BENGALURU: A city-based M.Sc student and her guide have developed an eco-friendly and economical solution which could help rid chemical-filled water bodies of its effluence Akshatha Chandrashekar, an M.Sc graduate from Ramaiah University of Applied Sciences, won a silver medal for Best Dissertation, which was based on her material to separate dye from wastewater in textile industry. She was guided by Jineesh A G and Niranjana Prabhu during her two-year course.
Unlike a conventional absorbent, Jineesh said the composite that they came up with was reusable and highly economical. The composite is made of two components — the Polyurethane matrix which is derived from vegetable oil (in her study, soya bean oil and cottonseed oil) and nanomaterial, that is Nano-cellulose, derived from pineapple leaves.
The nano-cellulose adsorbs the dye here. “However, industries work differently. They are known to use nano metal oxide, which when sprinkled, degrade dye molecule into smaller fragments. The nanomaterial also gets lost in the process,” said Jineesh. In the team’s experiment here, the biodegradable nano-cellulose was not allowed to be lost during the process. It was instead enclosed in a bio-based matrix, which looked like a foam (similar to that in a car seat). The composite (Polyurethane matrix and Nanocellulose) was then dipped in water to absorb the dye.
During the eight-hour-long experiment, Akshatha found that within 15 minutes, the composite removed 92 per cent of the effluent (rhodamine B) from the water. This was higher than the conventional methods which have attained 66 per cent so far, she said.
The flexible nature of the sponge-like composite allows it to be reused over and over again, unlike the precipitation method and photocatalysis, where nano-materials used are lost, once used.
Jineesh said the method which was developed in a laboratory has the potential to be scaled up to industrial scale to treat wastewater before being let into the river or lake. The method ensures highest adsorption of the effluent reported thus far.
The team is looking at the capacity of the composite after numerous de-absorptions, which could tell how many times the sponge can be reused before it is deemed useless.