Adsorptive Removal of Manganese Ions From Polluted Aqueous Media by Glauconite Clay- Functionalized Chitosan Nanocomposites: Adsorption, Kinetic, Isotherm, and Thermodynamic Investigations

Abstract

The presence of Mn(II) in water exceeding the permitted concentration declared by the World Health Organization (WHO) influences individuals, animals, and the ecosystem negatively. Therefore, there is a necessity for an efficient material to eliminate this potentially toxic element from wastewater. We herein focused on an adsorptive removal of Mn(II) ions from polluted aqueous media using natural Egyptian glauconite clay (G) and its nanocomposites with a modified chitosan (CS). The applied chitosan was modified with glutaraldehyde (GL), ethylenediaminetetraacetic acid (EDTA), sodium dodecyl sulfate (SDS) and cetyltrimethyl ammonium bromide (CTAB). The utilized nanocomposites were referred to as GL-CS/G, EDTA-GL-CS/G, SDS-CS/G, and CTAB-CS/G, respectively. The points of zero charge values of the as-prepared materials were estimated. The adsorption properties of the G clay and its nanocomposites toward the removal of Mn(II) ions from polluted aqueous media as well as the adsorption mechanism were explored using a batch technique. The glauconite (G) and its nanocomposites: GL-CS/G, CTAB-CS/G, EDTA-GL-CS/G, and SDS-CS/G, exhibited maximum adsorption capacity values of 3.750, 24.11, 26.25, 27.15, and 27.74mgg-1, respectively. The adsorption results fitted well the Langmuir isotherm and pseudo-second-order kinetic models. The determined thermodynamic parameters revealed that the Mn(II) ion adsorption process was endothermic, spontaneous, and physisorption controlled. Furthermore, the obtained adsorption results are encouraging and revealing a great potentiality for using the modified adsorbents as accessible adsorbents for Mn(II) ions removal from polluted aqueous solutions, depending on their reusability, high stability and good adsorption capacities.