The Synthesis And Application In Aqueous Environment Of ZnS Composite Nanomaterial

As one of the serious problems faced by the current social development, Water pollution shouldbe urgently solved. Photocatalytic oxidation technology, an emerging technology is widely applied inwastewater treatment. Photocatalyst has been largely researched as the core of the photocatalytictechnology. Nanomaterials with special optics, electricity, magnetism, heat, mechanical properties, havebeen widely used in the fields of photo-catalysis, solar cells, opto-electronic devices, biomedicine. Thesynthesis of new nanomaterials has been received great attention. As an important semiconductor, sulfideof Group II-VI, ZnS has been made tremendous progress in structure controlling, morphology codificationand performance study. However, the broad band gap of ZnS semiconductor materials restrains its practicalapplication, the composite structure has been introduced in order to minimize the recombination ratio ofphoto-induced electrons and holes.ZnS porous nanospheres were prepared first, then Ag₂S/ZnS and CoS/Zn1-xMnxS compositenanomaterials were synthesized by ion exchange method. The characterization and property studies wereperformed by X-ray diffraction, Scanning electron microscopy, Element energy spectrum analysis,Transmission electron microscopy and UV-vis diffuse reflectance spectroscopy, etc. In addition, thedegradation of methyl orange was investigated under visible light. And some meaningful results wereobtained, as follows:（1） Study of Ag₂S/ZnS composite: Ag₂S/ZnS photocatalysts with different percentage wereprepared under hydrothermal and ion exchange method. The surfaces of Ag₂S/ZnS（x） compoundswere coarse and the ordered ZnS nanospheres structure was retained. The photocatalysis results suggested that the Ag₂S/ZnS photocatalysts, which the mole ratio between Ag₂S and ZnS was1:4,displayed the highest photocatalytic activity for degradation of MO solution under visible light irradiation,and the photocatalytic mechanism of composite photocatalysis was discussed.（2） Study of CoS/Zn_0.8Mn_0.2S composite: Composite Zn1-xMnxS was prepared by hydrothermalmethod. CoS/Zn_0.8Mn_0.2S nanomaterials were synthesized using Zn_0.8Mn_0.2S as a template, becauseZn1-xMnxS had the best photocatalytic activity when x was0.2. The structure and morphology ofas-prepared samples were same as Zn_0.8Mn_0.2S nanospheres. The degradation results showed that trimetalsulfide without heavy metals could obviously improve photocatalytic activity. When CoS mole ratio was20%, CoS/Zn_0.8Mn_0.2S composite had the best catalytic degradation ratio.