Biochar‐mediated oxidation of phenol by persulfate activated with zero‐valent iron

Abstract BACKGROUND Biochar, a by‐product of the pyrolysis of biomass, was used to investigate activation of persulfate in the presence of zero‐valent iron, Fe(0), for the purposes of phenol degradation. Relevant factors of pH, persulfate concentration, and type of black carbon (biochar, activated carbon, and graphite) were examined. RESULTS Maximal removal of phenol was obtained at an initial pH of 2 in Fe(0)–biochar–persulfate systems. At a pH of 7, 89% of the phenol was degraded, with 2.60 mmol L −1 of persulfate, 300 mg of Fe(0), and 100 mg of biochar. Under optimal conditions, more than 95% of phenol degraded after 330 min. Electron paramagnetic resonance analysis showed that sulfate radical (SO 4 − ·) and hydroxyl radical (·OH) were involved in phenol degradation. A graphitic structure arising from a sp 2 covalent carbon network and oxygen‐containing functional groups on biochar were responsible for enhancement of phenol degradation. CONCLUSIONS Our study suggests that biochar‐mediated oxidation by persulfate with Fe(0) may be an effective treatment technology for removal of phenol from natural and engineered aquatic systems. © 2019 Society of Chemical Industry

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