Oil spills in the ocean tend to spread out to form a thin layer, even if in an enclosed container the oil seems so viscous it is almost lumpy.
This characteristic makes any resulting pollution very hard to pick up. In fact, current techniques tend to come up against physics pretty quickly – they work but they are fairly inefficient. Likewise, burning can only be applied to fresh oil slicks of at least 3mm thick and this process also creates secondary environmental pollution.
Unfortunately other methods tend to rely on dispersing the oil molecules; not only is there evidence that these detergent-like chemicals are themselves toxic to some kinds of marine life (even in relatively low doses), they cause the oil molecules to remain suspended in the water column for extended periods.
There is another way – change the composition to make it easier to handle.
A new idea from the Institute of Bioengineering and Nanotechnology (IBN) does just this; researchers have invented a smart oil-scavenging material – called a supergelator - that could help clean up oil spills without falling into the trap of secondary pollution.
These supergelators are derived from highly soluble, small organic molecules which, explains IBN, instantly self-assemble into a 3D network making nanofibres which entangle the oil particles: the resulting clump can then be skimmed off the water’s surface fairly easily.
“The most interesting and useful characteristic of our molecules is their ability to stack themselves on top of each other,” said IBN team leader and principal research scientist Dr Huaqiang Zeng. He explained that the researchers created and tested out different kinds of these nano-sized stacks, finding the best structure to yield the required properties.
IBN’s supergelators have been tested on various types of weathered and unweathered crude oil in seawater, and have been found to be effective in solidifying all of them. The ‘magic’ mix takes only minutes to solidify the oil at room temperature; in fact IBN’s in vitro demonstration works quickly, inside about 15 minutes – albeit this is a glass beaker in lab conditions.
Further, the old issue of ‘a new problem springing from an attempted solution’ has been addressed. The compounds dissolve easily in environmentally friendly solvents; tests results show that the supergelator is not toxic to human cells and is likewise harmless to zebrafish embryos and larvae – passing these hurdles make the supergelators suitable for use in large oil spill areas.
It might take a while to get to market: at present the Institute is looking for industrial partners to help it develop the technology for commercial use.
By Stevie Knight
