Finding quantitative characterization strategy to elucidate perm-selectivity behavior variation of RO-TFC membranes in acidic and alkaline chlorination environments

• Published in: Journal of water process engineering Vol. 66; p. 106125
• Main Authors: Chang, Chaoyue, Huang, Fuling, Santoso, Grace Vita, Wang, Qun, Wang, Jian, Liu, Zhaofeng
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2024
• Subjects: Chlorination; Polyamide; Quantitative characterization method; RO membrane; Structure and performance evolution; Polyamide; Chlorination; Quantitative characterization method; RO membrane; Structure and performance evolution
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2024.106125

RO-TFC membranes exposed to acidic and alkaline chlorination environments exhibited distinctive desalination behaviors, yet the microstructural alterations induced by chlorination lack effective means of characterization. In this study, a variety of quantitative characterization techniques were employed to analyze the separation layer of RO-TFC membranes subjected to varying pH levels and chlorination intensities. Evaluation experiments on perm-selectivity performance revealed a reduction in desalination rates with increasing chlorination intensity. Notably, water flux exhibited an augmentation in alkaline chlorination settings and a decline in acidic chlorination environments. The characterization investigation suggested that the extent of network crosslinking, as identified through ATR-FTIR, provided a more precise quantitative representation of the evolution of desalination rates in chlorinated RO membranes. Moreover, SAXS revealed that chlorination under acidic conditions causes the polymer particles constituting the separation layer to contract, as evidenced by a decrease in the radius of gyration and fractal dimension compared to the unchlorinated membrane. Conversely, chlorination under alkaline conditions leads to the swelling of these polymer particles, indicated by an increase in the radius of gyration and fractal dimension. Consequently, an integrated approach combining SAXS and ATR-FTIR emerges as a superior strategy for comprehending the perm-selectivity performance of chlorinated RO membranes. [Display omitted] •Diverse desalination responses were noted during acidic and alkaline chlorination.•ATR-FTIR offered quantitative evidence to elucidate the desalination process.•SAXS provided quantitative evidence to describe the water flux evolution.