Preparation, Characterization And Application Study Of Water Treatment Nanophase Materials

With the development of industry, the finite water resources suffers increasingly serious pollution. Eliminate the toxic and hazardous substances in water become an important task for environmental protection. The exploitation and application of nanomaterials and nanotechnology supply new way for high efficiency and low cost water treatment.The new nano-subnano function material (Ecosystem Improved Agent) developed by our team can get rid of"three-nitrogen", sulfuret, CODCr, BOD5 and heavy metal in water. The Ecosystem Improved Agent can also promote the sea cucumber growth, increase the survival percentage of sea cucumber and decrease the heavy metal content of prawn.The photocatalytic degradation of dye AB80 was investigated in aqueous with pulverous P25-TiO2. The dye was decolorized in 75 min and mineralized completely in 135 min under UV-light. The decoloration reaction of the AB80 followed pseudo-first order kinetics and the catalyst loading of 1.0 g/L was used as the optimal dosage. The adsorption of AB80 onto TiO2 was found to be well expressed by the Langmuir equation. With the increased of pH, the adsorptive capacity decreased quickly. It was found that the degradation rate of AB80 was affected intensively by the pH of the solution. High pH value was beneficial to the photocatalytic degradation reaction. The initial rate was biggest when the pH=10.0. Proper dosage of the electron accepters H2O2 could enhance the reaction rate; the reaction rate was 2.78 times quicker than control when the concentration of H2O2was 5mmol/L.Diatomite supported nano-TiO2 composite was prepared by sol-gel method. SEM analysis indicated that the coated TiO2 amount affected the pattern of photocatalyst composites. The low TiO2 content (14.5%) had not reunion. XRD analysis indicated that the TiO2 coated on the surface of diatomite was the mixed crystal of anatase and rutile, the average particle size is 11 nm. FT-IR analysis indicated that no chemical bond generated between TiO2 and diatomite, the binding force was van der waals force. The adsorptive-photocatalytic activity of composite was studied using dye AB80 and B-2BF as model pollutant. The results indicated that composite coated 14.5% TiO2 expressed the best adsorptive-photocatalytic activity, and its decolorizing rate for model pollutant was larger than that of the Degussa P25-TiO2. The photocatalytic activity of TiO2/diatomite was affected intensively by the pH of the solution. Weakly acidic condition was beneficial for the reaction. The actual dye wastewater can be well degraded by TiO2/diatomite, and the decolorization ratio was 100% after irradiation of 3.5h under the experiment condition. The photocatalyst inactivated reason and regenerated methods were studied. Regenerative method for the TiO2/diatomite was acid washing and high temperature burning. The repetitive-use of photocatalyst almost didn't affect the activity for the model dye wastewater, the photocatalytic activity reduced only 12% after repetitive-use the catalyst for 15 times. But for the actual dye wastewater, the repetitive-use of photocatalyst affected the activity, the photocatalytic activity reduced 41% after repetitive-use the catalyst for 7 times. For the TiO2/diatomite composite, the cost was low, synthesis method was simple and photocatalytic effect was good. It is expect that the composite would be widely used in environmental pollution control.Copper oxide nano-particles immobilized on diatomite were prepared by hydrolyzation of CuCl. The obtained products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The visible light photocatalytic degradation of dye AB80 and B-2BF with immobilized Cu2O was studied. The reunion of Cu2O decreased after immobilization, and the photocatalytic activity increased greatly. The optimal Cu2O content was 31.3% for the photocatalyst composite whose photocatalytic activity was 6 times as great as pure Cu2O. The nano-sized Cu2O can make good use of sunlight for photocatalytic reaction, furthermore, the photocatalytic activity of Cu2O was better than TiO2 under sunlight. Solar energy was free, and its supplies were unlimited. The cost of sunlight photocatalitic dye wasterwater was low and the process hadn't any contamination, so sunlight photocatalisis would be a promising technique for environmental management. The range of pH 5-pH 7 was optimum for the photocatalysis of B-2BF. The stability of catalyst was good, after repetitive-use the catalyst for 8 times, the photocatalytic degradation rate could remain above 75%.