Effects of cyanide and dissolved oxygen concentration on biological Au recovery
Effects of cyanide and dissolved oxygen concentration on biological Au recovery
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DOI：
10.1016/j.jbiotec.2006.01.038
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发表时间：
2006-07-25
影响因子：
4.1
通讯作者：
Takemoto, Tadashi
中科院分区：
文献类型：
--
作者：
Kita, Yoshito;Nishikawa, Hiroshi;Takemoto, Tadashi
含有痕量Au的废弃电子器件的数量目前正在增加。由于这种Au具有有价值的物理化学性质，因此希望回收这种Au。Au通常溶解在相对高浓度的氰化物中，这与环境风险有关。紫色色杆菌能够产生和解毒少量的氰化物，因此可能能够从废弃的电子设备中回收An。研究了氰化物和溶解氧浓度对生物回收Au的影响。C. violaceum足以溶解Au，而保持高氰化物浓度不会增强Au溶解。在70 h的试验期间内，增加氧浓度使Au的溶解从0.04 mmol/l增加到0.16 mmol/l。电化学测试证实了这一现象，测定了C. violaceum从-400 mV增加到-200 mV，而在无菌氰化物溶液中，氰化物浓度在0到1.5 mmol/l范围内恒定，溶解氧浓度在0到0.25 mmol/l范围内增加。因此，阐明了溶解氧浓度是影响细菌氰化浸金效率的主要因素。(c)2006 Elsevier B. V.保留所有权利。
The number of discarded electric devices containing traces of Au is currently increasing. It is desirable to recover this Au because of its valuable physicochemical properties. Au is usually dissolved with relatively high concentrations of cyanide, which is associated with environmental risk. Chromobacterium violaceum is able to produce and detoxify small amounts of cyanide, and may thus be able to recover An from discarded electric devices. This study investigated the effects of cyanide and dissolved oxygen concentration on biological Au recovery. Cyanide production by C. violaceum was sufficient to dissolve An, while maintaining a high cyanide concentration did not enhance Au dissolution. Increased oxygen concentration enhanced Au dissolution from 0.04 to 0.16 mmol/l within the test period of 70 h. Electrochemical measurement clarified this phenomenon; the rest potential of An in the cyanide solution produced by C. violaceum increased from -400 to -200 mV, while in the sterile cyanide solution, it was constant in cyanide concentrations ranging from 0 to 1.5 mmol/l and increased in dissolved oxygen concentrations ranging from 0 to 0.25 mmol/l. Therefore, it was clarified that dissolved oxygen concentration is the main factor affecting the efficiency of cyanide leaching of gold by using bacteria. (c) 2006 Elsevier B.V. All rights reserved.