High flux Fe/activated carbon membranes for efficient degradation of organic pollutants in water by activating sodium persulfate

Abstract

Efficient removal of organic pollutants in water is an important task and difficult problem in environmental treatment. In this paper, activated carbon supported Fe ions catalyst (Fe/AC) was prepared by a modulated hydrothermal approach for catalytic activating sodium persulfate (PS) to remove trace of humic acid (HA) in water. The effect of the dosage of Fe/AC and PS, the initial content of HA, pH, temperature, inorganic salt on the degradation of HA were analyzed. At the optimum condition, the advanced oxidation system achieved removal efficiencies of HA, TOC and chromaticity of 99.92%, 70.50% and 96.43%, respectively by adding 1.0 g/L Fe/AC and 0.30 g/L PS into 30 mg/L HA solution for 2 h. With increasing temperature and ionic concentration, the degradation rate was promoted. The regeneration efficiency of the catalyst was 66.70% as the reduction of active sites in AC. Electron paramagnetic resonance (EPR) and quenching tests were used to investigate the mechanism and both sulfate radicals (SO4−) and hydroxyl radicals (OH) were verified as dominant force responsible for HA degradation. Furthermore, a constant HA solution with PS was cross-flow filtrated by Fe/AC membrane within 20 h with excellent rejection of HA (93.33%) and high flux (298.8 L·m−2·h−1) under 0.1 MPa. The loaded Fe/AC effectively reduced the membrane fouling by HA and the coupled technology improved activation capacity of the Fe/AC. Other pollutions including amoxicillin, rhodamine B and methyl orange were employed to investigate the performance of the catalytic membrane. The combined technology exhibits an excellent performance of removing organic pollutants from water and provides a new idea for water environmental management.