Enhanced phenol-photodegradation by particulate semiconductor mixtures: Interparticle electron-jump

Degradation of phenol on suspended TiO2, ZnO, CdO, Fe2O3, CuO, ZnS and Nb2O5 particles under UV-A light exhibit identical photokinetic behavior; follow first-order kinetics, display linear dependence on the photon flux and slowdown with increase of pH. All the semiconductors show sustainable photocatalytic activity. Dissolved O2 is essential for the photodegradation and oxidizing agents like H2O2, Na2BO3, K2S2O8, KBrO3, KIO3 and KIO4, reducing agents such as NaNO2 and Na2SO3 and sacrificial electron donors like hydroquinone, diphenyl amine and trimethyl amine enhance the degradation. However, the photocatalysis is insensitive to pre-sonication. Two particulate semiconductors present together, under suspension and at continuous motion, enhance the photocatalytic degradation up to about four-fold revealing interparticle electron-jump.