Experimental Study On Fixed TiO₂ Preparation & Application In Degradation Of H₂S In Low Concentration

This paper studies how to make TiO₂ photocatalyst in the method of sol-gelatin (Sol-gel), which fixed on the glass fiber, and degradation of H₂S in low concentration with the kind of photocatalyst in self-produced gas-solid reactor. This kind of fixed photocatalyst was tested by XRD, we found that the particle mean size of photocatalyst which was got on this technological conditions was smaller than 10nm, and the main crystal types were rutile and anatase, this kind of fixed photocatalyst has a good degradation effect on H₂S. In this study it is the first time that we applied the photocatalytst which was carried on glass fiber cloth to degradation of H₂S and achieved good results. The purpose of this study is to broaden the application range of TiO₂ photocatalyst, and seek a way which is economical and high-effect to decompose the inorganic smell substance.Study shows that the reasones which influence the applicated in degradation of the low concentration of H2S can be incorporated two ways. One of them is the technology of photocatalyst making, such as the temperature of calcining, the number of fixed time and the modification of the photocatalyst making. The other is the condition of gas, as relative humidity, O₂ content and the nitial consistency of H₂S.The change of the calcining temperature can influence the size of the fixed TiO₂ photocatalyst, and does few effect on the main crystal type. We can get the rutile and anatase in defferent calcining temperaters. The smallest size of TiO₂ photocatalyst is 6.7nm, which is calcined in the temperature of 500℃, and this kind of photocatalyst has more anatase than the other kind of photocatalyst. In our study, this kind of photocatalyst has the best efficiency in the degradation of H2S. The number of fixed time is not the more, the better, but has a better number, when the number of fixed time is 3, which can get a good efficiency, so does the economy.Modification of photocatalys has been researched, in the process of preparation we added AgNO₃. XRD indicated that doped Ag⁺ has not changed the crystal type and particle mean size of photocatalyst, the experiment showed that doped little Ag⁺ has not obviously enhanced the photocatalytic efficiency of H₂S, while doped much would decrease the efficiency.H₂O can react to the nami TiO₂ photocatalyst, which have great influence in the degradation of H₂S. A better effect, 97% at the highest can be got when 60%～80%. The diversification of O₂ content influence the result of photocatalytic, when the content reaches the natural level, as it is 21% which got the better efficiency, if increased the O₂ content, the more O₂ will occupy the active positiones of TiO₂ photocatalyst, which would reduce the efficiency. So we need do nothing to increase the O₂ content, but have a good effect on degradation of H₂S. This showed well economical, so it was not necessary to increase O₂ content we could got high efficiency.In addition, this paper studied the moderate load of H₂S degradation by TiO₂ photocatalyst, the result shows that when the initial consistency is about 300mg/m³, prompted by the occasion that the load is about 34mgH₂S/mg TiO₂, which can get a good effect.