Reduction of Biofouling of a Microfiltration Membrane Using Amide Functionalities—Hydrophilization without Changes in Morphology

Abstract

A major goal of membrane science is the improvement of the membrane performance and the reduction of fouling effects, which occur during most aqueous filtration applications. Increasing the surface hydrophilicity can improve the membrane performance (in case of aqueous media) and decelerates membrane fouling. In this study, a PES microfiltration membrane (14,600 L m−2 h−1 bar−1) was hydrophilized using a hydrophilic surface coating based on amide functionalities, converting the hydrophobic membrane surface (water contact angle, WCA: ~90°) into an extremely hydrophilic one (WCA: ~30°). The amide layer was created by first immobilizing piperazine to the membrane surface via electron beam irradiation. Subsequently, a reaction with 1,3,5-benzenetricarbonyl trichloride (TMC) was applied to generate an amide structure. The presented approach resulted in a hydrophilic membrane surface, while maintaining permeance of the membrane without pore blocking. All membranes were investigated regarding their permeance, porosity, average pore size, morphology (SEM), chemical composition (XPS), and wettability. Soxhlet extraction was carried out to demonstrate the stability of the applied coating. The improvement of the modified membranes was demonstrated using dead-end filtration of algae solutions. After three fouling cycles, about 60% of the initial permeance remain for the modified membranes, while only ~25% remain for the reference.

Radiation-Induced Graft Immobilization (RIGI): Covalent Binding of Non-Vinyl Compounds on Polymer Membranes

“…Thus, additional chemical coupling steps such as EDC/NHS [ 49 ] might be suspended. Further specialized compounds with different functionalities have been grafted on membranes, e.g., photosensitizers [ 50 ], antimicrobial peptides [ 51 ], or piperazine, in order to produce hydrophilic amide layers [ 52 ]. However, there are scarcely any publications dealing with this novel type of grafting mechanism, since RIG is typically performed exclusively with vinyl monomers (i.e., RIGP).…”

Estradiol Removal by Adsorptive Coating of a Microfiltration Membrane

“…In this work, we report a novel and efficient method to prepare an adsorber membrane by creating an amide functional coating on porous microfiltration (0.45 µm) PES membrane surface using the concept of interfacial polymerization reaction [ 43 ]. The porous support membrane provides the mechanical stability required for operating under high permeation rates.…”