Synthesis of enhanced hydrophilic UiO-66-(COOH)2/PSF hybrid membrane for efficient separation of o/w and removal of water pollutants

Abstract

Metal-Organic frameworks (MOFs) are fascinating porous networks which are extensively investigated due to their several crucial potential applications. The ultrafiltration behaviour of MOF or its hybrid membranes are very exciting. Herein, polysulfone (PSF) was used with MOF, UiO-66-(COOH)2 (henceforth U) to developed hybrid membrane (U/PSF= 15UX; X = loading % of MOF) by direct blending method through phase inversion process. The attendance of non-coordinated –COOH moiety within MOF and in the hybrid membrane, is expected to enhance the hydrophilicity. Thus, we have added MOF individually from 1 to 10 wt% in each PSF solution for the fabrication of membrane composite. It is noted that the incorporation of more weight % of MOF, the hydrophilicity of the membrane is gradually enhanced as confirmed from the water contact angle (WCA) measurement. The resulting 15U6 membrane (X = 6 wt%) had a much greater water flow (up to 65.30 L m-2 h-1) than the simple PSF membrane (9.251 L m-2 h-1), almost 7 times is enhanced. The rejection % and the antifouling activity of the 15UX membrane were also enhanced. The optimized hydrophilic membrane is used for the separation of water from water/oil mixture. Further, it has employed for the separation of pollutants like humic acid and BSA protein from waste water. Quite interestingly, the optimised membrane showed the enhanced rejection percentages of w/o, BSA and HA from 83.54% to 97.78%, 81.10–93.08% and 82.06–95.52% respectively. The optimized membrane showed the good ultrafiltration recyclability up to eight with nominal changes in the separation efficiencies.