Mo-TiO2/AC光催化剂的制备及可见光降解L-酸的研究

采用溶胶-凝胶法制备了Mo⁶⁺掺杂TiO₂光催化剂,并将其负载于粒状活性炭上,以1-萘酚-5-磺酸(L-酸)为模型反应物,研究了对L-酸的光催化作用并讨论了不同光源以及负载次数对L-酸的去除率和溶液的总有机碳去除率的影响.结果表明, Mo⁶⁺掺杂扩大了TiO₂催化剂的光谱响应范围.负载于活性炭上的掺杂二氧化钛为锐钛矿相,粒径约为17.8　nm.负载次数增多,催化剂的活性下降.Mo⁶⁺的掺杂不影响负载催化剂的紫外光活性及对L-酸的吸附能力.100　mg·L^-1的L-酸溶液加0.4 g催化剂,在可见光下反应4 h,掺杂催化剂对L-酸和溶液总有机碳的去除率分别为57%和53%,而未掺杂的催化剂去除率分别为13%和10%.催化剂反复使用4次,催化活性没有变化.

Preparation of Mo-TiO2/Activated Carbon and Degradation of L-acid Under Visible Light

The photocatalyst of Mo⁶⁺ doped TiO₂ was prepared by a sol-gel method and immobilized to granular activated carbon by coating. The photodegradation of 1-naphthol-5-sulphonic acid (L-acid), and the effects of the loading numbers of the photocatalyst on activated carbon and the light sources on the removal efficiency of L-acid and TOC of solution were investigated. The experimental results show that the Mo⁶⁺ doping can help TiO₂ to extend the active scope to the visible-light region. The doped TiO₂ supported on activated carbon is anatase with the average particle diameter 17.8 nm. It has been found that the activity of catalyst is reduced with its loading number, and the Mo⁶⁺ doping does not affect the catalyst activity in the ultraviolet region and adsorption of L-acid. The removal efficiency of L-acid and TOC of solution is 57% and 53% respectively when 0.4 g doped photocatalyst is applied in 100 mg·L^-1 L-acid solution illuminated by visible light for 4 hours, while it is 13% and 10% respectively in the case of the undoped photocatalyst. The catalyst can be reused for 4 times to keep the degradation efficiency hardly changed.