A microbial method using commercially available baker's yeast was developed for efficiently and selectively collecting aqueous Au(III) ions in aqua regia leachates from waste printed circuit boards (PCBs) through biosorption under air at temperatures ranging from 10 °C to 34 °C. Even when the total concentration of base metals was much higher than the initial Au concentration in the PCB leachate with high acid concentrations of 4.7–5.6 mol/L, commercial dry baker's yeast exhibited an excellent ability to selectively collect aqueous Au ions from the leachate within 60 min. When the biosorption test was repeated as a three-stage batch operation, the percentage biosorption of Au from the PCB leachate increased from 61% to 99% with 36 g/L dry yeast cells at 34 °C. The experimental results for the three-stage batch biosorption test were consistent with theoretical predictions based on the material balance of Au in multistage equilibrium operations and the distribution coefficient of Au. Equilibrium data of the Au biosorption conformed to the linear isotherm, regardless of the yeast concentration and the initial Au concentration in the leachate. The distribution coefficient at 34 °C decreased by 30%, from 53.7 to 37.3 L/kg-dry cells, as the total base metal concentration in the leachate was increased tenfold, from 1.94 to 16.4–19.1 g/L. Moreover, the distribution coefficient of Au at 10 °C to 34 °C was analyzed to determine thermodynamic parameters according to the van't Hoff equation. The thermodynamic studies indicated that the biosorption of aqueous Au ions by baker's yeast was spontaneous and exothermic.

中文翻译：

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面包酵母对废弃印刷电路板浸出液中金（III）的生物吸附

开发了一种使用市售面包酵母的微生物方法，通过在 10 °C 至 34 °C 温度范围内的空气下生物吸附，高效、选择性地收集废弃印刷电路板 (PCB) 中王水浸出液中的水性 Au(III) 离子。即使当贱金属的总浓度远高于 PCB 浸出液中的初始金浓度且酸浓度高达 4.7-5.6 mol/L 时，商业干面包酵母也表现出优异的从浸出液中选择性收集水性金离子的能力。 60 分钟当以三阶段批量操作重复生物吸附测试时，在 34 °C 下使用 36 g/L 干酵母细胞时，PCB 浸出液中 Au 的生物吸附百分比从 61% 增加到 99%。三阶段批量生物吸附试验的实验结果与基于多阶段平衡操作中Au的物质平衡和Au的分配系数的理论预测一致。无论酵母浓度和浸出液中的初始金浓度如何，金生物吸附的平衡数据都符合线性等温线。 34°C 时的分配系数下降了 30%，从 53.7 L/kg-干细胞下降到 37.3 L/kg-干细胞，因为浸出液中的总贱金属浓度增加了十倍，从 1.94 g/L 增加到 16.4–19.1 g/L。此外，分析了Au在10℃至34℃下的分配系数，根据van't Hoff方程确定了热力学参数。热力学研究表明，面包酵母对含水金离子的生物吸附是自发且放热的。