Batch Adsorption Studies on Rice Husk with Methyl Violet Dye

The potential of rice husks powder (RHP) for the removal of methyl violet dye from aqueous solution was investigated. Batch adsorption studies were conducted and various parameters such as contact time, adsorbent dosage, initial dye concentration, pH and temperature were studied to observe their effects in the dye adsorption process. The optimum conditions for the adsorption of MV onto the adsorbent (RHP) was found to be: contact time (100 min) pH (10.0) and temperature (303 K) for an initial dye concentration of 50 mg/l and adsorbent dose of 1.0 g respectively. The experimental equilibrium adsorption data fitted best and well to the Freundlich Isotherm model for both dyes adsorption. The maximum adsorption capacity was found to be 1.66 mg/g for the adsorption of MV dye. The kinetic data conformed to the pseudo second order kinetic model. Thermodynamic quantities such as Gibbs free energy (ΔGº), enthalpy (Δº) and entropy (ΔSº) were evaluated and the negative values of ΔGº, ΔHº and ΔSº obtained indicate the spontaneous and exothermic nature of the adsorption process.