Study On Photocatalytic Degradation Of Cyanide By Catalysts Of Loaded TiO₂

Cyanide has been vastly applied to industries of gold extraction , plating .synthetic rubber, synthetic fibre, dye , coking and organic glass manufacture etc. As the increasing application , the cyanic waste water has been polluting the environment heavily, which menacing human being's health and animal's and fishe's lives seriously. So far, people haven't found a satisfying way to solve this problem. So a new method of photocatalytic degradation of cyanide by catalysts of loaded TiO2 is studied in this dissertation.First, the experiments have been done for photocatalytic degradation of cyanide with pure TiO2 powder(nm and μm particle). The effects of particle size, quantity of TiO2 and transparency of the solution on the photocatalytic degradation, of cyanide are tested. Second, the catalysts of loaded TiO2, marked as TiO2/SiO2 and TiO2/C, have been prepared. Then for the sake of sieving the catalyst with the best effect of degradation, the effects of degradation of the prepared catalysts have been compared, and the TG, DT, XRD and SEM analysis have been done. Third, the effects of the quantity of TiO2 ,the transparency of the solution anjd initial cyanide concentration on the cyanide photocatalytic degradation have been discussed. At last, the kinetics of the photocatalytic degradation of cyanide in the presence of loaded TiO2 have been studied.The conclusions will be drawn :(1) The transparency of the solution is a key factor that influences the effect of cyanide degradation. It's shown that in case of the higher transparency of the solution, the better effect of photocatalytic degradation, and the lower the worse.(2) The photocatalytic activities of catalysts loaded with TiO2 on degradation of cyanide solution are better than TiO2. The loaded catalyst of TiO2/SiO2 with 20% TiO2 shown the best effect, by which the photolysis percent gets to 45% in 150 minutes with the quantity of TiO2/SiO2 0.3 g/L and the initial cyanide concentration 50 mg/L.(3) The experiment results show that the reaction process of photocatalytic degradation of cyanide accords with the first-order kinetics. The quantity of TiO2, the transparency of the solution and the initial cyanide concentration all have ffects on the velocity of degradation of cyanide.