A Novel Thermoresponsive Catalytic Membrane with Multiscale Pores Prepared via Vapor‐Induced Phase Separation

Abstract

A novel thermoresponsive catalytic polyethersulfone membrane with multiscale pores is developed by constructing silver nanoparticles (Ag NPs) loaded poly(N-isopropylacrylamide) (PNIPAM) nanogels on pore walls of cellular pores as thermoresponsive gates and catalysts via vapor-induced phase separation. The Ag NPs are stably immobilized on the PNIPAM nanogels by an in situ reduction method based on the versatile adhesion and reduction properties of polydopamine. The micrometer cellular pores decorated with Ag NPs loaded PNIPAM nanogels are formed throughout the membrane and act as numerous microreactors with a large pore surface. The proposed membrane exhibits both satisfactory thermoresponsive characteristics and stable catalytic properties. The effects of operation temperature and reactant concentration of feed solution on the catalytic properties are investigated systematically. The results show that the apparent kinetic rate constant of catalytic reduction of 4-nitrophenol (4-NP) in water by reductant sodium borohydride (NaBH ), is ranging from 3.7 to 37.9 min at temperatures from 20 to 45 ºC and the molar ratio of NaBH to 4-NP from 100:1 to 500:1. When the reactant concentration in feed solution fluctuates, the permeability or throughput of the membrane is simply adjusted by virtue of the thermoresponsive characteristics of membranes to achieve high catalytic conversion of reactant.

Catalytic Membrane Reactor of Nano (Ag+ZIF-8)@Poly(tetrafluoroethylene) Built by Deep-Permeation Synthesis Fabrication

“…There have been also analogous studies about the catalytic reaction of the flow-through membrane, in which different membrane fabrication and reactants have been associated with. Xie et al fabricated an Ag immobilized thermoresponsive catalytic membrane by vapor-induced phase separation (VIPS) and applied it to the reduction of p -nitrophenol . The membrane was formed by co-blending presynthesized Ag NPs with the polymer.…”

“…Considering the excess of NaBH 4 in the mixture solution (molar ratio of p -NA to NaBH 4 1:200), the catalytic reaction can be viewed as a first-order kinetic process and conforms to the following equations where C t and C 0 are the downstream concentration and the upstream concentration of p -NA in the solution, respectively. The ratios of C t to C 0 were obtained from the relative intensity ratios of the respective absorbance ( A t / A 0 ) at 380 nm ( A t and A 0 are the downstream absorbance and the upstream absorbance of p -NA in the solution).…”

A Heat-Resistant Poly(oxyphenylene benzimidazole)/Ethyl Cellulose Blended Polymer Membrane for Highly Safe Lithium-Ion Batteries

“…The porosities of the different proportions of the membrane were 67.8, 81.8, and 91.7% (PBI/EC = 1:1, 1:2, and 1:3), respectively. The porosity of the PBI/EC blended membranes decreases with increasing PBI content in the casting solution because excessive PBI slows the rate of water vapor immersion into the membrane, resulting in a decrease in membrane porosity . At the same time, electrolyte uptake is related to the wettability on the separator surface and the porosity, which is evaluated by the change in weight before and after uptake.…”

“…The porosity of the PBI/EC blended membranes decreases with increasing PBI content in the casting solution because excessive PBI slows the rate of water vapor immersion into the membrane, resulting in a decrease in membrane porosity. 36 At the same time, electrolyte uptake is related to the wettability on the separator surface and the porosity, which is evaluated by the change in weight before and after uptake. When the ratio of the membranes is 1:1, 1:2, and 1:3, the electrolyte uptake rates are 365.3, 478.6, and 407.3%, respectively, which are much higher than that of the PE separator (117.4%).…”

Design of Switchable Enzyme Carriers Based on Stimuli-Responsive Porous Polymer Membranes for Bioapplications

“…Many current treatments of contaminated water sources are chemical intensive and energy intensive because of he formation of unwanted byproducts. The SR-PPMECs are able to conduct environmentally catalytic oxidative reactions for highly selective degradation and detoxification of the toxic organic contaminants from the water sources without harmful chemicals adding. ,,,− …”