Copper(II) ion removal from aqueous solutions using alginate nanoparticles/ carboxymethyl cellulose/ polyethylene glycol ternary blend: Characterization, isotherm and kinetic studies

Abstract

This study addresses the critical issue of removing copper(II) ions from water using an eco-friendly approach with natural biomaterials. Alginate, a natural polysaccharide, is employed as the primary adsorption material. The study involves the conversion of alginate into nanoparticles, and a ternary blend is prepared by mixing alginate nanoparticles with carboxymethyl cellulose and polyethylene glycol (AL-NPs/CMC/PEG). The blend's morphological and structural transformations have been comprehensively investigated using techniques such as DLS, FT-IR, XRD, TGA, and SEM. Batch experiments were conducted systematically to investigate crucial parameters, such as contact time (60–300 min), initial copper concentration (62.5 ppm–1000 ppm), solution pH (2–8), and adsorbent dosage (1–5 g). The results obtained are highly encouraging, revealing an impressive 80.9 % efficiency in the removal of copper ions. The acquired experimental data were then subjected to analysis with Langmuir and Freundlich, isotherm, as well as pseudo-first and pseudo-second-order kinetics studies. The outcomes from these isotherm and kinetics models indicated a favorable fit with the Freundlich isotherm, suggesting a strong affinity between the adsorbent and the metal ions. Furthermore, the kinetic studies revealed that the adsorption process closely adheres to pseudo-second-order kinetics, underlining the efficiency and reliability of the adsorption process. From desorption studies, 0.1 M HCl was an extremely effective eluant when compared to HNO3 and EDTA. It could be reused three time with appreciate efficiency. The research underscores the potential for an environmentally sustainable solution to address the persistent environmental challenge posed by copper ion contamination.