Microstructural analysis of activated carbons prepared from paper mill sludge by SANS and BET

Small-angle neutron scattering (SANS) and N₂-BET analysis were used to characterize the microstructure of a series of activated carbons produced from paper mill sludge using ZnCl₂. N₂-BET and SANS data indicate that the micro- and mesoporous surface areas of the carbons increase with the concentration of ZnCl₂ used in their preparation. Contrast variation SANS studies demonstrate the existence of two different phases, a zinc-rich particle phase and a bulk carbon phase with nanopores. Both phases are largely accessible to the solvent. The size and morphology of the pores and inclusions were determined from the SANS data. The pores are found to be roughly rodlike. The radii and volumes of the pores increase with increasing the amount of activating agent (ZnCl₂) used for the production of the carbons. On the basis of SANS results, we propose a conceptual model describing structural characteristics of the produced carbons.