REMOVAL OF METAL IONS FROM AQUEOUS SOLUTIONS USING ACTIVATED CARBON PREPARED FROM ZEA MAYS STEM

Abstract

Activated carbon prepared from Zea mays stem using chemical activation was used as adsorbent for the removal of metal ions from aqueous solution. The results indicate that the adsorption of Pb(II), Cu(II) and Cr(III) ions is pH, contact time, and concentration dependent while the adsorption of Hg(II) is very different. The maximum removal percentages obtained at pH 5-6 were 97.44 % for Pb(II), 98.37 % for Cu(II), 89.37 % for Cr(III) and there was no adsorption for mercury ions. The metal ion removal trend follows the order Pb(II) > Cr(III) > Cu(II). The results show that Langmuir model fitted well in most cases with R2 > 0.99. Consequently, the adsorption of Pb(II) and Cu(II) followed Langmuir isotherm model while that of Cr(III) best fitted on Freundlich isotherm model.

Keywords

• Activated carbon
• adsorption
• equilibrium isotherms
• metal ions