Role of hydrolyzed rice husk in pyrite bio-oxidation

Abstract This work seeks to understand the role of hydrolyzed rice husk in pyrite bio-oxidation. Solution parameters during the bio-oxidation process were monitored, and the bio-oxidation residues were characterized by Scanning Electron Microscopy, Raman Spectroscopy, and Fourier Transform Infrared Spectroscopy. Results showed that rice husk mainly affected pyrite bio-oxidation by promoting microbial reproduction and changing microbial community. It mainly inhibited the reproduction of Sulfobacillus and promoted the reproduction of Leptospirillum. There was a significant positive correlation between pyrite oxidation and the proportion of Leptospirillum. Rice husk had no obvious impact on the adhesion of different microorganisms on the pyrite surface. Quantity and hydrolysis of rice husk are the two factors that affect microbial communities. 1 g·L−1 of fully hydrolyzed rice husk can maximize the pyrite bio-oxidation by about 20% after 14 days. The promoting mechanism of rice husk on pyrite bio-oxidation is summarized based on the results, which provides theoretical support for future industrial applications.