Filtration of Elastic Polymers and Spherical Gels through a Silica-Deposited Layer on a Porous Membrane

Abstract

A 120-nm silica suspension was permeated through a porous polyethylene (PE) hollow-fiber membrane, as was a solution of deformable elastic particles of poly(N-isopropylacrylamide) (PNIPAM) gel and dextran. The amount adsorbed and flux of permeation were analyzed with ordinary differential equations to obtain adsorption coefficients, maximum amounts adsorbed, and pore-narrowing factors. The thickness of the “silica-deposited layer” on the membrane was 1 μm. In a batch adsorption mode, 5.0 mg of PNIPAM gel and 30 mg of dextran were adsorbed on the PE membrane, with no adsorption on the silica. The PE membrane pores were narrowed by a secondary layer of adsorbed PNIPAM gel. When filtered through the silica-deposited layer, PNIPAM gel occupies gaps, resulting in a reduced permeation flux. Dextran passed through the silica-deposited layer and was partially adsorbed on the PE membrane. The modified membrane can control adsorption, filtration, and flux permeation, which leads to dynamic membrane separations.

Electrospun Silica-Polyacrylonitrile Nanohybrids for Water Treatments

“…Colloids having the same size deform via shear stress and applied pressure. Conventionally, the deposited layer on the membrane surface had a drawback due to serious fouling [ 46 ]. Therefore, a lot of research is being conducted to minimize this phenomenon and develop the most effective method of controlling it by a different pretreatment of the feed method, such as coagulation, oxidation, ion exchange, carbon adsorption, and mineral oxide adsorption [ 47 ].…”