掺杂过渡金属离子的纳米TiO_2光催化降解制革废水

以石英砂为载体,液相沉积水解法制备的纳米TiO2膜为光催化剂,通过掺杂过渡金属离子对膜进行改性。在高压紫外灯光、低压紫外灯光和自然光照射条件下,分别对制革废水进行处理。以CODCr为评价指标,分析了不同光照条件对TiO2膜光催化性能的影响。结果表明,在高压紫外灯光照15 min后,Hg/TiO2膜光降解率最高,CODCr去除率为50.23%。通过探讨各种掺杂离子对膜的改性规律发现,改性效果与过渡金属离子电荷和半径的比值有关。对于同周期的元素,第二过渡周期的掺杂效果好于第一、第三过渡周期,但掺杂规律不像第一、第三过渡周期那样明显,随原子半径的减小而增大。对于同一族的元素,离子的掺杂作用基本上随着原子半径的增大而增大。

Study on photocatalytic degradation of tannery wastewater with transition metal-doped TiO2 nanoparticles

Using the nano-TiO2 thin film as photocatalyst and quartz sand as carrier.This film is prepared by liquid phase deposition and hydrolyzation processing and its characters are modified by doped some transition metal-ions.The actual tannery wastewater is degraded respectively by high-voltaged UV rays,low-voltaged UV rays and sun's rays.The photocatalytic characteristics of the TiO2 film are analyzed under different light irradiation conditions by the CODCr as evaluating standard.The experimental result shows that the Hg/TiO2 film has the highest degradative efficiency and the removal rate of CODCr reaches 50.23% after 15 min by the high-voltaged UV rays irradiation.Through discussing the rules of the film which is doped various transition metal-ions,we find that the effect of the varied characteristic is related to ratio of electric charges to semidiameter of transition metal-ions.For the chemical elements of the same period,the degradative effect of the second transition period is better than the first and third,but the degradative rule is not obvious as the first and third transition periods,the degradative effect is increased with the decreasing atom radius.For the chemical elements of the same clan,the effect of the doped-ions are increased with the increasing atom radius.