LOCAL MASS-TRANSFER AND CURRENT DISTRIBUTION IN BAFFLED AND UNBAFFLEDPARALLEL-PLATE ELECTROCHEMICAL REACTORS

Measurements of average and local mass transfer distributions were mad e in a parallel plate electrochemical cell using the limiting diffusio n current technique based on ferricyanide ion reduction at nickel elec trodes. The cell was operated with and without baffles. The local mass transfer coefficient values given by arrays of surface-flush mounted nickel mini-electrodes exhibited a distribution that reflected the com plex hydrodynamics associated with phenomena such as cell inlet and ex it effects and flow reversal at the baffles. In the unbaffled cell, th e behaviour was dominated by a global swirling motion in the cell driv en by the inlet jets. A relatively inactive zone appeared in the middl e of the cell. Overall, the cell exhibited superior mass transfer perf ormance when operated with baffles. The behaviour is compared with tha t in a similar cell described by Goodridge et al.