Chemical Physics Letters, Vol.433, No.4-6, 286-291, 2007
Complex motion of precipitation bands
Formation and dynamics of an Al(OH)(3) precipitation ring is studied by diffusing NaOH into a gel containing AlCl3. Limited feeding of the outer electrolyte (NaOH) is found to yield an intricate ring-dynamics which involves stopping and reversal of the direction of motion of the precipitation ring, and evolution into stationary multi-ring structures. A model of the ring-dynamics is developed by combining a phase separation scenario for the precipitation with the redissolution (complex formation) of the precipitate in the excess of the outer electrolyte. (c) 2006 Elsevier B.V.. All rights reserved.