Development of a sustainable ternary magnetic nanocomposite GCNI for efficient and synergistic photodegradation of Rhodamine B under solar irradiation: kinetic and mechanistic studies

Abstract

ABSTRACT In this study, a novel sunlight-active ternary magnetic nano-photocatalyst GCNI (Nanozero valent Iron @ Graphene oxide and Chitosan support) was fabricated. This easily retrievable magnetic nanocomposite was prepared by depositing NZVI (Nano Zero Valent Iron, Fe0) over binary GO-CS in seven different compositions for its best optimisation in the solar-light-promoted degradation of RhB. NC (Nano Composite) was characterised by SEM demonstrating their surface morphology. Further characterisation and properties of NC were also studied using XRD, FT-IR, VSM and BET and EDS techniques. The efficacy of the NC was investigated for the removal of RhB in comparison to binary GO-CS and bare NZVI. GCNI 1:1:3 was found to be the best suitable photocatalyst showing synergistic effect in the photodegradation of RhB under given conditions of pH, concentration and time. The mechanism of dye removal and degradation was further discovered by UV-VIS and mass spectroscopy techniques. FT-IR and XRD results of fresh and treated GCNI successively corroborated the mechanism. The sorption kinetics of RhB on to GCNI was found to be described by the pseudo-second-order kinetic equation. The parameters such as dye concentration, pH and the reaction time are varied to understand the effective removal of RhB in wastewater. The outcomes exhibited the highly efficient; up to 99.4% of dye removal, easy magnetic separation of photocatalyst, excellent reusability up-to 87.5% till six consecutive cycles, synergistic effect in adsorption and photo-degradation of dye.