Preparation and Characterization of New Poly (Ether-Ester-Urethane) Membrane and Its Comprehensive Potential Evaluation for Natural Organic Matter Rejection from Water

In this study, the novel poly (ether-ester) urethane membranes, synthesized from poly(dioxanone) (PDO) and poly (ethylene glycol) (PEG) triblock copolymers, were introduced for the humic acid removal as a model of natural organic matter from aqueous solution. These membranes were modified with Sulfonated Graphene Oxide (SGO). Bulk ring-opening polymerization and one-step bulk polycondensation were used to prepare triblock poly(p-dioxanone)-poly (ethylene oxide)-poly(p-dioxanone) (PEDO) and Poly (ether-ester) urethanes, respectively. The phase inversion method was used for preparation of impregnated poly(ether-ester) urethanes (PEEUs) membranes with 0,0.03,0.06,0.09, and 0.125 SGO/PEEU mass ratios. Membrane characterization involved Nuclear Magnetic Resonance (H1-NMR), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Fourier Transform InfraRed (FT-IR) spectrometer, tensile strength testing, and contact angle measurement. Results showed that modified membranes with PEG content of 11.23% and SGO/PEEU mass ratio of 0.09 exhibit significant differences in properties (morphology, thermal, hydrophilicity, and mechanical) and performance due to the presence of PEG and sulfonated graphene oxide. The total fouling ratio (Rt) value of the modified membrane (SGO/ PEEU mass ratio:0.09, PEG molecular weight: 600 g/mol) was obtained at 25.3%, which is due to the additive effect on fouling reduction. Also, the result of filtration rejection showed that the humic acid rejection increased up to 99% by SGO incorporation. According to the results, these membranes can be introduced as a comprehensive potential for the proper rejection of humic acid from water.