Single bubble probe atomic force microscope and impinging-jet technique unravel the interfacial interactions controlled by long chain fatty acid in anaerobic digestion. (1st March 2023)

• Record Type: Journal Article
• Authors: Duan, Jian-Lu; Han, Yi; Feng, Li-Juan; Ma, Jing-Ya; Sun, Xiao-Dong; Liu, Xiao-Yu; Geng, Fan-Shu; Jiang, Jia-Li; Liu, Mei-Yan; Sun, Yu-Chen; Peu, Pascal; Ni, Bing-Jie; Yuan, Xian-Zheng
• Is Part Of: Water research. Volume 231(2023)
• Publication Date: 2023-03-01
• Subjects: Long chain fatty acid -- Single bubble atomic force microscope -- Interfacial interaction -- Anaerobic digestion; LCFA long chain fatty acid -- VFA volatile fatty acid -- AFM atomic force microscope -- EDL electrical double layer -- AGS anaerobic granular sludge -- NaOL sodium oleate -- FTIR Fourier transform infrared -- VDW van der Waals; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2023.119657
• Languages: English
• ISSNs: 0043-1354

Abstract

Highlights: Long chain fatty acid inhibited methanogenesis by limiting substrates utilization. Anaerobic granular sludge absorbed long chain fatty acids. Long chain fatty acid enhanced bubble separation from anaerobic granules. Long chain fatty acid reduced the bubble-bubble coalescence probability. Long chain fatty acid changed adhesion forces between bubble and bubble. Abstract: Anaerobic digestion of lipid-rich wastewater generally suffers from foaming induced by long chain fatty acid (LCFA). However, a systematic understanding of LCFA inhibition, especially the physical inhibition on interfacial interaction still remains unclear. Here, we combined bubble probe atomic force microscope and impinging-jet technique to unravel the interfacial interactions controlled by long chain fatty acids in anaerobic digestion. We showed that LCFA had a significant inhibition on methane production in anaerobic reactors for the inhibition of the conversion of VFAs to methane. By measuring the LCFA influence on methanogenic archaea Methanosarcina acetivorans C2A, the results demonstrated that methanogenesis was limited for substrates utilization but not metabolic pathways. The impinging-jet technique results indicated that LCFA enhanced bubble separation from anaerobic granules and reduced the bubble-bubble coalescence probability. In addition, the bubble probe atomic force microscope (AFM) revealed that LCFA enhanced the adhesion force between bubbles by enhancing electrical double layer (EDL) repulsion and decreasing hydrophobic interactions. Overall, these results complement framework of LCFA inhibition in anerobic digestion and provide a nanomechanical insight into the fundamental interfacial interactions related to bubbles in anaerobic reactors. Graphical abstracts: Image, graphical abstract