A new microcalorimeter of adsorption for the determination of differential enthalpies

An adsorption microcalorimeter for the determination of the differential heat of adsorption is designed and built, and some of the results are presented here. For this purpose, a Calvet heat-conducting microcalorimeter is developed and is connected to a gas volumetric unit built in stainless steel to record adsorption isotherms. The microcalorimeter is electrically calibrated to establish its sensitivity and reproducibility, obtaining K = 154.34 +/- 0.23 W V-1 and, chemically, it is examined with a THAM-HCL system, obtaining Delta f= -30.49 +/- 0.05 kJ mol(-1). The adsorption microcalorimeter is used here to obtain adsorption isotherms and the corresponding differentials heats, using as reference solid, a zeolite ZSM-5 type. (C) 2008 Elsevier Inc. All rights reserved.