The ion exchange kinetics of VS-1 cation exchange fiber was studied. Under finite solution vol. (FSV), not only the effect of temperature, stirring speed, concentration and pH value of the solution on the heterophase isotope exchange of fiber was investigate, but the anal. solns. of the exchange equation were also obtained. By use of these solns., the intraparticle diffusion coefficients D and the film transmitting coefficients D/d under different conditions were calculated, and the reason that the ion exchange rate of fiber is faster than that of spherical resins was given with a proposed mechanism.

Key words: DYNAMICS, TRACE METHODS, ISOTOPE EXCHANGE, GADOLINIUM, ION-EXCHANGE FIBRES