Adsorption of reactive red dye using organo-montmorillonite

In this present work, organo montmorillonites (OMMT), chitosan modified montmorillonite (CTS/MMT), and chitosan modified organo montnorillonite (CTS/OMMT) clays were prepared as adsorbents for removing Reactive Red 120 (RR120) dye from synthesized aqueous solution. The characteristics of those adsorbents were analyzed by the FTIR, the autosorb, SEM, and XRD techniques. The analytical results show some evidence of intercalation of modified agents into montmorillonite (MMT) such as presenting of alkyl group, increasing of specific pore size, and basal spacing. The highest percent dye removal was obtained by using the OMMT. Thus it was selected for further experiments. The adsorption of RR120 onto OMMT was investigated in a batch and a fixed bed column. The factors affecting in batch tests such as contact time, initial dye concentration, initial pH, and temperature were investigated. The result revealed that adsorption of RR120 was initially rapid and reached equilibrium at 360 minutes. The adsorption capacity increased with the initial dye concentration and temperature but decreased slightly with initial pH. The uptake of RR120 increased with temperatures indicating an endothermic process. Kinetics data were well described by the pseudo-second order model. The equilibrium data were better fitted by the Langmuir isotherm providing maximum monolayer adsorption capacity of 265.00 mg/g at 65 C. In fixed bed column, influences of initial concentration, flow rate, and bed height were studied. The optimum condition was obtained under 100 mg/L inlet concentration, 1.4 mL/min flow rate, and 80 cm bed height. Thomas, Adams-Bohart, and Yoon-Nelson models were fitted with experimental data. These results suggested that the OMMT can be used as an effective adsorbent for removing RR120 from aqueous solutions.