Equilibrium, kinetics, and optimization studies of methylene blue removal from aqueous solution using corn stalk wastes

Methylene blue (MB) removal from aqueous solution has been investigated using corn stalk wastes as an available and low-cost adsorbent. The adsorbent was characterized using scanning electron microscopy, Brunauer-Emmett-Teller, and Fourier-transform infrared spectroscopy. The effects of independent variables and their interaction have been optimized using central compos-ite design (CCD) through response surface methodology. The statistical analysis of data through analysis of variance showed that the experimental data of CCD are fitted with a second-order polynomial regression. The maximum MB removal efficiency of 98% was observed at an ini-tial concentration of 10 mg dye/L, adsorbent dosage of 1.4 g/L, contact time of 50 min and pH 11. Kinetics and isotherm studies indicated that the experimental data can be well presented and described by the pseudo-second-order and Langmuir models, respectively. The produced acti-vated carbon from corn stalk wastes as a cheap and available adsorbent can be considered as an appropriate method for dye removal from aqueous environment.