Indian Scientists Design Material That Removes Microplastics From Water. Here's How

From oceans to mountains, microplastics have been found almost everywhere on the planet. According to the United Nations Development Programme (UNDP), these tiny particles of plastic less than 5 millimetres in size, have infiltrated our oceans, soil, and even the air we breathe. These tiny debris can enter our bodies through the water we drink and pose a massive threat to our health.

To combat the menace of plastic pollution, scientists at the Indian Institute of Science (IISc) have designed a sustainable hydrogel to remove microplastics from water. In a press release, Bengaluru-based IISc explained that the hydrogel has a unique intertwined polymer network that can bind the contaminants and degrade them using UV light irradiation.

Previously, scientists have tried using filtering membranes to remove microplastics, however, the membranes can become clogged with these tiny particles, rendering them unsustainable. The IISc team led by Suryasarathi Bose, a Professor at the Department of Materials Engineering, then turned to 3D hydrogels for a solution.

''The novel hydrogel developed by the team consists of three different polymer layers – chitosan, polyvinyl alcohol and polyaniline – intertwined together, making an Interpenetrating Polymer Network (IPN) architecture. The team infused this matrix with nanoclusters of a material called copper substitute polyoxometalate (Cu-POM). These nanoclusters are catalysts that can use UV light to degrade the microplastics. The combination of the polymers and nanoclusters resulted in a strong hydrogel with the ability to adsorb and degrade large amounts of microplastics,'' the press release stated. 

The team crushed food container lids and other daily-use plastic products to create two of the most common microplastics existing in nature: polyvinyl chloride and polypropylene. They also added a fluorescent dye to the microplastics to track how much was being adsorbed and degraded by the hydrogel under different conditions.

''The hydrogel was found to be highly efficient – it could remove about 95% and 93% of the two different types of microplastics in water at near-neutral pH (∼6.5),'' Mr Bose said.

Once the hydrogel has reached the end of its usefulness, it can be repurposed into carbon nanomaterials capable of removing heavy metals from polluted water.

The researchers now plan to develop a device that can be deployed on a large scale to help clean up microplastics from various water sources.