Understanding the Roughness-Fouling Relationship in Reverse Osmosis: Mechanism and Implications
| Autor: | Chuning Shang, Dicky Pranantyo, Sui Zhang |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Flux distribution
Osmosis Materials science Fouling business.industry Metal Nanoparticles Membranes Artificial General Chemistry Surface finish Mechanics 010501 environmental sciences Computational fluid dynamics 01 natural sciences Water Purification Fluid dynamics Environmental Chemistry Gold business Reverse osmosis Membrane surface Mechanism (sociology) Filtration 0105 earth and related environmental sciences |
| Zdroj: | Environmental sciencetechnology. 54(8) |
| ISSN: | 1520-5851 |
| Popis: | This paper investigates the relationship between roughness and fouling in reverse osmosis (RO) through specially designed experimental protocols and computational fluid dynamics (CFD) studies. Conventional polyamide thin-film composite membranes with a ridge-and-valley structure and an emerging type of smooth membranes are prepared. A wide range of foulants are used, and fouling under static, crossflow, and RO conditions are tested. Feature size on the membrane surface is important when foulants and the microscale structure show a similar size, and otherwise membrane-foulant interactions govern the static attachment. Under crossflow mode, fouling on the ridge-and-valley surface is not reduced to the same extent as that on smooth membranes, with the insufficient vortices in the valley region being identified as the key factor by CFD studies. In RO, uneven flux distribution as confirmed by gold nanoparticle filtration is also found to account for the much higher fouling rate of conventional membranes. Our study then suggests two strategies to design next-generation fouling-resistant RO membranes via structural optimization: first, a smooth selective layer should be maintained to ensure uniform flux distribution; second, one may mimic nature to fabricate patterned porous membranes as the support, so that it optimizes hydrodynamics while maintaining even fluxes. |
| Databáze: | OpenAIRE |
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