Facile Fabrication of a Continuous PVDF/ZIF-8-Lignosulfonate Membrane for Efficient Organic Pollutants Adsorption

Graphical A defect-free PVDF/ZIF-8-LS membrane prepared by loading a continuous ZIF-8-LS film layer on the PVDF membrane exhibited high and stable adsorption performance for CR and TC removal, because of a good compatibility between PVDF membrane and ZIF-8-LS layer. Lignosulfonate (LS) enhances ZIF-8 dispersion and active sites but faces challenges in recovery and secondary pollution due to its powdered form. To address this, a polyvinylidene fluoride (PVDF)/ZIF-8-LS composite membrane was fabricated via vapor deposition, where LS promoted dense ZIF-8 growth and interfacial compatibility with PVDF. The resulting PVDF/ZIF-8-LS membrane shows a higher continuous, uniform and dense ZIF-8-LS layer without macroscopic cracks or obvious defects. In addition, the PVDF/ZIF-8-LS exhibits the best adsorption capacity of 110.6 mg g −1 for Congo Red, about 8.8 mg g −1 higher than the PVDF/ZIF-8, and 110.2 mg g −1 for tetracycline, respectively. With 92% capacity retention after three cycles and stability across pH 2–10. The more active adsorption sites facilitates the contact between the ZIF-8-LS layer and the adsorbed substance, in addition to the electrostatic, H-bonding, π-π interactions, and coordination bond are also conductive to the adsorption of PVDF/ZIF-8-LS. The excellent adsorption performance and good recyclability of the PVDF/ZIF-8-LS composite membranes exhibit a potential for adsorbing other contaminants from water.