Preparation Of Loaded TiO₂ Catalyst And Its Application For Photocatalysis Of Hard Biodegradable Dye

TiO₂ photo-catalyst to degrade dyeing waste water is a new-style pollution treating approach, whose virtues are high treatment efficiency, simple technics equipment,operating condition controlling easily, no toxicity, low price and chemical stability, etc. However, there is great difficulty in separating and reusing TiO₂ powder, and the loss of active component is rather great. As new environmental-friend material, loaded TiO₂ catalyst agrees with sustainable development, and it will play an important act in the environmental protection, such as air purification, waste water treatrnent.In this paper, A101/sepiolite was prepared by the way of powder sintering, and A101 and modified sepiolite act as the Ti-precusor and substrate respectively. In addition, TBT/sepiolite was prepared by the method of sol-gel, and Ti(OC4H9)4 and modified sepiolite were chosen to serve as the Ti-precusor and substrate respectively. X-ray analysis and the experiment showed that two kinds of catalyst had good performance on adsorption and favorable photocatalysis character. They are catalystes that is character of economical and good capability.â‘ In this paper, modified sepiolite was prepared by the way of acidic modification, and natural sepiolite acted as the material. The results of optimum condition for modification of sepiolite showed that, the treatment acid was nitric acid,the treatment concentration of the acid was 15%, the processing time was 12h, the handling temperature was 20℃, and ratio of solid to liquid was 1:20. The experiment of the sepiolite specific surface areas and its absorption ability showed that, compared with natural sepiolite, the specific surface areas of modified sepiolite was obviously larger,and its absorption ability was increased obviously.â‘¡A101/sepiolite catalyst and TBT/sepiolite catalyst were prepared respectively, using modified sepiolite acted as substrate. The result of optimum condition for preparation of NO.3 A101/sepiolite showed that, the heat handling temperature was 400℃, and loading was 5%. The results of optimum condition for preparation of NO.4 TBT/sepiolite showed that, the heat handling temperature was 500℃, and ratio of TiO₂ to modified sepiolite was 1.5:1. In this experiment, rhodamine B was choosed as the object, and studied the effect to adsorption and photocatalysis character, which the loading process of A101/sepiolite catalyst and TBT/sepiolite catalyst brought. The result showed that the loading process decreased the specific surface areas and adsorption capacity of sepiolite. However, the photocatalysis character of loaded TiO₂ catalyst was strengthened, this may be ascribed to the interaction between TiO₂ and sepiolite.â‘¢Photocatalysis experiment was carried out to degrade rhodamine B solution by NO.3 A101/sepiolite and NO.4 TBT/sepiolite respectively. The result showed that both NO.3 A101/sepiolite and NO.4 TBT/sepiolite had an excellent effect on degradation of rhodamine B. Under optimum condition, the removal rate of rhodamine B and COD was 99.9% and 93.2% respectively by NO.3 A101/sepiolite, and 98.3% and 93.0% respectively by NO.4 TBT/sepiolite. The rhodamine B degradation process by photocatalyst NO.3 A101/sepiolite and NO.4 TBT/sepiolite respectively accords with dynamics model of Langmuir-Hinshelwood equation. Their rate constants are 93.46(L/min) and 156.25(L/min)respectively. Their adsorption equilibrium are 3.43×10-3 (L/mg) and 2.12×10-3 (L/mg)respectively.â‘£Photocatalysis experiment was carried out to degrade methyl orange solution by NO.3 A101/sepiolite and NO.4 TBT/sepiolite respectively. The result showed that both NO.3 A101/sepiolite and NO.4 TBT/sepiolite had an excellent effect on degradation of methyl orange. Under optimum condition, the removal rate of methyl orange and COD was 99.9% and 93.2% respectively by NO.3 A101/sepiolite, and 98.3% and 93.0% by NO.4 TBT/sepiolite respectively.⑤Reclaiming and repeated use of photocatalyst NO.3 A101/sepiolite and NO.4 TBT/sepiolite was studied. The result showed that, as reclaiming and repeated use to 5 times, the removal rate of 30mg/L rhodamine B was 83.3% and 76.8% respectively,and the removal rate of 300mg/L methyl orange was 68.1% and 63.1% respectively.