Simultaneous removal of Pb(II) and rifampicin from wastewater by iron nanoparticles synthesized by a tea extract

Abstract

Abstract Most environmental contaminants exist as a complex mixture of both metallic and organic pollutants and it is thus often a major challenge to remove both components simultaneously. In this paper, due to its low cost and environmentally friendliness, iron nanoparticles (Fe NPs) were successfully prepared using a one-step green synthesis for the simultaneous in-situ remediation of mixed contaminants. Specifically Fe NPs were used for the simultaneous removal of Pb(II) and rifampicin. The removal efficiency for Pb(II) and rifampicin were 100% and 91.6%, respectively. To better understand the mechanism of mixed contaminant removal by Fe NPs various characterization methods and the major conditions impacting removal efficiency were examined. It was concluded that (1) polyphenols and caffeine, both ubiquitous in green tea extracts, acted as both reducing and capping agents during the preparation of Fe NPs, reducing the agglomeration of Fe NPs and increasing their stability and reactivity; (2) the removal mechanism of contaminants involved Pb(II) being adsorbed onto the surface of Fe NPs due to the innate strong adsorption of metal ions onto iron oxides, while rifampicin and Pb(II) both interacted positively with the functional groups on the surface of Fe NPs. Overall, this study demonstrated that green synthesis Fe NPs had potential for use as inexpensive and efficient adsorbent for the simultaneous removal of both Pb(II) and rifampicin from wastewater.