Efficient degradation of phenol with high salinity wastewater by catalytic persulfate activation using chitosan biochar

In this study, chitosan biochar was prepared by one-step pyrolysis of chitosan and used to activate persulfate to remove phenol with high salinity wastewater. Chitosan biochar was characterized by scanning electron microscope, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy and FTIR spectrum. The effect of chitosan biochar dosage, persulfate dosage, and pH on the phenol removal was explored and optimized. Meanwhile 98% phenol removal rate and 80% phenol mineralization rate were achieved under the optimum conditions. Phenol was successfully oxidized and degraded into water, carbon dioxide and other small molecular organics. The system was different from the general persulfate advanced oxidation system, sulfate radical played a minor role, singlet oxygen played a major role. The leading role of non-radical 1O2 in degradation was determined by radical quenching experiments and ESR experiments. By simulating high salt wastewater and studying the effect of common anions and cations on the system, system's stability was also investigated.