Adsorption of iron and manganese ions using low-cost materials as adsorbents

The removal of toxic metal ions (iron and manganese) from aqueous solution by adsorption was studied. The batch process was used either to remove each metal ion singly or both metals as a multi-component system. The adsorbents used were low-cost materials, viz. palm fruit bunch and maize cob. The adsorption isotherms demonstrated that the adsorbents behaved in a favourable manner towards metal ion adsorption. The adsorption capacities for iron ions on palm fruit bunch and maize cob were in the 57-80% range and for the manganese ion in the 50-79% range for initial concentrations between 1 ppm and 10 ppm. With mixtures of both metal ions, removal of iron ions from the mixture was in the 54-79% range and for the manganese ion in the 54-76% range. The extended Langmuir model gave poor agreement with the data for the adsorption of mixtures of the two metal ions while the P-factor model yielded good agreement.