Adsorption of pyridine onto spent Rundle oil shale in dilute aqueous solution

Abstract

The adsorption of pyridine from aqueous solutions onto the solids generated by the processing of Rundle oil shale shows that the adsorption isotherm is of Langmuir type (L-4) with two plateaux. Cations which are leached from the spent shale or which are in retort water (Na, K, Ca, NH 4) have a marked effect on the adsorption; the anion effect, while measurable, is much less. The adsorption is controlled by a number of factors such as pyridine co-ordination, surface protonation and ion exchange. XRD studies show that the montmorillonite in the spent shale expands during the sorption process, indicating a re-orientation of the adsorbed pyridine. The results identify some of the mechanisms likely to control the transport and removal of N-heterocyclic compound in spent shale waste dumps.