Spectroscopic and elemental evaluation of Pb(II), Cu(II), and Hg(II) binding by salvia officinalis L. leaf extract.

Authors

Huri Tasci, Melek Gul, Ebru Batı Ay, Beril Kocaman

Published in

BMC chemistry. Jul 11, 2026. Epub Jul 11, 2026.

Abstract

Heavy metal contamination remains a major environmental concern because toxic ions such as Pb(II), Cu(II), and Hg(II) persist in ecosystems and pose serious risks to the environment and human health. Plant-derived extracts rich in phenolic acids, flavonoids, and other heteroatom-containing phytochemicals offer a promising natural matrix for metal binding through hydroxyl, carbonyl, and C-O-containing functional groups. This study presents a comparative matrix-level evaluation of interactions of Pb(II), Cu(II), and Hg(II) with Salvia officinalis L. leaf extract by integrating UV-Vis spectroscopic stoichiometry, apparent binding analysis, pH- and temperature-dependent spectral responses, EDTA-assisted reversibility, FTIR functional group assignments, and ICP-OES-based elemental validation. UV-Vis data were evaluated using Job's plot analysis, while apparent binding parameters were estimated using the extended Benesi-Hildebrand and Scatchard models, based on the observed stoichiometric behaviour. Pb(II) and Hg(II) exhibited apparent M₂L-type interaction patterns, whereas Cu(II) showed a 1:1 binding mode. Among the tested ions, Hg(II) produced the strongest spectroscopic binding response, followed by Pb(II) and Cu(II). The metal-extract interactions were strongly affected by pH and temperature, with more pronounced spectral responses under mildly alkaline conditions and at temperatures above 45 °C. EDTA addition indicated that the binding process was at least partially reversible, suggesting the potential regeneration of the extract-based metal-binding system. ICP-OES analysis supported the incorporation of metals into the extract-derived complexes, whereas changes in FTIR spectra indicated the involvement of hydroxyl, carbonyl, and C-O groups in metal coordination. Overall, the findings demonstrate the metal-dependent binding behavior of S. officinalis leaf extract and provide a useful spectroscopic and elemental basis for further studies on plant-derived metal-binding systems.

PMID:
42436507
Bibliographic data and abstract were imported from PubMed on 12 Jul 2026.

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