Adsorption of Hydrogen Sulfide on N-Containing Activated Carbon

N-Containing activated carbon (N-CAC) was prepared by impregnating activated carbon with N-containing additives. Adsorption isotherms of hydrogen sulfide on N-CACs were obtained by a gravimetric method at 30°. A positive correlation between N content and specific adsorption of hydrogen sulfide at an equilibrium pressure of 50 Torr was found. It is considered that the adsorption of hydrogen sulfide resulted in the volume filling of micropores of N-CAC, based on application of the Dubinin-Astakhov equation to the adsorption isotherms. The finding that the net differential heat of adsorption and differential molar entropy of adsorption decreased with increasing degree of filling of micropores indicated that the micropores of N-CAC were successively filled with hydrogen sulfide from the smallest pores to the largest ones, and that hydrogen sulfide molecules were compactly filled in the micropores at an early stage of filling.