TiO 2 nanoparticles (TiO 2 -NPs) in water were removed by enhanced coagulation with polyaluminum ferric chloride (PAFC) and cationic polyacrylamide (CPAM). The flocculation efficiency by PAFC and PAFC/CPAM for three different initial concentrations (0.2, 2, and 30 mg/L) of TiO 2 nanoparticles in pure water and a kaolin suspension system (kaolin concentration: 30 mg/L) were investigated with different coagulant dosages, pH values, precipitation times, and hydraulic conditions. Results showed that the removal rate of TiO 2 -NPs in the kaolin suspension system was slightly higher than that in a pure water system, and the removal rate of TiO 2 -NPs obtained by PAFC/CPAM was significantly higher than that by PAFC alone. The removal efficiency of TiO 2 -NPs increased with increased initial concentration of TiO 2 -NPs. Under the optimal conditions, the removal rates obtained by PAFC/CPAM for 30 mg/L initial concentration TiO 2 -NPs in pure water and the kaolin suspension system were 97.98% and 98.62%, respectively. Studies on the fractal dimension of flocs showed that the flocs produced by PAFC/CPAM had a larger fractal dimension than those using PAFC alone. This study demonstrated that turbidity in water helped improve the removal efficiency of TiO 2 -NPs, and enhanced coagulation can efficiently remove TiO 2 -NPs from water.

SBA-15 supported phosphotungstic acid has been synthesized under hydrothermal conditions via pH adjustment and characterized with various analytical and spectroscopic techniques including X-ray diffraction (XRD), N2 adsorption, transmission electron micrographs (TEM). XRD results indicate that the substitution of tungsten occurs in the silicate framework structure of SBA-15. Study on the catalytic activity of mesoporous PW/SBA-15 catalyst through the isomerization of the a-pinene was investigated. The best reactive conditions of a-pinene isomerization were follows: reaction temperature 130°C, dosage of PW/SBA-15 catalyst 2 %, reactive time 2 h. Then the rate of a-pinene conversion could achieve 94.56 %, the selectivity of camphene could achieve 48.5%.

To cope with the increasingly severe challenges of zinc oxide nanoparticles (ZnO-NPs) in the field of the aquatic environment, this paper uses poly-aluminum ferric chloride (PAFC) and cationic polyacrylamide (CPAM) as coagulants to enhance the removal of ZnO-NPs from water. In two environments (pure-water environment and kaolin environment) that simulate suspended solids, we studied the dosage, pH, precipitation time, and hydraulic power of ZnO-NPs at three different initial concentrations (1, 2, and 30 mg/L). The effects of various conditions on the performance of PAFC, CPAM, and PAFC/CPAM to remove ZnO-NPs were examined. Results showed that the overall removal rate of ZnO-NPs in the kaolin environment was slightly higher than that in the pure-water environment. In contrast the removal rate of ZnO-NPs in the PAFC/CPAM was significantly higher than that of PAFC or CPAM alone. The coagulation removal conditions of ZnO-NPs were optimized using a response-surface model. Under the best conditions, the removal rate of ZnO-NPs with an initial mass concentration of 30 mg/L in the PAFC/CPAM combination in pure-water and kaolin environments was 98.54% and 99.17%, respectively. Finally, by studying the changes in floc size during coagulation, enhanced coagulation was an efficient method of removing ZnO-NPs from water.

Supported phosphotungstic acid SBA-15 were synthesized under hydrothermal conditions and characterized by X-ray diffraction (XRD), N2 adsorption, transmission electron micrographs (TEM), scanning electron micrographs (SEM), Fourier-transform infrared spectroscopy (FT-IR). XRD and FT-IR results indicated that the substitution of tungsten occurs in the silicate framework structure of SBA-15. TEM and SEM investigations confirmed the presence of ordered high degree ordering hexagonal structure in the novel PW/SBA-15 material. Their catalytic activity was evaluated in the epoxidation of α-pinene. 2,3-epoxypinane was the main product. The results of epoxidation of α-pinene by PW(40)/SBA-15 were fellows: the conversion rate of α-pinene and the selectivity were 87.61% and 79.90% respectively.

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