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IIT Gandhinagar Develops Hydrogel “Super Sponge” To Clean Dye-Polluted Wastewater

• By  Textile Excellence
• June 15, 2026

Researchers at the Indian Institute of Technology Gandhinagar (IITGN) have developed a hydrogel-based material that can remove toxic industrial dyes from wastewater with very high efficiency. The work focuses on a carboxymethyl cellulose (CMC)-based hydrogel designed to act like a “super sponge” for dye adsorption.

The study, published in ACS Applied Polymer Materials, targets a major industrial pollution problem. Dye-based industries such as textiles, leather, paper, cosmetics, and packaging generate large volumes of wastewater. A significant portion of this wastewater is still released into the environment with limited treatment, especially in developing economies.

One of the commonly used industrial dyes is methylene blue. It is widely used in textiles, paper, rubber, silk, wool, and cosmetic applications. It is also used in some diagnostic applications. However, once released into water bodies, it can persist for long periods and cause environmental damage. Exposure to methylene blue-contaminated water has been linked to health risks such as nausea, breathing issues, eye irritation, and other toxic effects.

Hydrogel-based solution from IITGN

The IITGN team developed a hydrogel called CAPA using carboxymethyl cellulose, a biodegradable polymer derived from cellulose, along with acrylic acid and other components. Hydrogels are porous, water-absorbing materials that can be engineered to trap pollutants.

The researchers created multiple versions of the material by adjusting the amount of acrylic acid. This adjustment changed the surface charge and structure of the hydrogel, which directly affected its dye removal performance.

According to lead researcher Dr. Hitarth Patel, the key innovation was tuning a single ingredient to improve performance.

High removal efficiency

Among the tested variants, CAPA-2 showed the best results. It removed 99.6% of methylene blue from water under test conditions. It also recorded an adsorption capacity of about 475 milligrams of dye per gram of hydrogel. This is significantly higher than many earlier CMC-based materials, which typically range between 30 mg/g and 250 mg/g.

The material also showed the ability to remove other dyes such as crystal violet and rhodamine B, even when present together in the same solution. This is important because industrial wastewater usually contains mixed pollutants rather than a single dye.

How it works

The performance of the hydrogel is based on charge attraction. The material carries negatively charged sites, while methylene blue and similar dyes carry positive charges. This leads to strong electrostatic attraction between the dye molecules and the hydrogel surface.

The structure also includes nanoscale pores of around 25 nanometers. These pores help trap dye molecules, which are much smaller in size. In addition, hydrogen bonding and hydrophobic interactions further improve dye capture.

CAPA-2 performed well across different conditions. It maintained strong adsorption in neutral water and also showed stable performance in acidic and alkaline environments (pH 3 to 10). This is important for industrial use, where wastewater conditions vary.

Reusability and commercial potential

The hydrogel also showed good reusability. After four cycles of use, CAPA-2 retained most of its performance, with only a small drop in efficiency. This is a key factor for cost-effective industrial application.

Researchers say the next step is testing the material in real industrial wastewater, which contains more complex mixtures of chemicals and impurities compared to laboratory conditions.

If scaled successfully, such hydrogels could offer a lower-cost and energy-efficient option for dye removal, especially for textile and chemical industries facing stricter environmental compliance requirements.

Researchers say the next step is testing the material in real industrial wastewater, which contains more complex mixtures of chemicals and impurities compared to laboratory conditions. If scaled successfully, such hydrogels could offer a lower-cost and energy-efficient option for dye removal, especially for textile and chemical industries facing stricter environmental compliance requirements.