Article
Engineering, Environmental
Malgorzata Wasilewska, Adam Wojciech Marczewski, Dariusz Sternik
Summary: Temperature dependencies of adsorption equilibrium and kinetics of 2-, 3-, 4-nitrophenol by activated carbon were studied, showing an increase in adsorption rate and amount with rising temperature. Various models and equations were used for data analysis, and XPS technique was employed to study surface functional groups and adsorption mechanism, revealing weaker interactions of 2-nitrophenol molecules with carbon surface due to intramolecular hydrogen bonds.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2021)
Article
Engineering, Chemical
Kianoush Barani, Morteza Dehghani, M. R. Azadi, Ali Karrech
Summary: The study investigated the leaching of a polymetal gold ore using a synergistic lixiviant mixture of cyanide and glycine. Increasing cyanide concentration from 500 to 1500 ppm resulted in a higher gold dissolution rate. However, using 0.5-1 M/L glycine in 500 ppm cyanide can achieve 90% gold dissolution with increased copper dissolution.。Reducing cyanide consumption by approximately 80% was achieved at the optimal approach, but increasing glycine concentration also led to higher dissolution of other metals like Pb, Zn, Fe, Ag, and Cu.
MINERALS ENGINEERING
(2021)
Article
Engineering, Environmental
Wanying Zhou, Huiting Liang, Yuanye Lu, He Xu, Yongli Jiao
Summary: The study investigates the application of laboratory-generated biochar and activated carbon adsorbents in gold iodized solution for the recycling of waste mobile phone printed circuit boards (WMPCBs), aiming to solve problems associated with existing gold recovery technologies. Results showed that the adsorption efficiency of biochar and activated carbon reached 98% and 98.6% respectively, with biochar slightly inferior to activated carbon but similar in performance.
Article
Chemistry, Physical
Ke Li, Qian Li, Yan Zhang, Yongbin Yang, Tao Jiang
Summary: Thiourea leaching is a promising alternative to cyanidation for gold recovery. This study investigated the effect of metal ions on gold adsorption onto activated carbon from acidic thiourea solution. Metal ions such as Cu2+, Ag+, Pb2+, and Zn2+ interfered with gold adsorption, with Cu2+ and Ag+ having the greatest impact. Metal ions also adsorbed onto activated carbon, with their adsorption capacity following the order of Cu2+ > Ag+ > Pb2+ > Zn2+. The decrease in active sites on activated carbon occupied by metal ions resulted in a decrease in gold adsorption.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Chemistry, Physical
Nathalie de la Torre-Miranda, Laoise Reilly, Pierre Eloy, Claude Poleunis, Sophie Hermans
Summary: Cyanide salts, despite being toxic, are currently used in gold extraction processes as leaching agents. Thiosulfate, a greener alternative, is limited by the difficulty of recovering gold thiosulfate from the leachate using activated carbon, which is effective for gold-cyanide adsorption. To overcome this, activated carbon has been covalently functionalized with thiol groups (-SH) using cysteamine as a thiol-carrier molecule. The functionalized carbon achieves up to 100% gold recovery in 8-hour contact, and its performance is seemingly unaffected by the pH of the solution.
Article
Environmental Sciences
Hanjing Xu, Yuxue Liu, Hongxu Liang, Chengxiang Gao, Jingjing Qin, Lingcong You, Rui Wang, Jia Li, Shengmao Yang
Summary: Chemically activated carbon spheres were synthesized for the removal of Cr(VI) from aqueous solutions, showing high adsorption capacity and potential application prospects. The adsorption process of the activated carbon spheres towards Cr(VI) was mainly through single molecular layer adsorption and chemisorption, indicating their effectiveness in removing Cr(VI) pollutants.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Engineering, Chemical
Jian Wang, Ruixiang Wang, Yue Pan, Fupeng Liu, Zhifeng Xu
Summary: This paper proposes a novel copper-catalytic glycine thiosulfate collaborative system for gold leaching and constructs relevant thermodynamic diagrams and electrochemical models. The results show that this system has a wider pH range and lower consumption, providing a theoretical basis for gold leaching.
MINERALS ENGINEERING
(2022)
Article
Energy & Fuels
Joanna Lach, Agnieszka Ociepa-Kubicka, Maciej Mrowiec
Summary: This study evaluated the potential of using commercial and modified activated carbons for the removal of oxytetracycline from aqueous solutions. The activated carbons with larger specific surfaces showed better effectiveness, especially with adsorption from solutions at pH 6. Both methods of modifying activated carbon led to the production of adsorbents with higher monolayer capacities. The proposed modification method also boasted low electricity consumption.
Article
Materials Science, Multidisciplinary
Nathalie de la Torre-Miranda, Pierre Eloy, Ernesto de la Torre, Timothy Steenhaut, Claude Poleunis, Sophie Hermans
Summary: Thiosulfate is a non-toxic and efficient leaching agent that has the potential to replace cyanide in gold extraction. However, the challenge lies in the recovery of the formed gold thiosulfate complex. In this study, functionalized granular active carbon with covalently grafted primary and quaternary amine sites was proposed as a solution, achieving up to 100% gold recovery in acid and basic conditions.
MATERIALS CHEMISTRY AND PHYSICS
(2024)
Article
Chemistry, Multidisciplinary
Tahani Saad Algarni, Amal M. Al-Mohaimeed, Abdel-Basit Al-Odayni, Naaser A. Y. Abduh
Summary: This study investigated the potential advantage of ZnFe2O4-incorporated activated carbon (ZFAC) in the removal of cationic dye crystal violet (CV) from aqueous solutions. The results showed that ZFAC had a high adsorption capacity at optimal pH, temperature, and CV concentration, and the adsorption process followed the Langmuir isotherm model. Thermodynamic analysis indicated that the adsorption was spontaneous, endothermic, and a random process, supporting a physical adsorption mechanism.
Article
Engineering, Environmental
Yong Xiang, Wencai Bai, Jianggen Han, Zhouxuan Zang, Xiangmeng Chen, Li Xu, Guoji Liu
Summary: This study introduces a novel approach to address the challenges in Au(III) recovery by synthesizing metal sulfides through a one-step hydrothermal method. The synthesized CuS adsorbent demonstrates exceptional adsorption capacities, especially in extracting gold from complex solutions. Furthermore, CuS is successfully loaded onto sodium alginate aerogel for large-scale applications, overcoming the challenge of solution retrieval.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Environmental Sciences
Juan Zhang, Mingming Zhu, Isabelle Jones, Zhezi Zhang, Jian Gao, Dongke Zhang
Summary: Activated carbons produced from spent tyre pyrolysis char were evaluated for their performance in rhodamine B (RhB) adsorption. Factors such as RhB starting concentration, contact time, temperature, and initial pH were examined to understand their impact on the adsorption process. Results showed that activated carbons with higher mesoporosity had better adsorption capacity for RhB.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2021)
Article
Engineering, Chemical
Zhansheng Wu, Pengyun Liu, Zhilin Wu, Giancarlo Cravotto
Summary: This study aimed to enhance the adsorption capacity of activated carbon for naphthalene in aqueous solutions by preparing starch-based and pulverized coal-based activated carbons through a one-pot activation method. The findings showed that the pi-pi bond, H-bond, and hydrophobic effects played crucial roles in the adsorption process of naphthalene. Additionally, the optimized operating parameters were determined for effective column adsorption using the Thomas model.
Article
Environmental Sciences
Raja Selvaraj, Deepa Prabhu, P. Senthil Kumar, Gayathri Rangasamy, Gokulakrishnan Murugesan, Mouli Rajesh, Louella Concepta Goveas, Thivaharan Varadavenkatesan, Adithya Samanth, R. Balakrishnaraja, Ramesh Vinayagam
Summary: This study investigated the sustainable fabrication of magnetic iron oxide nanoadsorbent using activated carbon from inedible C. ramiflora fruit. The resulting nanocomposite exhibited a porous irregular dense matrix of amorphous evenly sized spherical nanoparticles and contained carbon, oxygen, iron, and phosphorous. It showed high adsorption capacity for tetracycline antibiotics and the adsorption process was confirmed to be endothermic, spontaneous, and with an enhanced degree of randomness.
Article
Environmental Sciences
Ramesh Vinayagam, Melisha Quadras, Thivaharan Varadavenkatesan, Devangshi Debraj, Louella Concepta Goveas, Adithya Samanth, Deepanraj Balakrishnan, Raja Selvaraj
Summary: This study focuses on the production of activated carbon from rubber fig leaves and its composite with iron oxide nanoparticles (RFAC@Fe2O3), as well as its ability to adsorb tetracycline. The physical and functional properties of RFAC@Fe2O3 nanocomposite were analyzed. The nanocomposite exhibited a high surface area, pore size, and mesoporous nature, making it suitable for adsorbing pollutants. The adsorption of tetracycline by RFAC@Fe2O3 was optimal at pH 4.0, and increased with higher nanocomposite dosage and stirring speed. The adsorption process followed the Freundlich isotherm and pseudo-second-order model.
ENVIRONMENTAL RESEARCH
(2023)
Article
Engineering, Chemical
J. J. Eksteen, E. A. Oraby, V. Nguyen
MINERALS ENGINEERING
(2020)
Article
Engineering, Chemical
Z. Deng, E. A. Oraby, J. J. Eksteen
MINERALS ENGINEERING
(2020)
Article
Engineering, Environmental
Huan Li, Elsayed Oraby, Jacques Eksteen
RESOURCES CONSERVATION AND RECYCLING
(2020)
Article
Engineering, Chemical
Z. Deng, E. A. Oraby, J. J. Eksteen
SEPARATION AND PURIFICATION TECHNOLOGY
(2020)
Article
Geochemistry & Geophysics
Callan Lowes, James Zhou, Teresa McGrath, Jacques Eksteen, Kevin Galvin
Article
Geochemistry & Geophysics
Huan Li, Elsayed Oraby, Jacques Eksteen, Tanmay Mali
Summary: This study presents a cyanide-free leaching method, glycine-ammonia leaching in the presence of permanganate, for treating low-grade and copper-bearing gold tailings. The addition of glycine, ammonia, and permanganate significantly enhanced gold and copper extractions. The solids content had no significant effect on copper extraction, while gold leaching kinetics was slightly better at lower solids content.
Article
Geochemistry & Geophysics
Zixian Deng, Elsayed Oraby, Huan Li, Jacques Eksteen
Summary: In this study, a hybrid approach using aqueous ammonia as a pH modifier and ceramic media was employed to leach copper from chalcopyrite. The glycine-ammonia system showed significantly better copper extraction compared to the traditional glycine-NaOH system. Adding ceramic beads during leaching improved copper extraction by breaking up particles and refreshing particle surfaces. Oxygen injection was essential for achieving high copper extraction at a solid content of 10%.
Article
Biotechnology & Applied Microbiology
Arya van Alin, Melissa K. Corbett, Homayoun Fathollahzadeh, M. Christian Tjiam, William D. A. Rickard, Xiao Sun, Andrew Putnis, Jacques Eksteen, Anna H. Kaksonen, Elizabeth Watkin
Summary: Microbial attachment and biofilm formation of Klebsiella aerogenes on monazite and xenotime minerals were investigated. The biofilm development process was observed and divided into three distinct stages. Higher coverage of biofilm was found on the high-grade monazite ore due to its rougher surface. Also, no selective attachment or colonization towards specific mineralogy or chemical composition was detected.
MICROBIAL BIOTECHNOLOGY
(2023)
Article
Microbiology
Arya Van Alin, Melissa K. Corbett, Homayoun Fathollahzadeh, M. Christian Tjiam, Andrew Putnis, Jacques Eksteen, Anna H. Kaksonen, Elizabeth Watkin
Summary: The adsorption behavior of micro-organisms during the initial attachment stage affects biofilm formation. Factors such as available attachment area and surface properties impact microbial attachment. This study investigated the initial attachment behavior of Klebsiella aerogenes on monazite and explored the role of extracellular DNA (eDNA). The ratio of planktonic and sessile subpopulations (P:S ratio), eDNA production, surface properties, particle size, available attachment area, and initial inoculation size were tested. The results showed that attachment occurred preferentially on larger particles, and decreasing the inoculation size or increasing the available area further promoted attachment. The presence of eDNA hindered bacterial attachment by creating repulsive interaction with bacteria.
Article
Engineering, Chemical
Elsayed Oraby, Huan Li, Zixian Deng, Jacques Eksteen
Summary: This study successfully recovered Ni and Co from flotation slime using an alkaline glycine-based leaching method, achieving higher extraction rates and faster leaching kinetics. Using ammonia as a pH modifier improved the leaching efficiency and resulted in higher impurity rejection.
MINERALS ENGINEERING
(2023)
Article
Engineering, Chemical
Elsayed Oraby, Zixian Deng, Huan Li, Jacques Eksteen
Summary: Traditional hydrometallurgical processes are unable to recover valuable metals from nickel tailings, but the proposed alkaline glycine leaching process can effectively extract nickel and cobalt from the tailings. The experimental results show that alkaline glycine-ammonia system has better leaching performance compared to ammonia alone. Furthermore, the use of resin-in-leach, grinding, increasing temperature, and controlling dissolved oxygen levels can all enhance the leaching efficiency.
MINERALS ENGINEERING
(2023)
Article
Mining & Mineral Processing
B. C. Tanda, E. A. Oraby, J. J. Eksteen
Summary: The study demonstrates that increasing temperature, glycine concentration, and reducing particle size can significantly enhance the leaching rate of copper, while stirring speed above 350 rpm does not have a significant influence.
MINERAL PROCESSING AND EXTRACTIVE METALLURGY-TRANSACTIONS OF THE INSTITUTIONS OF MINING AND METALLURGY
(2021)
Article
Mining & Mineral Processing
T. D. H. McGrath, A. R. Bax, J. J. Eksteen, J. L. McGrath
MINERAL PROCESSING AND EXTRACTIVE METALLURGY-TRANSACTIONS OF THE INSTITUTIONS OF MINING AND METALLURGY
(2020)
Article
Mining & Mineral Processing
N. P. Mkandawire, T. McGrath, A. Bax, J. Eksteen
MINERAL PROCESSING AND EXTRACTIVE METALLURGY-TRANSACTIONS OF THE INSTITUTIONS OF MINING AND METALLURGY
(2020)
Review
Mining & Mineral Processing
P. Bode, T. D. H. McGrath, J. J. Eksteen
MINERAL PROCESSING AND EXTRACTIVE METALLURGY-TRANSACTIONS OF THE INSTITUTIONS OF MINING AND METALLURGY
(2020)
Article
Metallurgy & Metallurgical Engineering
Arsyad Maulana Dzulqornain, Ana Belen Cueva-Sola, Kyeong Woo Chung, Jin-Young Lee, Rajesh Kumar Jyothi
Summary: This study presents a hydrometallurgical process for the separation of light rare earth elements (LREEs) using oxidation, precipitation, solvent extraction, and stripping techniques. Selective oxidation with potassium permanganate was employed for the separation of cerium (III). Solvent extraction with Cyanex 572 and cross-current scrubbing were used to achieve the separation of lanthanum (III) from neodymium (III) and praseodymium (III).
Article
Metallurgy & Metallurgical Engineering
Bo Chen, Shenxu Bao, Yimin Zhang
Summary: This study investigated the effects of Al, Fe, P, Si and Na on the precipitation characteristics of vanadium in the ultrasound precipitation system. The concentration upper limits and the negative influence on the precipitation kinetics were determined for each impurity. The findings provide theoretical and technical support for the industrial application of ultrasound precipitation technology.
Article
Metallurgy & Metallurgical Engineering
Chunlin He, Mingwei Qi, Yun Liu, Zunzhang Liu, Yuezhou Wei, Toyohisa Fujita, Guifang Wang, Shaojian Ma, Wenchao Yang, Junyuan Gan
Summary: In this study, D201 x 7 resin and tartaric acid were used as materials and complexing agents for the separation of germanium from sulfuric acid solution. The study successfully achieved the separation of germanium and demonstrated the high selectivity and adsorption performance of the resin.
Article
Metallurgy & Metallurgical Engineering
Xiaobo Zhu, Yue Liu, Chen Ma, Wang Li
Summary: A selective and highly effective method for the extraction and separation of V(IV) and Fe(III) using N235 and P507 as solvent extractants is proposed. The pH, composition, and concentration of the extractant mixture have significant effects on the extraction efficiency and separation factor. The mixing of P507 and N235 generates the P507 monomer, which enhances the extraction efficiency and weakens the stability of vanadium containing extraction complex. Cation exchange process forms the extraction complexes.
Article
Metallurgy & Metallurgical Engineering
B. Behnajady, J. Yousefi Seyf, S. Karimi, M. Moradi, M. Sohrabi
Summary: Deep eutectic solvents (DES) have potential as environmentally-friendly solvents for recovering metals from spent lithium-ion batteries (LIBs). Experimental and molecular dynamics simulation results showed that the chloride ions in DES can form complexes with lithium, manganese, and nickel ions, facilitating their extraction.
Review
Metallurgy & Metallurgical Engineering
Sebastian Kinas, Dorota Jermakowicz-Bartkowiak, Anna Dzimitrowicz, Piotr Cyganowski
Summary: The high demand for platinum-group metals (PGMs) and Re in economical and industrial applications related to environmental protection and energy conversion/storage has led to resource scarcity. Thus, it is crucial to recover and recycle these rare metals. This study critically reviews the recent progress in the effective recovery of PGMs and Re from materials relevant to sustainable technologies, emphasizing practical aspects, environmental impact, and issues related to the unit processes of recovery.
Article
Metallurgy & Metallurgical Engineering
Guopeng Yang, Qinggang Li, Guiqing Zhang, Mingyu Wang, Zuoying Cao, Wenjuan Guan, Jiawei Du, Shengxi Wu
Summary: The study proposes an efficient, clean, and economical process for recovering V2O5 from titanium-white waste through hydrogen peroxide stripping and precipitation of vanadium products by heating. Experimental results show that the use of D2EHPA as a modifier prolongs the duration of maximum stripping efficiency, enabling continuous operation.
Article
Metallurgy & Metallurgical Engineering
Guisu Yu, Shuainan Ni, Yun Gao, Ditang Mo, Zhiyuan Zeng, Xiaoqi Sun
Summary: This research proposes a novel green process for the selective recovery of rare earth elements (RE) from spent NdFeB permanent magnet using hydrophobic deep eutectic solvent (HDES). Through optimization of extraction conditions and stripping method, efficient and clean separation and recovery have been achieved.
Article
Metallurgy & Metallurgical Engineering
Jia Li, Xinsheng Wu, Xiaozhou Zhou, Li Zeng, Shengxi Wu, Mingyu Wang, Wenjuan Guan, Zuoying Cao, Qinggang Li, Guiqing Zhang
Summary: This paper presents a complete hydrometallurgical route for the full-component utilization of deep-sea polymetallic nodules (DPN), achieving high recovery efficiency and near-zero waste production with low energy consumption.
Article
Metallurgy & Metallurgical Engineering
Sanae Elmisaoui, Abderrazak M. Latifi, Lhachmi Khamar
Summary: A first principles model is developed to describe the dissolution mechanism of phosphate ore particles in a solution of phosphoric acid. The model accounts for non-uniform size of ore particles using particle size distributions and quantifies their influence on the model predictions. A global estimability analysis is carried out to determine the estimable parameters from experimental data, and the predictions show good agreement with the experimental data. The computed activation energy indicates that diffusion is the rate limiting step of the dissolution process.
