Ion Beam Irradiation Modifications of a Commercial Polyether Sulfone Water-Treatment Membrane

Environmental Context. The demand for more efficient and effective water-treatment processes is increasing. A popular method is the use of membrane filtration, to separate water from contaminants such as ions and microorganisms, however more selective membranes have a lower flux (permeate produced per unit area of membrane per unit time) and are more susceptible to fouling (an accumulation of surface-blocking materials). To aid flux and limit fouling, and thereby make membrane processes competitive with conventional technologies, a post-synthesis treatment is applied to alter the microstructure and surface of the water-treatment membrane.

Abstract. A commercial polyether sulfone (PES) water-treatment membrane was modified by ion beam irradiation. Bench-scale cross-flow filtration experiments were conducted to investigate the transport properties and fouling potential of the modified membrane with respect to the four major constituents of raw water: monovalent cations, divalent cations, natural organic matter (NOM), and bacterial presence. Results indicated modification led to a reduction in the charge of the membrane, as observed by lower rejection of monovalent cations and increased cross-linking of divalent cations on the membrane’s surface, along with a hardening of membrane pores, as observed by increased organic matter removal. The most significant result was with respect to NOM fouling, which was shown to become more reversible.