Enhanced photocurrent generation and photooxidation of benzene sulfonate in a continuous flow reactor using hybrid TiO_2 thin films immobiized on OTE electrodes

摘要

The enhancement of photocurrent and photodegradation of organic pullutants was investigated using hybrid TiO_2 thin films prepared by a combined paste/sol/gel technique to immobilize the TiO_2 particles onto optically transparent electrodes (OTEs); they were connected in series in a continuous flow, bench-top, two-compartment photoreactor. The benzene sulfonate (BS) of the model substrate surfactant used was photodegraded in aqueous media to test the efficacy of the TiO_2/OTE electrode preparation and the construction of the photoreactor. Results indicate that the hybrid TiO_2 film/OTE electrodes were more efficient than either the pasted TiO_2/OTE electrode or the sol-gel TiO_2/OTE electrode for the photodegradation of BS, as evidenced by the evolution of carbon dioxide and the photocurrent generatued. The extent of ring opening and generatred photocurrent during the photodegradation of BS with the hybrid (HY) ellectrode was correlated to the pasted TiO_2 electrode and to the number of dip-coatings in the sol-gel. High photocurents were generated in the cylindrical large photoreactor under continuous flow of the aqueous BS solution. Opimization of experimental factors for optimal efficiency of the setup was addressed with regard to the preparation of the HY electrodes, and to their size and location in the photorector.