Towards synergistic combination of biochar/ultrasonic persulfate enhancing removal of natural humic acids from water

Hongbo Liu (1) , Mengting Ye (1) , Zhenxing Ren (1) , Eric Lichtfouse (2, 3) , Zhongbing Chen (4)

1 University of Shanghai for Science and Technology
2 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement
3 Xjtu - Xi'an Jiaotong University
4 CZU - Czech University of Life Sciences Prague

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 SO 4-⋅. 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.

Mots clés: Humic acids (HAs); Biochar; Persulfate (PS); Ultrasonic treatment; Hydroxyl radical

Domaines: Matériaux; Ingénierie de l'environnement

Hongbo Liu, Mengting Ye, Zhenxing Ren, Eric Lichtfouse, Zhongbing Chen. Towards synergistic combination of biochar/ultrasonic persulfate enhancing removal of natural humic acids from water. Journal of Environmental Chemical Engineering, 2022, 10 (3), pp.107809. ⟨10.1016/j.jece.2022.107809⟩. ⟨hal-03669572⟩