The Functional Dependence of Leaching on The Surface Area-To-Solution Volume Ratio

1982 ◽  
Vol 15 ◽  
Author(s):  
Albert J. Machiels ◽  
Claudio Pescatore
Keyword(s):  
Surface Area ◽  
Functional Dependence ◽  
Mathematical Formulation ◽  
Volume Ratio ◽  
Computer Code ◽  
Point Of View ◽  
Theoretical Point ◽  
Leaching Experiments ◽  
Glass Leaching ◽  
Solution Volume

ABSTRACTThe effects of the surface area-to-solution volume ratio on waste glass leach rates are investigated from a theoretical point of view. Simple leach models are discussed first. Correlation variables to interpret the results of similar leaching experiments performed at different values of the surface area-to-solution volume ratio are obtained for static leach testing. For dynamic leaching conditions, the source term required for risk assessment is derived and its dependence on the leachant flow rate and leach specimen surface area is discussed. The findings are upheld by a more complex leach model, the mathematical formulation of which has been implemented in a computer code named LIX. When tested against actual PNL 76–68 glass leaching data, LIX shows excellent capabilities in reproducing the experimental evidence, in particular the effects of the surface area-to-solution volume ratio.

Glass Surface area to Solution Volume Ratio and its Implications to Accelerated Leach Testing

1982 ◽  
Vol 15 ◽  
Author(s):  
Larry R. Pederson ◽  
Charles Q. Buckwalter ◽  
Gary L. Mcvay ◽  
B. Lynn Riddle
Keyword(s):  
Solid State ◽  
Surface Area ◽  
Glass Surface ◽  
Volume Ratio ◽  
Leaching Tests ◽  
Soluble Glass ◽  
State Diffusion ◽  
Dissolved Silicon ◽  
Glass Leaching ◽  
Solution Volume

ABSTRACTLeaching tests of PNL 76–68 glass in deionized water have been performed using the standard MCC-l static leaching procedure but with varied glass surface area to solution volume ratios (SA/V). It was found that leaching could be strongly influenced by the SA/V ratio, due largely to an effect of silicon solubility limitations. The conclusion that solubility and not solid state diffusion is most important in regulating leaching rates is supported by (1) the similarities in depth profiles of all soluble glass components with none depleted to depths greater than that of silicon despite vastly different solid state diffusivities, and (2) the lack of dependence of leaching rates on reaction layer thicknesses. To more directly examine the influence of dissolved silicon on glass leaching rates, leaching tests were performed in silicic acid solutions and in two actual groundwaters. As expected, leaching rates of all soluble glass components were reduced by amounts roughly proportional to the silicon saturation fraction. Since solubility modifies leaching rates in all but very dilute solutions, short-term tests at high SA/V values can be used to predict solution concentrations for long-term tests at low SA/V values, although reaction layers formed are not of the same thickness. Glass leaching data for a range of leaching times and SA/V values can be represented by a single curve when plotted versus the product of SA/V and time. However, the use of SA/V variations may have limited usefulness in accelerated leach testing for multicomponent systems. Events such as silica colloid and certain alteration phase formations modify the above relationship.

The Effects of Surface Area to Solution Volume on Waste Glass Leaching

1983 ◽  
Vol 62 (2) ◽  
pp. 151-158 ◽  
Author(s):  
L. R. Pederson ◽  
C. Q. Buckwalter ◽  
G. L. McVay
Keyword(s):  
Surface Area ◽  
Waste Glass ◽  
Glass Leaching ◽  
Solution Volume

Uranium Sorption on α-Alumina: Effects of pH and Surface-Area/Solution-Volume Ratio

1994 ◽  
Vol 66-67 (s1) ◽  
Author(s):  
James D. Prikryl ◽  
Roberto T. Pabalan ◽  
David R. Turner ◽  
Bret W. Leslie
Keyword(s):  
Surface Area ◽  
Volume Ratio ◽  
Effects Of Ph ◽  
Solution Volume

Effects of Surface Area-to-Solution Volume Ratio on Chemical Durability of Nuclear Waste Glasses

1989 ◽  
Vol 176 ◽  
Author(s):  
X. Feng ◽  
I. L. Pegg ◽  
Y. Guo ◽  
AA. Barkatt ◽  
P. B. Macedo
Keyword(s):  
Surface Area ◽  
Nuclear Waste ◽  
Volume Ratio ◽  
Fixed Time ◽  
Waste Glass ◽  
Corrosion Mechanism ◽  
General Tendency ◽  
Savannah River ◽  
Report Data ◽  
Solution Volume

ABSTRACTWe report data on the relationship between nuclear waste glass durability, as measured by leachate concentrations and leach rates, and the ratio of glass surface area to solution volume, S/V. The study includes West Valley non-radioactive production glasses (SF6 and SF10), West Valley glasses containing U and Th designed at CUA (WVCM47, WVCM50, and WVCM59), Savannah River SRLTDS-131 glass, and Hanford waste glass HW-39 (for which existing literature data is used). While some of these glasses show departures of leachate concentrations from simple (S/V)t scaling others conform well. The departures are, in all cases, most evident at high values of S/V. It is therefore important, therefore to understand how glass composition determines which corrosion mechanism is dominant in order to assess the region of validity of extrapolations based on (S/V)t scaling. While leach rates show a general tendency to decrease with S/V and time, exceptions are evident for the less durable glasses which show minima and maxima in the S/V-dependence at fixed time.

scholarly journals Cell Surface Area to Volume Relationship During Apoptosis and Apoptotic Body Formation.

2021 ◽  
Vol 55 (S1) ◽  
pp. 161-170
Author(s):  
Francisco J. López-Hernández ◽  
Keyword(s):  
Surface Area ◽  
Membrane Surface ◽  
Volume Ratio ◽  
Total Surface Area ◽  
Point Of View ◽  
Apoptotic Bodies ◽  
Cell Content ◽  
Geometric Point ◽  
Endosomal Membranes ◽  
Cell Corpse

Apoptosis is a programmed form of cell death culminating in packing cell content and corpse dismantling into membrane sealed vesicles called apoptotic bodies (ABs). Apoptotic bodies are engulfed and disposed by neighboring and immune system cells without eliciting a noxious inflammatory response, thus preventing sterile tissue damage. AB formation requires a total surface area larger than the apparent, initial cell's surface area. Apoptotic volume decrease (AVD) is a two-stage process leading to an isotonic, osmotic reduction in cell water content driven by net K+ and Cl- extrusion. In this article, the role of AVD is presented from a geometric point of view through the process of AB formation. AVD decisively contributes to (i) endowing the cell with the appropriate electrolytic environment for apoptotic execution; (ii) increasing the membrane surface area-to-volume ratio, along with the mobilization of membrane reservoirs (cell rounding, membrane folds and endosomal membranes), so that the cell corpse can be dismantled into ABs; and (iii) reducing plasmalemmal stretch, tension and stiffness, thus facilitating membrane bulging, blebbing and vesicle expansion ultimately leading to separation and release.

Monte Carlo Modelling of Glass Dissolution: Comparison with Experiments

2000 ◽  
Vol 663 ◽  
Author(s):  
M. Lobanova ◽  
L. Maurer ◽  
P. Barboux ◽  
F. Devreux ◽  
Y. Minet
Keyword(s):  
Surface Layer ◽  
Volume Ratio ◽  
Protective Role ◽  
Glass Dissolution ◽  
Altered Surface ◽  
Alkali Oxides ◽  
Soluble Species ◽  
Glass Leaching ◽  
Solution Volume

ABSTRACTOne presents the results of numerical simulations of glass leaching. The glass is modelled as a random mixture of partly and totally soluble species, which represent silica, and boron or alkali oxides, respectively. It is shown that the dissolution rate and the thickness of the altered surface layer are strongly dependent on the glass composition, whereas the equilibrium solubility is not. The dependence of the layer thickness on the glass surface area to solution volume ratio is also emphasized. The protective role of the surface layer is shown to arise from its restructuring after the extraction of the soluble species. The simulation results are compared to an experimental study performed on series of SiO2-B2O3-Na2O glasses.

Uranium Sorption on α-Alumina: Effects of pH and Surface-Area/Solution-Volume Ratio

1994 ◽  
Vol 66-67 (s1) ◽  
Author(s):  
James D. Prikryl ◽  
Roberto T. Pabalan ◽  
David R. Turner ◽  
Bret W. Leslie
Keyword(s):  
Surface Area ◽  
Volume Ratio ◽  
Effects Of Ph ◽  
Solution Volume
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