Innovative use of Agricultural Waste for arsenic removal from drinking water

Introduction: Groundwater contamination with arsenic poses a significant environmental and health concern, affecting millions of people worldwide. However, researchers have discovered a promising solution by utilizing agricultural and food-industry biowastes as cost-effective biosorbents to remove arsenic from water. Explores a successful project implemented, highlighting the potential of these biosorbents and their future applications.

Arsenic contamination in groundwater is a pressing global issue, affecting over 200 million people worldwide. Southeast Asian countries, including China, India, Bangladesh, Vietnam, and Pakistan, bear a significant burden, with approximately 110 million people affected in the region.

Harnessing Agricultural Waste for Arsenic Removal

To address this problem, researchers have turned to agricultural and food-industry biowastes, known as biosorbents, as a cost-effective and eco-friendly method for removing arsenic from contaminated water. Biosorbents such as rice husk, sugarcane bagasse, water chestnut shell, and various fruit peels offer advantages over conventional techniques like reverse osmosis and coagulation/flocculation due to their affordability and sustainability.

A pioneering project was undertaken to evaluate the potential of agricultural and food-industry biowastes as low-cost agents for arsenic removal from drinking water. 

Groundwater samples were collected from rural areas to determine the level of arsenic concentration.

Various biosorbents, including corn cob, sugarcane bagasse, water chestnut shell, watermelon rind, pomegranate peel, java plum seeds, and eggshells, were collected for preparing biosorbents to remove arsenic from the water. Some biosorbents underwent modifications, such as xanthation of corn cob, activation of orange peel and sugarcane bagasse (charred forms), iron coating of sugarcane bagasse, and akaganéite mineral coating of water chestnut shell.

The results were promising, with modified biosorbents exhibiting higher arsenic removal capacity compared to natural biosorbents. In groundwater samples with arsenic levels ranging from 5–201 μg/L, the modified biosorbents proved more effective. Competing ions had minimal impact on arsenic adsorption, except for phosphate, which reduced adsorption by 15 to 20%.

The xanthated corn cob showed a 1.9 times increase in arsenic adsorption capacity, while charred sugarcane bagasse and iron-coated sugarcane bagasse displayed 2 and 1.5 times higher capacity, respectively, compared to natural sugarcane bagasse. Akaganéite-coated water chestnut shell exhibited double the adsorption capacity of its natural form.

The project team intends to further explore the biosorbent technology for removing multiple contaminants, such as heavy metals and organic substances, from groundwater and industrial wastewater. Additionally, they aim to develop methods for regenerating biosorbents, allowing for the reuse of arsenic-contaminated water and recovered arsenic, which could find applications in high-tech manufacturing processes.

Conclusion

By harnessing the potential of agricultural waste as biosorbents, researchers have made significant strides in addressing the global challenge of arsenic-contaminated groundwater. This innovative approach offers a cost-effective and environmentally friendly solution for removing arsenic, with potential applications beyond water treatment. With further development and support, this technology holds the promise of improving the lives of millions affected by arsenic contamination worldwide.

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Dr. Kirti Sisodhia

Content Writer

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