One-step engineering of multifunctional ZIF-8/PES membrane for synergistic separation of selected proteins, dyes and antibiotics

To address the persistent challenges of low separation efficiency and severe membrane fouling in water treatment, we engineered multifunctional mixed matrix membranes (MMMs) through a facile one-step phase inversion method by incorporating zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (0.1–1.0 wt%) into a polyethersulfone (PES) matrix. The effects of ZIF-8 loading (0.1–1.0 wt%) on the morphology, hydrophilicity, porosity, pore size, water flux of the MMMs were investigated. The optimal MMMs delivered a water flux of 299.2 L/m²·h, surpassing the pure PES membrane by 65.90 %. Furthermore, the optimized MMMs demonstrated a 516 % increase in permeate flux along with a 113 % increase in bovine serum albumin (BSA) rejection rate simultaneous, indicating their potential to break through the trade-off effect. The improved rejection rate of BSA was attributed to size exclusion and electrostatic repulsion, originating from the introduction of ZIF-8 nanoparticles. In addition, the rejection rate of Congo Red (CR), Rhodamine B (RhB) and tetracycline hydrochloride (TCH) elevated from 40.94 %, 15.40 % and 59.33 % to 95.40 %, 37.40 % and 96.80 %, respectively. This enhancement stems from the incorporated ZIF-8 nanoparticles, which simultaneously modulated the MMMs' structure and imparted specific interactions: Electrostatic attraction and π-π stacking to CR, electrostatic repulsion and π-π stacking to RhB, and π-π stacking to TCH. Furthermore, the MMMs exhibited improved antifouling performance with the increased flux recovery ratio and reduced irreversible fouling ratio. This facile one-step engineering strategy provides a scalable and efficient route to fabricate high permeability, multifunctional MMMs with increased rejection and improved antifouling performance for integrated separation of proteins, dyes, and antibiotics in complex wastewater.