Glass dissolution products

If the aluminate ion is a component in the chemical affinity term, then the activity of dissolved silica, by itself, cannot describe the change in rate with changes in chemistry of the contacting fluid. A number of attempts have been made to explicitly include Al activity in the chemical affinity term. Gin (1996) suggested that glass dissolution could be modelled using a mixed Si/Al term for the ion activity product ((2) ... 

For determinations in glass, dissolution of the matrix by treatment with HF and subsequent analysis of the trace concentrate is certainly a feasable approach. In high-quality glasses used e.g. for the production of fibers, even very low concentrations of trace elements may be relevant, so hydrofluoric acid of very high purity has to be used for the sample decomposition. This can be obtained by sub-boiling procedures in plastic apparatus. 

A. Hoppe, N.S. Giildal, and R.A. Boccaccini, A review of the biological response to ionic dissolution products from bioactive glasses and glass-ceramics, Biomaterials, 32 (11), 2757-2774, 2011. 

Xynos, I.D., Edgar, A.J., Buttery, L.D.K., Hench, L.L., and Polak, J.M. (2000) Ionic products of bioactive glass dissolution increase proliferation of human osteoblasts and induce insulin-like growth factor 11 mRNA expression and protein synthesis. Biochem. Biophys. Res. Commun., 276,461-465. 

Haro Durand, L.A., Vargas, G.E., Romero, N.M., Vera-Mesones, R., Porto-Lopez, J.M., Boccaccini, A.R., Zago, M.P., Baldi, A., Gorustovich, A., 2015. Angiogenic effects of ionic dissolution products released from a boron-doped 45S5 bioactive glass. J. Mater. Chem. B 3, 1142-1148. 

Potassium siUcates are manufactured in a manner similar to sodium siUcates by the reaction of K CO and sand. However, crystalline products are not manufactured and the glass is suppHed as a flake. A 3.90 mole ratio potassium siUcate flake glass dissolves readily in water at ca 88°C without pressure by incremental addition of glass to water. The exothermic heat of dissolution causes the temperature of the solution to rise to the boiling point. Lithium sihcate solutions are usually prepared by dissolving siUca gel in a LiOH solution or mixing colloidal siUca with LiOH. 

Most electroless silver appHcations are for silvering glass or metallizing record masters. Mirror production is the principal usage for electroless silver. The glass support is cleaned, catalyzed using a two-step catalyst, and coated on one side with an opaque silver film (46). Silver-plated nylon cloth is used as a bacteriostatic wound dressing. A tiny current appHed to the cloth causes slow silver dissolution. The silver acts as a bactericide (47). 

While the cuprous cyanide solution is warmed gently (to 60°-70°) on the water bath, a solution of p-tolyldiazonium chloride is prepared as follows Heat 20 g. of p-toluidine with a mixture of 50 g. of concentrated hydrochloric acid and 150 c.c. of water until dissolution is complete. Immerse the solution in ice-water and stir vigorously with a glass rod so that the toluidine hydrochloride separates as far as possible in a microcrystalline form. Then cool the mixture in ice and diazotise with a solution of 16 g. of sodium nitrite in 80 c.c. of water, added until the nitrous acid test with potassium iodide-starch paper persists. The diazonium chloride solution so obtained is poured during the course of about ten minutes into the warm cuprous cyanide solution, which is meanwhile shaken frequently. After the diazo-solution has been added the reaction mixture is heated under an air condenser on the water bath fox a further quarter of an hour, and then the toluic nitrile is separated by distillation with steam (fume chamber, HCN ). The nitrile (which passes over as a yellowish oil) is extracted from the distillate with ether, the p-cresol produced as a by-product is removed by shaking the ethereal extract twice with 2 A-sodium hydroxide solution, the ether is evaporated,... 

ISO 2558 1974 Textile glass chopped-strand mats for reinforcement of plastics -Determination of time of dissolution of the binder in styrene ISO 3344 1997 Reinforcement products - Determination of moisture content... 

Since the water movement will be very slow compared with the rate at which the wastes dissolve, we are concerned first and foremost with equilibrium solubility. Also, if only to relate behaviour on the geological time scale to that on the laboratory time scale, we will need to know about the mechanisms and kinetics of dissolution and leaching. The waste forms envisaged at present are glass blocks containing separated fission products and residual actinides fused into the glass and, alternatively, the uranium dioxide matrix of the used fuel containing unseparated fission products and plutonium. In the... 

As discussed in the previous section, trace elements are essentially retained in the solid combustion products and, because many are present on the surfaces of the particles, they are potentially leachable. Our data show the elements Mo, As, Cu, Zn, Pb, U, Tl, and Se will be readily accessible for leaching. A significant fraction of the V, Cr, and Ni, and a minor proportion of the Ba and Sr will also be potentially leachable because of the surface association, but most of these elements appear to be located in particles and will be released more slowly as the dissolution of the glass and other phases takes place. Rubidium, Y, Zr, Mn, and Nb are contained almost entirely within the particles and dissolution is potentially slower. The extent to which elements are leached also depends on their speciation and solubility in the porewaters, and the pH exerts a major control. In oxidizing solutions, elements such as, Cd, Cu, Mn, Ni, Pb, and Zn form hydrated cations that adsorb onto mineral surfaces at higher pH values and desorb at lower pH values. In contrast, the elements As, U, Mo, Se, and V, under similar Eh conditions, form oxyanions that adsorb onto mineral surfaces at low pH values and desorb at higher values (Jones 1995). 

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