Roncal-Herrero,T. and Oelkers,E.H.(2011): Does variscite control phosphate availability in acidic natural waters? An experimental study of variscite dissolution rates. Geochimica et Cosmochimica Acta, 75, 416-426.

『バリッシャー石(Al(PO4)・2H2O)は酸性天然水中でリン酸塩の可給性をコントロールするか? バリッシャー石溶解の実験的研究』


Abstract
 The dissolution rates of natural, well crystallized variscite (AlPO4・2H2O) were determined from the evolution of aqueous Al and P concentrations in closed and open-system mixed-flow reactors at 25℃ and pH from 1.5 to 9.0. Measured dissolution rates decrease with increasing pH, from 6×10-16 mol/cm2/s at pH 1.5 to 5×10-17 mol/cm2/s at pH 5.89, and then increase with increasing pH to 4×10-16 mol/cm2/s at pH 9.0. Geochemical modeling calculations, performed using measured dissolution rates, indicate that it would take no more than a few weeks or months to equilibrate a mildly acidic, Al and P-free solution with variscite. Hence, variscite can buffer aqueous phosphate concentrations in mildly acidic near surface environments. This conclusion is confirmed by consideration of the compositions of natural waters.』

1. Introduction
2. Theoretical background
3. Materials and methods
4. Results
 4.1. Closed-system experiments
 4.2. Open-system experiments
5. Discussion
 5.1. Variscite dissolution rates as a function of pH
 5.2. Can variscite control the phosphate concentration of natural waters?
6. Conclusions
Acknowledgments
Appendix A. Supplementary data
References


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