Dissertation > Environmental science, safety science > Processing and comprehensive utilization of waste > General issues > Wastewater treatment and utilization > Additives

Nanometer Mesoporous Polyoxometalate Photodegradation Organic Contamination of Industrial Wastewater

Author ZhaoXiaoLiang
Tutor GongJian;GuoYiZuo
School Northeast Normal University
Course Inorganic Chemistry
Keywords nanometer mesoporous polyoxometalate photodegradation organic contamination
CLC X703.5
Type Master's thesis
Year 2006
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A series of solid photocatalytic composites – nanometer scale and mesoporous ormicroporous materials were fabricated. It was tested that composites prepared here showedstable and efficient photocatalytic properties for the degradation of industrial wastewater.Moreover, two kinds of composites could exert their photocatalytic ability in the visible-lightarea. Compared with the traditional technology in the treatment of wastewater, solidpolyoxometalates are characterized by the following properties: (1) components for catalysisare not altered;(2) these solid polyoxometalates cannot produce additional pollution toenvironment during the process of photodegradation because of the nontoxic character;(3)these products can decompose almost all organic contaminations, especially those that cannotbe mineralized by other methods;(4)photocatalysis can be operated in the mild reactionsystem and additional chemical reagents are not needed;(5)some of these photocatalysts canexert photocatalytic activities under visible-light irradiation, therefore, much energy wassaved and a progress in the treatment of wastewater was made.Compared with the same field of domestic and overseas countries, the work we arepursuing has the following merits.1. With a sample method, five kinds of novel photocatalysts, polyoxometalates-basedoxides, were prepared and the preparation process can be repeated in the large scale.Additionally, chemical interactions (acid-basic reaction or coordination bands) exist betweenpolyoxometalates and oxides. The composites we have prepared are all nanomaterials such asmicroporous H3PW12O40/SiO2、H4SiW12O40/SiO2 、Na4W10O32/SiO2, bimodal pore systems(micro-mesoporosity) H3PW12O40/TiO2、 H6P2W18O62/TiO2, microporous H3PW12O40/Ta2O5 ,mesoporous hybrid catalysts [Ni(H2O)SiW11O39]6-?APS?SiO2 、[Ni(H2O)PW11O39]5-?APS?TiO2 and [Co(H2O)PW11O39]5-?APS?TiO2. Factors that couldinfluence the loading of polyoxometalates、morphology and physical-chemical properties ofproducts were explored in the present preparation methodology. Hereby, reaction conditionsthat could prevent the leakage of polyoxometalates from oxides were explored successfully.2. Satisfying effects were all achieved when the photocatalysts were used to decompose bothsingle organic contamination and wastewater of industry under the UV or visible-light irradiation.3. Two kinds of photocatalysts were selected as promising materials in the field ofindustry, that is, microporous H3PW12O40/SiO2、H4SiW12O40/SiO2 、Na4W10O32/SiO2 andbimodal pore systems (micro-mesoporosity) H3PW12O40/TiO2、 H6P2W18O62/TiO2. Noticeably,the two kinds of photocatalysts could exert their efficient photocatalytic activities under theexposure to UV and visible-light, respectively.

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