Simultaneous removal of trivalent and hexavalent chromium by activated carbon: Effect of solution pH and pore size distribution of adsorbent



Adsorption of trivalent (Cr(III)) and hexavalent chromium (Cr(VI)) from aqueous phase was simultaneously studied using commercial activated carbons (CACs). Solution pH and the porous characteristics of the adsorbent such as surface area, pore volume and pore size distribution (PSD) greatly influenced the removal capacity of Cr(III) and Cr(VI). The maximum removal of Cr(VI) and Cr(III) was obtained at pH 3.0 and 5.0, respectively. From this study, it was observed that adsorbents having micropores (<2.0 nm) were effective in the removal of Cr(VI) and Cr(III) from aqueous solutions. Existance of micropores results in high porous characteristics such as surface area and pore volume which play an important role in removal of metal ions. The surface functional groups are also greatly involved in the simultaneous removal of both Cr(III) and Cr(VI) ions from aqueous solutions. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 1030–1035, 2013