Enhanced performance and mechanism of bromate removal in aqueous solution by ruthenium oxide modified biochar (RuO2/BC)

Abstract

The removal of pollutants from water using agricultural waste-based biomaterials is gaining extensive attention. In this study, biochar loading ruthenium oxide (RuO2/BC), a novel composite for bromate removal from drinking water, has been prepared by the impregnation method. Based on the single-factor design, a Box-Behnken design (BBD) of the response surface methodology (RSM) was applied to access the mutual interactions and effects between the three factors and optimized preparation conditions (activation time is 3.9 h, activation temperature is 612.2 °C and mass ratio of biochar to RuCl3 is 38.9: 1). The effects of initial solution pH, RuO2/BC dosage and initial bromate concentration on bromate removal by RuO2/BC were investigated. The Field Emission Scanning Electronic Microscopy (FESEM), Brunauer-Emmett-Teller (BET), Energy Dispersive X-Ray Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS) and Zeta potential were used to characterize the properties of prepared composite. Results showed that bromate removal by RuO2/BC was highly pH dependent and the bromate reduction kinetics followed the pseudo-first-order kinetic model. The detailed mechanism including adsorption and reduction of bromate by the synergistic effect of RuO2 and biochar (CC, CO and OH) was demonstrated. These results proposed a new approach for the remediation of bromate contaminated water.