IIT Guwahati Scientists Use Fruit Waste to Treat Polluted Wastewater
Researchers at the Indian Institute of Technology (IIT)-Guwahati have developed a sustainable and cost-effective method to remove pollutants from industrial wastewater using biochar made from fruit waste.
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Waste from common fruits—pineapple and mosambi—can remove toxic chemical wastes from industrial wastewater, researchers from the Indian Institute of Technology, Guwahati, have shown.
Led by Dr. Gopal Das, Professor in the Department of Chemistry, the team has demonstrated how biochar derived from fruit waste, such as pineapple crowns and mosambi (sweet lime) fibers, can efficiently absorb nitroaromatic compounds—a class of hazardous chemicals commonly found in wastewater from industries like dyes, pharmaceuticals, pesticides, and cosmetics.
The researchers have developed a sustainable and cost-effective method that delivers results in just five minutes. Their findings have been published in the journal Chemical Engineering Science, in a paper co-authored by Prof. Gopal Das, his research scholar Neha Gautam, and Dr. Deepmoni Deka, Senior Technical Officer at the Centre for the Environment, IIT Guwahati.
Nitroaromatic compounds pose a significant threat to both human health and ecosystems. Widely used in various industrial applications, these chemicals are continuously discharged into water bodies, leading to severe pollution.
Once in the environment, they persist for long periods, accumulating in aquatic systems and affecting both marine life and human populations. Exposure to these compounds has been linked to toxicity, cancer, and genetic mutations, making their removal from wastewater both important and challenging.
Current Methods:
Existing treatment methods—including catalytic degradation, electrochemical processes, and biological treatments—often require expensive catalysts, specific environmental conditions, or complex equipment, according to the researchers.
Some of these techniques also generate harmful by-products, adding to the environmental burden. The need for a low-cost, efficient, and environmentally friendly alternative has driven the team to explore novel approaches to wastewater treatment.
To address this problem, the IIT Guwahati 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 fibers, which are typically discarded 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 recognized nitroaromatic pollutant found in industrial wastewater.
ACBC achieved a 99% removal efficiency for 4-nitrophenol, while MFBC removed nearly 97% of the contaminant. Additionally, the biochars demonstrated an exceptionally fast adsorption rate, reaching equilibrium in just five minutes. This rapid uptake is a major advantage over conventional methods, which often require longer processing times and greater energy input.
By significantly reducing the time needed for pollutant removal, this method enhances both efficiency and practicality for large-scale applications.
Another key 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. This feature makes the approach not only sustainable but also economically viable for industries seeking long-term wastewater treatment solutions.
According to Prof. Gopal Das, “By using fruit waste to tackle industrial pollution, we are not only addressing water contamination but also promoting a circular economy approach to waste management.”
The potential applications of this method extend beyond industrial wastewater treatment. Biochar-based filtration systems could be integrated into water purification setups for rural communities, providing an affordable way to remove harmful organic contaminants from drinking water.
Additionally, the same technology could be applied to environmental remediation efforts, helping restore polluted water bodies and improve soil quality in areas affected by industrial discharge, the researchers say.
As the next step in prototype development, the method will undergo lab-scale testing, followed by field trials and market validation, before progressing to full-scale commercial production. To facilitate successful commercialization, the research team aims to collaborate with key stakeholders who can provide the necessary support to bring the product to market.
