Adsorption of lead ions (Pb2+) from wastewater using effective nanocomposite GO/CMC/FeNPs: Kinetic, isotherm, and desorption studies

Abstract

In this paper, we propose a new, effective, and easy-to-implement technology for hydrothermal synthesis of an adsorption material based on carboxymethylcellulose (CMC) and graphene oxide (GO) decorated with iron nanoparticles (FeNPs) for water purification from heavy metals. The purpose was to study the effect of the iron content in the materials on their physicochemical and adsorption properties. The synthesized materials were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. Complex adsorption studies were performed using the example of lead ion removal from contaminated aqueous media. The influence of pH and contact time on the process efficiency was studied. The mechanism of adsorption was analyzed using pseudo first-order and pseudo second-order, intraparticle diffusion, and Elovich kinetics models. The results showed an optimal pH of 6 and contact time of 30 min. The process is best described by a pseudo second-order model. The material with a mass content of iron nanoparticles of 18% (CMC/GO + Fe 18 wt%) showed the largest adsorption capacity for Pb ions (1850 mg g−1). Adsorption isotherms of lead ions from aqueous media by the synthesized composite materials were studied using Dubinin–Radushkevich and BET models. The adsorption process is based on the chemical interaction of extracted ions with the surface of an adsorbent. Desorption studies showed the possibility of using the GO/CMC/FeNPs in real processes for purification of aqueous media. The obtained maximum value of adsorption capacity for the CMC/GO + Fe 18 wt% material was 1850 mg g−1, which is one of the highest in the literature for composite materials based on GO and vegetable raw material processing products.