High-performance CPES nanofiltration membrane decorated by cinnamon extract with efficient antibacterial/anti-fouling property for post treatment of biologically treated industrial wastewater

In this work, cinnamon extract/ coupling modified polyether sulfone (CiE/CPES) mixed matrix membrane with excellent anti-fouling and antibacterial properties was synthesized by the phase inversion method. To characterize the modified membrane, SEM, AFM, ATR - FTIR, EDX, WCA and porosity measurements were performed. SEM images showed the wider finger-like pores compared to the unfilled-CPES membrane. AFM images exhibited that with the addition of CiE to the polymer matrix the surface of CiE/CPES membranes has been significantly smoothed. BSA was used as a foulant to evaluate the anti-fouling properties and the results showed excellent flux recovery ratio (more than 95%) in all weight percentages of CiE, which indicates the significant improvement of self-cleaning property of fabricated membranes. To confirm the antibacterial properties of CiE, agar diffusion test was performed. A clear large halo around the CiE was observed for both model bacteria. The average halo radius was 41.63 mm for E. coli and 47.25 mm for S. aureus, which showed better performance compared to other routine studies. Also, the bacteria suspension immersion test and SEM analysis were investigated. The results showed a significant reduction of bacteria on the membrane surface compared to the control sample, which confirmed the excellent performance of CiE in the membrane. Besides, to measure the separation performance of the membranes, the biologically treated soft drink industrial wastewater (BTW) rejection was evaluated. The results provided very good efficiency in BTW purification. For further study, the desalination performance of the membranes was evaluated by examining the rejection of different salt solutions, and the order of rejection in all prepared membranes followed MgSO4 > MgCl2 > NaCl.

Automated summary

In this study, a cinnamon extract/coupling modified polyether sulfone mixed matrix membrane with excellent anti-fouling and antibacterial properties was successfully synthesized. The modified membrane was characterized through various analysis techniques, and the results showed that the membrane had wider finger-like pores and a significantly smoother surface. It exhibited excellent self-cleaning and antibacterial properties, with high flux recovery ratio and a clear large halo in the agar diffusion test. The membrane also showed a significant reduction of bacteria on its surface in the bacteria suspension immersion test. Furthermore, the membrane demonstrated good efficiency in purifying biologically treated industrial wastewater and effective rejection of different salt solutions.