Efficient photocatalytic degradation of ciprofloxacin using novel dual Z-scheme gCN/CuFe2O4/MoS2 mediated peroxymonosulphate activation

Abstract

Modulation in the constituent composition of heterojunction composite materials can efficiently separate photogenerated charge carriers and promote significant improvement towards visible light aided photocatalytic degradation of recalcitrant pollutants. Herein, a novel ternary heterojunction composite g-CN/CuFe2O4/MoS2 (CNCuMo) has been fabricated by improvising g-C3N4 as a fuel and the supporting matrix. The stable dual Z-scheme heterojunction manifested superior visible light driven catalytic activity through efficient electron/hole (e-/h+) separation and generation of reactive species through peroxymonosulphate (PMS) activation. Various surface bound redox cycles play prominent roles in transport of photogenerated charge carriers, activation of adsorbed PMS species and generation of reactive radicals. Benefiting from their synergistic effects, visible light aided photocatalytic degradation of refractory antibiotic Ciprofloxacin (CIP) was studied. 98% CIP was degraded (with 74.8% mineralization) using 0.1 g/l of ternary composite with 10 wt% MoS2 (CNCuMo(10)) and 0.5 g/l of PMS, within 60 min of visible light irradiation. Scavenging experiments confirmed the simultaneous activity of both radical and non-radical species towards degradation. The system also exhibited satisfactory CIP degradation efficiency in various surface water matrixes. LCMS/MS analysis of the identified intermediates interpreted the probable degradation pathways of CIP molecules. Magnetic retrievability, recyclability for five cycles, good structural stability and low metal ion leaching tendency of the synthesized photocatalyst elucidate its potential application for degradation of emerging pollutants for water decontamination.