RESUMO
Ground water, the major source of drinking water in rural and semi-urban areas of Assam, contains an excessive amount of iron varying from 1 to 10 mg/L or more. People in Assam invariably use household iron filter units-indigenously developed using locally available wooden charcoal and river sand as filter media. The present work is aimed to evaluate effectiveness of wooden charcoal and river sand for its iron adsorption capacity. The experiments were carried at a fixed pH of 5.5 with zero dissolved oxygen levels. Batch kinetic studies indicated rapid uptake of Fe(II) by wooden charcoal in the first 20 min. while the uptake with sand was relatively slower. The adsorption seemed to govern by diffusion within pores of adsorbents and Fe(II) removal mechanism appeared to be complex. Equilibrium studies indicated favorable adsorption of Fe(II) on both adsorbents and followed Langmuir isotherm. Column studies indicated relatively quicker breakthrough through sand bed as compared to charcoal bed. Overall, wooden charcoal and sand both seemed to have potentials for Fe(II) removal.