TiO2光电催化氧化有机物的反应被认为是表面反应,有机物在TiO2表面的吸附是其降解的先决条件,因此系统研究有机物在TiO2表面的吸附行为,可以为进一步的光电催化降解提供实验依据。现采用阳极氧化法在基体钛表面原位合成B2O3·TiO2/Ti催化剂为吸附剂,系统地研究了腐殖酸在膜催化剂上的吸附行为,探讨了温度、溶液pH值、腐殖酸初始浓度、外加偏压等因素对吸附的影响,结果表明:低温、酸性条件下有利于腐殖酸在膜催化剂上吸附,吸附量随初始浓度、外加偏压的增加而增大,B2O3·TiO2/Ti催化剂吸附腐殖酸的等温线数据可用Freundlich等温吸附方程描述,吸附过程遵循Lagergren二级吸附动力学模型。
The TiO2 photo-electrocatalytic oxidation of organics is considered as a surface reaction and one of its essential terms for degradation of organics is the organics adsorption ability of TiO2. Thereby the study of the organics adsorption on the surface of the adsorbant is important and it may provide experimental evidence for further photo-electrocatalytic degradtion of the organics. B2O3-TiO2/Ti film was in-situ synthesized on the surface of Ti plate by anodic oxidation and was used as the adsorbent in our work. The effects of the adsorption temperature, pH value of the solution, initial concentration of the adsorbate (humic acid, HA) and the applied bias voltage on the adsorption of HA on catalyst B2O3·TiO2/Ti film was investigated. The results show that the lower temperature and pH value of the solution are favorable to the adsorption of HA on the surface of B2O3.TiO2/Ti catalyst, and the adsorbed amount of HA increases with the increases of initial HA concentration in the solution and the applied bias voltage. It was also found that the thermoisopleth data of HA adsorption on B2O3·TiO2/Ti film can be described by Freundlich thermoisopleth adsorption equation and the adsorptive courses agree well with Lagergren second-order adsorptive kinetics model.