• Researchers at the Indian Institute of Science (IISc) have designed a sustainable hydrogel to remove microplastics from water.

• Microplastics — tiny plastic particles up to 5mm in diameter — find their way into food, water and air. 

• Microplastics pose a great threat to human health. 

• They are also an environmental hazard, found even in remote areas like polar ice caps and deep ocean trenches.

How was the hydrogel developed?

• Most microplastics are a product of incomplete breakdown of household plastics and fibres. 

• Researchers at the IISc designed a sustainable hydrogel to remove microplastics from water. 

• The material has a unique intertwined polymer network that can bind the contaminants and degrade them using UV light irradiation.

• Scientists have previously tried using filtering membranes to remove microplastics. However, the membranes can become clogged with these tiny particles, rendering them unsustainable. Instead, the IISc team decided to turn to 3D hydrogels.

• 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 nano-clusters of a material called copper substitute polyoxometalate (Cu-POM). 

• These nano-clusters 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.

Plastic pollution

• Plastic pollution is a global problem. 

• Unlike other materials, plastic does not biodegrade. This pollution chokes marine wildlife, damages soil and poisons groundwater, and can cause serious health impacts.

• More than 400 million tonnes of plastic is produced every year worldwide, half of which is designed to be used only once. Of that, less than 10 per cent is recycled.

• An estimated 19-23 million tonnes end up in lakes, rivers and seas annually. That is approximately the weight of 2,200 Eiffel Towers all together.

• It is estimated that each person on the planet consumes more than 50,000 plastic particles per year, and many more if inhalation is considered.

• Microplastics are tiny pieces of plastic material typically smaller than five millimetres.

• From the deepest points of the ocean to the food and water we consume, microplastics are a growing threat to human and planetary health.

• These tiny plastic particles are present in everyday items, including cigarettes, clothing and cosmetics.

• Microplastics enter the ocean from marine plastic litter breaking down, run-off from plumbing, leakage from production facilities and other sources.

• When ingested by marine life such as birds, fish, mammals and plants, microplastics have both toxic and mechanical effects, leading to issues including reduced food intake, suffocation, behavioral changes and genetic alteration.

• In addition to entering the food chain through seafood, people can inhale microplastics from the air, ingest them from water and absorb them through the skin. 

• Microplastics have been found in various human organs, and even in the placenta of newborn babies.

Major sources of microplastics

• Primary microplastics are items that have intentionally been manufactured in a small size, such as microfibers from clothing, microbeads and plastic pellets 

• Most of the microplastic waste in the environment is made up of fragments from large pieces of litter such as plastic bags, bottles or packaging. These are known as secondary microplastics.

• Microplastics known as cellulose acetate fibres comprise the majority of cigarette filters. With six trillion cigarettes consumed by one billion smokers annually, these fibres reach every corner of the world. Cigarette butts are the most common plastic litter on beaches, making marine ecosystems highly susceptible to microplastic leakages. When they break down, cigarettes release microplastics, heavy metals and many other chemicals that impact ecosystems’ health and services.

• Plastics – including polyester, acrylic and nylon – comprise approximately 60 per cent of all clothing material. Due to abrasion, clothing and textiles with these materials shed microplastics known as microfibres when washed or worn. 

• Cosmetics and personal care products are other staples of grooming routines that can be loaded with microplastics. These products often contain primary microplastics, which are intentionally manufactured and added, often to provide texture — from hand sanitizer and soap to toothpaste and deodorant.

• Plastic particles from these products can be absorbed into the skin or, in the case of products like lipstick or lip balm, directly ingested. Microplastics that remain on the skin are eventually washed down the drain and could make their way to the ocean.

• Once released into the environment, microplastics are practically impossible to remove and will remain there for hundreds, if not thousands, of years.

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