Characterization of Cu(II) ion adsorption behavior of the polyacrylic acid-polyvinylidene fluoride blended polymer

Abstract

A blended polymer adsorbent prepared using acrylic acid and polyvinylidene fluoride was used to remove copper from aqueous solutions. The polymer was prepared using thermally induced polymerization and phase inversion. The blended polymer was characterized by X-ray diffraction analysis (XRD), environmental scanning electron microscopy (ESEM), X-ray photoelectron spectroscopy (XPS), and N <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> adsorption/desorption experiments. The sorption data was fit to linearized adsorption isotherms of the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherms models. The batch sorption kinetics was evaluated using pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetic reaction models. ΔH <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sup> is greater than 0, ΔG <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sup> is lower than 0, and ΔS <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sup> is greater than 0, which shows that the adsorption of Cu (II) by the blended polymer is a spontaneous, endothermic process. The adsorption isotherm fits better to the Freundlich isotherm model and the pseudo-second-order kinetics model gives a better fit to the batch sorption kinetics. The adsorption mechanism is assumed to be ion exchange between the cupric ion and the carboxylic acid functional group of the blended polymer.