Preparation And Photocatalytic Properties Of Metal Doped Of CaSO₄/TiO₂Composite Powder

With the increasingly serious global environmental problems, the development ofefficient low-power, high environmental functional materials has become an urgent task.Other semiconductor materials with TiO2catalysts heterogeneous photocatalytic oxidation asa new pollution control technology is gaining attention. TiO2because of its high activity,strong oxidation resistance, safe and nontoxic, chemically stable, insoluble and become one ofthe advantages of environmentally friendly catalyst has good development prospects.Currently, the majority on the preparation of TiO2using butyl titanate as raw sol-gelmethod, which is relatively high cost of raw materials, process complexity, so the use ofinexpensive, simple preparation method to prepare high performance TiO2become the maintarget of today’s researchers. TiOSO4is an inexpensive inorganic reagents, and the widevariety of sources, non-toxic, and use it to prepare titanium dioxide, low cost and simpleprocess, through strict control of process conditions can be obtained small particle size,narrow particle size distribution, good dispersion CaSO4/TiO2nano composite powder.However, low CaSO4/TiO2composite powder photocatalyst prepared solar energy utilizationefficiency, and because the catalyst is nanopowders, difficult recovery, thesis several issueshave been studied for titania doped and photocatalytic properties. According to the researchcontent of this article is divided into three parts:First, Iron-doped CaSO4/TiO2composite powder was prepared by precipitation methodusing TiOSO4and CaO and Fe2(SO4)3as raw material at prices. The composite powdersamples were characterized by X-ray diffraction (XRD)、IR、SEM and EDX. Results showedthat the optimum conditions for preparation of the composite material were as follows: theoptimum pH of precipitation was9, the amount of Iron-doped was2%, and the calcinationtemperature was600℃. When the powder dosage was4g/L, UV light exposure time was150min, the degradation rate can reach93.8%, and at the same time under visible lightirradiation degradation rate of85.3%.Second, prepared according to the method of the second chapter, the doping metal tosilver, silver source AgNO3as prepared size of about12nm doped silver CaSO4/TiO2composite powder and used XRD、SEM and EDX samples were characterized. The compositepowder prepared the optimum pH of precipitation was12, the amount of Iron-doped was1 %, and the calcination temperature was600℃. When the powder dosage was4g/L, UV lightexposure time was150min, the degradation rate can reach98.7%, and at the same timeunder visible light irradiation degradation rate of91.5%.Third, with attapulgite as a carrier under Chapter III of silver in the best conditions forthe preparation of composite powders of titanium-doped CaSO4/TiO2source, using ultrasonicdispersion-reprecipitation prepared attapulgite load of silver doped CaSO4/TiO2compositematerials, and with XRD、IR、SEM and EDX methods for sample characterization. Thephotocatalytic activities were evaluated by degradation of activeness scarlet, and comparedthe pure attapulgite, photocatalytic properties of Ag-doped CaSO4/TiO2and attapulgite loadsilver CaSO4/TiO2composite powder. The result showed that: attapulgite as a carrier, not onlycan achieve immobilized TiO2is conducive to the recovery of the catalyst reuse, and canimprove the photocatalytic degradation efficiency and reduce the cost of wastewatertreatment.