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Surface modification of nanofiltration membranes to improve the removal of organic micropollutants: Linking membrane characteristics to solute transmission
- Source :
- Water Research. 203:117520
- Publication Year :
- 2021
- Publisher :
- Elsevier BV, 2021.
-
Abstract
- Surface modification of nanofiltration (NF) membranes has great potential to improve the removal of organic micropollutants (OMs) by NF membranes. This study used polydopamine (PDA) as a model coating to comprehensively link the changes in membrane properties with the changes in transmission of 34 OMs. The membrane characterization demonstrated that a thicker, denser, and more hydrophilic PDA coating can be achieved by increasing the PDA deposition time from 0.5 to 4 hours. Overall, the transmissions of target OMs were reduced by PDA-coated NF membranes compared to unmodified NF membranes. The neutral hydrophobic compounds showed lower transmissions for longer PDA coating (PDA4), while the neutral hydrophilic compounds tended to show lower transmissions for shorter PDA coating (PDA0.5). To explain this, competing effects provided by the PDA coatings are proposed including sealing defects, inducing cake-enhanced concentration polarization in the coating layer for neutral hydrophilic compounds, and weakened hydrophobic adsorption for neutral hydrophobic compounds. For charged compounds, PDA4 with the greatest negative charge among the PDA-coated membranes showed the lowest transmission. Depending on the molecular size and hydrophilicity of the compounds, the transmission of OMs by the PDA4 coating could be reduced by 70% with only a 26.4% decline in water permeance. The correlations and mechanistic insights provided by this work are highly useful for designing membranes with specific surface properties via surface modification to improve the removal of OMs without compromising water production.
- Subjects :
- Environmental Engineering
Surface Properties
education
02 engineering and technology
Permeance
010501 environmental sciences
engineering.material
01 natural sciences
Water Purification
Adsorption
Coating
Waste Management and Disposal
0105 earth and related environmental sciences
Water Science and Technology
Civil and Structural Engineering
Concentration polarization
Chemistry
Ecological Modeling
Membranes, Artificial
021001 nanoscience & nanotechnology
Pollution
Membrane
Chemical engineering
engineering
Surface modification
Nanofiltration
0210 nano-technology
Hydrophobic and Hydrophilic Interactions
Layer (electronics)
Subjects
Details
- ISSN :
- 00431354
- Volume :
- 203
- Database :
- OpenAIRE
- Journal :
- Water Research
- Accession number :
- edsair.doi.dedup.....155840dc4baedd98f910649bce8141da