Superb microplastics separation performance of graphene oxide tuned by laser bombardment

Abstract

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. Laser bombardment-modified graphene oxide membranes exhibit a labyrinth-like structure, significantly enhancing microplastics separation efficiency and flux without the introduction of any surface-modifying nanomaterials, minimizing the risk of secondary nanoparticle leakage pollution. This practical technology holds the potential to effectively reduce microplastic levels in drinking water by up to 99%, significantly reducing the health risks associated with cardiovascular disease, immune disorders, and cancers resulting from microplastic ingestion. Moreover, microplastic removal is meaningful for safeguarding aquatic organisms, preserving water ecosystem health, and enhancing resilience against microplastic-induced hazards

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