Optimization of lead (II) removal from water and wastewater using a novel magnetic nanocomposite of aminopropyl triethoxysilane coated with carboxymethyl cellulose cross-linked with chitosan nanoparticles

Abstract

The removal of heavy metals from industrial wastewater is nowadays one of the most interesting challenges in water remediation using adsorbent nanomaterials. The present study presents a novel adsorbent (Fe3O4@CS@CMC-SiNH2) nanocomposite (NC), by functionalization of the carboxymethyl cellulose (CMC) cross-linked to magnetic chitosan nanoparticles (Fe3O4@CS NPs) with aminopropyl triethoxysilane layer (APTES), and evaluate its performance toward lead (II) removal from wastewater. The synthesized NCs were characterized using several techniques. The optimization of the adsorption process was performed using the Response Surface Methodology with the Box-Behnken Design model. The optimal conditions for lead (II) ion removal were found to be; pH of 5.1, a dose of 0.10 g/L, and a temperature of 36 ℃ using Fe3O4@CS@CMC-SiNH2 NCs which proved to have superior adsorption performance with a maximum adsorption capacity of 555.56 mgPb(II)/gNC, and fast achievement of the adsorption equilibrium (30 min). Favorable monolayer chemisorption was estimated and proved to be a coordination bond between the NH amide and lead (II) ions using FTIR, as well as up to seven adsorption–desorption cycles were effective for lead (II) ion removal from aqueous solutions. In addition, the Fe3O4@CS@CMC-SiNH2 NCs showed 98.10%, and 97.21 % removal of lead (II) ions in the absence, and the presence of other contaminants of heavy metals such as cadmium (II) and mercury (II). Moreover, the Fe3O4@CS@CMC-SiNH2 NC exhibited high efficiency in the removal of lead (II) ions from wastewater, can be easily separated from water by magnetic separation, showed satisfactory reusability for five cycles of the adsorption–desorption process of lead (II) ion removal from tap water and wastewater. Consequently, Fe3O4@CS@CMC-SiNH2 NC is a prospective adsorbent nanomaterial for lead (II) ions removal from wastewater.