Solubility Of Hydroxide Research Articles

Solidification/stabilization Process For Steel Foundry Dust Using Cement Based Binders: Influence Of Processing Variables

The influence of processing variables: mixing time, waste/binder ratio and water/solid ratio on the solidification/stabilization process of steel foundry dust has been studied. The characterization of the final product was based on the Toxic Characterization Leaching Procedure (TCLP) followed by the biotoxicity (bioluminescence assay) and concentration of the metals, Cr, Cd, Pb and Zn in the leachates. The final product characteristics depend mainly on the waste/binder ratio, as a function of the metal hydroxide solubilities. The results of this work allow one to establish the optimization of a solidification/stabilization process for steel foundry dust.

Solidification/Stabilization Process for Steel Foundry Dust Using Cement Based Binders: Influence of Processing Variables

The influence of processing variables: mixing time, waste/binder ratio and water/ solid ratio on the solidification/stabilization process of steel foundry dust has been studied. The characterization of the final product was based on the Toxic Characterization Leaching Procedure (TCLP) followed by the biotoxicity (bioluminescence assay) and concentration of the metals, Cr, Cd, Pb and Zn in the leachates. The final product characteristics depend mainly on the waste/binder ratio, as a function of the metal hydroxide solubilities. The results of this work allow one to establish the optimization of a solidification/stabilization process for steel foundry dust.

Solubility of alkali metal chlorides and hydroxides in water

Solubility of alkali metal chlorides and hydroxides in water

Aqueous solubility of Y, Ba and Cu oxalates in the system [Y(OH) 3, Ba(OH) 2, Cu(OH) 2]-H 2C 2O 4-[HNO 3/NaOH]-H 2O

Solubility isotherms have been calculated for the system [Y(OH) 3-Ba(OH) 2-Cu(OH) 2]-H 2C 2O 4-[HNO 3/NaOH]-H 2O at T = 25°C, using a numerical algorithm involving the equilibria between soluble complexes, and including the effect of ionic strength. Using this algorithm, the solubility isotherms of several precipitates in simultaneous equilibrium with the same solution have been calculated. The results highlight the importance of complex formation in determining the solubility of Y, Ba and Cu oxalates, particularly the hydroxo and oxalato complexes, and their sensitivity to pH. Neglecting the effect of ionic strength can lead to erroneous solubility estimations; the magnitude of the error depends on the nature of the precipitates and the equilibrium conditions. In specific cases, the solubility of certain metal oxalates and hydroxides can be strongly affected by the presence of other precipitates. This effect depends on the exact pH of the solution. The strongest effects are found for CuC 2O 4·0.5H 2O and Cu(OH) 2 in the presence of BaC 2O 4·2H 2O, and for Y 2(C 2O 4) 3·9H 2O and Y(OH) 3 in the presence of BaC 2O 4·2H 2O. The examples presented show that each case must be treated specifically.

Thermodynamic properties of the aluminate ion and of bayerite, boehmite, diaspore and gibbsite

A critical review of the literature concerning the solubility of aluminium hydroxides and oxyhydroxides has revealed some problems concerning the measurements in alkaline solutions; in addition, it has led us to regard the solubility measurements of gibbsite in acid solutions as being very questionable. As a result of this review, solubility measurements have been made in weakly concentrated alkaline solutions (which allow for easy thermodynamic modelling) for: - synthetic bayerite: dissolution and precipitation between 21 and 65°C; - synthetic gibbsite: dissolution between 21 and 70°C; - synthetic boehmite: dissolution and precipitation between 70 and 300°C; - natural diaspore: dissolution between 130 and 300°C. Our measurements permit the determination of the solubility products of these minerals with good accuracy and allow for the calculation of their thermodynamic properties as well as of the Gibbs free energy of formation of the aluminate ion, Al(OH) 4 #75 . The following values are proposed for the Gibbs free energy of formation at 298.15 K: Al(OH) 4 #75 : -1305.42 kJ/mol; gibbsite: -154.889 kJ/mol; bayerite: -1149.80 kJ/mol; boehmite: -917.82 kJ/mol; diaspore: -924.59 kJ/mol. Therefore, we can propose that the order of increasing stability of the aluminium hydroxides and oxyhydroxides at 25°C is: diaspore > boehmite ∼ gibbsite > bayerite

Comment on “Aluminum hydroxide solubility in aqueous solutions containing fluoride ions at 50°C” by B. Sanjuan and G. Michard

Comment on “Aluminum hydroxide solubility in aqueous solutions containing fluoride ions at 50°C” by B. Sanjuan and G. Michard

Reply to Comment by B.S. Hemingway on “Aluminum hydroxide solubility in aqueous solutions containing fluoride ions at 50°C” by B. Sanjuan and G. Michard

Reply to Comment by B.S. Hemingway on “Aluminum hydroxide solubility in aqueous solutions containing fluoride ions at 50°C” by B. Sanjuan and G. Michard

Comment on “Aluminum hydroxide solubility in aqueous solutions containing fluoride ions at 50°C” by Bernard Sanjuan and Gil Michard

Comment on “Aluminum hydroxide solubility in aqueous solutions containing fluoride ions at 50°C” by Bernard Sanjuan and Gil Michard

The Solubility and Hydrolysis of Aqueous Aluminium Hydroxides in Dilute Fresh Waters at Different Temperatures

This study is mainly focusing on the effect of temperature and pH on the chemistry of Al(OH)3(s) using available thermodynamic data. The calculations show that a doubling of the [H+] or a decrease in temperature by 15°C, approximately yields the same solubility increase of the various Al(OH)3(s) presented. The relative concentration of aqueous aluminium hydrolysis complexes is also highly temperature dependent. At 25°C and pH 5, the calculated distribution of dissolved, inorganic aluminium hydroxides corresponds to about 36% of Al3+, 37 % of Al(OH)2+, 26 % of Al(OH)2+ and 1 % of Al(OH)30. At the same pH but at 0°C, about 84%, 13%, 2% and 0% are present as Al3+, Al(OH)2+, Al(OH)2+ and Al(OH)30, respectively. This temperature effect is of major importance as the hydroxide species are supposed to be the most toxic species to aquatic biota. Literature reports on the equilibrium constants Al(OH)3(s), log*Ks, vary from about 8 to 11, a variation in the product by a factor of 1000. In natural soil/water systems the solubility products of crystalline and amorphous solid aluminium sources are unknown and the solubility may also be coupled to combined weathering/ion exchange processes. In addition substantial amount of aluminium may be present as organic complexes where aluminium by cation exchange reactions may enter the solution as monomeric inorganic species. Thus, if a low value for the equilibrium constants of Al(OH)3(s) is used as reference when calculating the degree of aluminium saturation, an apparent oversaturation will often be demonstrated. To estimate the degree of aluminium saturation in natural waters whould therefore only be of theoretical interest.

Occurrence and removal of hydroxide precipitates on ion-exchanged faujasite-type zeolites: zinc molecular sieves

Faujasitic zeolites have been shown to acquire a hydroxide surface deposit following ion exchange with zinc solutions. This phenomenon was studied using XRD and SEM techniques. The surface deposits can be removed by aqueous ammonia. The formation of the deposits can be explained in terms of the alkalinity of the zeolite surface, the acidity of the exchanging salt solution and the solubility of metal hydroxide. New procedures can prevent, or reduce, surface hydroxide deposits on zeolites A, X and Y.

Alkaline preflush in a low-permeability clayey sandstone

The objective of this study is to identify the mechanisms governing the propagation of alkaline solutions in a definite field case where mineralogical and petrophysical properties have a particular influence on the selection of the proper alkaline agent. In the first part, the divalent ion removal process is studied by means of flow experiments under different operating conditions, giving more or less importance to precipitation mechanism. Results are examined with the help of ion exchange isotherms and salt and hydroxide solubility data. Consequences on flow properties are discussed. In the second part, hydroxide breakthrough times are compared for two alkaline agents, i.e. carbonate and metasilicate, and a mathematical model, based on ion exchange and chemical equilibria of species in solution, is used for the interpretation of results. The relationship between rock mineralogy and hydroxide consumption is discussed.

The Solubility of Plutonium Hydroxide in Dilute Solution and in High-Ionic-Strength Chloride Brines

The Solubility of Plutonium Hydroxide in Dilute Solution and in High-Ionic-Strength Chloride Brines

Effect of Coriolus versicolor on physico-chemical properties of Eucalyptus globulus wood

The purpose of this study was to determine the progressive changes in physical and chemical properties of Eucalyptus globulus wood under the action of a representative white rot fungus, Coriolus versicolor. Observations concerning the nature and relative effects on weight loss, hot water solubility, 1% sodium hydroxide solubility, Klason lignin, holocellulose, intrinsic viscosity and degree of polymerisation of holocellulose, pentosans, methoxyl value, neutral sugar composition and nitrobenzene oxidation products are discussed.

Corrosion Mechanisms for Zinc Exposed to the Atmosphere

Physical and chemical information on zinc corrosion layer formation, evolution, morphology, and chemical makeup is organized and presented, together with information on minerals containing zinc and other crystalline structures that might be expected to be present. The chemical reactions involved in the formation of these constituents during the corrosion process are then surveyed. The pH of the aqueous surface film is found to be crucial to the corrosion process, since it controls the dissolution of the passive oxyhydroxide surface. (The outdoor pH is largely a function of atmospheric and and is low in fogs and some rains, near neutral in dew, and generally lower in winter than in summer; indoors, the surface acidity is controlled by the composition of deposited particles.) The transition from traditional winter maxima in outdoor zinc corrosion to the more recent summer and fall maxima is explained as the juxtaposition of annually‐varying rates of bisulfite oxidation by and of atmospheric concentrations. Indoors, most of the surface degradation can be attributed to adsorbed sulfate aerosol particles; the indoor corrosion rates can be constrained to negligible levels by maintaining moderate relative humidities. Zinc is the only one of the common industrial metals for which a product containing carbonate is abundant, but sulfates and chlorides appear as well. In each case, the predominant forms are the slightly soluble hydroxide mixed salts. While full quantitative analyses of atmospheric zinc corrosion are not yet possible, it is clear that the process can only be understood in the context of the anionic surface chemistry of zinc.

Adsorption of trace metals on aluminium oxide: A simulation of processes in freshwater systems by close approximation to natural conditions

The interaction of the trace metals Cu, Co, Zn, Ni, Pb and Cd with aluminium hydroxide precipitated in-situ from homogeneous solution was studied. Using total concentrations of 10 −4 M Al, 10 −7 M Zn, Cu, Co, Ni and 10 −8 M Pb and Cd a removal of Zn, Cu, Pb, Cd from solution occurred together with Al, while Co and Ni concentrations in solution remained unchanged. The binding of Cu, Pb and Zn, Cd is in agreement with the effect predicted by using published (resp. evaluated for Zn and Cd), values for stability constants of surface complexes on preformed Al 2O 3-suspension. The different behaviour of these elements and of Co and Ni is expected from the hydrolysis and adsorption tendencies. The experimental conditions correspond to natural conditions in lake waters, where due to the pH-dependent solubility of aluminium hydroxide, in-situ precipitation may occur and cause the scavenging of trace elements.

Prediction of the solubility of aluminium oxides and hydroxides at high temperature and pressure

Prediction of the solubility of aluminium oxides and hydroxides at high temperature and pressure

Die Auflösung yon Zinkmetall und die Löslichkeit von Zinkhydroxid durch Messung der elektrischen Leitfähigkeit im System Zink/Wasser

AbstractIn conjunction with colorimetric determination of zinc concentration, sensitive conductivity measurement in solutions consisting of flowing deionized water saturated with hydroxide‐covered metallic zinc enabled conclusions to be drawn regarding the composition of the solutions. The equivalent conductivities of the ions and of a series of solutions allowed us to determine the ion concentrations of the solutions and the degrees of dissociation. In this way the non‐ionic portion was defined also. We thus acquired reliable data for determining the solubility of zinc hydroxide and zinc oxide in water as the sum of the dissolved components. These solubilities are lower than those given in the literature so far. The data can be used to calculate the normal thermodynamic constants, which agree well with the known values. As we were able to determine the undissociated zinc hydroxide in solution fairly reliably, it has also been possible for us to state the first dissociation constant of zinc hydroxid

Thermodynamic and kinetic observations on lialo 2: adsorption, dissolution, and evolution of water vapor

Isotherms for 673 and 773 K are presented for surface adsorption of H 2O(g) and for solubility of OH − in LiAlO 2 as a function of H 2O(g) partial pressure. The Freundlich adsorption isotherms for 673 and 773 K, respectively, are: log(θ) = (−1.590 ± 0.691) + (0.497 ± 0.064) log(p H 2O ) , and log(θ) = (−1.112 ± 0.061) + (0.497 ± 0.052) log(p H 2O ) , where θ is the fraction of surface covered, and p H 2O is the partial pressure of H 2O(g) in Pa. Hydroxide dissolution is exothermic. LiAl 5O 8 can be a second phase or a solute depending on conditions to give isotherms with slopes of 0.5 or 0.4, respectively. The hydroxide solubility isotherms for 673 and 773 K, respectively, are: log(x OH) = (−4.667 ± 0.096) + (0.399 ± 0.088) log(p H 2 ) , and log(x OH) = (−4.899 ± 0.079) + (0.499 ± 0.063) log(p H 2O ) , where x OH is the mole fraction OH −. The rate of H 2O(g) evolution from LiAlO 2 showed the kinetics of the process to be second order in hydroxide with an activation energy of 61.5 ± 7.9 kj, a value less than that reported for H 2O(g) evolution from Li 2O or from LiOH.

Solubility of colloidal ferric hydroxide

Considerable evidence supports the concept that phosphate1–4, trace-metal cations5–7, and rare-earth elements8 are strongly influenced by chemical interactions with suspended solids in turbid rivers and estuaries. Among the most active of suspended particu-lates are metal-hydroxide colloids, which exist as dispersions or as surface coatings on larger suspended solids. Elucidation of the chemical mechanisms governing colloidal and dissolved species interactions is hampered by ignorance concerning fundamental chemical parameters describing the colloidal phases. Colloidal ferric hydroxides have long been known to interact with a variety of dissolved species in natural waters, yet reported solubility products for ferric hydroxides range over three orders of magnitude9. Without such fundamental information, more refined issues, such as the extent to which solid solution formation governs dissolved species, are impossible to resolve. Here we re-examine the solubility properties for colloidal ferric hydroxide reported over the past 60 years, and combine them with results from experi-ments with dialysed ferric-hydroxide suspension performed in this laboratory. After correction of historical data for ferric complexation and variations in ionic strengths, the combined data are consistent with the mass action equation, αFe3+α2.35OH = 10−31.7 where α, is the activity of species i.

The solubility of colloidal ferric hydroxide and its relevance to iron concentrations in river water

Concentrations of dissolved iron in equilibrium with colloidal ferric hydroxide were experimentally determined by dialysis followed by atomic absorption spectroscopy. The results were compared to values obtained from the literature. The referenced values were determined by electrochemical methods under a wide variety of experimental conditions which necessitated corrections for the presence of ferric complexes and for variations in ionic strengths. The combined set of historical and present data was consistent with the mass action equation, α Fe 3+ α 2.35 OH − = 10 −31.7, where α i , is the activity of species i. The equation is proposed to represent the solubility of aqueous ferric hydroxide colloids. Published data from rivers, corrected for incomplete separation of colloidal from dissolved iron and, dialyzed samples of Delaware River water with pH values adjusted to range between 5 and 8 were fit to the solubility equation. Both sources of evidence demonstrated concentrations of dissolved iron to be near saturation with colloidal ferric hydroxide.