Superb microplastics separation performance of graphene oxide tuned by laser bombardment

Microplastics have been identified as a significant environmental threat to aquatic ecosystems and human health. Consequently, there is an urgent need for efficient separation methods for small-sized MPs. In this study, a super-hydrophilic graphene oxide (GO) membrane is successfully prepared by facilely depositing GO on a microfiltration substrate, without introducing any surface modification materials, especially nanoparticles, which may cause secondary pollution. Laser bombardment reduces GO lamellar size (23.6% of its original size) and creates an abundance of defects and undulating wrinkles, enabling the deposited GO membrane to have more and shorter pathways for water. As a result, the filtration permeance for 10 μm polyvinyl chloride reaches up to 3396 L m^-2 h^-1 bar^-1, a 1-2-order-of-magnitude enhancement compared to the unirradiated GO membrane, and is also superior to most nanoparticle-modified GO membranes. Simultaneously, the labyrinth structure endows the membrane with a high filtration efficiency of approximately 99% for the majority of MPs. This excellent performance remains virtually unchanged after repeated use. The integration of outstanding separation effects and health safety presents opportunities for practical applications in long-term MP-in-water separation.