Effects of magnetic exposure on an ion-exchange process are investigated, employing ion-exchange resins. The electrolyte solution, resin suspension, and water are mixed in a container, and the mass transfer coefficient is determined by measuring the change of the ionic concentration in the bulk. Two methods of magnetic exposure are performed: case (1) in which only the electrolyte solution is exposed to the magnetic field and case (2) in which only the resin suspension is exposed to the magnetic field. The following features are found in both cases: (i) the film mass transfer rate reduces by about 5% when the exposure time is greater than 25 min, (ii) the magnetic effect is reduced by adding the alcohol, (iii) the magnetic effect remains for about 3 days but disappears after 6 days, and (iv) the magnetic effect is observable in the solutions of structure-disordering ions, but not in the solutions of structure-ordering ions. As for the temperature dependence, the magnetic effect decreases with temperature in case (1) but it stays constant in case (2). It is postulated that the magnetic effects are attributable to the stabilization of water molecules around the structure-ordering ion and those an the resin surface. (C) 1999 Academic Press.