Dissolution kinetic

In a detailed study the dissolution kinetics of shock-modified rutile in hydrofluoric acid were carefully studied by Casey and co-workers [88C01], Based on the defect studies of the previous sections in which quantitative measures of point and line defects were obtained, dissolution rates were measured on the as-shocked as well as on shocked and subsequently annealed powders. At each of the annealing temperatures of 200, 245, 330, 475, 675, 850, and 1000 °C, the defects were characterized. It was observed that the dissolution rates varied by only a factor of 2 in the most extreme case. Such a small effect was surprising given the very large dislocation densities in the samples. It was concluded that the dissolution rates were not controlled by the dislocations as had been previously proposed. 

Metal/environment interface—V ne cs of metal oxidation and dissolution, kinetics of reduction of species in solution nature and location of corrosion products him growth and him dissolution, etc. 

Hodge, F. G. and Wilde, B. E., Effect of Chloride Ion on the Anodic Dissolution Kinetics of Cr-Ni Binary Alloys in Dilute H2SO4 , Corrosion, 26, 146 (1970)... 

Fig. 19.15 Schematic representation of range of corrosion potentials expected from various chemical tests for sensitisation in relation to the anodic dissolution kinetics of the matrix (Fe-l8Cr-IONi stainless steel) and grain boundary alloy (assumed to be Fe-lOCr-lONi) owing to depletion of Cr by precipitation of Cr carbides of a sensitised steel in a hot reducing acid (after Cowan and Tedmon )...

Kassner used a rotating disc, for which the hydrodynamic conditions are well defined, to study the dissolution kinetics of Type 304 stainless steel in liquid Bi-Sn eutectic. He established a temperature and velocity dependence of the dissolution rate that was consistent with liquid diffusion control with a transition to reaction control at 860 C when the speed of the disc was increased. The rotating disc technique has also been used to investigate the corrosion stability of both alloy and stainless steels in molten iron sulphide and a copper/65% calcium melt at 1220 C . The dissolution rate of the steels tested was two orders of magnitude higher in the molten sulphide than in the metal melt. 

Dissolution kinetics are influenced by pH, potential and the ions present in the test solution, and this forms the basis of selective metallographic etching techniques that have been used for some time . The potentiostat is often used to hold the potential of a multi-phase alloy constant at a level... 

Blum, A. E. and Stillings, L. L. (1995). Feldspar dissolution kinetics. In "Chemical Weathering Rates of Silicate Minerals" (A. F. White and S. L. 

White, A. F. (1983). Surface chemistry and dissolution kinetics of glassy rocks at 25 . Geochim. Cosmochim. Acta 47,805-815. 

V. Drillet and D. Defives. Clay dissolution kinetics in relation to alkaline flooding. In Proceedings Volume, pages 317-326. SPE Oil-fleld Chem Int Symp (Anaheim, CA, 2/20-2/22), 1991. SPE Number 21030. 

F Langenbucher. In vitro dissolution kinetics Description and evaluation of a column-type method. J Pharm Sci 58 1265, 1969. 

T Higuchi, S Dayal, I Pitman. Effects of solute-solvent complexation reactions on dissolution kinetics Testing of a model by using a concentration jump technique. J Pharm Sci 61 695, 1972. 

KG Mooney, MA Mintun, KJ Himmelstein, VJ Stella. Dissolution kinetics of carboxylic acids I Effect of pH under unbuffered conditions. J Pharm Sci 70 13-22, 1981. 

M Simpson, EL Parrott. Dissolution kinetics of a three-component solid I Ethylpara-ben, phenacetin, and salicylamide. J Pharm Sci 72 757-764, 1983. 

PW Taylor Jr, DE Wurster. Dissolution kinetics of certain crystalline forms of prednisolone II Influence of low concentrations of sodium lauryl sulfate. J Pharm Sci 54 1654-1658, 1965. 

JH DeSmidt, JCA Offringa, DJA Crommelin. Dissolution kinetics of griseofulvin in sodium dodecylsulphate solutions. J Pharm Sci 76 711-714, 1987. 

Ruby MV, Davis A, Kempton JH, et al. 1992. Lead bioavailability Dissolution kinetics under simulated gastric conditions. Environ Sci Technol 26 1242-1248. 

Figure 4.3. Dissolution kinetics of CaC03 by NaOAc-HOAc solutions at varying pHs. a Dissolution of pure CaC03 by NaOAc-HOAc (0.1 g CaC03, 25 mL buffer solution), b and c Dissolution of soil CaC03 by NaOAc-HOAc at pH 5.0 (1.0 g soil, 25 ml buffer solution) (after Han and Banin, 1995. Reprinted from Commun Soil Sci Plant Anal, 26, Han and Banin A., Selective sequential dissolution techniques for trace metals in arid-zone soils The carbonate dissolution step, p 565, Copyright (1995), with permission from Taylor Francis US)...

In summary, sodium acetate buffer solutions at pH 5.5 and at the soil to solution ratio of 1 25 only extract the carbonate from calcareous soils with 10-20% of carbonate, and, at pH 5.0, all of the carbonate from soils with 30-50% of carbonate is dissolved. A second extraction with a fresh buffer solution is required for soils with more than 50% carbonate. The dissolution kinetics of carbonate showed that six hours of extraction are generally sufficient for complete carbonate dissolution. The part of the carbonate fraction not dissolved at the carbonate fraction step is mainly... 

Apatite is used to remediate Pb contaminated soils because apatite dissolution releases phosphate, which combines with Pb to form highly insoluble Pb-phosphate minerals. Apatites follow linear (zero-order) dissolution kinetics (Manecki et al., 2000) with rates of Pb uptake by the apatites decreasing in the same order as the apparent dissolution rate... 

Mechanisms of dissolution kinetics of crystals have been intensively studied in the pharmaceutical domain, because the rate of dissolution affects the bioavailability of drug crystals. Many efforts have been made to describe the crystal dissolution behavior. A variety of empirical or semi-empirical models have been used to describe drug dissolution or release from formulations [1-6]. Noyes and Whitney published the first quantitative study of the dissolution process in 1897 [7]. They found that the dissolution process is diffusion controlled and involves no chemical reaction. The Noyes-Whitney equation simply states that the dissolution rate is directly proportional to the difference between the solubility and the solution concentration ... 

Bisrat et al. concluded that for sparingly soluble, suspended drugs, diffusional transport plays a major role in the dissolution kinetics [19]. They studied the effect of particle size and viscosity on dissolution rate and apparent diffusional distance (.h-App) of oxazepam and griseofulvin. The term apparent diffusional distance was used as a simplified measure of the distance over which diffusion dominates and was calculated as follows ... 

G. Shan, K. Igarashi, H. Ooshima. Dissolution kinetics of crystal in suspension and its application to L-aspartic acid crystals. Chem. Eng. 

Nicklasson, M., Brodin, A., Sundelof, L.-O., Studies of some characteristics of molecular dissolution kinetics from rotating discs, Int. 

Erosion is typically characterized by either occurring on the surface or in the bulk. Surface erosion is controlled by the chemical reaction and/or dissolution kinetics, while bulk erosion is controlled by diffusion and transport processes such as polymer swelling, diffusion of water through the polymer matrix, and the diffusion of degradation products from the swollen polymer matrix. The processes of surface and bulk erosion are compared schematically in Fig. 1. These two processes are idealized descriptions. In real systems, the tendency towards surface versus bulk erosion behavior is a function of the particular chemistry and device geometry (Tamada and Langer, 1993). Surface erosion may permit the... 

Blum, A.E. and L.L. Stillings, 1995, Feldspar dissolution kinetics. Reviews in Mineralogy 31,291-351. 

Berner, R.A. Morse, J.M. 1974. Dissolution kinetics of calcium carbonate in seawater. IV. Theory of calcite dissolution, American Journal of Science, 274,108-134. 

Sjoberg, E.L. Rickard, D.T. 1984. Calcite dissolution kinetics surface speciation and the origin of the variable pH dependence, Chemical Geology, 42, 119-136. 

ABSTRACT Atmospheric carbon dioxide is trapped within magnesium carbonate minerals during mining and processing of ultramafic-hosted ore. The extent of mineral-fluid reaction is consistent with laboratory experiments on the rates of mineral dissolution. Incorporation of new serpentine dissolution kinetic rate laws into geochemical models for carbon storage in ultramafic-hosted aquifers may therefore improve predictions of the rates of carbon mineralization in the subsurface. 

Serpentine Dissolution Kinetics from Experimental Data and Implications for Carbon Storage... 

Blum, A.E. Stillings, L.L. 1995. Felsdpar dissolution kinetics. In White, A.F. Brantley, S.L. (ed.), Reviews in mineralogy, 31 Chemical weathering rates of silicate minerals, Mineralogical Society of America, USA, 291-352. 

This dissolution kinetics study demonstrates the high sensitivity and high contrast potentials of the new resist. 

The resist has a high sensitivity and high resolution capability. The suitable photo absorption, excellent dissolution kinetics and no swelling during development contribute to such superior characteristics of this resist. 

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