X-ray photoelectron spectroscopy analysis for a reaction on the surface oftin metal in a continuous mercury analyzer

In order to understand the reaction in a continuous mercury analyzer with t he dry-type reduction process, the surface of granular tin metal in a dry-t ype reduction process was characterized by X-ray photoelectron spectroscopy (XPS). First, the method for chlorinating the surface of tin metal was inv estigated. It was found that the surface of tin metal was more deeply chlor inated by impregnating with 1 mol/1 hydrochloric acid for 2 hours than by p assing 600 ppm hydrochloric acid gas through the reactor for the number of same hours. Subsequently, the change on the surface of granular tin metal b y impregnating with I mol/1 hydrochloric acid was observed in the case of p assing air with mercury(II) chloride gas and moisture through the reactor. Tin (II) chloride on tin metal changed into tin (II, IV) oxide upon exposur e to air or moisture. Depth profiles indicated that a tin(IV) oxide layer w as formed on a tin(II) oxide layer. These results suggested that the reduci bility of tin metal depended on the ratio of the chlorinated surface. As fo r the reaction on the surface of tin metal pre-coated with 1 mol/1 hydrochl oric acid, the resulting X-ray photoelectron spectra were in good agreement with the reaction estimated from the mass balance in the actual experiment .