Oil spills have been one of the major sources of environmental degradation haunting earth.
In order to effectively remove crude oil from the sea, Indian scientists have developed a simple system, which is not only cheap but also environment-friendly.
Oil spills have the power to pollute and even destroy marine ecosystems. “Marine oil spills are disasters that cannot be completely avoided as long as we drill for oil or transport it across the ocean,” according to researchers. An effective measure, therefore, would be to remove oil slicks by absorption into a separable solid phase.
Kana M Suresan and Annamalai Prathap, scientists at the Indian Institute of Science, Education and Research (IISER) in Thiruvananthapuram, Kerala,combined absorption and gelation processes, and tightly bound the oil to a porous matrix. They then simply scooped the solid particles out of the water. Despite being full of oil, the granules did not sink, but floated on the surface.
The scientists also demonstrated that squeezing the congealed granules could help recover the spilt oil. Since cellulose is an environment-friendly, cheap and porous carrier matrix, they impregnated it with an oleogelator, a cheap organic compound. The simple impregnation step proved to be key in converting the cellulose into an effective oil-absorbing and recycling system, reported The Indian Express.
“Phase-selective organogelators are amphiphiles which can congeal oils selectively from a biphasic mixture of oil and water,” the scientists wrote in the journal Angewandte Chemie.
How does the process work?
Gelation (solidification by freezing) occurs when the gelator molecules get dissolved in the oily phase, and form a three-dimensional fibre network through hydrogen bonding.
The oil becomes trapped in this fibrillar network to form a rigid gel. Thus, gelation turns the liquid oil phase into a solid one, which can be simply scooped out.
One of the additional advantages of the process of impregnation is that the gelator renders the cellulose matrix hydrophobic. It does not suck in water as the naked cellulose does.
However, it “absorbed all the oil, and the rigid globules containing the congealed oil could be scooped out after two hours, leaving the clean water,” the researchers told the publication.