Enhanced flux and antifouling property on municipal wastewater of polyethersulfone hollow fiber membranes by embedding carboxylated multi-walled carbon nanotubes and a vitamin E derivative

Fouling of membranes is a key issue for their industrial applications. In this study, carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) were embedded in hollow fiber membranes (HFMs) developed by blending polyethersulfone (PES), and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS, a vitamin E derivative) to remarkably enhance their permeation flux and fouling-resistance. The antifouling performance of HFMs was examined by calculating the change in pure water permeability (PWP) due to fouling by protein and synthetic municipal wastewater (SMWW). Modified HFMs containing 1 wt% TPGS and 0.025 wt% MWCNTs-COOH showed the highest hydrophilicity and lowest surface roughness among all HFMs, which resulted in ~187% higher PWP as compared to that of the pristine HFMs, and the highest flux recovery ratio (FRR) of 89.3 ± 2.1% and 81.4 ± 3.5% after protein and SMWW fouling, respectively. There are literature studies with higher FRR, but they have very low PWP, whereas some studies have reported high PWP with low FRR. In contrast to the literature, the results reported here have both high flux (PWP) and high antifouling property (FRR). Thus, the novel PES composite HFMs containing TPGS and MWCNTs-COOH showed the excellent antifouling property, which makes them potentially useful for wastewater treatment.