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A polyvinylidene fluoride-based membrane bearing the diethylenetriaminepentaacetic acid chelating group was employed to recover Cu(II) from the Cu(II)-ethylenediaminetetraacetic acid complex aqueous solution. Effects of Ca(II), Fe(II), and Fe(III) on Cu(II) uptake were investigated by static batch adsorption tests and dynamic adsorption filtration. Isotherms, kinetics, and breakthrough curves of Cu(II) uptakes in the presence of the three cations at concentrations of 1 mmol L−1were elucidated. The three cations showed a positive effect on the Cu(II) uptake; the stimulative roles were in the order of Fe(III) > Fe(II) > Ca(II). They did not alter the adsorption behavior of the membrane; adsorption isotherms and kinetics could be described by Langmuir and Lagergren second-order models, and Cu(II) adsorption was a spontaneous and exothermic process. The presence of Ca(II), Fe(II), and Fe(III) increased the sorption capacity of the membrane stack by 1.3, 1.9, and 3 times. Breakthrough time and the exhaustion time of membrane stacks were also extended. [ABSTRACT FROM AUTHOR] more...

A 3-aminopropyltrimethoxysilane-diethylenetriaminepentaacetic acid/polyvinylidene fluoride (APTMS-DTPA/PVDF) chelating membrane was employed to remove Cu(II) from an aqueous solution. The influence of Co(II), Ni(II), tartrate, and ethylenediaminetetraacetic acid (EDTA) on the sorption of Cu(II) was investigated by a series of dynamic adsorption tests and by density-functional theory (DFT) calculations. Isotherms and kinetics of the membrane sorption process towards Cu(II) in the presence of the two other cations and the two complexing reagents were elucidated. The DFT descriptors, such as chemical potential, electronegativity, electrophilicity index and charge transfer, and the complexation energy, were calculated. Cu(II) showed higher electrophilicity than Co(II) and Ni(II), and the sorption of Cu(II) by the chelating membrane in the absence of tartrate and EDTA was stronger than in their presence. Ni(II) tended to form a more stable complex with the complexing ligand than Co(II). EDTA interfered more strongly with Cu(II) uptake than tartrate. Adsorption isotherms and adsorption kinetics were fitted to the Langmuir and the Lagergren second-order models. The [Cu(APTMS-DTPA)]2−complex exhibited higher charge transfer and a more negative complexation energy than [Co(APTMS-DTPA)]2−, [Ni(APTMS-DTPA)]2−, Cu-tartrate, and Cu-EDTA. [ABSTRACT FROM AUTHOR] more...