Effect of some oxidation treatments on the textural characteristics and surface chemical nature of an activated carbon

The changes produced in an activated carbon by treatment in aqueous solutio ns of (NH4)(2)S2O8 and H2O2 are compared with the modifications produced by oxygen plasma. These changes are monitored by measuring the textural chara cteristics (surface areas, porosity, pore size distributions) and surface c hemical groups. The former are studied by N-2 and CO2 adsorption, mercury p orosimetry and hydrocarbon adsorption at zero surface coverage. The chemica l surface groups are determined by chemical titrations and FTIR Spectroscop y. The results show large differences between the changes produced by treat ment in aqueous solutions and those produced by oxygen plasma. Whereas both treatments in aqueous solution modify the textural characteristics, oxygen plasma maintains the surface area and pore network. However, plasma treatm ent introduces larger amounts of oxygen chemical groups than treatment in a queous solution. (C) 2000 Academic Press.