Sulfobacillus thermosulfidooxidans: an acidophile isolated from acid hot spring for the biosorption of heavy metal ions

摘要

Heavy metal contaminations in acid mine drainage (AMD) have posed a serious health and environmental risk. Biosorption is a promising in situ remediation technique to remove heavy metals from AMD. In this study, the potential of thermophilic acidophilus Sulfobacillus thermosulfidooxidans was used as biosorbent to remove heavy metal ions (Cd2+, Cu2+, Zn2+ and Ni2+) from acidic solution. The results indicated that the maximum adsorption capabilities of S. thermosulfidooxidans in the order of Ni2+ > Cd2+ > Zn2+ > Cu2+ at initial heavy metal concentrations range from 0.5 to 6 mM in single-metal system while showed an extremely high affinity toward Cu2+ in quaternary metal coexisting system. pH was positively related to adsorption capacity, and isothermal models also indicated monolayer adsorption played a major role in the biosorption process. Additionally, the deprotonation of carboxyl and phosphoryl contributed to the adsorption of heavy metal ions which were identified by ProtoFit analysis. Fourier transform infrared spectroscopy (FTIR) further proved these two kinds of functional groups as well as amino groups participated in the biosorption process. This study provided a new strategy for in situ bioremediation of heavy metal ions in AMD.