The adsorption of Cr(III) and Cr(VI) on activated carbons in the presence of phenol Original Research Article

Activated carbons, as selective ion exchangers, can be used to the removing of heavy metals, e.g., chromium from water. It is possible to adsorb anion Cr(VI) and cation Cr(III) on the surface of activated carbons because there can be present functional groups of acid and of basic character on these carbons. In the work there are shown the results of adsorption chromium (III) and (VI) at two pH values 6 and 9. The pH value of the solution, from which a given ion is adsorbed, has influence on the dissociation of functional groups and on the form in which a given ion occurs. And thus this pH value has influence on adsorption effects. In the case of chromium (VI) adsorption on WG-12 carbon there was obtained a high degree of removing (over 94%). Adsorption effects were similar regardless of pH value from which the process was conducted. There were obtained much lower adsorption effects, during the process of Cr(III) adsorption. The degree of removing from the solution of pH = 6 was 74%; and from the solution of pH = 9 about 60%, respectively.