Influence of AlN, TiN and SiC reduction on the structural environment of lead in wastecathode-ray tubes glass: an x-ray absorption spectroscopy study

Abstract

This paper reports an x-ray absorption spectroscopy (XAS) analysis of the local structurearound lead contained in foam glasses prepared with waste funnel cathode-ray tube glasses(CRT) and three reducing agents AlN, TiN and SiC. The XAS data were collected at the Pb–LIII edge to measure the influence of the reducing agent concentration on the unreduced leadcontent present in the glass. XANES spectra have been demonstrated to be a linearcombination of both pure metallic lead and funnel glass spectra, with a significantmodification of the funnel spectra for the highest contents of reducing agent. We haveshown that the average coordination number of lead decreases in the case of TiNand SiC but remains constant in the case of AlN. The coordination number wasfound to be more affected for TiN than for SiC. Nevertheless, Pb–O bond lengthswere determined to be constant close to 2.23 Å whatever the reducing agent and itscontent.