Determining the reliability of nanofiltration (NF) membranes for the removal of contaminants of emerging concern, including polyfluoroalkyl substances (PFASs), pharmaceuticals, and personal care products (PPCPs), is important for ensuring drinking water safety. This study aimed to clarify the factors that influence the removal of nine major PFASs during submerged NF treatment via extrapolation based on the factors that influence PPCP removal. The rejection of nine PFASs in ultra-filtered dam water by a polypiperazine-amide (NF270) membrane increased from 71 % to 94 % at a low permeate flux of 5 L/m h as the PFAS molecular dimensions increased. PFASs with a carboxylic acid (-COH) were rejected to a greater extent than PFASs with a sulfo group (-SOH). Further, negatively charged PFASs or PPCPs were rejected to a greater extent than uncharged and positively charged PPCPs. Our findings suggest that the rejection of PFASs can vary because of the (i) clearance distance between the PFASs' molecular dimensions and NF membrane pore diameter and (ii) intensity of electrostatic repulsion between the PFASs' functional groups and NF membrane surface. Our study indicates that submerged NF can achieve high PFAS rejection; however, variations in rejection among PFASs can become more prominent owing to a low permeate flux.
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http://dx.doi.org/10.1016/j.wroa.2024.100233 | DOI Listing |
Nat Commun
December 2024
School of Civil & Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
Per- and polyfluoroalkyl substances (PFASs) have recently garnered considerable concerns regarding their impacts on human and ecological health. Despite the important roles of polyamide membranes in remediating PFASs-contaminated water, the governing factors influencing PFAS transport across these membranes remain elusive. In this study, we investigate PFAS rejection by polyamide membranes using two machine learning (ML) models, namely XGBoost and multimodal transformer models.
View Article and Find Full Text PDFMolecules
September 2024
Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA.
The widespread production and use of multi-fluorinated carbon-based substances for a variety of purposes has contributed to the contamination of the global water supply in recent decades. Conventional wastewater treatment can reduce contaminants to acceptable levels, but the concentrated retentate stream is still a burden to the environment. A selective anion-exchange membrane capable of capture and controlled release could further concentrate necessary contaminants, making their eventual degradation or long-term storage easier.
View Article and Find Full Text PDFWater Res X
September 2024
Graduate School of Integrated Science and Technology, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
Determining the reliability of nanofiltration (NF) membranes for the removal of contaminants of emerging concern, including polyfluoroalkyl substances (PFASs), pharmaceuticals, and personal care products (PPCPs), is important for ensuring drinking water safety. This study aimed to clarify the factors that influence the removal of nine major PFASs during submerged NF treatment via extrapolation based on the factors that influence PPCP removal. The rejection of nine PFASs in ultra-filtered dam water by a polypiperazine-amide (NF270) membrane increased from 71 % to 94 % at a low permeate flux of 5 L/m h as the PFAS molecular dimensions increased.
View Article and Find Full Text PDFSci Total Environ
May 2024
College of Marine Science and Biological Engineering, Qingdao University of Science and Technology, Qingdao 266042, China. Electronic address:
Membrane separation technology is widely recognized as an effective method for removing perfluoroalkyl substances (PFASs) in water treatment. ZIF-L, a metal-organic framework (MOF) family characterized by its mat-like cavities and leaf-like morphology, has garnered considerable interest and has been extensively employed in fabricating thin-film nanocomposite (TFN) membranes. In this study, a robust, high-performance TFN membrane to remove PFASs in a nanofiltration (NF) process was created through an interfacial polymerization approach on the surface of polysulfone (PSF), incorporating ZIF-L within the selective layer.
View Article and Find Full Text PDFWater Environ Res
February 2024
Department of Civil and Environmental Engineering, New Jersey Institute of Technology, Newark, New Jersey, USA.
Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are now widely found in aquatic ecosystems, including sources of drinking water and portable water, due to their increasing prevalence. Among different PFAS treatment or separation technologies, nanofiltration (NF) and reverse osmosis (RO) both yield high rejection efficiencies (>95%) of diverse PFAS in water; however, both technologies are affected by many intrinsic and extrinsic factors. This study evaluated the rejection of PFAS of different carbon chain length (e.
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