Chemical instability and periodic precipitation of CuCrO4 in batch and flow reactors

Abstract

Periodic precipitation of copper chromate in one and two dimensional gel media have been studied employing a variety of experimental techniques. Experiments are performed by varying the initial electrolyte concentrations, temperature and <em>p</em>H of the medium. Influence: of gravity and an external electric field on precipitation patterns have been studied. New type of batch and flow reactors have been designed for this purpose. Segmentation and irregular patterns with in concentric Liesegang rings have been observed at low [CrO<img src='http://www.niscair.res.in/jinfo/four1.gif' border=0>]. Newly designed DPL and gel-ring continous-flow reactors have been used for two dimensional studies. Two dimensioanal experiments have been profomed to study the growth of weakly soluble salts in a thin film of agar-agar and PVA sandwich between two microslides. An influence of gravity on the diffusion of chromate ions into PVA film has also been studied.