Combined effect of adsorbent chitosan and photosensitizer polypyrrole in ternary chitosan-polypyrrole-TiO₂ photocatalyst leading to visible light activity and superior functionality

Abstract

The combined effect of the components in the ternary chitosan-polypyrrole-TiO₂ (Chit-Ppy-TiO₂) photocatalytic system has been investigated. The role of each component in this catalyst is validated by the visible light degradation of the model dye methylene blue. The reaction parameters, viz., amount of catalyst, dye concentration, oxidant concentration and temperature are studied in detail. The ternary system exhibits greater activity when compared to both the single and binary component catalysts (chitosan-TiO₂ and polypyrrole-TiO₂). The superior functionality of Chit-Ppy-TiO₂ (1:1:100 wt ratio) originates from the combined effect of greater dye adsorption of chitosan, visible light sensitization of polypyrrole and the catalytic functionality of TiO₂. The ternary photocatalyst is recyclable even after fourth run without appreciable loss in its activity.