KINGSTON, Ont. -- Queen's University researchers have devised a "green chemistry" solution to one of the oil industry's biggest problems in a cost-effective way.
Their findings will be published in the international journal Science on Friday August 18.
The study addresses the recurring problem of separating oil and water mixtures, and targets diverse applications including cleaning up oil spills, and extracting oil deposits from tar sands and reservoirs. Other potential beneficiaries are plastics manufacturers, chemical and pharmaceutical companies, mining companies and makers of cleaning products.
The new process can be used whenever industry requires an emulsion (the mixture of two liquids in which droplets of one are suspended evenly throughout the other), explains lead researcher and Queen's Chemistry Professor Philip Jessop. This might occur when cleaning spills, extracting oil from the ground, de-greasing metal equipment or metal surfaces, and manufacturing chemical products such as plastics.
Since oil and water don't normally mix, it's necessary to add a "surfactant" (surface active agent) in the layer between them before you can create an emulsion. "The problem is that in many situations, you later want the water and oil to separate again," he continues. But of the 'switchable' surfactants known so far, one is very expensive and contains metals, another is extremely toxic, and the third type is activated by light which doesn't work well with opaque emulsions.
Old-fashioned soap can be made to "switch" but that requires large amounts of acid to be added, which is not desirable, says Dr. Jessop, Canada Research Chair in Green Chemistry. The surfactant developed by the Queen's team is also completely reversible and does not require metals, acid, or light. Exposure to carbon dioxide (CO2) activates it, while bubbling air through the liquid turns it off again. CO2 and air were chosen because they are chea
Contact: Nancy Dorrance