Efficient peroxydisulfate activation with nZVI/CuO@BC nanocomposite derived from wastes for degradation of tetrabromobisphenol A in alkaline environment

Abstract

Peroxydisulfate (PDS) is a promising oxidant for sulfate radical based advanced oxidation processes (SAOPs), however its efficient activation is still a challenge. In this study, biochar-supported nano-zerovalent iron (nZVI) and copper oxide (CuO) nanocomposite (nZVI/CuO@BC), derived from low-cost wastes including scrap iron filings, copper leaching solution and corn stalks, was successfully fabricated for PDS activation to enhance tetrabromobisphenol A (TBBPA) degradation in alkaline environment. Under the conditions of 100 mg/L nZVI/CuO@BC, 0.2 mM PDS, pH 8.0 and 25 °C, 86.32% of PDS was activated and 98.46% of TBBPA was degraded within 45 min in nZVI/CuO@BC-activated PDS system. When the PDS concentration was 2 mM, the nZVI/CuO@BC-activated PDS system realized efficient debromination and mineralization of TBBPA at the ratio of 79.12% and 79.36%, respectively. The results of EPR studies and radical scavenger experiments revealed that both hydroxyl radical (·OH) and sulfate radical (SO4·-) were responsible for TBBPA degradation. The nZVI could active PDS indirectly through electron transfer mechanism and exhibited synergistic effects with CuO on PDS activation. Furthermore, the nZVI/CuO@BC-activated PDS system showed good potential to degrade TBBPA in real water environment. Therefore, nZVI/CuO@BC could be a novel strategy for efficient PDS activation and TBBPA degradation in alkaline environment.