Platinum group metals;
Spent automotive catalyst;
Two-step bioleaching;
Spent medium leaching;
BACILLUS-MEGATERIUM;
ELECTRONIC WASTE;
GOLD RECOVERY;
GROUP METALS;
CYANIDE;
EXTRACTION;
GROWTH;
COPPER;
D O I:
10.1016/j.biteb.2022.101069
中图分类号:
Q81 [生物工程学(生物技术)];
Q93 [微生物学];
学科分类号:
071005 ;
0836 ;
090102 ;
100705 ;
摘要:
Bioleaching of platinum group metals (PGM) from spent automotive catalyst (SAC) was studied using two mesophiles, Pseudomonas fluorescens and Bacillus megaterium. Leaching studies under different conditions were carried out to investigate the formation of biocyanide and its role in PGM solubilisation. Both P. fluorescens and B. megaterium produce cyanide as a secondary metabolite that forms water-soluble complexes with PGM. Factors that affect bioleaching, namely initial pH of culture, free cyanide ion concentration, and pulp density were examined. Two leaching strategies - two-step bioleaching and spent medium leaching were applied. P. fluorescens showed higher extraction compared to B. megaterium. Using spent medium leaching for pretreated SAC at 0.5% (w/v) pulp density and initial pH 10, P. fluorescens yielded the highest extraction of platinum (58%), palladium (65%) and rhodium (97%) on day 1. This study demonstrates the bioleaching potential of cyanogenic bacteria for the extraction of PGM from SAC.