Monitoring trace amounts of lead and arsenic adsorption by X-ray absorption fine structure combined with fluorescence spectrometry

X-ray absorption. ne structure combined with fluorescence spectrometry was used for the speciation of trace amounts of lead and arsenic adsorbed. The Pb2+ species were effectively adsorbed on a layered material Mg6Fe2(OH)(16)(CO3)center dot 3H(2)O from 100 ppb - 1.0ppm test aqueous solutions. A eutectic mixture of PbCO3 and Pb(OH)(2) coagulated in the case of a 1.0ppm Pb2+ solution, and in contrast, the major species was ion-exchanged Pb2+ in the case of the adsorption from the 100 ppb aqueous solution. The arsenic species were effectively adsorbed on intercalated Fe-montmorillonite from 50 ppb - 16ppm test aqueous solutions. In this concentration range, As3+ in the solution was oxidized upon adsorption. The adsorbed structure was suggested to be [As-V(OH)(2)(mu-OFe)(2)] both in the cases of adsorption of As3+ and As5+.