Tea polyphenol-coated ZIF-8 blends polyethersulfone for modulating water flux and antibacterial properties of ultrafiltration membranes

Abstract

In this study, a green and convenient tea polyphenol modification strategy was developed for the fabrication of high-performance ZIF-8/PES ultrafiltration membranes. Compared with traditional ZIF-8/PES membranes, the introduction of tea polyphenols effectively enhances the interfacial compatibility between ZIF-8 and PES, reduces particle aggregation, and improves membrane stability. At the same time, this endows the membrane with hydrophilicity, enhances anti-fouling properties, provides antibacterial functions, and improves the compatibility of ZIF-8 with the PES matrix. Unlike traditional toxic or complex modification methods, this green approach simultaneously enhances hydrophilicity, permeability, rejection rates, and anti-fouling and antibacterial properties through the synergistic effect between ZIF-8 and tea polyphenols. ZIF-8 provides structural support, regulates membrane porosity, facilitates size sieving, and releases Zn²⁺ to exert antibacterial effects. They overcome the trade-off between pore size and flux together, thereby demonstrating excellent performance in terms of both high rejection and high flux. This study provides a new environmentally friendly method for designing high-performance hybrid membranes with higher structural stability and multifunctionality. The optimized ZIF-8@tea polyphenol/PES membrane exhibits a flux of 638.4 L m⁻² h⁻¹ bar⁻¹. The rejection rates of bovine serum albumin and Congo red reach 99% and 96.9%, respectively. The inhibition zone against Escherichia coli is 1.4 mm.