Effective Removal of Lead from Solution by Sulfate Reducing Bacteria Cultured with Sugar Byproducts

Abstract

Sulfate reducing bacteria (SRB) are widely used to remove heavy metals because of their high efficiency. However, the metabolic processes of SRB require additional carbon sources, and the development of low-cost carbon sources has gradually attracted attention. The utilization of sugar byproduct resources, as the low-cost carbon sources, has great practical significance for environmentally sustainable development in Guangxi, China. This study aims to cultivate SRB with low-cost sugar byproducts, apply them to controlling a lead-polluted environment, and study the effects and mechanisms of controlling lead pollution. The research results show that the best culture effect of SBR can be obtained by mixing the filter mud and vinasse in a ratio of 1:1 to 3:1. SRB have average lead removal rates of more than 96.97% in solutions with different lead concentration of 10∼100 mg/L, and SRB have a higher tolerance to high concentrations of lead due to factors such as the organic substance composition of sugar byproducts and the porosity of filter mud. Scanning electron microscopy combined with energy dispersive spectrometry and X-ray diffraction analysis show that SRB mainly cause Pb2+ to form PbS precipitate through redox reactions to remove lead from the solution. Therefore, low-cost filters of a mud and vinasse mixture can be used as a medium for SRB and exhibit high heavy metal removal efficiency, thus providing a new utilization of filter mud and vinasse.