Methylene blue adsorption via maize silk powder: Kinetic, equilibrium, thermodynamic studies and residual error analysis

The potential of maize silk powder (MS) as a natural, widely available and low-cost agricultural waste in order to adsorb methylene blue (MB) from an aqueous solution has been studied. The adsorbent surface morphology has been studied using SEM and FTIR. The effect of operating conditions such as contact time, solution pH and initial MB concentration and the important frequently missed parameters such as salt effect (using NaCl and Na2HFO4), temperature effect (for Delta H degrees, Delta G degrees and Delta S degrees), solution pH and detailed error analysis have been determined. A rate study indicated the process followed pseudo-second order kinetics. The adsorption equilibrium was modeled for best fit using ten commonly-used isotherm models and the Jovanovic equation gave the best correlation of the experimental data. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.