IIT (BHU) and Parul University Build a Graphene Nanocomposite That Strips Up to 92.91% of a Toxic Dye From Wastewater
IIT (BHU) and Parul University researchers report a tin oxide–graphene–polypyrrole nanocomposite that removed up to 92.91% of Eriochrome Black T dye under optimised conditions. Cost, regeneration and performance on real mixed effluent remain scale-up questions.
Researchers at IIT (BHU) Varanasi and Parul University in Vadodara have developed a three-part nanocomposite that removes a widely used industrial dye from water. Reported on 4 November 2026, the work combines tin oxide nanoparticles, graphene and the conducting polymer polypyrrole into an adsorbent. Under optimised conditions it removed up to 92.91% of the azo dye Eriochrome Black T (EBT) from water.
The study was a collaboration between the School of Biochemical Engineering at IIT (BHU) and the Department of Chemical Engineering at Parul University. Dr Vishal Mishra of IIT (BHU) is on the team. The paper, "Adsorptive Removal of Eriochrome Black T by Using SnO₂/Graphene/Polypyrrole: Implementation of Response Surface Methodology", is identified in coverage as a Springer journal paper; the full publisher text was not accessible in this review.
Why this dye
Eriochrome Black T is a synthetic azo dye used in textile and leather processing and as an indicator in laboratory titrations. Like many azo dyes, it is chemically stable and breaks down slowly in the environment. Even small amounts colour water, which reduces light penetration and photosynthesis in rivers. Some azo dyes and their breakdown products are toxic to aquatic life and a possible risk to human health.
India is one of the world's largest textile producers. Dyeing and finishing clusters in Gujarat, Tamil Nadu, Rajasthan and Uttar Pradesh discharge large volumes of coloured effluent, and conventional treatment often fails to decolourise it fully. Inexpensive, effective ways to remove dyes are therefore a practical regulatory need, not only an academic topic.
How the material works
The nanocomposite relies on adsorption. Dye molecules stick to the surface of the material and can then be filtered out with it. Each of the three components has a role:
- Graphene provides a very large surface area and can bind the aromatic rings of dye molecules through π–π stacking.
- Tin oxide (SnO₂) nanoparticles add active surface sites and help stop graphene sheets from re-stacking, which can keep more surface area available.
- Polypyrrole, a conducting polymer, contains nitrogen groups that can attract anionic dyes such as EBT through electrostatic interactions.
The team used response surface methodology (RSM) to tune the process. RSM is a statistical design-of-experiments method that varies several factors at once, typically pH, adsorbent dose, initial dye concentration and contact time. It then finds the combination that gives the best removal using far fewer experiments than changing one factor at a time. The reported 92.91% figure is conditional on the study’s optimisation, rather than a universal removal rate for wastewater.
From lab to effluent plant
The result is a laboratory demonstration on a single dye. Real textile effluent contains mixtures of dyes, salts, surfactants and fluctuating pH. To be useful in practice, the material will have to work on real wastewater, survive several adsorb-and-regenerate cycles, and be cheap to make in bulk. Those scale-up, regeneration and real-effluent questions were not independently established in this review, which are the usual next steps for this kind of work.
Why it matters
The study is an example of Indian nanomaterials research applied to a local environmental problem. Graphene-based adsorbents are a busy research field worldwide, and Indian groups have contributed a large share of the published work. If combinations such as SnO₂/graphene/polypyrrole can be made cheaply and reused, they could become part of the effluent treatment plants that India's textile clusters are required to run, contributing to cleaner rivers and to the government's water-quality goals.
Sources
- https://www.uniindia.com/north-india/science-iit-bhu-parul-water-wastewater-dye/235329
- https://www.etvbharat.com/hi/state/iit-bhu-researchers-achieve-a-breakthrough-developed-a-graphene-based-nanocomposite-ups26110407493
- https://link.springer.com/article/10.1007/s10904-026-04521-4