Advances in sustainable techniques and design of nano-materials for environmental mitigation have become essential for protecting our environment from various pollutants. Working on this vision, our team at chemistry department IIT Delhi is working on a bouquet of sustainable solutions ranging from special carbon nanotubes for water treatment to technologies to convert waste paper to useful materials.

The team has developed carbon nanotubes with exceptional adsorption properties that have incredible potential in water treatment by treating them with metal oxides.The distinctive and tuneable physical, chemical and configurational properties of carbon nanotubes (CNTs), has prompted their combination with metal oxides to fabricate carbon composites showing remarkable adsorption property with remarkable potential in water treatment. The MWCNT/Alumina (RMAC) nodules (spheres) with effective adsorption capacity were synthesised through a process called the aqueous sol-gel route.

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In this technology, we have used a combination of alumina and carbon nanotubes and made small spheres of 5 mm diameter. These spheres were were found to be effective absorbents specially of metals and dyes from polluted water   The spheres technically called nodules are recyclable and do not create sludge. Industrially as well as domestically if they are applied in the series of other RO pre-treatment processes, the polluted wastewater can be purified and made available for industrial and domestic reuse.

Appropriate recycling of waste to reusable materials is much sought after in the management of waste materials.The tin cans which are used for storage of food and beverages, generates a significant amount of metal scrap in our daily life. The tin cans are made of iron coated by a layer of tin and can be used for making tin-iron catalyst for oxidation kind of chemical reactions. We have found a method to obtain nanocomposites of SnO2-Fe3O4from scrap tin-plated metal containers and use these composites for the degradation of organic pollutant.Our research has found that the composites of SnO2and Fe3O4with specific proportion exhibits significant photocatalytic efficiency for degradation of organic pollutants, under UV and visiblelight .The tin-iron catalyst developed by our team is suitable for the treatment of wastewater generated from dye, polymer, paints and pharma industries.

Recently we have obtained results on waste to wealth conversion as start-up venture funded by IIT Delhi, wherein the waste paper trash such as teacups, food containers, paper plates etc. are being recycled to make useful products such as handmade paper, blotting paper, file covers, envelops and many other items. In our day to day life, we had a trash generated from usedpaper teacups, wrappers, paper plates, food containers, newspapers, printed papers etc. Which may be recycled by technology developed by IITDand can be converted to useful products such as file covers, envelopes, writing papers, paper dishes and so on. We have utilized the same process in obtaining nanocellulose for advanced applications from paper trash. The technology developed by us is very simple and can be practised at home. You need to have equipment like a kitchen mixer and a pressing machine. Thus constant efforts in research are essential to search for newer and affordable technologies for environmental mitigation.

N.B.: The work on Tin-iron catalyst was done in collaboration with Dr. Menka Jha, Institute of Nano Science Technology, Mohali, Punjab.

Dr Ashok Ganguli
Professor & Head, Department of Chemistry,
Institute Chair Professor,
Indian Institute of Technology, Delhi

References

[1]Kunde, G. B., Sehgal, B., & Ganguli, A. K. (2019). Synthesis of mesoporous rebar MWCNT/alumina composite (RMAC) nodules for the effective removal of methylene blue and Cr (VI) from an aqueous medium. Journal of hazardous materials374, 140-151.

[2] Devi, M. M., Singh, H., Kaur, K., Gupta, A., Nishanthi, S. T., Bera, C., Ganguli, A. K.& Jha, M. (2019). New approach for the transformation of metallic waste into nanostructured Fe3O4 and SnO2-Fe3O4 heterostructure and their application in the treatment of organic pollutant. Waste Management87, 719-730.

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