Study On Preparation And Photocatalytic Activity Of The Nano-TiO₂/Serpentine Mine Tailings Composite Material

??????????????(??????????)???,????????????TiO2???????TiCl4????,???????????TiO2/???????????????????????????????????????,??????????????????????????????????????XRD?EDX (EDS)?SEM?FT-IR?TEM?XPS??????????????????????????,?????????????TiO2?89.8wt%,TiO2????10-30nm???TiO2??????????????Si-O-Ti?????,??TiO2?????????,???????????????TiO2??,??????????????????????TiO2??????????????,?SiO2??????????,?????500-800nm?????BET???????120.4m2/g,???????15.1nm,?????????0.183cm3/g,????????????????????????????????????????????,??????????Cr(?)?????????????,?????90%??,???????????????????????,??????????????????Serpentine mine acid leaching tailings (hereinafter referred to "serpentine tailings" as a short term) was calcined as the mineral substrate to load nanometer titanium dioxide.The nano TiO2/serpentine tailings composite material was prepared by means of hydrolysis-depositing, in which process TiCl4 was used as the precursor. Four factors were identified as major factors on photocatalysis properties of composite material by orthogonal experiments; the optimal preparation conditions were selected. Impact of process technology factors on the material properties were analyzed by single factor experiment method as well. XRD, EDX (EDS), SEM, FT-IR, TEM, XPS analysis instruments and measures were applied to characterize structure and properties of the composite material. The results showed that anatase TiO2 was in accounting for 89.8wt% in the whole product, grain size was about 10?30 nm. TiO2 mainly combined with the serpentine tailings substrate by Si-O-Ti bonds, serpentine tailings particle surface and internal points are coated by nano-TiO2 evenly. TiO2 particles are dispersive into a certain depth below the surface of serpentine tailings particles, forming a mixed coating interface with the SiO2 layer, of which the thickness was about 500?800 nm. Composite material possessed larger surface area and amounts of pore volume. Its volume and surface area parameters were listed as below:single point BET specific surface area was 120.4 m2/g, adsorption average pore diameter was 15.1 nm, total single-point adsorption pore volume was 0.183 cm3/g. Based on analysis of characterization and measurements, composite powder material's preparation mechanism was studied in microscopic scale. Application experiments showed that good ultraviolet light photocatalysis degradation effects were obtained in treating wastewater containing phenol and Cr (?). Wastewater degradation rate exceeded 90%. The nano TiO2/serpentine mine tailings composite material, of which was a new type of low energy-consuming, high efficient and environmental-protecting material can be used repeatedly after function recovery treatment.