Graphitic carbon nitride membranes intercalated with nano-sized Fe-MOF for enhanced water purification via synergistic separation and Fenton-like processes

Abstract

Versatile two-dimensional nanomaterials have offered a promising prospect to enhance the water purification efficiency and overcome the fouling obstacle in membrane technology. In this work, a graphitic carbon nitride (g-C3N4) nanosheet membrane intercalated with the nano-sized Fe-based metal-organic framework (MIL-100(Fe)) is developed for the enhanced removal of aqueous organic contaminants by synergically promoting separation and Fenton-like processes. The g-C3N4/MIL-100(Fe) membrane is constructed through a self-assembly route in which the nano-MIL-100(Fe) is anchored into g-C3N4 layers by the coordination bonds between Fe nodes and pyridinic N. The MIL-100(Fe) intercalation not only enlarges the interlayer spacing to raise the membrane permeability, but also expedites the electron transfer between Fe2+ and Fe3+ to improve the Fenton-like activity. With a stable water flux of 98.2 L m2·h−1·bar−1 under wide-range pH and pressures, the g-C3N4/MIL-100(Fe) membrane shows high dye removal efficiency (≥99%) and prominent self-cleaning ability. Mechanism insight proposes a combination of size exclusion, electrostatic interaction and steady radical generation. The intercalation of nano-MIL-100(Fe) into g-C3N4 membranes can realize the mutual promotion between separation and Fenton-like processes, the synergistic effect of which provides an effective and feasible strategy for aqueous pollution abatement.