Abstract:The ability of aerobic granular sludge(AGS) to adsorb crystal violet(CV) from aqueous solutions was studied. Adsorption studies were carried out at different pH

adsorbent dosage

initial dye concentrations

NaCl concentration and temperature.Adsorption mechanism was measured through the adsorption isotherm and adsorption dynamics

thermodynamics and Fourier transform infrared spectroscopy(FTIR).The experimental results showed that the best adsorption condition was pH value of 2.0

adsorbent dosage of 2 g/L and temperature at 35 ℃.Equilibrium adsorption capacity(qe)was positive correlation with initial concentration of dye

but negative correlation with NaCl concentration.Adsorption datas were modeled using Langmuir and Freundlich adsorption isotherms.Equilibrium data of the adsorption process fitted very well to the Freundlich model.The results of kinetics study showed that the pseudo-second-order model fitted to the experimental data well.The thermodynamic parameters were evaluated.ΔH°>0

ΔS°>0 and ΔG°<0 demonstrated that the adsorption process was spontaneous and endothermic for dye.Furthermore the positive value of ΔS° reflected good affinity of the CV dye.The FTIR analysis indicated that functional groups on aerobic granular sludge would play an important role for the adsorption of the studied dye.These results showed that aerobic granular sludge could be effectively used as a low-cost adsorbent for the removal of CV dye from wastewater.