Spectroscopic evidence for clarifying the mechanism of toxic element removal by marble waste. (February 2022)

• Record Type: Journal Article
• Authors: Fiorito, Elio; Fantauzzi, Marzia; Brundu, Laura; Atzei, Davide; Elsener, Bernhard; Rossi, Antonella
• Is Part Of: Vacuum. Volume 196(2022)
• Publication Date: 2022-02
• Subjects: Marble waste powder -- X-ray photoelectron spectroscopy (XPS) -- Inductively coupled plasma atomic emission spectroscopy (ICP AES) -- Surface reactivity -- Lead -- Manganese; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2021.110721
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: Powdered marble waste (MW) resulting from cutting processes in the Orosei marble district is tested as sorbent for toxic elements from wastewater in compliance with the European circular economy strategy. MW consists of a calcite polymorph of CaCO3 with a Mg content of about 0.28 wt%. This article focuses on surface analysis by X-ray photoelectron spectroscopy (XPS) of MW used as sorbent, combined with solution analysis by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The goal is to distinguish between different removal mechanisms of Pb 2+ and Mn 2+ from model solutions over a wide concentration range, from 0.1 μM to 100 mM. The results showed a removal efficiency (RE) of about 100% for Pb, independent of the initial concentration, and up to about 100% for manganese, providing its initial concentration is lower than 0.1 mM. These findings help in the development of remedial processes and analytical strategies for water remediation. Highlights: Marble waste can be exploited for toxic elements removal from wastewaters. The removal efficiency depends on the removal mechanism. In the case of lead the precipitation of lead carbonate dominates. Ion-exchange is proposed to be the principal mechanism for Mn-removal. Ca-Mn at the surface limits the RE% of Mn when insufficient surface Ca is available for the ion – exchange process.