Adsorption of Sulphur Compounds on Impregnated Silica

The sorption properties of silica gel, impregnated with different amounts of diethanolamine(DEA) are tested towards H 2 S, CH 3 SH and CS 2 by recording break through curves. Loading of silica gel with DEA first results in the formation of a monolayer, showing a lower reactivity towards H 2 s and C S2 than the DEA molecules in excess to this layer. The substrate becomes inactive for CH 3 SH when this monolayer is filled. The attribution of a different interaction between S-compounds and DEA molecules in concentrations < 1.5 mmol/g dr. and > 2 mmol/g dr. to the formation of a monolayer interacting directly with the silica surface, is supported by FTIR-PAS measurements of the different DEA-loaded samples.