Flyash augmented Fe3O4 as a heterogeneous catalyst for degradation of stabilized landfill leachate in Fenton process

In this study magnetite (Fe3O4) was augmented over coal flyash and analyzed for the effectiveness as a catalyst in heterogeneous Fenton process for the degradation of persistent organic pollutant present in stabilized landfill leachate. Fe3O4 and flyash augmented Fe3O4 was prepared by simple chemical precipitation method and both had magnetic nature. XRD, FTIR and SEM with EDX characterization were consummated for both catalysts. The Fenton experiments were performed in batch mode and to identify the optimal operating condition for effective COD removal the leachate pH, catalysts and H2O2 dosages were varied. The reusability of the catalysts was studied. To understand the degradation mechanism adsorption study, Fenton oxidation of benzoic acid and scavenging experiments with KI and NaF were performed. It was witnessed that flyash augmented Fe3O4 exhibited 84.7% of COD degradation which was 12.3% of higher removal efficiency than Fe3O4 at optimum pH 3, 0.05 M H2O2 and 1000 mg/L of catalyst dosage in 100 min reaction time. This flyash augmented Fe3O4 showed 68% of TOC removal and good increment in biodegradability. Poor NH3-N removal was observed in the Fenton treatment process. Decrease in aromaticity was found based on SUVA(254) value and also indicated the removal of organic matter. Similarly, reusability and stability were higher than Fe3O4. The results indicate that flyash augmented Fe3O4 is a competent catalyst in heterogeneous Fenton process for treatment of mature leachate. The usage of waste material flyash with Fe3O4 decreases the co-aggregation of Fe3O4 and improves the catalytic performance. (C) 2019 Elsevier Ltd. All rights reserved.