Revolutionizing environmental clean-up: novel CORN-MOF-2/PVDF composite membranes for the removal of multi-pollutants

Abstract

The increasing prevalence of complex multi-pollutants, including heavy metals, dyes, and pharmaceutical residues, in wastewater streams demands advanced materials capable of efficient and selective separation. This study addresses the critical challenge of removal of diverse pollutants by developing CORN-MOF-2/PVDF composite membranes, in which novel CORN-MOF-2(Ce) was functionalized into a PVDF matrix by a nonsolvent-induced phase-inversion method (NIPS). The introduced MOF enhanced the hydrophilicity of the resulting membranes and provided a higher permeability of 434.95 L m⁻² h⁻¹ bar⁻¹. Membrane performance was evaluated through a series of filtration tests using synthetic wastewater containing heavy metal ions, dyes and pharmaceutical compounds. The CORN-MOF-2/PVDF membranes transitioned into a more selective interface, leading to absolute rejection of a wide range of pollutants—99% for dopamine hydrochloride (DP), Cr₂O₇²⁻, Alcian blue (AB), and Congo red (CR). Furthermore, the study extended to investigate the removal efficiency of the optimized membrane under different pH conditions, achieving optimal performance at neutral pH. A combination of size exclusion, affinity-based bonding, and charge-based interactions was followed to attain superior rejection rates. The simultaneous removal of multiple pollutants from the aqueous system demonstrates the superior versatility and efficiency of the fabricated membranes in handling complex multi-component contaminations. The treated water resulting from this work adheres to the WHO's standards for safe water. Additionally, antifouling studies showed a flux recovery ratio of >95% after multiple cycles.