不同光强下光催化降解对氯苯甲酸钠动力学

以对氯苯甲酸钠为模型污染物,研究了不同光强条件下的光催化降解动力学.结果表明对氯苯甲酸钠的光催化降解动力学可以用Langmuir-Hinshelwood模式来描述,但其中的动力学参数与光强有关.速率常数k_r随入射光强的升高而增加,而表观吸附常数K_s却随入射光强的升高而降低.k_r和K_s^-1近似与光强呈幂函数的关系.说明提高光强虽然可以增加光催化降解速率但会降低其能量利用效率,如何使用低光强照射可能是提高光催化氧化反应器能量利用效率的重要因素之一.

Kinetic Study on Photocatalytic Degradation of p-Chlorobenzoate at Different Light Intensities

Kinetics of photocatalytic degradation were investigated at different light intensities using para chlorobenzoate as a model pollutant. It was experimentally found that the Langmuir Hinshelwood model could satisfactorily describe all the kinetic processes. However, the two crucial parameters involved in the L H model were dependent of the incident light intensity. With elevated light intensity, the rate constant, k_r, increased whereas the apparent adsorption constant, K_s, decreased. Grossly, both k_r and K_s^-1 were correlated with the light intensity in a power law. The experimental discovery implies that the photonic efficiency would be much deteriorated with increased radiation intensity although the reaction rate can be enhanced. Applying mild light intensity might be one of the critical strategies in photocatalytic reactor design to improve the photonic efficiency.