纳米TiO_2薄膜光催化降解苯酚和氯代苯酚的研究

PHOTOCATALYTIC DEGRADATION OF PHENOL AND CHLORINATED PHENOLS USING NANOMETER TiO2 THIN FILMS

采用溶胶-凝胶法制备纳米TiO2薄膜,研究了初始浓度、pH和外加H2O2对TiO2薄膜光催化降解苯酚、对氯苯酚和2,4-二氯苯酚影响。结果表明,纳米TiO2薄膜对于苯酚和氯代苯酚均有较高的光催化活性,相同条件下,2,4-二氯苯酚的光催化降解速率>4-氯苯酚>苯酚。在本实验条件下,随着反应物初始浓度的升高,相同时间内,苯酚和氯代苯酚的降解效率均逐渐降低。在中性条件下,苯酚和氯代苯酚的光催化反应速率均强于酸性条件下,其中pH对苯酚光催化降解的影响幅度最大。适量的H2O2有助于提高苯酚和氯代苯酚光催化降解速率。

Photocatalytic degradation of phenol, 4-chlorophenol and 2, 4-dichlorophenol was investigated using TiO2 film prepared by sol-gel process. The effects of initial concentration, pH and the addition of H2O2 on the photoactivities of TiO2 thin film were studied. The results indicate that the TiO2 film has much higher photocatalytic activity on the degradation of phenol and chlorinated phenols. The photodegradation rates decrease in the sequence, 2,4-dichlorophenol>4-chlorophenol>phenol. For all of phenol, 4-chlorophenol and 2, 4-dichlorophenol, an increase in the molar influent concentration resulted in a decrease in removal efficiency. The photoactivities are greatly dependent on the solution pH, and it is more effective for phenol and chlorinated phenols to be degraded under neutral condition. It is likely to contribute for the acid-base equilibra on the surface of the nanoparticles. The proper addition of hydrogen peroxide can improve the degradation rate.