COLLIDING jets of water can create mini implosions powerful enough to
catalyse chemical reactions. The trick could lead to a new way to break down
pollutants, chemists say.
Kenneth Suslik and his colleagues from the University of Illinois at
Urbana-Champaign report in this month鈥檚 Journal of the American Chemical Society
(vol 119, p 9303) that they can force two jets of water through tiny holes
drilled in gemstones. The jets meet at a speed of 725 kilometres per hour, and
the collision creates small regions of low pressure which vaporise water,
creating bubbles.
As the bubbles quickly collapse, their temperature increases to several
thousand degrees centigrade, Suslik says. This breaks the bonds of surrounding
water molecules to create free hydrogen atoms and hydroxide (OH) radicals, which
in turn destroy other molecules. 鈥淛ust as you can pull on a solid until it
breaks, if you have enough pressure, you break the solvent,鈥� says Suslik. He
says the process is similar to sonoluminescence, in which sound waves create gas
bubbles that heat up and emit light as they collapse (鈥淏ubbles hotter than the
Sun鈥�, 快猫短视频, 29 April 1995).
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Suslik鈥檚 team has already used the water jets to attach iodine atoms to
iodine molecules. The same process could be used to break down organic
pollutants such as insecticides and dry-cleaning fluid, they say. 鈥淲hat鈥檚
surprising is that a fast-moving liquid can cause high-energy chemistry,鈥� says
Suslik. 鈥淎t first glance, that鈥檚 not supposed to happen.鈥�
