摘要
The demand of silver is increasing rapidly in recent decades, because silver and its related products are widely used in modern industry and decoration. It is necessary to recover silver from waste water using an efficient and environmental friendly method due to its environmental and economic benefits. In this paper, we eliminated the interference of Cl-and light conditions, and then studied the characterization and biosorption performance of silver by Bacillus licheniformis. The max biosorption amount was 87.4 mg/g(dry weight) with the initial Ag+concentration of 100 mg/L at pH 6.0. XRD pattern showed that the product was an amorphous compound. SEM/EDS-mapping and FT-IR results implied that phosphate, amino and carboxyl groups located on the cell walls involved in the biosorption of Ag^+. The XPS spectra result showed that the value of EB of Ag 3d_(5/2_(367.51 eV) corresponded to the energy values for Ag(Ⅰ), and indicated Ag^+ adsorbed to the surface of cell still maintained mono-valence. The results confirm that B. licheniformis just adsorb Ag+ but cannot covert soluble Ag^+ to silver nano-particles(AgNP).
基金
financially supported by the National Basic Research Program of China(973 Program,No.2014CB846003)
the National Natural Science Foundation of China(No.41372346,21477129)
