Guwahati, March 25: Researchers at the Indian Institute of Technology-Guwahati (IIT-G) have developed a sustainable and cost-effective method to remove toxic pollutants from industrial waste water using biochar made from fruit waste.
Led by Gopal Das, a professor at the department of chemistry, the team has shown how biochar derived from fruit waste such as pineapple crowns and mosambi (sweet lime) fibre, can efficiently absorb nitroaromatic compounds, a class of hazardous chemicals commonly found in waste water from industries such as dyes, pharmaceuticals, pesticides and cosmetics.
The findings of the research have been published in the journal, Chemical Engineering Science, in a paper co-authored by Prof. Das along with his research scholar Neha Gautam, and Deepmoni Deka, senior technical officer, Centre for the Environment, IIT-G.
Nitroaromatic compounds pose a significant threat to both human health and ecosystems. These chemicals are widely used in various industrial applications. But their continuous discharge into water bodies leads to severe pollution.
Existing treatment methods, including catalytic degradation, electrochemical processes and biological treatments, often require expensive catalysts, specific environmental conditions, or complex equipment. Some of these techniques also generate harmful by-products, adding to the environmental burden.
To address this problem, the IIT-G research team investigated the potential of biochar, a carbon-rich material produced from fruit waste through a process called pyrolysis. This process involves decomposing organic materials at high temperatures in the absence of oxygen to produce char, gas and liquid products.
The team chose pineapple crowns and mosambi fibre, which are usually thrown away as waste. They transformed these materials into two types of biochar: ACBC (Ananas Comosus Biochar) and MFBC (Citrus Limetta Biochar). These biochars were then tested for their ability to remove 4-nitrophenol, a widely recognised nitroaromatic pollutant found in industrial wastewater.
“ACBC achieved a 99 percent removal efficiency for 4-nitrophenol, while MFBC removed nearly 97 percent of the contaminant. Additionally, the biochars also demonstrated an exceptionally fast adsorption rate, reaching equilibrium within just five minutes,” a statement issued by IIT-G on Tuesday said.
Another important aspect of the study was the recyclability of the biochar. Both ACBC and MFBC retained their high performance over multiple cycles, meaning they can be reused several times without losing effectiveness.
Speaking about the significance of the research, Prof. Das said, “This work demonstrates how waste materials can be transformed into valuable resources for environmental protection.”
The potential applications of the method extend beyond industrial wastewater treatment. Biochar-based filtration systems could be integrated into water purification setups for rural communities, and also applied to environmental remediation efforts, helping restore polluted water bodies and improve soil quality in areas affected by industrial discharge.