Development of pH-sensitive membranes with enhanced antifouling performance for the valorisation of side streams in the pulp industry

Description

The pulping industry is characterised by large water consumption and side streams which are so far often not fully valorised because the components of interest are either diluted and/or difficult to recovery in a way suitable for further processing. Membrane processes could have a great potential in the valorisation of these streams but fouling reduces their efficiency and significantly increases the cost of separation. The most effective approaches to increase the fouling resistance of membranes are: (1) increasing the hydrophilicity of selective membrane layer, (2) reducing the surface roughness, (3) adjusting charge properties and (4) utilizing steric repulsion effects. The goal of this study was to develop novel membranes with enhanced antifouling performance via the modification of the conventional non-solvent-induced phase separation (NIPS) technique by addition of polyelectrolyte to the coagulation bath. The main concept is that using aqueous solution of polyelectrolyte as a coagulation medium upon membrane preparation via NIPS leads to the modification of the selective layer due to immobilization of the charged hydrophilic macromolecules in the membrane matrix. Flat-sheet polysulfone ultrafiltration membranes were prepared via NIPS. Distilled water, and 0.1-2.0% aqueous solutions of poly(acrylic acid) of three molecular weights (PAA; Sigma Aldrich; 100 kDa, 250 kDa, 450 kDa) were used as coagulation bath. The influence of PAA molecular weight and concentration in the coagulation bath on the physico-chemical properties, zeta-potential, hydrophilic/hydrophobic balance of the membrane selective layer, pore structure, transport properties and antifouling performance in ultrafiltration of thermomechanical pulp was studied. It was found that the increase of PAA concentration yields an increase of flux, fouling recovery ratio and cleaning efficiency of membranes without sacrificing membrane rejection with regard to hemicellulose and lignin as reference components.

Period	2020 Dec 7 → 2020 Dec 11
Event title	12th International Congress on Membranes and Membrane Processes
Event type	Conference
Location	London, United KingdomShow on map
Degree of Recognition	International