Magnetic field effect on the kinetics of oxygen dissolution into water

The effect of a magnetic field on the gas dissolution process into degassed water was studied. Under magnetic fields up to 10T, the equilibrium concen tration of paramagnetic oxygen gas was not changed, whereas the dissolution rate was significantly accelerated. The mechanism was found to be based on magnetically induced convection in water due to the non-uniformity of magn etic susceptibility created by the dissolution of oxygen into the water pha se. This paper presents a theoretical discussion of the mechanism in terms of the hydrodynamics on the analogy of thermal convection. To confirm this argument, two kinds of experiments were carried out. The degree of accelera tion of oxygen dissolution depended on the product of the magnetic field in tensity and its gradient, B . dB/dz. The maximum acceleration occurred at t he maximum position of B . dB/dz on the bore axis of the magnet. In contras t, the dissolution of diamagnetic carbon dioxide gas was not accelerated by the magnetic field. However, under the coexistence of oxygen gas, the diss olution rate of carbon dioxide became fast. These observations support the proposed mechanism.