Application of medlar core powder to remove methylene blue from aqueous solution

Document Type : Original Article


1 Department of Chemistry, Faculty of Science, University of Guilan, Rasht, Iran

2 Department of Chemistry, Faculty of Science, University of Guilan, Rasht, Iran.



The efficiency of medlar core powder as a low-cost adsorbent for removing a cationic dye methylene blue (MB) from aqueous solution has been investigated by using batch mode and continuous systems experiments. The effects of different parameters namely amount of adsorbent, initial dye concentration, contact time, temperature and pH solution of dye solution have been studied to understand the adsorption behavior of the adsorbent under various conditions. Various techniques for characterizing the adsorbent have been applied including, zero point charge measurement (pHpzc), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The experimental isotherm data have been analyzed using Langmuir and Freundlich isotherm equation. Methylene blue adsorption fitted the Langmuir isotherm. The kinetic results of adsorption obeyed a pseudo-second order model. Thermodynamic parameters including the Gibbs free energy ΔG°, enthalpy ∆H° and entropy ∆S° have revealed that the adsorption of methylene blue on the medlar core powder is feasible, spontaneous and endothermic. The maximum removal percent 25mL of methylene blue solution is 96.4% for 100 mɡ/L of MB under conditions, pH=7 at a temperature 25 °C and 0.08 ɡ/L of adsorbent.