苯酚及氯代苯酚化合物TiO_2催化光致降解

PHOTODEGRADATION OF PHENOL AND CHLORINATED PHENOLS USING A TiO_2-COATED PHOTOREACTOR

在载于玻璃反应器内壁的薄层TiO_2催化作用下,水溶液中苯酚、对氯苯酚、2,4-二氯苯酚和2,4,6-三氯苯酚的光致降解均遵守一级反应动力学.其一级反应表现速率常数k_(o b)为7.0×10^(-3)-2.8×10^(-2)min^(-1),其大小顺序为:苯酚<对氯苯酚<2,4-二氯苯酚<2,4,6-三氯苯酚.加入少量H_2O_2(1.9×10^(-2)mol·L^(-1))均能提高这些化合物的TiO_2催化光致降解速率(k’_(o b)=1.5×10^(-2)-3.3×10^(-2)min^(-1)).经一定时间光照后(λ≥345nm,1.5—4.5b)这些化合物几乎完全降解,光致降解率大于95％,COD去除率大于96％.

Photocatalytic degradation of phenol, 4-chlorophenol, 2,4-dichloro-phenol, and 2,4,6-trichlorophenol in aqueous solution followed first order kinetics when irradiated in a TiO2-coated photoreactor. The apparent first-order rate constants kob (7.3× 10-3min-1-2.8×10-2min-1) increased in the order of phenol, 4-chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol. Addition of H2O, (1.9×10-2mol×L-1) made their first-order rate constants larger (k'ob = 1.5×10-2min-1-3.3×10-2min-1). These compounds were almost completely degradated after certain period of irradiation (1.5-4.5h), and photodegradation up to 95% and COD removal up to 96%.