Hydrophilicity-Enhanced NH₂-MIL-88B(Fe) Integrated Photocatalytic Membrane Reactor for Simultaneous Rejection and Degradation of Low-Density Polyethylene in Water Matrices

Microplastic (MP) plastic particles with diameters of up to 5 mm have emerged as pervasive global pollutants, posing serious risks to both human and environmental health. In this study, a photocatalytic membrane reactor (PMR) was designed to perform dual functions of filtration and photocatalytic decomposition of low-density polyethylene (LDPE) particles. An NH2-modified MIL-88B(Fe) (NM88B) photocatalyst was prepared and then used as a precursor to grow a photocatalyst membrane (MRS-NM88B) on an alumina membrane via the modified reactive seeding (MRS) method. Compared with unmodified MIL-88B(Fe) (M88B), NM88B exhibited higher hydrophilicity with enhanced permeance flux and better photocatalytic performance. The PMR fabricated using the MRS-NM88B membrane successfully rejected and degraded LDPE particles, demonstrating a high LDPE particle removal efficiency of 96.9% under dark conditions and a 22.3% mass loss of LDPE particles under light irradiation. Furthermore, the PMR can be applied to real river water for effective filtration and degradation. The results demonstrate the potential of this PMR for microplastic removal and degradation in wastewater treatment applications.