Shock-wave-induced nucleation leading to crystallization in water

Abstract

It is well known that super-cooled materials can be crystallized under the application of shock waves. This is the first report describing crystallization from unsaturated liquids. Shock-wave-induced crystallization of salts from environmental ground and sea water samples is explored. A table-top pressure-driven shock tube is utilized so as to produce the required shock waves of Mach numbers 1.1, 1.2, 1.4, 2.2 and 4.7. The demonstration comprises a train of acoustic shock pulses applied to the water samples. As a consequence of the impact of the shock waves, the colourless water becomes turbid, following which tiny crystallites are precipitated at the bottom of the vessel after a few minutes. The obtained precipitate is subjected to powder X-ray diffraction and energy-dispersive X-ray spectroscopy analysis to confirm the nature of the settled particles and the elements present in them, respectively. From the observed results, it is concluded that shock-wave-induced crystallization in water provides an alternative method for removing dissolved salts from both ground and sea water samples.