Ion Movement in Wyoming Bentonite During Electroosmosis

Abstract

AbstractThe comparative rates of removal of the ions from Wyoming bentonite‐quartz sand systems during electroosmosis were as follows: Na+ > K+ > Mg++ > Ca++. The differential movement of ions tends to separate the cations as they move through the media. The percentage of an ion removed by a given amount of electricity was increased by the addition of a complementary ion.The rate of Na+ and K+ removal was proportional to the amount of these ions remaining in the system and decreased steadily as electroosmosis proceeded. The rate of Ca++ removal tended to remain more or less constant until the Ca++ concentration in the cell had been reduced to about 0.5 symmetry.In the early stages of electroosmosis the transference numbers of Na+ and K+ in systems containing no free salt were very near unity. Under similar circumstances the transference number for Ca++ was greater than in some salt solutions but did not approach unity.The amount of water flow per milliequivalent of cation removed was greatest for Ca++, intermediate for K+, and least for Na+.