Functionalization of Na2Ca2Si3O9/Ca8Si5O18 Nanostructures with Chitosan and Terephthalaldehyde Crosslinked Chitosan for Effective Elimination of Pb(II) Ions from Aqueous Media

Abstract

Lead poses significant health risks to humans, including neurological and developmental impairments, particularly in children. Additionally, lead pollution in the environment can contaminate soil, water, and air, endangering wildlife and ecosystems. Therefore, this study reports the straightforward fabrication of Na2Ca2Si3O9/Ca8Si5O18 nanostructures (NaCaSilicate) utilizing a sol-gel technique. Additionally, the produced nanostructures underwent further modification with chitosan (CS@NaCaSilicate) and chitosan crosslinked with terephthalaldehyde (CCS@NaCaSilicate), resulting in new nanocomposite materials. These samples were developed to efficiently extract Pb(II) ions from aqueous media through complexation and ion exchange mechanisms. Furthermore, the maximum adsorption capacity for Pb(II) ions by the NaCaSilicate, CS@NaCaSilicate, and CCS@NaCaSilicate samples is 185.53, 245.70, and 359.71 mg/g, respectively. The uptake of Pb(II) ions was characterized as spontaneous, exothermic, and chemical, with the best description provided by the Langmuir equilibrium isotherm and the pseudo-second-order kinetic model. Furthermore, a 9 M hydrochloric acid solution effectively eliminated Pb(II) ions from the synthesized samples, attaining a desorption efficacy surpassing 99%. Additionally, the fabricated samples exhibited efficient reusability across five successive cycles of adsorption and desorption for capturing Pb(II) ions.