstate catalyst exhibits exceptional performance, with an apparent quantum yield of 0.027%-nearly double that of commercial TiO2 (0.014%)-and achieves recovery efficiency of 80%-100% for platinum, surpassing 21 tested photocatalysts. The process adheres to a solid-phase dissolution model and remains against ionic interference. Time-dependent density functional theory (TD-DFT) calculations corroborate experimental UV-vis spectra, while electron-hole pair analyses elucidate atomic and molecular contributions to photocatalytic activity. Density functional theory (DFT) further validates the thermodynamic feasibility of the reaction pathways. By combining high efficiency, ambient operational conditions, and scalability, this work establishes decatungstates as a sustainable benchmark for green precious metal recovery, addressing the limitations of traditional methods and advancing innovation in resource circularity.

Enhanced Redox Capacity and Hydrogen Bonding Interactions for Efficient Metal Recovery from Spent Batteries

AbstractGreen and efficient recycling of critical metals from spent lithium‐ion batteries is of great importance. Deep eutectic solvents (DESs) show great potential to replace conventional inorganic acids due to their eco‐friendly, low‐cost, and superior leaching performance. However, the low solid–liquid ratio, high leaching temperature, and complex stepwise recovery processes may lead to large solvent and energy consumption. Herein, a selection principle is proposed according to the enhanced redox capacity and abundant hydrogen bonding interactions, which help to design novel ternary DESs. The results demonstrate that the DESs could disrupt metal–oxygen bonds efficiently and reduce high‐valent metals to form low‐valent metal complexes in solution. Besides, water as a dilutant can reduce the viscosity of DESs and benefit to form abundant hydrogen bonds. As a result, the DESs can achieve high‐metal leaching efficiency of 98.65% (Li), 96.92% (Ni), 96.94% (Co), and 95.53% (Mn) at relatively low temperature (60 °C) and high solid–liquid ratio (RS/L = 10), respectively. The regenerated cathodes via co‐precipitation methods exhibit excellent electrochemical performance similar to that of commercial ternary cathodes. Finally, the economic and environmental evaluation of the entire process shows high profitability and low environmental impact.

Recovery of valuable metals from spent hydrodesulfurization (HDS) catalysts: A comprehensive research review and specific industrial cases.

Recovery of valuable metals from spent hydrodesulfurization (HDS) catalysts: A comprehensive research review and specific industrial cases.

Effect of microwave roasting in the leaching of the transition metals Ni, Fe, and Co from the low-grade nickel laterite

Abstract In many cases, low-grade nickel laterite ores with nickel (Ni) content of 1.2% or less have been left as land disposal at the mining areas. We are looking for an alternative, more environmentally friendly method to process this waste in a hydrometallurgical scheme. This study investigates the effectiveness of microwave-assisted recovery of transition metals—specifically nickel (Ni), iron (Fe), and cobalt (Co)—from low-grade nickel laterite (Ni<1.5%). The methodology involves roasting the sulfuric acid-nickel laterite mixture and leaching it at room temperature. The results reveal that microwave roasting significantly enhances metal recovery, achieving remarkable rates of 98.6% for nickel, 96.9% for iron, and 99.0% for cobalt, even under low microwave powers of 100 W, 180 W, and 300 W, with only 5 minutes of heating time. A solid-to-solution ratio of 1.2 g/mL was maintained throughout the process. While higher microwave power did lead to a slight decrease in recovery efficiency due to temperatures exceeding the boiling point of sulfuric acid, the overall process remained highly efficient. The mineralogical analysis indicated that the nickel laterite is primarily composed of dolomite, calcite, goethite, nepouite, vermiculite, and cristobalite, highlighting the complexity of the material. Additionally, extending the heating duration at lower powers can reduce acid consumption, contributing to the environmental sustainability of the extraction method compared to conventional techniques. These findings underscore not only the potential of microwave technology in mineral processing but also promote more sustainable practices in the recovery of valuable metals from low-grade ores.

Metal recovery in mobile phone waste: Characterization of metal composition and economic assessment through shredding and screening processes.

Metal recovery in mobile phone waste: Characterization of metal composition and economic assessment through shredding and screening processes.

Adsorption isotherms, kinetics, and thermodynamics of Au(III) on chitosan/palm kernel fatty acid distillate/magnetite nanocomposites.

Adsorption isotherms, kinetics, and thermodynamics of Au(III) on chitosan/palm kernel fatty acid distillate/magnetite nanocomposites.

Dynamic redox-regulation of layered Fe-Cr(III) hydroxides for heavy metals capture: Exploring sustainable utilization of Fe-Cr residues

Dynamic redox-regulation of layered Fe-Cr(III) hydroxides for heavy metals capture: Exploring sustainable utilization of Fe-Cr residues

Recovery of platinum group metals from spent automotive catalysts: Review of conventional techniques and vacuum metallurgy

Recovery of platinum group metals from spent automotive catalysts: Review of conventional techniques and vacuum metallurgy

Intensified and selective recovery of critical metals from aqueous extracts: Fundamentals and system design

Intensified and selective recovery of critical metals from aqueous extracts: Fundamentals and system design

Efficient separation and recovery of valuable metals from bismuth sulfide concentrate in methanesulfonic acid medium

Efficient separation and recovery of valuable metals from bismuth sulfide concentrate in methanesulfonic acid medium

Enhanced simultaneous recovery of phosphorus and metals from incinerated sewage sludge ash via combined wet-chemical extraction and cation exchange resin

Enhanced simultaneous recovery of phosphorus and metals from incinerated sewage sludge ash via combined wet-chemical extraction and cation exchange resin

Comprehensive recovery of valuable metals from laterite via neutralization sludge

Comprehensive recovery of valuable metals from laterite via neutralization sludge