黏土和氧化锰颗粒物对TiO_2光催化降解萘酚蓝黑的影响

Effect of Clay Minerals and Natural Manganese Oxides on Photocatalytic Degradation of Naphthol Blue Black over TiO_2

考察了悬浆体系中共存的黏土矿物和天然锰矿2类颗粒物对TiO2光催化降解萘酚蓝黑的影响,并利用紫外-可见漫反射光谱对受杂质颗粒污染前后的TiO2样品进行了表征.实验结果表明:当pH=6时,体系中共存的黏土矿物对TiO2光催化活性影响不大,其反应行为符合一级动力学方程;在pH为6,9,10的体系中天然锰矿对TiO2的光催化活性都有严重的抑制效应,其抑制程度依次为pH10,pH6,pH9;而在pH=3的体系中天然锰矿对TiO2的光催化活性没有抑制作用.研究发现,受黏土矿物污染后TiO2的吸收带边几乎不变,而受天然锰矿污染后TiO2的吸收带边蓝移约40nm,光吸收强度明显减弱,从而导致TiO2的光催化活性降低.

The effect of clay minerals and natural manganese oxides on the TiO2 photocatalytic degradation of naphthol blue-black was investigated. The TiO2 samples polluted by clay minerals and natural manganese oxides were characterized by UV-vis DRS. The results showed that the photoeatalytic activity of TiO2 Was slightly inhibited by clay minerals at pH= 6,and the reaction was fitted to L-H first-order kinetic process. The activity of TiO2 was significantly inhibited by natural manganese oxides at neutral and alkaline pH, following the order of pill0, pH6,pHg. While the activity of TiO2 was not inhibited at pH=3. The result suggests that the inhibition can be changed or even eliminated through adjusting the pH values of the solution. The absorption edge of the TiO2 sample polluted by clay minerals remained unchanged. On the contrary,the absorption edge of the TiO sample polluted by natural manganese oxides was blue-shifted and its absorption intensity was decreased,leading to the deactivation of TiO2.