Abstract

Trichloroethylene (TCE) is a prominent groundwater pollutant due to its stability, widespread contamination, and negative health effects upon human exposure; thus, an immense need exists for enhanced environmental remediation techniques. Temperature-responsive domains and catalyst incorporation in membrane domains bring significant advantages for toxic organic decontamination. In this study, hollow fiber membranes (HFMs) were functionalized with stimuli-responsive poly-N-isopropylacrylamide (PNIPAm), poly-methyl methacrylate (PMMA), and catalytic zero- valent iron/palladium (Fe/Pd) for heightened reductive degradation of such pollutants, utilizing methyl orange (MO) as a model compound. By utilizing PNIPAm’s transition from hydrophilic to hydrophobic expression above the LCST of 32 ◦C, increased pollutant diffusion and adsorption to the catalyst active sites were achieved. PNIPAm-PMMA hydrogels exhibited 11.5× and 10.8× higher equilibrium adsorption values for MO and TCE, respectively, when transitioning from 23 ◦C to 40 ◦C. With dip-coated PNIPAm-PMMA-functionalized HFMs (weight gain: ~15%) containing Fe/Pd nanoparticles (dp~34.8 nm), surface area-normalized rate constants for batch degradation were determined, resulting in a 30% and 420% increase in degradation efficiency above 32 ◦C for MO and TCE, respectively, due to enhanced sorption on the hydrophobic PNIPAm domain. Overall, with functionalized membranes containing superior surface area-to-volume ratios and enhanced sorption sites, efficient treatment of high-volume contaminated water can be achieved.

Document Type

Article

Publication Date

7-2023

Notes/Citation Information

© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

Digital Object Identifier (DOI)

https://doi.org/10.3390/nano13142041

Funding Information

This research was funded by the National Institute of Environmental Health Sciences- Superfund Research Program (NIEHS-SRP) Grant P42ES007380. Rollie Mills is funded by the National Science Foundation (NSF)-Graduate Research Fellowship Program (GRFP).

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