ABSTRACT:

The presence of dyes in water bodies have had significant effects on photosynthetic activities in aquatic life-forms due to reduced penetration of light and may also be toxic to certain forms of aquatic life due to presence of metals and chlorides in them. A study was carried out on removal of dye from its solution using sand dunes as adsorbent material. Procion Red Mx2B (Triazynyl dye) commonly used by textile industries and local dyers was used for this study. Sand dune fractions of particle sizes 106µm, 212µm and 300µm were used. Laboratory batch equilibrium studies were carried out to investigate the adsorption behaviour of the dye on sand dune. Adsorption on all three particle size ranges were adequately described by the Freundlich adsorption isotherm and adsorption was found to be higher for smaller particle sizes. Description of the adsorption by the Langmuir adsorption isotherm was poor, especially for larger particle sizes of adsorbent. Packed bed studies were also carried out using laboratory scale and filters. The effects of particle size, bed height, influent concentration and pH on the dye removal efficiency were investigated and removal efficiency was found to be favoured by smaller particle sizes, higher bed heights, lower influent concentration and lower pH.