From the results of adsorption, each isotherm shows a distinct knee band, which is characteristic of microporous adsorbents with capillary condensation in micropores. In order to reveal the causes of the differences in adsorption capacity and specific surface area after the samples were washed with various strengths of sulfuric acid, surface morphology and pore structure were investigated by SEM. X-ray diffraction patterns indicated that activated carbon containing metal species show better performance for metal and metal compound removal by post-treatment. with acid. The FT-IR spectra of metal-activated carbon samples show that the acid post-treatment was consequently associated with the removal of metals with an increased surface functional group containing oxygen of the activated carbon. The type and quality of oxygen groups are determined on the method proposed by Boehm. For the chemical composition microanalysis of metal-activated carbons transformed by post-treatment with sulfuric acid, samples were analyzed by EDX.

Keywords: adsorption isotherm; metal-activated carbon; SEM/EDX; XRD; Boehm titration; FT-IR