A cost-effective way of treating waste water and filtering out ions of hazardous and heavy metals has been developed by The Defence Institute Advanced Technology (DIAT), India. It can also separate fine gold particles from industrial water and chemical waste. The polymer assembly can filter fine gold particles or nano-gold particles which are 2 to 4 nanometre in size (a nanometre if a billionth of a metre). This gold has uses in anti-ageing and bio-medical patches, anti-fungal and anti-bacterial fabrics and more importantly sensors that can be employed in defence equipment. The 'cost effective polymer matrix system' also incorporates some naturally available additives such as coir (made of coconut husk), molasses, jute, citrus peels and cellulosics.
Talking to The Indian Express, Balasubramanian K, head, Materials Engineering, DIAT said, "The project started when I decided to work on developing a user-friendly, cost-effective way of waste-water treatment. I had a PhD student to help me and we developed a polymer that could filter hazardous metallic ions like mercury, arsenic, copper, nickel, cobalt and chromium." Two IITians, Fuhar Dixit and Tushar Sahetya, found Balasubramanian's work interesting and approached him for development of synthetic polymers. "After successful results with other ions, we decided to try the polymer on gold ions. The concentration of gold is measurable in parts per billion, which is miniscule. We kept the polymer in the dye (industrial waste) for over 24 hours and interestingly found pinkish deposits on the polymer. Gold, on the other hand should have been yellow. But nano-gold has pinkish colour and the deposits on our polymer were nothing but nano-gold.