title: Experimental and robust modeling approach for lead(II) uptake by alginate gel beads: influence of the ionic strength and medium composition.
abstract: Systematic kinetic and equilibrium studies on the lead ions removal ability by Ca-alginate gel beads have been performed by varying several internal parameters, namely, number of gel beads, nature and composition of the ionic medium and pH, which allowed us to model a wastewater in order to closely reproduce the composition of a real sample. Moreover, the effects brought about the different ionic species present in the reacting medium have been evaluated. Differential Pulse Anodic Stripping Voltammetry (DP-ASV), has been systematically used to perform kinetic and equilibrium measurements over continuous time in a wide range of concentration. Kinetic and equilibrium data have been quantitatively analyzed by means of robust approach both for the non-linear regression and the subsequent residuals analysis in order to significantly improve the results in terms of precision and accuracy. Alginate gel beads have been characterized by SEM and an investigation on their swelling behavior has also been made. Removal efficiency of the calcium-alginate gel beads has been calculated and results obtained have showed a relevant dependence on ionic strength, composition of ionic media, pH of solution and number of gel beads. The number of gel beads takes part as key crucial components, i.e., the higher the number of beads the greater the amount of Pb(II) species removed from the sample, the lower the time needed to reach the maximum removal efficiency of 90%.
authors.affiliation: Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, Viale delle Scienze, I-90128 Palermo, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Cataldo
authors.affiliation: Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, Viale delle Scienze, I-90128 Palermo, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Gianguzza
authors.affiliation: Dipartimento di Scienze della Terra e del Mare, Università degli Studi di Palermo, Via Archirafi 22, I-90123 Palermo, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Merli
authors.affiliation: Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, Viale delle Scienze, I-90128 Palermo, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Muratore
authors.affiliation: Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, Viale delle Scienze, I-90128 Palermo, Italy. Electronic address: daniela.piazzese@unipa.it.
authors.forename: Daniela
authors.initials: D
authors.lastname: Piazzese
authors.affiliation: Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, Viale delle Scienze, I-90128 Palermo, Italy.
authors.forename: Maria Liria Turco
authors.initials: ML
authors.lastname: Liveri
keywords: Adsorption isotherms; Adsorption kinetics; Alginate gel beads; Differential Pulse Anodic Stripping Voltammetry; Heavy metal; Ionic strength; Lead; Metal adsorption; Robust statistics; Wastewater treatment