Enhanced Degradation of Methyl Orange and Trichloroethylene with PNIPAm-PMMA-Fe/Pd-Functionalized Hollow Fiber Membranes

• Published in: Nanomaterials (Basel, Switzerland) Vol. 13; no. 14; p. 2041
• Main Authors: Mills, Rollie, Tvrdik, Cameron, Lin, Andrew, Bhattacharyya, Dibakar
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.07.2023; MDPI
• Subjects: Activated carbon; Adsorption; Aquatic resources; Azo compounds; bimetallic catalysts; Catalysts; Contamination; Decontamination; Degradation; Dyes; Environmental cleanup; Environmental restoration; Groundwater; Groundwater pollution; hollow fiber membrane; Hollow fiber membranes; Hydrogels; Hydrogen; Hydrophobicity; Immersion coating; Iron; Isopropylacrylamide; Membranes; methyl orange; Nanoparticles; Palladium; PCB; Perchloroethylene; Phase transitions; PNIPAm; Pollutants; Poly-N-isopropylacrylamide; Polychlorinated biphenyls; Polymers; Polymethyl methacrylate; Polymethylmethacrylate; Rate constants; Sodium; Solvents; Sorption; Surface area; Surface chemistry; thermoresponsive; Trichloroethene; Trichloroethylene; VOCs; Volatile organic compounds; Water pollution; Water, Underground; United States > US; Singapore; PNIPAm; hollow fiber membrane; thermoresponsive; water detoxification; zero-valent iron; bimetallic catalysts; trichloroethylene; methyl orange
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano13142041

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 (d ~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.