Thermoresponsive PNIPAm–PMMA-Functionalized PVDF Membranes with Reactive Fe–Pd Nanoparticles for PCB Degradation

Abstract

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 (k SA ) values were determined in the convective flow mode to be 0.13, 0.28, 0.72, and 1.36 L/m 2 /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 m 2 /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 k SA values were 0.12 L/m 2 /h at 25 °C and 0.35 L/m 2 /h at 35 °C.

Advanced stimuli-responsive membranes for smart separation

“…The membrane comprising polystyrene-b-poly(acrylic acid) (PS-b-PAA) also exhibited pH responsiveness but in the opposite manner owing to the distinct pH-responsive behavior of PAA blocks. 125 Besides pH-responsive polymers, other stimuli-responsive polymers like PNIPAM, [126][127][128][129][130] PVCL, 131,132 PDEAEMA, 133,134 and PANI, 135 have also received tremendous attention in the synthesis of stimuli-responsive membranes with tunable pore sizes based on their stretching/shrinking properties. For example, Bhattacharyya and coworkers fabricated PVDF membranes with PNIPAM-filled pores.…”

Thermoresponsive Polymers for Water Treatment and Collection

“…An efficient way to enhance the functions and practicality of these hybrid microgels is to immobilize them onto commercial polymeric membranes, which will make the catalytic degradation process more convenient. For instance, Pd and Fe–Pd bimetallic nanoparticles were immobilized within thermoresponsive PNIPAm- co -PAA- and poly­(NIPAm- co -methyl methacrylate)-functionalized polyvinylidene difluoride (PVDF) to degrade 2-chlorobiphenyl and o -nitroaniline. , In one approach, as the temperature was increased from 25 to 35 °C, the diffusion coefficient of 2-chlorobiphenyl increased from 6.6 × 10 –11 to 8.7 × 10 –11 m 2 s –1 and its mass adsorption increased from 40% to 70%, respectively. The promoted diffusion and adsorption in the membrane enhanced the overall catalytic degradation of 2-chlorobiphenyl.…”

Dual-Functional Nanofiltration and Adsorptive Membranes for PFAS and Organics Separation from Water

“…These characteristics allow for the introduction of metals and charged molecules, , grafted molecules, and scaffolds for physical immobilization ,, for applications such as catalysis, adsorption, and the development of responsive materials. The separation of PFAS and other pollutants from contaminated water sources has also been studied. , Successful coupling of a polyamide thin-film layer on top of a functionalized open support presents some intriguing opportunities to create a single-step process, which concentrates and further purifies PFASs from an aqueous solution with a minimum decrease of the membrane water permeance. To the best of our knowledge, this has not been achieved yet because the synthesis of a polyamide layer on top of an open structure remains a challenge.…”