| 本论文研究以蛇纹石尾矿酸浸渣(以下简称蛇纹石尾矿渣)为原料,采用煅烧工艺制备负载纳米TiO2的矿物载体；以TiCl4为前驱体,采用水解沉淀法制备纳米TiO2/蛇纹石尾矿渣复合材料。通过正交实验确定了四个主要因素对复合材料光催化性能的影响,筛选出较优的制备工艺条件；通过单因素实验分析了工艺因素对材料性能的影响。应用XRD、EDX (EDS)、SEM、FT-IR、TEM、XPS仪器分析技术对复合材料结构与性能进行了表征。结果表明,制备的复合材料中锐钛矿晶型TiO2占89.8wt%,TiO2晶粒度为10-30nm左右；TiO2与蛇纹石尾矿渣载体之间主要以Si-O-Ti化学键结合,纳米TiO2与基体融合程度完好,载体颗粒表面和内部点位均有纳米TiO2负载,且负载均匀性较好；蛇纹石尾矿渣载体颗粒负载的TiO2渗入载体材料表面以下一定深度,与SiO2形成混合的负载界面层,厚度大约为500-800nm；复合材料BET单点比表面积为120.4m2/g,吸附平均孔径为15.1nm,单点吸附总孔体积为0.183cm3/g,具备较大的比表面积和孔体积。在表征和分析基础上探讨了复合粉体材料的制备机理。应用实验表明,该材料对含酚废水和含Cr(Ⅵ)废水紫外光催化降解效果较好,降解率可达90%以上,使用过的催化复合材料经回收处理后可多次重复使用,是一种高效、低耗的新型环保功能材料。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 (Ⅵ). 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. |
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