Technology: Can food additives eat up oil spills?

 作者:曾咔     |      日期:2019-02-28 06:16:01
By FABIAN ACKER Two harmless food additives could work together as a cheap and clean method of cleaning up oil spills. Guy Kalocsai, a Hungarian inventor who lives in Australia, says part of his motivation in developing the method was fears about the effects of oil pollution on the Great Barrier Reef. The mixture of reagents is added to oil or petrol, either as it floats on water or after it has settled on the shoreline. The spill then turns into a nonsticky solid resembling plasticine, which can be handled and collected more easily than the raw oil. It is lighter than water so it will float, and on shore it can be peeled off rocks, sand or coral. The biggest advantage of the invention is its low cost – about $0.71 per litre of oil spilled – compared to other techniques. For example, it has so far cost about $50 per litre spilt to clean up the damage from the Exxon Valdez’s spill in Alaska. Kalocsai is reluctant to discuss the exact nature and proportion of the mixture, or exactly how the process works, until all the patents are published and granted. But he will say that the effect of the two reagents is to produce very small, solid particles that rapidly absorb the hydrocarbons. ‘The best results are obtained when there is excess water present, which is why the process is particularly appropriate for oil spills,’ he says. Because the reagents consist of food additives that have already been approved by the US Food and Drug Administration and the European Commission, they are believed to be non-toxic to humans. Tests have shown that coral and fish are unaffected after 50 days’ exposure to the materials. The effect of adding the materials to an oil-on-water mixture is to reduce its surface area by 74 per cent, but increase its depth by 400 per cent, according to tests carried out in Australia in the past year. In an oil spill, the strategy would be to spray the compounds around the slick’s periphery, to form a floating barrier. After this, traditional methods or further spraying with the compounds could be used to attend to the rest. An even more effective use of the mixture could be to prevent spills before they happen, by using the process inside oil tankers that are holed at sea. The oil could be solidified by pour-ing in the reagents, or preferably forcing them in through nozzles at the bottom of the ruptured tank so the oil solidifies upwards, reducing the potential spill. In ideal conditions, the oil coagulates in 20 seconds; in reality, the time would depend on the rate and efficiency of mixing. Ironically, the effectiveness would be improved in stormy weather – when tankers are more likely to have problems. The process is reversible by using a third reagent, which would make it straightforward to empty the tank once the ship had reached port, and help to defray costs because the oil returns to its original condition. Kalocsai suggests that the process could be used as a complement to cracking plants, which break the lighter components of oils into short-chain hydrocarbons. The heavier oils could first be solidified and removed for later reliquification,