Adsorption and catalytic reduction of rifampicin in wastewaters using hybrid rGO@Fe/Pd nanoparticles

Abstract

Ubiquitous use of antibiotics worldwide has resulted in their significant efflux into the environment impacting ecosystem health to such a degree that antibiotic removal has become a key environmental issue. Here one target antibiotic, rifampicin, was successfully removed from aqueous solution using a hybrid nanomaterial (rGO@Fe/Pd NP) having an adsorption capacity of 90.9 mg g−1. The factors influencing rifampicin removal by rGO@Fe/Pd NPs and each constituent component of the hybrid nanomaterial were also investigated. Adsorption and reduction kinetics indicated that rifampicin conformed to a pseudo-second-order model. While X-ray diffraction and Fourier transform infrared spectroscopy showed that rifampicin was adsorbed by rGO@Fe/Pd NPs, scanning electron microscopy and X-ray photoelectron spectroscopy showed that rifampicin was reduced by nano iron and during this process, nano palladium acted as a catalyst. Liquid chromatography-mass spectrometry, confirming that rifampicin was indeed catalytically degraded by rGO@Fe/Pd NPs, as evidenced by a decrease in ion mass ratio from 823.41 (M+1H) to 611.21 (M+1H) or 606.37 (M+1H). A mechanism for rifampicin degradation based on adsorption and catalytic reduction was proposed. In addition, the practical removal efficiency of rifampicin was successfully validated in aquaculture sewage water (71.9%) and for municipal sewage (58.1%). This article provides a strong scientific basis for the degradation mechanism of rifampicin by rGO@Fe/Pd NPs indicating that this hybrid material has great potential for practical applications.