硅胶负载纳米TiO_2光催化降解4BS染料的研究

Photocatalytic degradation of 4BS dyestuff over TiO_2/SiO_2

采用凝胶蒸干法制备TiO_2/SiO_2(G)催化剂,以直接耐酸大红4BS染料废水为目标污染物,研究催化剂制备方法、催化剂用量、溶液pH、初始浓度和催化剂重复使用等因素对光催化降解的影响。结果表明,600℃焙烧的TiO_2/SiO_2(G)效果较好,晶相组成以锐钛矿为主,具有良好的光催化活性和稳定性。最佳催化剂投加量为2 g·L^(-1),反应体系pH为4.0,反应120 min,4BS溶液的浓度去除率达99.8%,COD去除率达95.9%。催化剂重复使用后催化效果有所下降,但仍保持在90%左右。在相当宽的浓度范围,4BS的反应服从一级反应动力学,随着染料初始浓度的增大,表观速率常数随之减小。

TiO2/SiO2 photocatalysts were prepared by sol-gel method and influence of preparation methods, catalyst dosage, pH, 4BS concentration and repeated use of the catalyst on the photodegradation of direct fast scarlet dye 4BS was investigated. The results showed that the catalyst calcined at 600 ~C mainly existed in anatase phase and exhibited good photocatalytic activity and stability. The optimal condition was catalyst dosage 2 g ·L^-1 , pH 4.0 and reaction time 120 min, with 4BS photodegradation rate of 99.8 % and COD removal rate of 95.9 %. Activity of the photocatalyst declined after repeated use, remaining at about 90% of its original activity. The degradation reaction folloowed the first-order kinetics within a wider range of 4BS concentration, and the reaction rate constant declined with 4BS concentration.