a polymer developed to help farmers improve water retention in fields may have more to offer. The substance, called Jalshakti, can hold water up to 100 times its weight, which it then slowly releases. Now, researchers at the Nagpur-based National Environmental Engineering Research Institute (neeri) have found that Jalshakti can soak up toxic dyes from wastewater.

The scientists, led by Rita Dhodapkar, found that Jalshakti could remove up to 98 per cent methylene blue, 93 per cent safranine t and 84 per cent crystal violet in ambient conditions. These dyes are used mainly in the textile industry and are also present in the effluent.

The researchers compared Jalshakti with activated carbon, which is commonly used to remove dye residues from effluents. "Our work shows that though it does not have the versatility of activated carbon (which can remove both acidic and basic dyes), Jalshakti is extremely good for alkaline dyes, Dhodapkar told Down To Earth. More importantly, it costs just Rs 50 a kg compared to Rs 1,000-2,000 per kg for activated carbon, she said.