(646d) Biofouling and Cleaning Effectiveness of Surface Nanostructured, Reverse Osmosis Membranes

Adequate suppression of membrane biofouling is necessary for the successful use of reverse osmosis (RO) membranes in brackish desalination and water reuse applications. In this study, the recently developed atmospheric pressure plasma-induced graft polymerization (APPIGP) method was utilized to generate a high surface density of active surface sites on a polyamide membrane for subsequent graft polymerization using suitable water soluble vinyl monomers. Surface structuring via graft polymerization was then employed to form a brush layer of polymeric chains that are terminally and covalently attached to the polyamide surface of an optimized (with respect to flux and salt rejection) of a thin-film composite (TFC) polyamide (PA) membrane. The chemical and physical features of the resulting surface nano-structured (SNS) TFC-PA membrane was first tuned with respect to wettability, by the selected vinyl monomer chemistry, as well as the reaction conditions, to achieve the desired surface architecture. Performance evaluation of the SNS-TFC-PA RO membranes was subsequently carried out by examining their biofouling propensities as assessed via flux decline studies using secondary treated municipal waste water effluent, permeability recovery by DI water and chemical (Na₂·EDTA) cleaning, and residual biofilm thickness. The results of the present study demonstrate that it is feasible to tailor-synthesize SNS-TFC-PA membranes of high permeability and salt rejection, with the added benefit of increased fouling resistance.