Sustainable and effective gold(I) separation from aurocyanides wastewater and its mechanism using guanidinium ionic liquids

Zhu, Guiping; Xiong, Jiaxing; Zhou, Yu; Zhou, Qiaoshu; Ren, Boxian; Wang, Shixiong; Yang, Xiangjun; Jiang, Fengzhi

doi:10.1016/j.jclepro.2023.139405

Cited by 6 publications

(4 citation statements)

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“…The extraction rate of the other coexisting ions is less than 13%. To more comprehensively evaluate the selectivity exhibited by these systems toward Au(I), separation coefficient (β) expressed as eq was introduced for comparative analysis β A u / normalM = D A u D normalM where D Au and D M are the distribution ratios of Au(I) and metal ions.…”

Section: Resultsmentioning

confidence: 99%

“…As the concentration of KSCN increased, stripping efficiency gradually increased, and the percentage could be as high as 99.7% when the concentration reached 6.0 mol/L. This is due to the small charge density of SCN – anions, which makes it easier to bind to guanidinium cations, allowing Au(S 2 O 3 ) 2 3– to exchange into the stripped phase . Therefore, 6.0 mol/L KSCN was selected as the stripping agent for use in the follow-up cycle experiment.…”

Section: Resultsmentioning

confidence: 99%

“…To more comprehensively evaluate the selectivity exhibited by these systems toward Au(I), separation coefficient (β) expressed as eq 9 was introduced for comparative analysis. 58 = D D…”

Section: Acs Sustainablementioning

confidence: 99%

“…This is due to the small charge density of SCN − anions, which makes it easier to bind to guanidinium cations, allowing Au(S 2 O 3 ) 2 3− to exchange into the stripped phase. 58 Therefore, 6.0 mol/L KSCN was selected as the stripping agent for use in the followup cycle experiment.…”

Section: Acs Sustainablementioning

confidence: 99%

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Green Aqueous Two-Phase Systems Constructed by Guanidinium Ionic Liquid for Efficient Recovery of Gold(I) from Thiosulfate Solution

Ma,

Chen,

Qiu

et al. 2024

ACS Sustainable Chem. Eng.

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Although thiosulfate leaching is a more sustainable alternative to the toxic cyanidation process for gold extraction, recovering Au(I) from pregnant thiosulfate solutions remains a significant challenge. In this study, novel aqueous two-phase systems (ATPSs) were constructed using green guanidinium ionic liquids (GILs) and inorganic salts for recycling gold thiosulfate from weak alkaline solutions. Key parameters including salt type, salt content, GIL content, extraction time, equilibrium pH, and initial Au(I) concentration were extensively explored. The extraction efficiencies of Au(I) reached 95.8% for [C 3 -Gun]Cl, 96.5% for [C 4 -Gun]Cl, and 97.7% for [C 5 -Gun]Cl system under optimal conditions. Spectral analysis and density functional theory calculations reveal that the main mechanism for Au(I) extraction is that Au(S 2 O 3 ) 2 3− anions replace Cl − anions in GILs, which then interact with guanidinium cations through electrostatic force. In addition, KSCN solution can efficiently strip gold thiosulfate with an efficiency of more than 99% and regenerate the GIL-rich phase simultaneously. The results of five extraction/stripping cycles showed that the extraction efficiency of Au(I) decreased slightly from 98.0 to 90.4%, while the stripping percentage decreased slightly from 99.7 to 92.3%, confirming that GIL-ATPS has excellent cycling performance. These results demonstrate that green ATPSs consisting of GILs provide a sustainable and efficient approach to gold recovery from thiosulfate solutions.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…To more comprehensively evaluate the selectivity exhibited by these systems toward Au(I), separation coefficient (β) expressed as eq 9 was introduced for comparative analysis. 58 = D D…”

Section: Acs Sustainablementioning

confidence: 99%

Section: Acs Sustainablementioning

confidence: 99%

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