Sonophotocatalytic Degradation of Scarlet Red dye using Fe-Bi2O3 Catalyst and its Process Optimization by Response Surface Methodology

Abstract

The catalyst Fe-Bi2O3 was synthesized by ultrasound irradiation and used as a catalyst for the sonophotocatalytic degradation of scarlet red dye. The synthesized catalyst were characterized by SEM, XRD and DRS. SEM image reveals the formation of nanorod structure of the catalyst, XRD reveals the size of the catalysts were in nano range and DRS shows the blue shift in optical absorption for the Fe-Bi2O3 catalyst. The Fe-Bi2O3 was identified to be a composite and found to enhance degradation than bare Fe and Bi2O3 were used. The degradation was further enhanced by the addition of electron acceptors (H2O2), initial pH and gas bubbling (air, oxygen, nitrogen, argon). This was due to the acceleration in the generation of ^•OH radicals and ^•OH radical-pollutant interaction in the presence of Fe-Bi2O3 catalyst. Sonophotocatalytic treatment gave higher degradation of 61% for the catalyst dosage of 3 g/l. Further, the sonophotocatalytic treatment process was optimized using response surface methodology based software s namely MODDE and Design Expert. Both the experimental and theoretical optimized conditions provided similar degradation trend.

Keywords: Fe-Bi2O3, ultrasound, scarlet red dye, sonophotocatalysis, MODDE, Design Expert