An Optimized Approach Towards Fabricating Microfiltration Membranes from Recycled Discarded Fishing Nets

Abstract

Discarded fishing nets, predominantly composed of polyamide-6 (PA6), are a major source of marine microplastic pollution and represent an untapped resource of high performance engineering polymers. This study presents a sustainable upcycling approach that repurposes this waste material into functional microfiltration membranes for environmental remediation. Membranes were fabricated via the non-solvent-induced phase separation (NIPS) method using PA6 concentrations ranging from 8–14 wt.% and gelation times between 0–10 minutes, yielding tunable structures. Scanning electron microscopy (SEM) revealed that higher polymer concentrations led to denser membrane architectures, while intermediate gelation times (6–8 minutes) produced the smallest and most uniform pores. Filtration tests demonstrated the membranes' ability to completely remove microplastics ≥400 nm, with hydrodynamic flux closely correlated to pore size, porosity, wettability, and membrane thickness. These findings highlight the potential of recycled PA6 membranes as an environmentally responsible and cost-effective solution for microplastic removal, transforming plastic waste into a tool for combating plastic pollution.