School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran, Iran.
School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran, Iran; Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia.
J Environ Manage. 2018 Jul 1;217:775-787. doi: 10.1016/j.jenvman.2018.04.043. Epub 2018 Apr 24.
In this study, Aspergillus niger (A. niger) as an environmentally friendly agent for fungal bioleaching of waste printed circuit boards (WPCBs) was employed. D-optimal response surface methodology (RSM) was utilized for optimization of the bioleaching parameters including bioleaching method (one step, two step and spent medium) and pulp densities (0.5 g L to 20 g L) to maximize the recovery of Zn, Ni and Cu from WPCBs. According to the high performance liquid chromatography analysis, citric, oxalic, malic and gluconic acids were the most abundant organic acids produced by A.niger in 21 days experiments. Maximum recoveries of 98.57% of Zn, 43.95% of Ni and 64.03% of Cu were achieved based on acidolysis and complexolysis dissolution mechanisms of organic acids. Based on the kinetic studies, the rate controlling mechanism for Zn dissolution at one step approach was found to be diffusion through liquid film, while it was found to be mixed control for both two step and spent medium. Furthermore, rate of Cu dissolution which is controlled by diffusion in one step and two step approaches, detected to be controlled by chemical reaction at spent medium. It was shown that for Ni, the rate is controlled by chemical reaction for all the methods studied. Eventually, it was understood that A. niger is capable of leaching 100% of Zn, 80.39% of Ni and 85.88% of Cu in 30 days.
在这项研究中，采用黑曲霉（Aspergillus niger）作为真菌生物浸出废印刷电路板（WPCBs）的环保剂。利用 D-最优响应面法（RSM）优化生物浸出参数，包括生物浸出方法（一步法、两步法和废培养液）和浆体密度（0.5g/L 至 20g/L），以最大限度地从 WPCBs 中回收 Zn、Ni 和 Cu。根据高效液相色谱分析，黑曲霉在 21 天实验中产生的最丰富的有机酸是柠檬酸、草酸、苹果酸和葡萄糖酸。基于有机酸的酸解和络合溶解机制，实现了 Zn 的 98.57%、Ni 的 43.95%和 Cu 的 64.03%的最大回收率。基于动力学研究，发现一步法中 Zn 溶解的速率控制机制是通过液膜扩散，而两步法和废培养液中则是混合控制。此外，在一步法和两步法中，Cu 溶解的速率受扩散控制，而在废培养液中则受化学反应控制。结果表明，对于 Ni，所有研究方法的速率都受化学反应控制。最终，结果表明黑曲霉能够在 30 天内浸出 100%的 Zn、80.39%的 Ni 和 85.88%的 Cu。
