Removal of Methylene Blue from Aqueous Solution by Tunics of the Corm of the Saffron

Abstract

Removal of Methylene Blue (MB) from aqueous solutions was investigated using low-cost, natural, and eco-friendly biosorbent, Tunics of the Corm of the Saffron (TCS). The effect of various parameters including pH, contact time, adsorbent dose, initial dye concentration, and temperature on the adsorption was studied. TCS was characterized using SEM, TGA, and DTA. The adsorbent surface functional groups were identified with Fourier Transform InfraRed (FT-IR)spectroscopy. pHpzc of TCS was determined (5.8). The adsorption data of MB ontoTCS followed the Langmuir isotherm with a biosorption capacity of 137mg/g. The kinetic data were evaluated using pseudo-first-order and pseudo-second-order model equations and the data were fitted well with the pseudo-second-order kinetic model (R2>0.99). Thermodynamic parameters revealed that the adsorption process was feasible, spontaneous, and exothermic (∆H<0). The findings of the present study indicated that TCS can be successfully used for the removal of MB from an aqueous solution.