Abstract: Applying microreactor technology to photocatalytic reactions is a novel and potential technical innovation. Photocatalytic planar microreactors were fabricated by metal etching technology, and copper ion doped TiO₂ was immobilized as coatings by the sol-gel method. X-ray diffraction, scanning electron microscope and UV-visible diffuse reflection were used for characterization of photocatalyst. The microreactors were tested for the degradation of methyl orange and the optimal doping concentration of copper ion was found to be 0.04% (mole ratio to Ti). The degradation ratio of methyl orange with an initial concentration of 10 mg·L^-1 could reach 45% within 90 s in the microreactor. Degradation ratios of methyl orange in microreactors under controlled irradiation were measured, and the copper ion doped photocatalytic microreactors showed better utilization of irradiation energy. The study of kinetics illustrated that the degradation of methyl orange in the microreactors was a first order reaction of incomplete oxidation with a much greater rate constant (k) comparing to regular reactors. The rate constant increased with the decreasing of initial concentration (C₀), and there was a good linear relationship of lnk and lnC₀.

Key words: photochemistry, catalyst, planar microreactor, titanium dioxide, copper ion doping, methyl orange

摘要： 将微反应器技术应用于光催化反应是一项新兴且极具潜力的技术创新.采用金属蚀刻技术制造了板式微反应器,并通过溶胶-凝胶法在微反应器中负载了铜离子掺杂改性的TiO₂光催化剂涂层.使用X射线衍射分析、扫描电子显微镜以及紫外-可见漫反射吸收光谱对催化剂进行表征,并以甲基橙的降解反应来评价微反应器的光催化效果.结果表明,铜离子掺杂能够有效提高微反应器的光催化性能,掺杂浓度为0.04%(摩尔比于Ti)时效果最优,能够在90 s的停留时间内使初始浓度为10 mg·L^-1的甲基橙溶液降解45%;光催化微反应器中甲基橙的降解过程为不完全氧化的动力学一级反应,其反应速率常数(k)远高于常规反应器体系,并随着甲基橙溶液初始浓度(C₀)的减小而增大,且lnk-lnC₀具有良好的线性关系.

关键词: 光化学, 催化剂, 微反应器, 二氧化钛, 铜离子掺杂, 甲基橙