Application of agricultural byproduct corncob for treating methylene blue in aqueous solution

In this study, agricultural byproduct corncob was utilized as an effective adsorbent to remove cationic dye methylene blue (MB) in aqueous solution. Effects of several experimental parameters such as initial MB concentration, pH, adsorbent dose, and temperature were studied to predict optimum conditions. Moreover, adsorption equilibrium and rate were evaluated using various isotherm and kinetic models. Results indicated that adsorption kinetic data were best fit by pseudo-second order model. The maximum adsorption capacity of corncob for MB dye was obtained at 417.1 mg/g. Adsorption energy of MB by corncob was obtained at 3.352 kJ/mol. Freundlich exponent (n) was 3.108 and the value of 1/n was 0.32. Considering these results for the MB adsorption process, using corncob was a magnificent physical process. Calculated thermodynamic parameters such as ΔG˚, ΔH˚ and ΔS˚ indicated that adsorption process was spontaneous and endothermic in nature. Based on these experimental results, corncob is a commercially viable new eco-friendly bioadsorbent efficient for MB dye removal in aqueous solution.