Catalytic degradation of estrogen by persulfate activated with iron-doped graphitic biochar: Process variables effects and matrix effects

Abstract

Advanced oxidation processes (AOPs) based on sulfate radicals (SO4∙-) is being actively investigated as an effective technology for aqueous organic pollutants degradation. In this work, a novel iron-doped graphitic biochar (Fe@GBC), which was synthesized by one-step method using biomass-derived biochar as precursor and potassium ferrate (K2FeO4) as activator, was applied to activate persulfate (PS) for the degradation of 17β-estradiol (E2). The characterizations indicated that Fe@GBC was successfully doped with iron particles and possessed a porous graphitic carbon structure. In order to evaluate the applicability of Fe@GBC, the effects of various reaction parameters, such as initial pH, catalyst dosage, PS concentration, as well as the reusability and stability of Fe@GBC were systematically investigated. With the synergistic effect of doped iron particles and porous graphitic carbon structure, Fe@GBC exhibited a high activity for PS activation and great degradation capacity to E2 (almost 100% degradation efficiency within 90 min). Through radical quenching experiments and electron spin resonance (ESR) analysis, it found that both SO4∙- and OH∙ were responsible for the degradation of E2, while SO4∙- played a dominant role. Moreover, Fe@GBC/PS also exhibited good degradation performance in complex water matrices. Overall, the facile one-step synthetic strategy and superior performance make Fe@GBC an alternative catalyst for persulfate activation and aqueous pollutants degradation.