Study On Synthesis Of New Nano-structured Materials And Their Application In Water Treatment

In this paper, CdS and zero-valent iron were modified respectively. The degradation capacities of pollutants in water of these two composite system were studied, the dosage of which was1g/L, using methyl orange(10mg/L) and hexavalent chromium(10mg/L) as target decomposition materials.SrAl2O4:Eu2+,Dy3+of bulk phase and SrAl2O4:Eu2+,Dy3+nano-rods were synthesised through high temperature solid-state method and hydrothermal method, respectively. Pure CdS nano-particles, CdS/SrAl2O4:Eu2+,Dy3+(solid-state method) and CdS/SrAl2O4:Eu2+,Dy3+(hydrothermal method) were successfully prepared by sol-gel method. The composite system was found to exhibit a higher photocatalytic activity compared with pure CdS under visible light or UV light. The photocatalytic activity reached the maximum when the composite ratio of CdS and CdS/SrAl2O4:Eu2+,Dy3+(hydrothermal method) was1:2with a degradation rate of methyl orange of96.3%under visible light for30min, which is2.5times of the degradation rate by pure CdS. There was no effective degradation of methyl orange by the composite system in dark environment after30min UV irradiation. Both pure CdS and composite system could almost completely remove hexavalent chromium under visible light for10min while the latter was a little better. Analysis suggests that the enhancement of photocatalytic activity is caused by the improvement of light use efficiency which may due to hole migration from phosphor to CdS and reuse of luminescence after modification treatment.Fe/Al2O3was successfully prepared via a homogeneous coprecipitation process. The degradation of methyl orange reached the maximum when the composite ratio of was5:1with a degradation rate of48%after1h oscillation time, which was higher than43%by zero-valent iron. The degradation of hexavalent chromium reached the maximum when the composite ratio of was5:2with a degradation rate of97%under the optimum pH3condition after1h oscillation time, the corresponding saturated adsorption of which was9.7mg/g. It was proposed that the morphology of Al2O3changes from nanotube structure to semicanal/tubular flocculent structure after modification treatment, which was more favorable to the adsorptive reduction of pollutants and could enhance the chemical stability of zero-valent iron.