Fabrication of antifouling UiO-66 nanofiltration membranes via surface fluorination engineering

Membrane fouling is a primary hindrance in the efficient utilization of nanofiltration technology in wastewater treatment, which increases energy requirements and reduces membrane life. In this work, a highly antifouling UiO-66 nanofiltration (NF) membrane was fabricated via a facile surface engineering for dye rejection, where fluoromonomer with a long fluoroalkyl chain was fast UV-polymerized on the surface of UiO-66. Fluoroalkyl chains have low surface energy and provide the surface with non-stick and fouling-release properties, and fluoroalkyl is highly incompatible with dyes. Meanwhile, the bridged rigid fluoroalkyl produces an effective barrier to repel the foulants because of the narrowed pore structure and smooth surface. Results showed that the resulting membrane shows an excellent NF performance including high rejection of Methyl Blue, Cango Red and Chrome Black T (all over 99.7 %) with a high water permeance of 249.6 L m2 h−1 bar−1, and salt permeation of MgSO4 (89.26 %) and NaCl (99.02 %). The long-term stability testing exhibits basically stable performance for separating the CT/NaCl mixture. The outcome of the work offers an effective strategy to solve the membrane fouling and maintain the outstanding separation performance by fluorination modification. This newly UiO-66-based NF membrane showed excellent application potential in the dye wastewater treatment.