A new type of activated carbon containing nitrogen (No. 10) with a higher capacity for hydrogen sulfide adsorption than earlier types was prepared by impregnating raw activated carbon (No. 5) with a 20% MMU solution and then heating it at 850°C. Isotherms of hydrogen sulfide on AC-CN were obtained using a gravimetric method and at 30°C. The structure of AC-CN micropores and supermicropores has been discussed based on applying the binomial equation (3) to adsorption isotherms.
Treatment with MMU solutions caused the AC-CN micropore and supermicropore radii to contract and expand, respectively. Increases of approximately 15.5% in micropore volume and decreases of approximately 22.8% in supermicropore volume for AC-CN (No. 10) probably do not result from the expansion of micropore radii but from the numerical increase of micropores due to simultaneous decreases in supermicropore volume.