STUDIES OF REACTIONS ON METAL-IMPREGNATED CHARCOAL - CHARACTERIZATIONAND THE THERMAL-DESORPTION OF WATER

Copper- and chromium-impregnated and non-impregnated charcoals have be en characterized by X-ray photoelectron spectroscopy and scanning elec tron microscopy, showing the composition and distribution of elements in the charcoal substrate. Water (as D2O) was reacted with dried charc oals and its gradual thermal desorption was studied by mass spectromet ry. The impregnated charcoal retains substantially more water over a w ider temperature span. It is suggested that Cr3+, in particular, incre ases the number of high-energy adsorption sites. Thermal desorption al so results in decomposition of metal hydroxides and reduction of Cu2to Cu+ and Cr6+ to Cr3+. (C) 1997 Elsevier Science Ltd.