DESTRUCTIVE ADSORPTION OF CHLORINATED HYDROCARBONS ON ULTRAFINE (NANOSCALE) PARTICLES OF CALCIUM-OXIDE .2.

As a one-step approach to the safe destruction of chlorocarbons, the r eaction of carbon tetrachloride with ultrafine particles of calcium ox ide to give calcium chloride and carbon dioxide (CCl4(g) + 2CaO(s) --> CO2(g) + 2CaCl(2)(s)) has been studied in detail. Calcium oxide prepa red by an aerogel/hypercrytical drying method (AP-CaO) is superior to a conventionally prepared (CP-CaO) sample, and both are vastly superio r to commercial CaO (CM-CaO). Optimum temperature for this gas-solid r eaction is 450 degrees C, although AP-CaO reacted with reasonably high capacity as low as 300 degrees C. The effects of surface -OH, added w ater, CCl4 pressure, and a wide range of temperatures are discussed. C onditions for the suppression of by products C2Cl4 and Cl2CO are prese nted. Morphological changes in the particles after CCl4 reaction were studied by atomic force microscopy. A wide range of other techniques h ave been applied toward complete characterization of the process and p roducts, including FT-IR, pulsed U-tube reaction studies, gravimetric adsorption, X-ray diffraction, and GC-MS.