Polymeric nanocomposites of iron–oxide nanoparticles (Ionps) synthesized using terminalia chebula leaf extract for enhanced adsorption of arsenic(v) from water

Abstract

This study demonstrates the ecofriendly synthesis of iron–oxide nanoparticles (IONPs) and their stabilization with polymers, i.e., chitosan (C) and polyvinyl alcohol (PVA)–alginate (PA), along with a further investigation for the removal of arsenic(As(V)) from water. IONPs with an average diameter of less than 100 nm were prepared via a green synthesis process using an aqueous leaf extract of Terminalia chebula. Batch experiments were conducted to compare the removal efficiency of As(V) by these adsorbents. Factors such as pH and adsorbent dosages significantly affected the removal of arsenate As(V) by IONPs and polymer-supported reactive IONPs. Several adsorption kinetic models, such as pseudo first-order, and pseudo second-order Langmuir and Freundlich isotherms, were used to describe the adsorption of As(V). The removal of As(V) by IONPs follows the Langmuir adsorption isotherm. The highest monolayer saturation adsorption capacity as obtained from the Langmuir adsorption isotherm for IONPs was 28.57 mg/g. As(V) adsorption by polymer-supported IONPs best fit the Freundlich model, and maximum adsorption capacities of 34.4 mg/g and 40.3 mg/g were achieved for chitosan-and PVA–alginate-supported IONPs, respectively. However, among these absorbents, PVA–alginate-supported IONPs were found to be more effective than the other adsorbents in terms of adsorption, stability, and reusability.