Adsorption of Acid Carmoisine B by Fly Ash/Chitosan Composite

Abstract

With synthetic wastewater, the adsorption characteristics of acid carmoisine B (AC B) on fly ash/chitosan (FA/CTS) composite material prepared by FA loaded with CTS were investigated using a lab-scale batch experiment technique. The optimum preparation conditions for FA/CTS composite were obtained and the composite was further characterized by SEM. The adsorption rate of AC B onto FA/CTS is very fast and the adsorption can reach equilibrium in 60 minutes. Temperature may accelerate the adsorption rate. Equilibrium experimental data are well fitted to linear Langmuir model with the saturated adsorption capacity of 232.56 mg/g at 25°C and the nature of a monolayer adsorption. Dubinin-Radushkevich (D-R) isotherm model was applied to describe the nature of AC B sorption, and it has been found that AC B sorption mainly occurred chemically, but physisorption also exists at same time. The values of thermodynamic parameters, the change of free energy (ΔG◦), enthalpy (ΔH◦) and entropy (ΔS◦) of sorption calculated, show that the sorption process of AC B on FA/CTS is spontaneous and endothermic at 25~55°C. The results indicate that there is significant potential for FA/CTS as an effective adsorbent material for AC B removal from dye wastewater.