Strontium sorption to amorphous silica and goethite was measured as a function of pH and dissolved strontium and carbonate concentrations at 25 degrees C. Strontium sorption gradually increases from 0 to 100% from pH 6 to 10 for both phases and requires multiple outer-sphere surface complexes to fit the data. All data are modeled using the triple layer model and the site-occupancy standard stat...

As models of the composition and heterogeneous chemical reactions of the troposphere undergo refinement, novel application of state-of-the-art analytical techniques will be necessary to propound realistic characterizations of mineral dust chemistry. In this study, strontium carbonate particles treated with gaseous nitric acid and nitrogen dioxide were examined with X-ray absorption fine structu...

The interaction of reagent grade strontium sulphate and celestine concentrate with aqueous solutions of oxalic acid, sodium oxalate and ammonium oxalate for the production of strontium carbonate were investigated for different oxalate compound:SrSO4 mole ratios and reaction times using x-ray diffraction analysis and dissolution tests. Under the same experimental conditions, it was found that aq...

Biomineralisation offers the potential for in-situ sequestration and subsequent reduction in the bioavailability of heavy metals and radionuclides in the subsurface environment. Calcium carbonate minerals are known to sorb and form solid solutions with a range of target elements, and are readily produced by the actions of common microorganisms on simple chemical precursors. The ability of a com...

The United States Environmental Protection Agency Contaminant Candidate List 3 lists strontium as a contaminant for potential regulatory consideration in drinking water. Very limited data is available on strontium removal from drinking water and as a result, there is an immediate need for treatment information. The objective of this work is to evaluate the effectiveness of coagulation/filtratio...

Sorption of dissolved strontium on kaolinite, amorphous silica, and goethite was studied as a function of pH, aqueous strontium concentration, the presence or absence of atmospheric CO(2) or dissolved phosphate, and aging over a 57-day period. Selected sorption samples ([Sr(aq)](i) approximately 0.5-1x10(-3) m) were examined with synchrotron X-ray absorption spectroscopy (XAS) at low (13-23 K) ...

We introduce giant liposomes to investigate phase transformations in picoliter volumes. Precipitation of calcium carbonate in the confinement of DPPC liposomes leads to dramatic stabilization of amorphous calcium carbonate (ACC). In contrast, amorphous strontium carbonate (ASC) is a transient species, and BaCO3 precipitation leads directly to the formation of crystalline witherite.

[1] It has been suggested that the incorporation of strontium into biogenic aragonite may be influenced by the degree of carbonate saturation in aquatic environments. We measured the Sr/Ca ratios of river water and the aragonitic shells of freshwater bivalves (Margaritifera margaritifera) from two sites with different carbonate saturation states in the River Ehen, Cumbria, UK. Shell Sr/Ca and r...

Solid titration was used to explore the solubility isotherms of partially (Srx-HAp, x=1, 5, 10, 40, 60 mol.%) and fully substituted strontium hydroxyapatite (Sr-HAp). Solubility increased with increasing strontium content. No phase other than strontium-substituted HAp, corresponding to the original titrant, was detected in the solid present at equilibrium; in particular, dicalcium hydrogen phos...