ToF-SIMS depth profiling analysis of the uptake of Ba2+ and Co2+ ions by natural kaolinite clay.
The sorption behavior of Ba(2+) and Co(2+) ions on a natural clay sample rich in kaolinite was studied using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Depth profiling at 10-A steps was performed up to a 70-A matrix depth of the clay prior to and following sorption. The results showed that Co(2+) is sorbed in slightly larger quantities than Ba(2+), with significant numbers of ions fixed on the outermost surface of the clay. Depletion of the ions K(+), Mg(2+), and Ca(2+) from the clay lattice was observed to accompany enrichment with Co(2+) and Ba(2+) ions. The data obtained using X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM) indicated insignificant structural and morphological changes in the lattice of the clay upon sorption of both Ba(2+) and Co(2+) ions. Analysis using energy dispersive X-ray spectroscopy (EDS) showed that the average atomic percentage (+/-S.D.) of Ba and Co on kaolinite surface were 0.49 +/- 0.11 and 0.61 +/- 0.19 , respectively, indicating a limited uptake capacity of natural kaolinite for both ions.
Shahwan
T
T
Department of Chemistry, Izmir Institute of Technology, 35430 Urla, Izmir, Turkey. talalshahwan@iyte.edu.tr
Erten
H N
HN
Black
L
L
Allen
G C
GC
D000538:Aluminum Silicates / Q000737:chemistry*; D017609:Barium Compounds / Q000737:chemistry* / Q000493:pharmacokinetics; D002712:Chlorides / Q000737:chemistry* / Q000493:pharmacokinetics; D000077215:Clay; D003035:Cobalt / Q000737:chemistry* / Q000493:pharmacokinetics; D007616:Kaolin / Q000737:chemistry*; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods*; D013499:Surface Properties
D000538:Aluminum Silicates; D017609:Barium Compounds; D002712:Chlorides; C024986:barium chloride; D007616:Kaolin; D003035:Cobalt; C025913:cobaltous nitrate; D000077215:Clay