Studies on the kinetics of nitrous oxide adsorption on resin char

Adsorption of nitrous oxide on resin char was investigated with a thermogra vimetric system in this study; The char was prepared from pyrolysis of phen ol-formaldehyde resins, followed by gasification of the resulting char in n itrous oxide to 18.5% burn-off. The temperature range used in the adsorptio n experiments was 35-80 degreesC, and the partial pressure of nitrous oxide varied within 25-101 kPa. Experimental data showed that the adsorption iso therms were approximately linear in partial pressure of nitrous oxide. The adsorption was found to be reversible, based on the results of desorption e xperiments. Simulation of the adsorption kinetics with a modified Langmuir model has shown that the rate of adsorption had apparent orders of 4 and 5 with respect to the adsorptive sites and the nitrous oxide pressure, respec tively. The rate constant of desorption was shown to increase with temperat ure, whereas that of the forward pathway of the reversible adsorption was l ess sensitive to temperature. According to the simulated results, the rever sible adsorption was exothermic with an enthalpy change of -11.5 kcal/mol.