Enhanced photocatalytic degradation of antimicrobial triclosan using rGO–TiO₂ composite under natural solar illumination

In the present study, the enhancement in the photocatalytic degradation of triclosan after incorporation of reduced graphene oxide (rGO) in pristine TiO₂ is investigated. Triclosan is an antimicrobial compound found in commonly used personal care products. The study involved the synthesis of reduced graphene oxide–titania composite using the improved Hummer and hydrothermal methods. The optimum rGO content in the composite was found to be 10 wt% (RT10). The composite was characterized using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), UV–Vis spectroscopy, Scanning electron microscopy (SEM), and Brunauer–Emmett–Teller surface area (BETSA). The experimental conditions viz. catalyst dose, initial triclosan concentration, and solution pH were studied. The surface area of the composite was substantially higher than either of TiO₂ and GO. The photocatalytic reaction followed pseudo-first-order kinetics with the highest rate constant of 0.251 h⁻¹ obtained for RT10. The scavenging experiment indicated the role of hydroxyl radical in the degradation mechanism. The composite displayed efficient degradation under natural sunlight attributed to narrowing of band gap. It also performed effectively in secondary effluent containing triclosan despite matrix effect. Thus, the composite has potential application as a promising photocatalyst in tertiary treatment of water and wastewater.