Raman spectroscopy of selected lead minerals of environmental significance

Abstract

The Raman spectra of the minerals cerrusite (PbCO3), hydrocerrusite (Pb2(OH)2CO3), phosgenite (Pb2CO3Cl2) and laurionite (Pb(OH)Cl) have been used to qualitatively determine their presence. Laurionite and hydrocerrusite have characteristic hydroxyl stretching bands at 3506 and 3576 cm-1. Laurionite is also characterised by broad low intensity bands centred at 730 and 595 cm-1 attributed to hydroxyl deformation vibrations. The minerals cerrusite, hydrocerrusite and phosgenite have characteristic CO (v1) symmetric stretching bands observed at 1061, 1054 and 1053 cm-1. Phosgenite displays complexity in the CO (v3) antisymmetric stretching region with bands observed at 1384, 1327 and 1304 cm-1. Cerrusite shows bands at 1477, 1424, 1376 and 1360 cm-1. The hydrocerrusite Raman spectrum has bands at slightly different positions from cerrusite with bands at 1479, 1420, 1378 and 1365 cm-1. The complexity of the ￮3 region is also reflected in the ￮2 and ￮4 regions with the observation of multiple bands. Laurionite is characterized by two intense bands at 328 and 272 cm-1 attributed to PbO and PbCl stretching bands. Importantly all four minerals are characterized by their Raman spectra enabling the mineral identification in leachates and contaminates of environmental significance.