Affinity and Selectivity of Immobilized N-Methyl-<scp>d</scp>-glucamine for Mercury(II) Ions

N-Methyl-d-glucamine (NMDG) immobilized onto cross-linked poly(vinylbenzyl chloride) beads is found to have a high affinity and selectivity for Hg(II) from nitric and hydrochloric acid solutions. In HNO3, complexation is &gt;98% from a solution at pH 3, which decreases to 11.2% from 1 M HNO3. Hg(II) is complexed to a greater extent from HCl: 95.4% is complexed from 1 M HCl and &gt;99.5% from solutions at pH 1.0 and greater. Control studies with immobilized sorbitol show that coordination of Hg(II) by the -OH groups is an important component of the mechanism. Complexation by sorbitol is dependent on the pH. Log−log plots of the distribution coefficients versus the hydrogen ion concentration at equilibrium show the importance of the changing nature of the solution species: since ion exchange is not mechanistically possible with sorbitol, the pH dependency reflects the effect of pH on shifting the species in solution from noncoordinating Hg(NO3)42- and HgCl42- to coordinating Hg(NO3)+ and HgCl2. Comparison to re...