Study On Catalytic Activities For Degradation Of CN～- In Water By Compounding Catalysts

This paper analyzed and summarized main treatment technologies about cyanic waste water, and explored the new method to get rid of cyanogen with the compounding type catalyst. At first, the catalysts of serial TiO2 were produced by Sol-gel-dipping and the catalysts of serial Cu were produced by dipping. Under the experiment conditions, utilized the catalysts which had been produced to degrade the cyanic waste water and appraised activity of the catalysts by the degradation rate of CN~- .In addition, researched the effect factors about the catalytic activity of the catalysts for degrading CN ,such as the percentage of Cu, TiO2 used in the preparation , the size of the carriers, pH of the water, the quantity of catalysts, the rate of permeating light, the density of CN~- used in the degradation test and other factors. Furthermore, the catalysts were characterized by TG-DTA, SEM and XRD etc. At last, the kinetics of the photocatalytic degradation of CN~- have been studied for the catalysts of serial TiO2 . The results of the experiments showed:(1) It was discovered that the photocatalytic activity of the catalysts for degrading CN~- depended on the particle size of the carriers . The TiO2/AC catalysts in size of millimeter showed much higher photocatalytic activities than those of micron, which indicated that the particle size of the carriers is the key factor that influenced the photocatalytic activities.(2) The effect on catalytic degradation of CN~- are different with different carriers, and The TiO2/AC catalysts showed much higher photocatalytic activities than Cu/TiO2/AC,TiO2/5A under the experiment conditions. More than 90% of CN~ in water was degraded when the loading quantity of TiO2 is 35%, pH=10.0 and the initial cyanide concentration is 50 mg/L in the paper.(3)The catalytic activities of Cu/AC on degradation of CN~- are better than that ofTiO2/AC\ Cu/TiO2/AC^ Cu/5A and TiO2/5A. The degradation rate is above 85% in 0-40 minutes with the quantity of 10%Cu/AC is 2.5g/L, pH^.O and the initial cyanide concentration is 50mg/L,which reach the national discharge standard for only two hours and the energy consumption is low too.(4) The reaction process of photocatalytic degradation of CNbasically accords with the first-order kinetics .