Lead (II) complexation with 3-mercaptopropyl-groups in the surface layer of silica nanoparticles: Sorption, kinetics and EXAFS/XANES study

Košak, Aljoša; Padeznik Gomilsek, Jana; Lobnik, Aleksandra; Bauman, Maja

doi:10.1016/j.molliq.2016.11.115

Journal Article

PUBDB-2017-00635

Lead (II) complexation with 3-mercaptopropyl-groups in the surface layer of silica nanoparticles: Sorption, kinetics and EXAFS/XANES study

Košak, A. (Corresponding author) ; Bauman, M. ; Padeznik Gomilsek, J. ; Lobnik, A.

2017
Elsevier New York, NY [u.a.]

Journal of molecular liquids 229, 371 - 379 (2017) [10.1016/j.molliq.2016.11.115]

This record in other databases:

Please use a persistent id in citations: doi:10.1016/j.molliq.2016.11.115

Abstract: In this work, mono-dispersed mercapto-functionalized silica (SiO$_2$@SH) particles with a narrowparticle size distributionof around (420±10) nmwere prepared by the sol–gel method for the adsorption of aqueous dissolvedlead (Pb$^{2+}$) ions from modeled wastewater. Transmission Electron Microscopy (TEM), in combination with Energy-Dispersive X-ray Spectroscopy (EDXS), was used to obtain information about the particle size and morphologyof the prepared samples. Dispersive X-ray Spectroscopy (EDXS) indicated strong signals of Si and S, implyingsuccessful completion after the mercapto (-SH) functionalization of the silica (SiO$_{2}$) surfaces. Fourier TransformInfrared Spectroscopy (FTIR) was used to determine the occurrences of Si–O–Si and -SH vibrations within thesamples and, thus, come to a conclusion about the formations of the mercapto-functionalized samples. Analysiswas performed of Pb$^{2+}$ adsorption with mercapto-groups (-SH) on the surface of the SiO$_{2}$@SH particles. The resultsfor Pb$^{2+}$ adsorptions fromthemodeledwastewater showed affinity of around 55% and the obtained value ofthe maximum amount of adsorbed Pb$^{2+}$ ions with the SiO$_{2}$@SH samples was 10.82 mg/g under the conditionsused during this study. The results of the adsorptions were fitted with the Langmuir and Freundlich isothermmodels and the pseudo-first and pseudo-second kinetic models were evaluated. We employed Pb-L3 edge Xrayabsorption spectroscopy techniques XANES (X-ray Absorption Near Edge Structure) and EXAFS (ExtendedX-ray Absorption Fine Structure) for probing the local environments of Pb within the tentative Pb-S complexafter adsorptions of Pb$^{2+}$ by the mercapto groups. The EXAFS/XANES analysis indicated complete Pb$^{2+}$ complexationwith two -SH groups of the prepared SiO$_{2}$@SH samples.

Classification: