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Pechenyuk, S. I.; Matveenko, S. I.; Семушин, В. В.

doi:10.1023/a:1013026300138

Cited by 4 publications

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“…This agrees with the earlier obtained data on the unusual properties of Cr III oxohydroxide, especially on its abnormally high spe cific surface. 16 The sizes of hydrogel particles calculated taking into account intramicellar water agree well with the results of visual observations. Since these coarse par ticles differ slightly in density from water, they can be only strongly hydrated hydrogels.…”

Section: Resultssupporting

confidence: 80%

“…Due to partial crystallization, the concentrations of impurity ions and intramicellar water 4 and sedimentation rate change. We succeeded to develop a method for determination of the specific surface S sp of the oxohydroxide hydrogels from the limiting amount adsorbed of the OH groups 16 and showed that the S sp values for the freshly prepared MOH are independent of the pH of their precipitation. The S sp values of Fe III , Cr III , Zr IV , and In III oxohydroxides are equal to 585, 930, 420, and 240 m 2 g -1 , respectively.…”

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confidence: 99%

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Determination of particle size in aqueous suspensions of hydrogels of iron(III), indium(III), aluminum, chromium(III), titanium(IV), and zirconium(IV) oxohydroxides

2005

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Dispersion of hydrogels of Fe III , In III , Al III , Cr III , Ti IV , and Zr IV oxohydroxides in an aqueous medium was studied by sedimentation analysis. The hydrogel dispersion depends on the metal nature, pH of precipitation, and suspension concentration. The systems are predomi nantly polydisperse, and the gel particle size ranges from 2 to 140 µm. The data obtained suggest that the gel particles are formed by three dimensional networks consisting of polymeric chains metal-oxygen and contain cavities filled with water.The role of nanoparticles in the genesis of gel systems has intensely been studied. 1 Hydrogels of tri and tetra valent metal oxohydroxides (MOH) are interesting repre sentatives of these systems. 2-6 The study of the rheologi cal properties of freshly prepared monolith gels, 7-10 whose three dimensional framework retained, suggests that the MOH hydrogels possess noticeable shear strength. They are continuous polymeric matrices in which liquid crys talline phases consisting of fragments with unstable struc ture can be formed. It remains unclear how far these conclusions can be extended to suspensions of gels ob tained by the fast alkali hydrolysis of aqueous solutions of the corresponding metal salts with continuous stirring in a vortex mode followed by washing from a mother liquor by multiple centrifuging and repulping. 3 In this work, we attempted to reveal the state of the MOH gels in suspensions using sedimentation analysis, which is widely used to determine the fractional composi tion of microheterogeneous systems. There are many vari ants of apparatus equipment and mathematical methods for processing results of sedimentation analysis, 11-15 which is poorly used for studying hydrogels. 13, 14 We have previously found that the properties of ob jects called MOH hydrogels change remarkably due to the interaction with electrolyte solutions. This concerns acid base and sorption characteristics, 5,6 consistency, and even color of the hydrogels. Due to partial crystallization, the concentrations of impurity ions and intramicellar water 4 and sedimentation rate change. We succeeded to develop a method for determination of the specific surface S sp of the oxohydroxide hydrogels from the limiting amount adsorbed of the OH groups 16 and showed that the S sp values for the freshly prepared MOH are independent of the pH of their precipitation. The S sp values of Fe III , Cr III , Zr IV , and In III oxohydroxides are equal to 585, 930, 420, and 240 m 2 g -1 , respectively.In this work, we studied the freshly precipitated at different pH and washed Fe III , In III , Al III , Cr III , Ti IV , and Zr IV oxohydroxides. The dispersion of their suspensions was studied by the sedimentation method in a gravitation field at different suspension concentrations in water and in an electrolyte (NaCl and Na 2 SO 4 ) solution. We at tempted to determine how the S sp values of the MOH hydrogels depend on dispersion. ExperimentalThe method of fast alkali hydrolysis of metal salt solutions was used to obtain MOH hydrogels...

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Section: Resultssupporting

confidence: 80%

mentioning

confidence: 99%