IIT Guwahati researchers use a hollow fiber membrane to remove micro-plastics from seawater before salt extraction

<p style="text-align:justify"><span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><b><span century="" gothic="" style="font-family:"><span style="color:black">GUWAHATI, </span></span></b><b><span century="" gothic="" style="font-family:">20th April <span style="color:black">2021:</span> </span></b><span century="" gothic="" style="font-family:">Indian Institute of Technology Guwahati researchers 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. <b>Prof. Kaustubha Mohanty and Dr. Senthilmurugan Subbiah, Department of Chemical Engineering, IIT Guwahati, have recently published the results of this research in the journal Environmental Technology &amp; Innovation, in a paper co-authored by their research scholar, Mr. Naveenkumar Ashok Yaranal.</b></span></span></span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><span century="" gothic="" style="font-family:">Plastic pollution is rampant all over the world and while there is some level of awareness, the seriousness is not yet understood. Micro-plastics &ndash; plastic pieces smaller than one-fifth of an inch &ndash; are now found in almost all oceans and marine animals. What&rsquo;s worse, sea salt has been found to have considerable amounts of micro-plastic.&nbsp; Research performed in East Asia has shown that 90 percent of the table salt brands sampled worldwide has micro-plastics. Another study by IIT Bombay showed that eight brands of Indian sea salt were contaminated with micrometre sized particles of polyesters, polyethylene terephthalate (PET), polyamide, polyethylene, and polystyrene.&nbsp; Micro-plastics ingested by human beings can disrupt hormones, leading to infertility, and cause&nbsp; nervous system problems, and even cancer.</span></span></span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><span century="" gothic="" style="font-family:">While there have been many studies to identify and quantify micro-plastics in various food products, including salt, there have been fewer attempts at finding ways to remove them. <b>The IIT Guwahati team has, for the first time, shown efficient removal of micro-plastics from synthetic seawater using hollow fibre microfiltration (HF-MF) membranes. </b></span></span></span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><i><span century="" gothic="" style="font-family:">&ldquo;In our hollow fibre membrane filter, hundreds of tiny straw-like tubes are bundled together to create a filter matrix,&rdquo;</span></i><span century="" gothic="" style="font-family:"> <b>explained Dr. Mohanty.</b> The walls of these tubes are filled with microscopic pores, and when water is passed through the tubes, the micro-plastics are trapped inside, thus freeing water of this pollutant. </span></span></span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><span century="" gothic="" style="font-family:">Hollow fibre membranes are already used extensively in daily life applications such as RO pre-treatment, industrial water/wastewater, juice processing, and other biotech applications, including in dialysis membranes used for kidney ailments.&nbsp; The hollow fibres are made of many kinds of materials and the ones used by the IITG team was made of polypropylene and a silk protein called sericin.</span></span></span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><i><span century="" gothic="" style="font-family:">&ldquo;We were able to remove 99.3 % of the micro-plastics present in seawater, without any reduction in the salt content&rdquo;</span></i><span century="" gothic="" style="font-family:">, <b>said the key researcher.</b> If this filtered water is used to extract salt, it would be free from micro-plastics. The researcher clarifies that this can only remove micro-plastics from seawater before salt extraction, and obviously cannot remove micro-plastics that get added during salt production, such as through the use of descaling agents in the desalination process itself.</span></span></span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><span century="" gothic="" style="font-family:">Some advantages of hollow fibre membrane technology that make it promising for pre-treatment of seawater include simplicity of installation and use, cost effectiveness, no need for power supply, no generation of waste, and operability under low water pressure.</span></span></span></span></p>