Investigation of the use of rice husk as adsorbent for removal of dyes

In this study, rice husk was used as adsorbent and removal of Malachite green (MG) and Reactive red 45 (RR45) dyes from aqueous solutions were investigated by batch adsorption method. The adsorption studies were carried out effect of initial dye concentration, pH and time for both of dyes. Langmuir and Freundlich isotherm models have been tested for the removal of dyes from aqueous solutions of rice husk. The Langmuir isotherm model (R2=0,9998) is more fitted than Freundlich isotherm model (R2=0,6578) for removal of malachite green. As for the reactive red 45, it was seen that the experimental data were not consistent with the theoretical data and both Langmuir and Freundlich isotherm models were insufficient in explaining the adsorption model due to the low correlation coefficient. Adsorption kinetics were also studied and the results obtained in the removal of both dyes were found to be compatible with the pseudo second order kinetic model. Both rice husk and dye loaded rice husk were characteristic by scanning electron microscope (SEM). As a result, it has been reported that rice husk can be used as an effective, economical and easily obtainable adsorbent for the removal of dyes.