磷钨酸/SiO_2光催化降解甲基橙研究

Preliminary Study on Photocatalytic Degradation of Methyl Orange by Phosphotungstic Acid/SiO_2

[目的]将杂多酸固载在载体上制得固载化催化剂。[方法]以溶胶-凝胶法合成的SiO2作载体,固载磷钨酸制得固载化光催化剂,并对甲基橙溶液进行催化降解、矿化处理。[结果]在催化剂浓度为4.2 g/L的条件下,光照1.5 h,4 mg/kg甲基橙溶液的脱色率达到98.8%,但矿化率仅有47.6%;而光照6.0 h后,矿化率可达92.7%。这意味着甲基橙的光催化降解是先发生脱色过程,然后再进一步矿化成CO2,且所制备的光催化剂在没有进行任何处理的条件下,重复使用10次,脱色率依然保持在65%以上。[结论]成功制备了固载化光催化剂,该固载化磷钨酸光催化剂对甲基橙的光催化降解反应具有较好的催化活性,且对甲基橙溶液的脱色和矿化并不同步。

[ Objective ] Heteropolyacid was loaded onto the surface of photocatalytic carrier effectively. [ Method ] The loaded phosphotungis acid photocatalyst, which prepared by supporting phosphotungis acid on SiO2 carrier synthesized by sol-gel process. The photocatalytic and mineralizable behaviors of the composites were evaluated by degradation of aqueous methyl orange solution under the irradiation of two UV lamps 4254 nm）. [ Results] When the catalyst was irradiated 1.5 h, under the optimum conditions of the inltial concentration of the methyl orange solution of 4 mg/kg, catalyst quantity of 4.2 g/L, the decolofing ratio of methyl orange was up to 98.8% ,and its ratio of mineralization was up to 47.6% ; while irradiated 6.0 h, the mineralizing ratio of methyl orange was up to 98.8% . The loaded catalysts can be reused 10 times and still keep well activity. [ Conclusions ] The results showed that the loaded phasphotungis acid catalysts revealed well photocatalysic activity on photodegradation of methyl orange, but the rates of decolor and mineralization werent synchronous.