Adsorption of Methylene Blue from Aqueous Solution Using Spent Coffee/Chitosan Composite

Abstract

This study aimed to investigate the adsorption of Methylene Blue from aqueous solution using different concentrations of spent coffee/chitosan composite. Adsorption parameters such as pH, contact time, initial Methylene Blue concentration, and temperature were investigated. Characterization of the adsorbent was performed with Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX). The FTIR findings showed that the hydrogen bond is a predominant contributor to the adsorption of MB by absorbed. The equilibrium data were analyzed with Langmuir and Freundlich isotherms, and kinetic models were also applied. The maximum adsorption capacity was noted to increase with an increase in temperature, from 298 to 308 K, but then decreased from 308 to 318 K. The highest maximum adsorption capacities among all coffee/chitosan beds were 75.76 mg g–1 at 298 K, 108.7 mg g–1 at 308 K, and 33.67 mg g–1 at 318 K. These results show that a waste coffee/chitosan composite is a cost-effective, eco-friendly material for removing methylene blue from aqueous solution.