Removal of Methylene Blue from aqueous solution by adsorption on sand

The removal of Methylene Blue (MB) dye from aqueous solution present as a pollutant material in textile waste water was studied at 298 K in terms of its adsorption behaviour. Local sand sample was used as an adsorbent in this work. The textural properties of the sand including surface area, mean pore radius and total pore volume were examined from the low-temperature adsorption of nitrogen at 77 K. The conditions for maximum adsorption of the dye on sand were optimized. It was seen that under optimized conditions, up to 92% dye could be removed from solution onto the sand surface. The adsorption data were fitted to Freundlich and Dubinin-Raduushkevich equations for the calculation of various adsorption parameters. The Freundlich constants n and A were determined as 0.9682 and 0.639 mol/g, respectively. The sorption energy calculated by the Dubinin-Raduushkevich equation was found to be 1.22 kJ/mol. The adsorption behaviour of the dye was also investigated in terms of added cations and anions. It was found that the dye adsorption decreased considerably in the presence of thiosulphate, potassium, nickel and zinc ions.