Sono-photocatalytic degradation of 2-chlorophenol in water: kinetic and energetic comparison with other techniques.

The degradation of 2-chlorophenol in water was kinetically investigated using the following different techniques, employed either separately or simultaneously, always with the same experimental set-up: light irradiation (315-400 nm), sonication, photocatalysis with different types of TiO2, photocatalysis with sonication. The influence of the reaction volume and of different gas mixtures, containing Ar and O2, as well as O2/O3, was also investigated. Finally, an energetic comparison among these different techniques was performed, focused on an industrial application of some of them.

Enzymatic activity under tangential flow conditions of photochemically grafted membranes containing immobilized catalase.

Catalase has been immobilized within sandwich membranes prepared by the photoinduced grafting of an epoxy-diacrylate prepolymer onto commercial asymmetric cellulose membranes. The enzymatic activity of the membrane composite of hydrogen peroxide decomposition has been studied in a recirculation apparatus under tangential flow conditions without ultrafiltration. The enzymatic membranes were exposed to very low mechanical stresses and showed a very good catalytic performance and durability. Initial reaction rates, measured at 25 degrees C as a function of both substrate concentration and enzyme amount immobilized per unit membrane surface, indicate that the mechanism of action of catalase is not altered after immobilization, although substrate diffusion through the original thin layer of membranes may become rate controlling.