Removal of Congo red from aqueous solution using saw dust as a low cost adsorbent

In this study the use of low cost adsorbent has been studied as an alternate of activated carbon for the adsorption of Congo red from aqueous solution. Saw dust was used to remove Congo red from aqueous solution by batch adsorption techniques. Effect of contact time, amount of adsorbent, initial concentration of dye, temperature of the solution and pH of the solution were studied. It was seen that maximum dye removal was reached at 90 min. Amount of dye adsorbed per unit mass of adsorbent increased with increasing initial dye concentration (25 to 100mg/l) and solution temperature (25 to 70 °C) while it decreased with increasing adsorbent dosages (0.25 to 1.0 g/50 ml) and pH of the solution (5.7 to 10). The equilibrium adsorption isotherms have been analyzed by Freundlich and Langmuir models at different initial concentrations of 25, 50, 75 and 100 mg/l, and the results were discussed in detail. The results showed that saw dust could be used as an effective and low cost adsorbent for the removal of dyes from aqueous solution.