Thermoresponsive PNIPAm-PMMA-functionalized PVDF membranes with reactive Fe-Pd nanoparticles for PCB degradation

Fe-Pd nanoparticles are immobilized in stimuliresponsive poly-N-isopropylacrylamide (PNIPAm)- and polymethyl methacrylate-functionalized polyvinylidene fluoride membranes using ion exchange for 2-chlorobiphenyl (PCB-1) degradation via the reductive pathway. PNIPAm is introduced into the reactive membrane system, and its thermoresponsive behavior is leveraged to enhance PCB-1 diffusion and adsorption into the reactive domain. The surface area-normalized rate constant (kSA) values were determined in the convective flow mode to be 0.13, 0.28, 0.72, and 1.36 L/m²/g at 15, 25, 35, and 45 °C, respectively, with an activation energy of 60 kJ/mol (3 wt % Pd). The diffusion coefficients for PCB-1 were 6.6 × 10-11 and 8.7 × 10-11 m²/s at 25 and 35 °C, respectively. The adsorption of PCB-1 onto PNIPAm hydrogels also increased from 40 to 70% as the temperature was increased above its lower critical solution temperature of 32 °C. The batch-mode kSA values were 0.12 L/m²/h at 25 °C and 0.35 L/m²/h at 35 °C.