IIT-Guwahati researchers have developed a microfiltration process to remove microplastics from seawater before edible salt is extracted from it.

Microplastics — plastic pieces smaller than one-fifth of an inch — are now found in almost all oceans and marine animals. Worse, sea salt has been found to have considerable amounts of microplastic. Research shows that 90 per cent of the table salt brands sampled worldwide has microplastics. One research by IIT-Bombay revealed that eight Indian salt brands were contaminated with micrometre-sized particles of polyester, polyethylene terephthalate (PET), polyamide, polyethylene, and polystyrene — the ingestion of which could lead to infertility and cancer.

Kaustubha Mohanty and Senthilmurugan Subbiah of IIT-Guwahati have shown efficient removal of microplastics from synthetic seawater using hollow-fibre microfiltration (HF-MF) membranes made with a silk protein called sericin. The walls of these membranes hold microscopic pores, which could filter 99.3 per cent of the microplastics present in seawater, without any reduction in the salt content.

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