GUWAHATI, April 20: Researchers from the Indian Institute of Technology Guwahati (IIT-G) have developed a microfiltration process to remove microplastics from seawater in order to prevent the inclusion of plastic residues in edible salt extracted from it, an official statement issued here on Tuesday, said.
The results of the research by Prof. Kaustubha Mohanty and Dr. Senthilmurugan Subbiah, from the department of chemical engineering, IIT-G, have been recently published by the in the journal, Environmental Technology & Innovation, in a paper co-authored by a research scholar, Naveenkumar Ashok Yaranal.
Plastic pollution is rampant across the world and while there is some level of awareness, the seriousness is not yet understood.
Microplastics – plastic pieces smaller than one-fifth of an inch – are now found in almost all oceans and marine animals. What’s worse, sea salt has been found to have considerable amounts of microplastic.
Microplastics ingested by human beings can disrupt hormones, leading to infertility, and cause nervous system problems, and even cancer.
While there have been many studies to identify and quantify microplastics in various food products, including salt, there have been fewer attempts at finding ways to remove them.
The IIT Guwahati team has, for the first time, shown efficient removal of microplastics from synthetic seawater using hollow fibre microfiltration (HF-MF) membranes.
“In our hollow fibre membrane filter, hundreds of tiny straw-like tubes are bundled together to create a filter matrix,” explained Prof. Mohanty.
The walls of these tubes are filled with microscopic pores, and when water is passed through the tubes, the microplastics are trapped inside, thus freeing water of this pollutant.
Hollow fibre membranes are already used extensively in daily life applications such as RO (reverse osmosis) pre-treatment, industrial water/wastewater, juice processing, and other biotech applications, including in dialysis membranes used for kidney ailments.
The hollow fibre used by the IIT-G team has been made of polypropylene and a silk protein called sericin.
“We were able to remove 99.3 percent of the microplastic present in seawater, without any reduction in the salt content,” said the key researcher.
If this filtered water is used to extract salt, it would be free from microplastics.
The researcher clarifies that this can only remove microplastics from seawater before salt extraction, and obviously cannot remove microplastics that get added during salt production, such as through the use of descaling agents in the desalination process itself.