Vyas Shruti, Ting Yen-Peng
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.
Chemosphere. 2016 Oct;160:7-12. doi: 10.1016/j.chemosphere.2016.06.060. Epub 2016 Jun 25.
Spent catalyst bioleaching with Acidithiobacillus ferrooxidans has been widely studied and low Mo leaching has often been reported. This work describes an enhanced extraction of Mo via a two stage sequential process for the bioleaching of hydrodesulphurization spent catalyst containing Molybdenum, Nickel and, Aluminium. In the first stage, two-step bioleaching was performed using Acidithiobacillus ferrooxidans, and achieved 89.4% Ni, 20.9% Mo and 12.7% Al extraction in 15 days. To increase Mo extraction, the bioleached catalyst was subjected to a second stage bioleaching using Escherichia coli, during which 99% of the remaining Mo was extracted in 25 days. This sequential bioleaching strategy selectively extracted Ni in the first stage and Mo in the second stage, and is a more environmentally friendly alternative to sequential chemical leaching with alkaline reagents for improved Mo extraction. Kinetic modelling to establish the rate determining step in both stages of bioleaching showed that in the first stage, Mo extraction was chemical reaction controlled whereas in the subsequent stage, product layer diffusion model provided the best fit.
利用氧化亚铁硫杆菌对废催化剂进行生物浸出已得到广泛研究，且经常有低钼浸出率的报道。本文描述了一种通过两阶段连续工艺强化从含钼、镍和铝的加氢脱硫废催化剂中提取钼的方法。在第一阶段，使用氧化亚铁硫杆菌进行两步生物浸出，15天内实现了89.4%的镍、20.9%的钼和12.7%的铝浸出。为提高钼浸出率，对生物浸出后的催化剂进行第二阶段生物浸出，使用大肠杆菌，在此过程中，25天内剩余钼的99%被浸出。这种连续生物浸出策略在第一阶段选择性浸出镍，在第二阶段浸出钼，是一种比用碱性试剂进行连续化学浸出以提高钼浸出率更环保的替代方法。通过动力学建模确定生物浸出两个阶段的速率决定步骤表明，在第一阶段，钼浸出受化学反应控制，而在随后阶段，产物层扩散模型拟合效果最佳。
