We are celebrating our second article in Environmental Science: Advances (IF=6.7). 

A kinetic model for coupled swelling and Cd(II) sorption in commercial superabsorbent polymer beads – Angie E. Orduz; Graciela P. Zanini; Carlos D. Garcia; Marcelo Avena

Abstract: A simple kinetic model describing the swelling of commercial superabsorbent polymer (SAP) beads in Cd(II) solutions was developed and tested. In the absence of Cd(II), the swelling follows the typical first-order kinetic behavior expected for SAPs. However, with increasing Cd(II) concentrations, the swelling curves progressively deviate from this behavior, reaching a maximum and then evolving toward lower equilibrium swelling values. To account for this particular behavior, the model considers that the gradual binding of Cd(II) to carboxylate groups within the polymer network progressively decreases the swelling capacity of the beads. The proposed model successfully reproduced the experimental swelling curves over the range of Cd(II) concentrations studied. Measured Cd(II) sorption kinetics were also consistent with the proposed model. Importantly, a single rate constant was required to describe both the decrease in swelling capacity and the Cd(II) sorption process, supporting the proposed kinetic coupling between swelling and Cd(II) sorption and being consistent with the progressive penetration and binding of Cd(II) within the polymer network. These findings offer new insights into the coupling between swelling dynamics and metal ion sorption in superabsorbent polymers, contribute to a better understanding of the mechanisms controlling Cd(II) uptake by SAP materials, and support their potential use for metal removal and preconcentration.

We have also created an interactive dashboard to play with the data!