SHORT-TERM EFFECTS OF MAGNETIC-FIELDS ON DIFFUSION IN STIRRED AND UNSTIRRED PARAMAGNETIC SOLUTIONS

The aim of this work was to examine, experimentally and theoretically, the effect of magnetic fields on the diffusion rate of a paramagnetic solution through an inert membrane. The diffusion system consisted of two compartments which were separated by an inert membrane of cellulose acetate. One compartment was filled with solutions of nickel(II) chloride (0.5, 1.0, or 2.0 M), the other with distilled water. The applied magnetic fields had a direction perpendicular to the membrane. The flux densities were between 0 and 820 mT for static magnetic fields and between 0 and 5 mT for 50-Hz fields. In the experiments, both stirred and unstirred solutions were used. The experimental results showed that static magnetic fields caused a significant (P less-than-or-equal-to 0.05) increase in the maximum diffusion rate for exposed solutions relative to unexposed solutions due to 670- and 820-mT magnetic fields was found to be 39% and 68%, respectively, for 1 M solutions. The observed effect is shown to be proportional to the concentration of the solution, the concentration gradient in the solution, and the square of the magnetic flux density. However, no significant (P less-than-or-equal-to 0.05) effect of 50-Hz magnetic fields (up to 5 mT) on the diffusion rate in stirred and unstirred solutions was detected. A theory for the effect of the static magnetic field based upon the theories of diffusion and electromagnetism has been developed. The observed effect is explained in terms of the variable-reluctance principle.