Use of MgO for repeated calcination with regard to its sorption density for F - and chemical stability was examined. Magnesium oxide was produced by the calcination of MgCO 3 at 1273 K for 1 h. The sorption of 9.82 mM F - on the calcined product and the calcinations of solid residues were carried out five times to evaluate trends in sorption density for F - and the stability of the chemically regenerated sorbents. The order of sorption density of F - (Q/mol g -1) apparently seems to depend on the specific surface area. However, Q′ values after normalization of the sorption density for the specific surface area (Q′/mmol m -2) were found to be correlated with the solid basicities of the calcined products which were derived from CO 2-TPD curves for the calcined products. The number of weak base sites, calculated from the peak intensity at 373 K in CO 2-TPD, was considered to be responsible for the removal of F - through hydration. Large quantities of NaMgF 3 and elemental Mg were evaporated by the calcination at 1273 K of the solid residues formed after sorption of F -.
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Filtration and Separation