Calcium carbonate as sorbent for lead removal from wastewaters.

Autor: Fiorito E; Department of Chemical and Geological Sciences, Università di Cagliari, Campus of Monserrato (CA), I09042, Monserrato, Italy., Porcedda GE; Department of Chemical and Geological Sciences, Università di Cagliari, Campus of Monserrato (CA), I09042, Monserrato, Italy., Brundu L; Laboratorio Chimico Nuorese, Via Mughina 121, 08100, Nuoro, Italy., Passiu C; Department of Materials, ETH Zürich, CH-8093, Zürich, Switzerland., Atzei D; Department of Chemical and Geological Sciences, Università di Cagliari, Campus of Monserrato (CA), I09042, Monserrato, Italy., Ennas G; Department of Chemical and Geological Sciences, Università di Cagliari, Campus of Monserrato (CA), I09042, Monserrato, Italy., Elsener B; Department of Chemical and Geological Sciences, Università di Cagliari, Campus of Monserrato (CA), I09042, Monserrato, Italy., Fantauzzi M; Department of Chemical and Geological Sciences, Università di Cagliari, Campus of Monserrato (CA), I09042, Monserrato, Italy. Electronic address: fantauzzi@unica.it., Rossi A; Department of Chemical and Geological Sciences, Università di Cagliari, Campus of Monserrato (CA), I09042, Monserrato, Italy. Electronic address: rossi@unica.it.
Jazyk: angličtina
Zdroj: Chemosphere [Chemosphere] 2022 Jun; Vol. 296, pp. 133897. Date of Electronic Publication: 2022 Feb 23.
DOI: 10.1016/j.chemosphere.2022.133897
Abstrakt: Low-cost and largely available industrial by-products such as calcite (CaCO 3 ) have been considered as sorbents to remediate wastewaters from toxic elements, such as lead, in compliance with the European circular economy strategy. To date few articles are reporting results on lead sorption at the calcite-water solution interface by X-ray photoelectron spectroscopy (XPS) and this investigation aims to clarifying the mechanism of the interaction of Pb 2+ model solutions over a wide concentration range, from 0.1 μM to 80 mM, with commercial calcite. X-ray powder diffraction (XRPD), scanning electron microscopy (SEM, EDX) and XPS analysis indicate that when CaCO 3 particles are soaked in Pb 2+ 0.1 mM and 1 mM solutions, hexagonal platelets of hydrocerussite [(PbCO 3 ) 2  Pb(OH) 2 ] precipitate on its surface. When the concentration of Pb 2+ is equal or higher than 40 mM, prismatic acicula of cerussite [PbCO 3 ] precipitate. Solution analysis by atomic emission spectroscopy (ICP-AES) and ICP-mass spectrometry (ICP-MS) indicate that Pb 2+ removal efficiency is nearly 100%; when the initial Pb 2+ concentration was equal to 0.1 μM it was below the limit of detection (LOD) and the efficiency could not be determined. The sorption capacity (q e ) increases linearly with increasing initial Pb 2+ concentration up to a value of 1680 (20) mg/g when the initial Pb 2+ concentration is 80 mM. These findings suggest that heterogeneous nucleation and surface co-precipitation occur and calcite can be well considered a very promising sorbent for Pb 2+ removal from wastewaters within a wide initial concentration range.
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Databáze: MEDLINE
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