亚甲基蓝表面修饰纳米TiO_2降解造纸废水动力学  

Degradation kinetics of wastewater from papermaking on nanosized titanium dioxide surface modified with Methylene Blue

作　　者：黄泱[1] 李顺兴[1] 傅碧玉[1] 

机构地区：[1]漳州师范学院化学与环境科学系,漳州363000

出　　处：《环境工程学报》2012年第8期2544-2550,共7页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金资助项目(20977074);漳州师范学院科学研究资助项目(SK09012)

摘　　要：以亚甲基蓝(MB)作为表面修饰剂,采用简单的化学吸附法制备亚甲基蓝表面修饰的纳米TiO2光催化剂(TiO2-MB)。经表面修饰后,TiO2-MB光催化剂波长响应范围红移至可见光区575 nm处。探讨了光催化剂量、光照时间和溶液pH值对TiO2-MB光催化降解造纸废水的影响;研究了纳米TiO2-MB对造纸废水的暗吸附规律和光降解性能。结果表明:纳米TiO2-MB对造纸废水的吸附规律都较好地符合Langmuir和Freundlich吸附等温模型,属于吸热反应;光催化降解动力学符合Langmuir-Hinshelwood动力学模型。在160 W高压汞灯光照80 min,3.0 g/L纳米TiO2-MB光催化降解pH=2.0的造纸废水(COD:2 069.8 mg/L),COD去除率可达94.7%,处理效果远高于避光条件下。光催化剂经8次使用仍具有较高的催化活性。Nanometer size titanium dioxide modified with Methylene Blue （TiO2-MB）was prepared using chemical adsorption method. Through surface modification, the formation of TiO2-MB results in a red shift of UV-Vis reflectance spectra, towards the visible region, up to 575 nm. The influences of amount of catalyst, irra- diation time and pH value on the photocatalytic degradation of papermaking wastewater on TiO2-MB were also studied. The adsorption and photocatalytic oxidation proceses of wastewater from papermaking on nano-TiO2-MB were studied. The results indicate that the adsorption law of wastewater from papermaking on nano-TiO2-MB fit in well with the Langmuir model and Freundlich model. Thermodynamic study showed the adsorption was an endo- thermic process. The photodegradation fits in with Langmuir-Hinshelwood kinetic mode. The optimal photodegra- dation conditions were obtained： catalyst amount of 3.0 g/L, papermaking wastewater＇ s pH value of 2.0, and irradiation time of 80 min with 160 W of high-pressure mercury lamp, the COD removal rate of papermaking wastewater reached 94.7%. The photodegradation efficiency was higher than the adsorption efficiency. The used photocatalyst could be used for the eighth time with high efficiency.

关 键 词：纳米TIO2 光催化降解 表面修饰 亚甲基蓝 造纸废水 

分 类 号：X703.1[环境科学与工程—环境工程]