尿素为氮源的N-TiO₂的制备及对印染废水的降解

Preparation of N-TiO₂ with Urea as Nitrogen Source and Degradation of Printing and Dyeing Wastewater

摘要: 采用溶胶–凝胶法，以钛酸四丁酯为钛源，以尿素为氮源，制备了氮掺杂二氧化钛光催化剂。样品经干燥、研磨、焙烧后，以紫外光灯为光源，亚甲基蓝染料溶液为目标污染物，氮掺杂二氧化钛为光催化剂进行吸附和光催化降解，分别研究考察了氮掺杂二氧化钛催化剂投加量、pH值、紫外光照射时长等因素的变化对吸附光催化降解亚甲基蓝脱色率的影响。实验结果表明，氮掺杂二氧化钛具有良好的光催化性能，最佳反应条件：氮掺杂二氧化钛投加量为50 mg，溶液初始pH为7，温度为25℃，光催化反应时间为2 h，亚甲基蓝的降解率可达90.37%，在酸性条件下的亚甲基蓝吸附和光催化降解率较低，在中性和碱性条件下对亚甲基蓝的吸附性能较好，其光催化降解率较高，光催化降解亚甲基蓝反应为动力学一级反应。

Abstract: Using sol-gel method, tetrabutyl titanate as the titanium source and urea as the nitrogen source, a nitrogen-doped titanium dioxide photocatalyst was prepared. After the samples were dried, ground, and roasted, the UV lamp was used as the light source, the methylene blue dye solution was the target pollutant, and the nitrogen-doped titanium dioxide was used as the photocatalyst for adsorption and photocatalytic degradation. The dosage of the nitrogen-doped titanium dioxide catalyst was studied separately. The effects of nitrogen-doped titanium dioxide catalyst dosage, pH value and ultraviolet light irradiation time on the decolorization rate of methylene blue were investigated. The experimental results show that nitrogen-doped titanium dioxide has good photocatalytic performance. The best reaction conditions are: the dosage of nitrogen-doped titanium dioxide is 50 mg, the initial pH of the solution is 7, the temperature is 25˚C, and the photocatalytic reaction time is 2 h. The degradation rate of methylene blue can reach 90.37%, the adsorption and photocatalytic degradation rate of methylene blue under acidic conditions is low, the adsorption performance of methylene blue under neutral and alkaline conditions is better, its photocatalytic degradation rate is high. Photocatalytic degradation of methylene blue is a kinetic first order reaction.