Thin-Film Composite Membrane Compaction: Exploring the Interplay among Support Compressive Modulus, Structural Characteristics, and Overall Transport Efficiency

• Published in: Environmental science & technology 2024-05, Vol.58 (19), p.8587-8596
• Main Authors: Xu, Chunyan, Wang, Zhongzhen, Hu, Yuhang, Chen, Yongsheng
• Format: Article
• Language: English
• Subjects: Alternative energy sources; Compaction; Design optimization; Energy efficiency; Fractions; Industrial wastes; Industrial wastewater; Mechanical properties; Membranes; Membranes, Artificial; Modulus of elasticity; Permeability; Physical properties; Physico-Chemical Treatment and Resource Recovery; Polymers; Polymers - chemistry; Pores; Porosity; Thin films; Tissue engineering; Viscoelasticity; Void fraction; Wastewater; Wastewater treatment; Water demand; Water reuse; Water scarcity
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/acs.est.4c01639

Water scarcity has driven the demand for water production from unconventional sources and the reuse of industrial wastewater. Pressure-driven membranes, notably thin-film composite (TFC) membranes, stand as energy-efficient alternatives to the water scarcity challenge and various wastewater treatments. While pressure drives solvent movement, it concurrently triggers membrane compaction and flux deterioration. This necessitates a profound comprehension of the intricate interplay among compressive modulus, structural properties, and transport efficacy amid the compaction process. In this study, we present an all-encompassing compaction model for TFC membranes, applying authentic structural and mechanical variables, achieved by coupling viscoelasticity with Monte Carlo flux calculations based on the resistance-in-series model. Through validation against experimental data for multiple commercial membranes, we evaluated the influence of diverse physical parameters. We find that support polymers with a higher compressive modulus (lower compliance), supports with higher densities of “finger-like” pores, and “sponge-like” pores with optimum void fractions will be preferred to mitigate compaction. More importantly, we uncover a trade-off correlation between steady-state permeability and the modulus for identical support polymers displaying varying porosities. This model holds the potential as a valuable guide in shaping the design and optimization for further TFC applications and extending its utility to biological scaffolds and hydrogels with thin-film coatings in tissue engineering.