Kinetics, thermodynamics and isotherm studies on adsorption of methyl orange from aqueous solution using ion exchange resin Amberlite IRA-400

Abstract

Study on removal of anionic dye methyl orange (MO) from aqueous solution was investigated using ion exchange resin Amberlite IRA-400 batch adsorption process. Effect of operating adsorption factors that influence on the adsorption process such as contact time (1-300 min), initial dye concentration (25-500 ppm), solution pH (2.5-11.5), resin dose (5-100 g/L) and temperature (293-353 K) were studied. The extent of MO adsorption was increased with increase in the contact time, agitation speed, temperature, initial dye concentration and adsorbent dose but decreased with increase/decrease of the solution pH (maximum at pH-6.5). Equilibrium data were analyzed by both Langmuir isotherm and Freundlich adsorption isotherm. The maximum monolayer adsorption capacity of Amberlite IRA-400 was resulted as 74.4 mg/g at 303 K. The value of separation factor (R-L) from Langmuir equation and Freundlich constant (n) indicated on favorability of adsorption. Thermodynamic parameters such as Delta G degrees,Delta H degrees and Delta S degrees were calculated and the positive value of Delta H degrees (4.13, 3.63 and 7.09 kJ mol(-1)) for corresponding initial MO dye concentrations: 50, 100 and 200 ppm, respectively, in the solution indicated that the adsorption was of endothermic in nature. Kinetics result revealed that the adsorption of MO is of pseudo second-order and chemisorptions type.