Sep 25 2019
Researchers from the Queensland University of Technology (QUT) have developed a new, safe method to clean up oil spills with the help of compounds that are as equally useful as common household cleaning products.
Associate Professor Jingsan Xu (left) with research associate Dr Chenhui Han. (Image credit: Queensland University of Technology)
In the past two decades, more than 700 oil spills have occurred around the world, not only polluting coastlines and oceans but also threatening the existence of marine ecology and other wildlife.
According to Associate Professor Jingsan Xu, the team from QUT’s Science and Engineering Faculty had invented a non-hazardous, economical, easily processed foam for removing oil.
He stated that if an oil spill takes place, the foam can be sprayed onto its surface to rapidly absorb the waste. The same concept could be applied to cooking or other oil spills in the home. The foam can then be easily scraped away for safe disposal.
A paper titled “Reversible Switching of the Amphiphilicity of Organic-Inorganic Hybrids by Adsorption-Desorption Manipulation,” which reports the study outcomes, has recently been published in The Journal of Physical Chemistry.
Thousands of tons of oil have been disgorged into our oceans over the decades. One of the most memorable was the Exxon Valdez oil spill in Prince William Sound, Alaska, in 1989 which spilled 37,000 metric tons of crude oil and is considered one of the worst ever human-caused environmental disasters.
Jingsan Xu, Associate Professor, Science and Engineering Faculty, Queensland University of Technology
Xu added, “More recently, the Deepwater Horizon oil spill in the Gulf of Mexico in 2010 had the dubious honour of becoming the largest marine oil spill in the history of the petroleum industry. Although there are methods for cleaning up oil spills, they are usually very messy and difficult to contain while some methods, such as in situ burning, create more hazards for the environment.”
Sorbents—large sponges—are also used but only for the removal of final traces of oil or in places skimmers cannot get to. The key to saving the environment from maximum damage is to mop up the oil as quickly as possible. So what we have focussed on is the adaptability and possibilities associated with surfactants which are already widely used in research, industrial production and daily lives via household cleaning products.
Jingsan Xu, Associate Professor, Science and Engineering Faculty, Queensland University of Technology
He further stated, “Surfactants are compounds that lower the surface tension between two liquids, between a gas and a liquid, or between a liquid and a solid—in other words, they can be detergents, wetting agents, emulsifiers, foaming agents, and dispersants. One way to remove the floating oil from sea surface is adsorption.”
Xu continued, “Hydrophobic porous foam—low density material that can float on liquid—is a promising candidate to achieve that and we recently reported on the synthesis of a hydrophobic hybrid foam which showed excellent adsorption performance to a range of organic liquids.”
Professor Xu and the team have currently developed what they term a “hybrid surfactant” by mixing stearic acid—an oil-soluble molecule—with water-dispersible alumina nanofibers via chemisorption at the oil-water interface.
“Our hybrid surfactant exhibits reversible switching between hydrophilic (molecules attracted to water) and lipophilic (able to dissolve in fats, oils, lipids, and non-polar solvents) states by manipulating the adsorption-desorption volume of stearic acid attached to the alumina nanofibers,” he said.
Therefore, the emulsions stabilised by this organic−inorganic hybrid can reversibly transform between oil-in-water and water-in-oil type by simple mechanical manipulation. Unlike conventional approaches, no other external stimulus is needed to set the amphiphilic properties of the hybrid surfactant. This protocol may have significant applications in cosmetic, food and other fields.
Jingsan Xu
“As a bonus, organic-inorganic three-dimensional solid foams can be readily prepared based on the emulsion system, which demonstrates a strong potential for use in evaporating oil spills—in the ocean or the kitchen—in a very quick fashion,” concluded Xu.
Mop up oil spills safely the QUT way
(Video credit: Queensland University of Technology)