Removal of humic substances by the synergistic effect of biochar adsorption and activation of persulfate. (December 2021)

• Record Type: Journal Article
• Authors: Liu, Hongbo; Ye, Mengting; Dong, Xinyi; Ren, Zhenxing; Long, Shiping; Lichtfouse, Eric
• Is Part Of: Journal of water process engineering. Volume 44(2021)
• Publication Date: 2021-12
• Subjects: Adsorption -- Oxidization -- Corn stalk biochar -- Humic acids (HA) -- Persulfate (PS); Water-supply engineering -- Periodicals; Saline water conversion -- Periodicals; Seawater -- Distillation -- Periodicals; Sanitary engineering -- Periodicals; Sewage -- Purification -- Periodicals; 627
• DOI: 10.1016/j.jwpe.2021.102428
• Languages: English
• ISSNs: 2214-7144

Abstract

Abstract: Combined adsorption and oxidation using biochar to activate persulfate has been recently applied to remove contaminants, yet most of the experiments are carried out using artificial synthetic water instead of real waters. Here we tested the removal of humic substances which is abundant and affecting water quality in natural waters, by persulfate combined with corn stalk biochar. Results showed that, compared with biochar prepared at 400 °C, 600 °C and 700 °C, biochar prepared at 900 °C after modified by hydrochloric acid had greater specific surface of 459.260 m 2 /g, richer porosity and higher removal of humic acids of more than 80% at pH 5.0–9.0 in pure water. Treatment of real river water showed decrease of 80.4% and 69.7% of total organic carbon (TOC) and UV254, respectively. The addition of tert-butyl-alcohol (TBA) and methanol (MeOH) inhibited the removal to a certain extent suggesting the existence of OH and SO4 − . It was speculated that in addition to the adsorption of biochar, the oxygen-containing functional groups on its surface might act as active sites to promote the production of oxidized species. This work provides a method for corn stalks utilization in accordance with environmental sustainability and resource recovery. Graphical abstract: Unlabelled Image Highlights: Humic acid was well removed within the biochar (900 °C)/persulfate system. High TOC and UV254 removal were also achieved in real water. Possible mechanisms of humic acid removal by the combined process were interpreted. The adsorption of biochar and the oxidation of OH and SO4 − were the main removal pathways.