Molecular imprinting of cellulose acetate-sulfonated polysulfone blend membranes for Rhodamine B by phase inversion technique

Abstract

A functional polymer, sulfonated polysulfone (SPS) with a degree of substitution of 0.10, was prepared and then blended with cellulose diacetate (CA) as the matrix polymer for the preparation of molecularly imprinted polymer (MIP) membranes via phase inversion from a casting solution containing a template. Polyethylene glycol was found to be compatible with these polymers and was subsequently used as pore forming agent. Optimization studies with the aim to enhance the membrane permeability, were carried out with respect to solvent, polymer blend composition and total polymer concentration. The effects onto pore structure were also studied by membrane water uptake and specific surface area measurements. In conclusion from these investigations, dimethyl sulfoxide was chosen as the solvent, the CA/SPS composition was maintained at 90/10 (w/w) to minimize non-specific template binding and the total polymer concentration was set at 13 wt.%. MIP membranes based on CA/SPS blends with Rhodamine B (RhB) as template were prepared using the optimized conditions. Results for re-binding of RhB during filtration through MIP as well as Blank membranes, prepared without RhB, provide evidence for surface imprinting of the porous membranes.