Modified cellulose/poly(3,4-ethylenedioxythiophene) composite as photocatalyst for the removal of sulindac and carbamazepine from water

Abstract

Pharmaceutical compounds have been widely recognized as emerging contaminants around the world. Advanced oxidation processes using photocatalysts and ultraviolet radiation have been a successful integrated strategy for the removal of active pharmaceutical ingredients from polluted waters. In this research, an environmentally-friendly photocatalytic system operating under ambient conditions was developed. A conductive polymer composite was synthesized using gamma irradiated cellulose as template and coated with poly(3,4-ethylenedioxythiophene). Gamma irradiation was applied as a green technology to functionalize cellulose, improving its stability in water and reducing its size. Our process proved to be a feasible technique to obtain stable particles in dispersion, confirmed by measuring their surface ζ-potential in water. The conductive polymer onto the composite catalyzed the photodegradation of highly persistent compounds sulindac and carbamazepine, showing outstanding catalytic effects within 7 h of exposure under near ultraviolet (UV-A) light at pH 7. Removal efficiency of sulindac reached 89% and degradation of carbamazepine was 30% after pouring the composite into the photodegradative treatment. Similar results were achieved from mixture of both compounds. The composite reusability revealed that particle stability and photocatalytic activity were preserved even after repeating the degradation cycle. Our study showed a promising novel photocatalyst, synthetized through green technologies that can be used as a potential treatment for pharmaceutically active contaminants in water.