MoS2-壳聚糖气凝胶原位还原金硫代硫酸根络合离子的基础研究

Study on in-situ Photo-reduction of Au(SO) by MoS-Chitosan Aerogel

硫代硫酸盐提金技术因环境友好、可处理复杂矿石等优点,被认为是最具潜力的无氰提金技术,然而该技术尚未能实现规模化工业应用,其主要技术瓶颈是浸出液中的金硫代硫酸根络合离子(Au(S2O3)23-)无法高效富集。为此,构建了三维多孔MoS2-壳聚糖气凝胶(MoS2-CSA),深入考察了MoS2-CSA回收Au(S2O3)23-的性能。结果表明,MoS2-CSA不仅具有极好的Au(S2O3)23-富集能力(高达718.3 mg/g,于107.6 mg/L Au(S2O3)23-溶液),而且可将Au(S2O3)23-原位还原为金纳米颗粒,既解决了硫代硫酸盐提金技术中Au(S2O3)23-难以高效富集的技术瓶颈,同时极大地简化了传统提金技术中金络合离子的回收工艺。此外,MoS2-CSA克服了纳米材料无法有效固液分离的难点,实现了简易的回收。机理研究表明,MoS2-CSA具有强烈的光电响应能力,在可见光激发下可产生大量光生电子,实现了金的原位还原。研究结果为硫代硫酸盐提金技术中Au(S2O3)23-的回收提供了新的思路,有望推动硫代硫酸盐提金技术的快速发展。

Thiosulfate gold leaching is considered as the most promising technique for gold extraction due to its environmental friendliness and high adaptability. However,thiosulfate gold leaching technology has not been used widely in industry because there were no efficient adsorbents for recovering gold-thiosulfate complex from solutions. Three-dimensional MoS2-chitosan aerogel(MoS2-CSA)with porous structure was synthesized,and its recovery to Au(S2O3)23-was studied systemically. It was found that MoS2-CSA not only effectively recovered Au(S2O3)23-with an extremely high capacity of 718.3 mg/g,but also directly in-situ reduced the Au(I)to gold nanoparticles. The results demonstrated that this work proposes a solution for overcoming the technical bottleneck of Au(S2O3)23-recovery,and greatly simplified the recovery process of gold complex ions in the traditional gold extraction technology. Besides,the spent MoS2-CSA was easy to recover from solution. It was found that the reduction mechanism was due to the photo-generated electrons produced by MoS2. This study provided a new insight for recovering Au(S2O3)23-from leaching solutions,which was expected to promote the rapid development of thiosulfate gold extraction technology.