Preparation and characterization of PEGDE-EDTA-modified magnetic chitosan microsphere as an eco-friendly adsorbent for methylene blue removal

Abstract

Chitosan has been acknowledged as the emerging prominent pollutant remover with environmentally friendly properties. Herein, we have developed magnetic chitosan (MC) microsphere with functional group enrichment using polyethylene glycol diglycidyl ether (PEGDE) and ethylenediaminetetraacetic acid (EDTA) to remove aqueous methylene blue. The success of the functional group enrichment was proven by the characterization carried out in Fourier transform-infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and Scanning Electron Microscope (SEM) analyses. The adsorption capacity of methylene blue onto the prepared MC increased as much as 37.62% after the addition of EDTA. The optimum adsorption parameters recorded in this study were 30minutes contact time and pH level of 10. At such optimum conditions, the adsorption capacity and removal percentage reached 5.04±0.03 mg/g and 80.64±0.12%, respectively. Adsorption studies using various models revealed that the best fit of experimental data with that of theoretical was generated by the Freundlich model equation (R2 = 0.95283; root-mean-square-errors = 27.22). Exothermic adsorption was observed according to the thermodynamic study (∆H = -124.43 kJ/mol). In conclusion, our adsorbent prepared from green materials and methods could effectively remove the methylene blue from water medium.

Keywords

• Azo dye
• EDTA
• Freundlich
• Iron oxide
• Magnetic chitosan
• PEGDE