Efficient and selective removal of cesium from aqueous solution using copper hexacyanoferrate nanoparticles supported on poly(methacrylic acid-co-itaconic acid)

A new poly(methacrylic acid-co-itaconic acid) [poly(MAA-co-IA)] hydrogel encapsulated copper hexacyanoferrate (CuHCF) nanoparticles was synthesized. The prepared samples were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, X-ray diffraction, and thermogravimetric analysis–differential scanning calorimetry. The prepared composite CuHCF/poly(MAA-co-IA) was examined for adsorption of Cs+ by batch technique. The effect of various factors like solution pH, Cs+ initial concentration, agitation time, the temperature of the solution, and competition ions was investigated. CuHCF/poly(MAA-co-IA) composite exhibited high adsorption capacity (1.48 mmol g−1) of Cs+ occur at a pH equal to 9, initial concentration of 8 mmol L−1 Cs+ at room temperature (25°C). The adsorption of Cs+ was kinetically rapid, and the equilibrium was reached within 40 min. Between Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherms models, the data were well fitted with the Langmuir model, suggesting that the uptake of Cs+ was monolayer and homogeneous. The adsorption kinetics parameters were fitted well to the pseudo-second- order model, and the Elovich equation indicated that chemisorption is the predominant adsorption mechanism. The intraparticle diffusion model shows that more than one controlling step may influence Cs+ loading. Thermodynamic parameters were calculated in the temperature range of 25°C–55°C and revealed that Cs+ sorption was endothermic, spontaneous, and more favourable at the higher temperature. The selectivity of the composite for Cs+ in the existence of Na+ and K+, Li+, Ca++ Mg++ ions was exceptional. Up to 98% desorption of Cs+ was completed with 2M KCl.