Guwahati, Sept 26: Researchers at the Indian Institute of Technology-Guwahati (IIT-G) have developed a silica nanoparticles-coated cotton fabric that can separate oil from oil-water mixture.
The research aims to convert large-scale agricultural waste into a sustainable value-added product to mitigate environmental hazards such as biomass burning and marine oil pollution.
The nanoparticles have been developed by utilising rice husk, an agricultural waste, as the primary source material.
The findings of the study can aid in development of economical, sustainable platforms for separating oil/water mixtures or harmful components from aqueous/non-aqueous mixture.
Oil spills owing to industrial discharge or mishap causes irreversible damage to the aquatic ecosystems. Conventional cleaning techniques, such as skimming or in-situ burning, are ineffective, costly and cause additional pollution.
Researchers around the world have been trying to develop energy-efficient materials to separate the oil and water mixtures. However, the sustainable and economically viable conversion of biomass to modified silica for oil spill mitigation had not been explored earlier.
Explaining the eco-friendly method, Prof. Vaibhav V. Goud from the department of chemical engineering, IIT-G, said, “Our technology has multiple beneficial effects on the environment. Rice husk is an agriculture byproduct, rich in silica, which is generated in millions of tons every year. It generally ends up being burnt unscientifically causing air pollution. With our technique this waste rice husk is converted to 3D sorbents that mitigates oil contamination by following a selective active-filtration process.”
In this process, inexpensive farm waste (rice husk) is gradually heated and efficiently converted to charcoal, also known as bio-char. Subsequently, the bio-char is subjected to further heating to transform it to silica nanoparticles.
The size of these nanoparticles can be customised by adjusting the pH of the bio-char. To render the nanoparticles water-repellent, they are treated with special chemicals known as silanes. Finally, these treated nanoparticles are coated over a cotton material creating a natural, three-dimensional sorbent for separating oil-water mixture.
Explaining the significance of their work, Prof. Goud, said, “Our experiments at IIT-G have demonstrated that the coated cotton fabric particularly absorbed oil, while the uncoated sample absorbed both oil and water. The developed super hydrophobic material has shown a remarkable 98 percent efficiency and retained its functionality even after repeated use and exposure to harsh environments.”
The details of the natural 3D oil absorbing material have been published in the prestigious international journal, Biomass and Bioenergy.
The paper has been co-authored by Prof. Goud and research scholar Sutapa Das.