Towards synergistic combination of biochar/ultrasonic persulfate enhancing removal of natural humic acids from water. Issue 3 (June 2022)

• Record Type: Journal Article
• Authors: Liu, Hongbo; Ye, Mengting; Ren, Zhenxing; Lichtfouse, Eric; Chen, Zhongbing
• Is Part Of: Journal of environmental chemical engineering. Volume 10:Issue 3(2022)
• Publication Date: 2022-06
• Subjects: Humic acids (HAs) -- Biochar -- Persulfate (PS) -- Ultrasonic treatment -- Hydroxyl radical; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2022.107809
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: Removal of natural organic matter (NOMs) from actual water is a major challenge in the context of worldwide pollution of natural water resources. The removal of humic acids in a system combining biochar adsorption and ultrasonic persulfate oxidation was studied in this paper. The effects of biochar addition, persulfate concentration and initial pH were investigated. A high removal rate of humic acids up to 92.5% was achieved for the combined biochar/ultrasonic/persulfate system, versus 84.0% for combined biochar/persulfate, 52.0% for sole biochar, 50.0% for combined biochar/ultrasonic, 10.0% for combined persulfate/ultrasonic, 4.0% for sole ultrasonic and 1.0% for sole persulfate systems. Ultrasonic treatment increased the removal efficiency of humic acids to 90.0% within 60 min. Mechanisms towards synergistic combination of the biochar/ultrasonic/persulfate system were investigated by gel permeation chromatography, electron paramagnetic resonance and quenching experiments together with the characterization of biochar. Hydroxyl radical and the adsorption of biochar were the major contributors to the proposed synergistic adsorption-oxidation removal mechanism, followed by the sulfate radical SO4 - ·. The results of three-dimensional fluorescence diagram, fluorescence regional integration and TOC analysis indicated that the system presented promising application prospects to remove NOM pollutants from real water. Graphical Abstract: ga1 Highlights: Ultrasonic treatment increased humic acids removal rate of real river water by 90%. Ultrasonic treatment improved the performances of biochar induced AOPs. Synergy of sonochemistry, catalytic chemistry and adsorption was achieved. A systematic mechanism of humic acids removal in river water was proposed.