Insights into the effect of ethyl xanthate on the adhesion and biofilm formation by Acidianus manzaensis on chalcopyrite

Abstract

Adhesion and biofilm formation play important roles in the bio-dissolution of metal sulfides, which can initiate dissolution and enhance bioleaching. Ethyl xanthate, a commonly used flotation reagent, remained in flotation concentrates of metal sulfides and may have an impact on the bioleaching of metal sulfides. Therefore, it is important to analyze the effect of ethyl xanthate on microbial initial adhesion and biofilm formation. The results showed that the adhesion percentage of Acidianus manzaensis on chalcopyrite decreased with increasing ethyl xanthate concentration after adsorption equilibrium, due to the toxicity of ethyl xanthate to A. manzaensis. However, a low concentration (0.01 mg/L) of ethyl xanthate had little effect on the growth of A. manzaensis. The hydrophobicity of chalcopyrite increased after the addition of ethyl xanthate, leading to an increase in total interaction energy and adhesion force. The presence of ethyl xanthate inhibited the early growth of biofilm and delayed the formation of microcolonies on chalcopyrite. While biofilm coverage was larger with the addition of ethyl xanthate than that of the control when biofilm was mature. Furthermore, in the presence of ethyl xanthate, more and larger microcolonies were observed on the chalcopyrite surface when biofilm was matured, resulting in an increased corrosion degree and more jarosite produced on the chalcopyrite surface. This study suggested that a low concentration (0.01 mg/L) of ethyl xanthate could promote the dissolution of chalcopyrite, which could be significant for bioleaching of flotation reagent-bearing flotation concentrates.