Qizheng Weng , Weiquan Zhan , Xuan Zhang , Shaoxian Song , Zhenlong Zeng , Hnin May Lwin , José Luis Arauz-Lara , Feifei Jia
{"title":"Electrochemical reduction and recovery of trace gold(I) from environmentally friendly thiosulfate leaching solutions using carbon electrodes","authors":"Qizheng Weng , Weiquan Zhan , Xuan Zhang , Shaoxian Song , Zhenlong Zeng , Hnin May Lwin , José Luis Arauz-Lara , Feifei Jia","doi":"10.1016/j.carbon.2024.119799","DOIUrl":null,"url":null,"abstract":"<div><div>Efficient recovery of Au(S<sub>2</sub>O<sub>3</sub>)<sub>2</sub><sup>3−</sup> at low concentrations is a key challenge for the development of environmentally friendly, cyanide-free thiosulfate leaching methods in industry. In the study, carbon materials including activated carbon (AC), graphite, and graphene were used as electrodes for electrochemical reduction and recovery (electro reduction-recovery) of trace gold(I) from thiosulfate leaching solutions (Au(S<sub>2</sub>O<sub>3</sub>)<sub>2</sub><sup>3−</sup>). The results demonstrated that Au(S<sub>2</sub>O<sub>3</sub>)<sub>2</sub><sup>3−</sup> could be efficiently recovered in the form of Au<sup>0</sup> with nearly 100 % recovery from both simulated and actual gold ore leaching solutions, significantly simplifying traditional recovery and reduction processes. Even in the presence of impurities such as cations and S<sub>2</sub>O<sub>3</sub><sup>2−</sup>, recovery remained high, around 90 %. Among the parameters studied, applied voltage was the most critical for optimizing recovery, as it enhanced ion migration and significantly improved gold reduction. The study investigated the relationship between the intrinsic properties of carbon materials and their electrochemical reduction and recovery capabilities. Rich porosity of carbon materials promoted interactions with Au(S<sub>2</sub>O<sub>3</sub>)<sub>2</sub><sup>3−</sup>, enhancing the electric double layer capacity, while π–π∗ satellite transitions played a dominant role in the charge transfer, thereby improving the reduction rate. This research offers new insights of the mechanisms behind the recovery of trace Au(S<sub>2</sub>O<sub>3</sub>)<sub>2</sub><sup>3−</sup> from thiosulfate leaching solutions through carbon electrodes.</div></div>","PeriodicalId":262,"journal":{"name":"Carbon","volume":null,"pages":null},"PeriodicalIF":10.5000,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Carbon","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0008622324010182","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Efficient recovery of Au(S2O3)23− at low concentrations is a key challenge for the development of environmentally friendly, cyanide-free thiosulfate leaching methods in industry. In the study, carbon materials including activated carbon (AC), graphite, and graphene were used as electrodes for electrochemical reduction and recovery (electro reduction-recovery) of trace gold(I) from thiosulfate leaching solutions (Au(S2O3)23−). The results demonstrated that Au(S2O3)23− could be efficiently recovered in the form of Au0 with nearly 100 % recovery from both simulated and actual gold ore leaching solutions, significantly simplifying traditional recovery and reduction processes. Even in the presence of impurities such as cations and S2O32−, recovery remained high, around 90 %. Among the parameters studied, applied voltage was the most critical for optimizing recovery, as it enhanced ion migration and significantly improved gold reduction. The study investigated the relationship between the intrinsic properties of carbon materials and their electrochemical reduction and recovery capabilities. Rich porosity of carbon materials promoted interactions with Au(S2O3)23−, enhancing the electric double layer capacity, while π–π∗ satellite transitions played a dominant role in the charge transfer, thereby improving the reduction rate. This research offers new insights of the mechanisms behind the recovery of trace Au(S2O3)23− from thiosulfate leaching solutions through carbon electrodes.
期刊介绍:
The journal Carbon is an international multidisciplinary forum for communicating scientific advances in the field of carbon materials. It reports new findings related to the formation, structure, properties, behaviors, and technological applications of carbons. Carbons are a broad class of ordered or disordered solid phases composed primarily of elemental carbon, including but not limited to carbon black, carbon fibers and filaments, carbon nanotubes, diamond and diamond-like carbon, fullerenes, glassy carbon, graphite, graphene, graphene-oxide, porous carbons, pyrolytic carbon, and other sp2 and non-sp2 hybridized carbon systems. Carbon is the companion title to the open access journal Carbon Trends. Relevant application areas for carbon materials include biology and medicine, catalysis, electronic, optoelectronic, spintronic, high-frequency, and photonic devices, energy storage and conversion systems, environmental applications and water treatment, smart materials and systems, and structural and thermal applications.