预处理电子废物和耐碱产氰细菌的突变促进了金的生物回收。
Pretreatment of e-waste and mutation of alkali-tolerant cyanogenic bacteria promote gold biorecovery.
机构信息
Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
出版信息
Bioresour Technol. 2014;152:80-5. doi: 10.1016/j.biortech.2013.10.108. Epub 2013 Nov 6.
Gold was recovered from electronic scrap material (ESM) as gold-cyanide complex by Chromobacterium violaceum which produces cyanide as a secondary metabolite. The effect of pretreatment and mutation of alkali-tolerant bacteria was examined. Pretreatment dissolved most of the base metals, thereby reducing competition for the cyanide ion from other metals. As the pKa of HCN is 9.3, alkaline pH increases the cyanide ion concentration available for bioleaching, and the bacteria were mutated to grow at pH 9, 9.5 and 10. Results showed that at 0.5% pulp density of pretreated ESM, mutated bacteria attained gold biorecovery of 18% at pH 9, 22.5% at pH 9.5 and 19% at pH 10 while that of unadapted bacteria (at pH 7) yielded only 11% recovery. Results showed that gold bioleaching efficiency from electronic scrap was enhanced under alkaline conditions with mutated bacteria compared to bioleaching at physiological pH (around 7) of C. violaceum.
从电子废料（ESM）中用 Chromobacterium violaceum 回收金-氰化物配合物，后者作为次生代谢产物产生氰化物。考察了预处理和耐碱菌突变的效果。预处理溶解了大部分基础金属，从而减少了其他金属对氰化物离子的竞争。由于 HCN 的 pKa 为 9.3，碱性 pH 增加了可用于生物浸出的氰化物离子浓度，并且对细菌进行了突变以在 pH 9、9.5 和 10 下生长。结果表明，在预处理 ESM 的 0.5%纸浆密度下，突变细菌在 pH 9 下达到 18%的金生物回收率，在 pH 9.5 下达到 22.5%，在 pH 10 下达到 19%，而未适应细菌（在 pH 7 下）仅产生 11%的回收率。结果表明，与 Chromobacterium violaceum 的生理 pH（约 7）相比，在碱性条件下用突变细菌进行生物浸出可提高从电子废料中提取金的效率。
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