Synergistic design of graphene oxide mediated polyaniline/α-Fe2O3 ternary heterostructure: Advancing photocatalytic degradation and adsorption efficiency

Abstract

With the growing threat of organic pollutants in water bodies, there is an urgent need for sustainable and efficient water decontamination methods. This research focused on synthesizing a novel Z-scheme ternary heterostructure composed of graphene oxide (GO)-mediated polyaniline (PANI) with α-Fe2O3 and investigated for its potential in brilliant green (BrG) and ciprofloxacin (CIP) degradations under visible light. The ternary composite demonstrated exceptional photocatalytic activity, with the optimized 10%PANI/GO/α-Fe2O3 (10PGF) photocatalyst achieving 99.8% degradation of BrG in 25 min and 93% CIP in 90 min of irradiation. The 10PGF composite achieved rate constants of 0.222 min−1 for BrG and 0.0295 min−1 for CIP. The rate constant of BrG degradation was 15 and 10 times faster than PANI and α-Fe2O3, respectively, while CIP degraded 8.9 and 6.1 times faster. The degradation of the pollutants was facilitated by both O2•− and •OH, confirmed by capturing active species, nitroblue tetrazolium test and PL terephthalic acid probe. The proposed Z-scheme mechanism elucidated the charge carrier movements and active species involvement, revealing the enhanced photocatalytic performance of the ternary composite. The 10PGF ternary composite demonstrated exceptional recyclability over five repeated cycles, with XRD analysis confirming no structural changes in the material. Moreover, the adsorption studies were also performed, which showed strong correlation (R2 = 0.974) for Langmuir isotherm and follows pseudo-second order kinetics.