Preparation Of Magnetic-modified Tio₂/cds Photocatalysts And Study Of Degradation Characteristics

Since dyes wastewater has the characters of containing much pollutant, and high chromaticity, it has become one of the difficult treatment wastewater. The photocatalyst was modified upon the base of production of our group, and the magnetic Fe₃O₄/TiO₂ and Fe₃O₄/TiO₂/CdS photocatalysts were prepared.The degraduation of bromamine acid solution by the two photocatalysts was studied. Then prelimimary research of the mechanism of degradation on dyes wastewater with bromamine acid treatment photocatalysis was carried out in this paper.In this paper, the Fe₃O₄/TiO₂ photocatalyst was prepared by sol-gel technology, We mainly studied several factors to the Degradability for the bromamine acid solution in the sun light , such as Fe adulterant proportion, calcination temperature, calcination time in the Preparation process and obtained the best dosage of photocatalyst. The Experiment Results show that Fe adulterant proportion was 3%, calcining temperature was 500℃and calcining time was 2h and the best dosage of photocatalyst was 1g/L.On this base, the prepared Fe₃O₄/TiO₂ photocatalyst was coupled CdS by marinating-calcining, and then the magnetic Fe₃O₄/TiO₂/CdS composite photocatalyst was prepared. The composite catalyst has a certain response to visible light and easy separation. The influence factors to the catalytic activity of the proportion of Fe and CdS, calcination temperature, calcination time were researched. the catalyst was characterized by UV-Vis,XRD,TEM,XPS.The bromamine acid solution was degraded by the magnetic Fe₃O₄/TiO₂/CdS composite photocatalyst under UV light.We investigated the catalyst dosage, the initial concentration of the bromine acid solution, the different catalysts, the H₂O₂ dosage, the re-use times of the catalyst on the degradation to the bromine acid solution. The best conditions of the catalyst preparation were that the best adulterant proportion of Fe and CdS were both 3%, the best calcination temperature was 500℃, the best calcination time was 2h; the best degradation dosage of photocatalyst was 1g/L for the of 30mg/L bromine acid solution and high initial concentration of the bromine acid solution is not conducive to the degradation. The degradation of the solution was decreased significantly when the concentration of the bromine acid solution was higher than 50mg/ L; the magnetic composite Fe₃O₄/TiO₂/CdS catalyst had the best effective on the degradation to the bromine acid solution with CdS/TiO₂ compared to P25, TiO₂, Fe₃O₄/TiO₂ catalyst. TiO₂, P25 took the second place and Fe₃O₄/TiO₂ was the worst one; a certain amount of H₂O₂ can increase the degradation effect of Fe₃O₄/TiO₂/CdS catalyst significantly to the bromine acid solution. The catalyst can be reused, it can still maintain a high activity after five used times.