Sonochemical synthesis of ZnS nanolayers on the surface of microbial cells and their application in the removal of heavy metals

In order to improve the adsorption performance of microorganisms, we synthesized a novel material - phanerochaete chrysosporium cells covered with a layer of ZnS nanoparticles (ZnS-cells). The preparation of the ZnS-cells is based on the Sonochemical method to synthesize the ZnS nanoparticle layer on the surface of the microbial cells. The ZnS-cells were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR). Characterization results showed that wurtzite ZnS was coated on the cell surface in the form of nanoclusters by sonochemical reaction, and the formation of ZnS was related to the carboxyl group on the cell surface. Batch experiments showed that the ZnS-cells exhibited high adsorption efficiency for Pb2+ and Cd2+, the removal rate of Pb2+ and Cd2+ by ZnS-cells was 140 % and 160 % higher than that of pure P. chrysosporium, respectively. Studies on the adsorption mechanism showed that the removal of heavy metals by ZnS-cells mainly depended on the complexation of surface functional groups on the surface of the cells and the ion exchange of ZnS nanofilms.