Displacement Band Chromatography of Hydrogen Sulfites for Enrichment of Sulfur Isotopes

Abstract

Experimental studies were conducted on the enrichment of sulfur isotopes by displacement band chromatography. In these studies, a band of hydrogen sulfite (bisulfite) ions from a sulfurous acid or bisulfite-salt solution was continuously displaced by bisulfate ions from a sulfuric acid or bisulfate-salt solution in a column packed with aminated polystyrene-divinyl benzene resin under varied process conditions. The sulfur isotopes were enriched through isotopic exchange between the bisulfite ions on the resin and the sulfurous acid and/or bisulfite-salt solution in contact with the resin within the moving band. During the isotopic exchange, S-34 isotope was favored in the resin phase and S-32 isotope in the liquid phase. As a result, the S-34 isotope was gradually enriched at the rear of the band, and S-32 isotope at the front. The effects of the various process conditions were evaluated on separative power, height equivalent to a theoretical plate, and operational simplicity. The highest separative power, 3.05 g S-34/cm³/yr, was achieved with an ammonium bisulfite feed displaced by a sulfuric acid displacer at 65°c operating temperature.