Sulfur, colloidal properties

Hard, compressed grains of black powder are not porous—the sulfur appears to have colloidal properties and to fill completely... 

Mixed cultures of sulfur bacteria are used industrially for the desulfurization of wastewater and waste gases by biological conversion to elemental sulfur which has colloidal properties [56, 57]. 

Klingensmith WC III, Tsan ME, Wagner HN Jr (1976) Factors affecting the uptake of ""Tc-sulfur colloid by the lung and kidney. J Nucl Med 17 681 Lin MS, Winchell HS (1972) A kit method for the preparation of a technetium-tin(II) colloid and a study of its properties. J Nucl Med 13 58-65 Marciniak M (1981) Bivalent tin metabolism and toxicity after intravenous injection in rats. Acta Physiol Pol 32 2... 

Council of Europe (2005 a) Technetium ""Tc colloidal rhenium sulphide injection. Emopean pharmacopeia 5.0, monograph, no 126. Council of Europe, Maisonneuve, Sainte-Ruffine Council of Europe (2005 b) Technetimn " Tc sulfur colloid injection. Emopean pharmacopeia 5.0, monograph, no 131. Coimcil of Emope, Maisonneuve, Sainte-Ruffine Haney TA, Ascanio I, Gighotti JA, Gusmano EA, Bruno GA (1971) Physical and biological properties of a " Tc-sulfur colloid preparation containing disodium edetate. J Nucl Med 12 64-68... 

Hydrolysis of solutions of Ti(IV) salts leads to precipitation of a hydrated titanium dioxide. The composition and properties of this product depend critically on the precipitation conditions, including the reactant concentration, temperature, pH, and choice of the salt (46—49). At room temperature, a voluminous and gelatinous precipitate forms. This has been referred to as orthotitanic acid [20338-08-3] and has been represented by the nominal formula Ti02 2H20 (Ti(OH). The gelatinous precipitate either redissolves or peptizes to a colloidal suspension ia dilute hydrochloric or nitric acids. If the suspension is boiled, or if precipitation is from hot solutions, a less-hydrated oxide forms. This has been referred to as metatitanic acid [12026-28-7] nominal formula Ti02 H2O (TiO(OH)2). The latter precipitate is more difficult to dissolve ia acid and is only soluble ia concentrated sulfuric acid or hydrofluoric acid. 

Drugs that are used to treat hyperkeratosis, a thickening of the stratum corneum, are called keratolytics. Examples of these agents are salicylic acid, urea, lactic acid, and colloidal or precipitated sulfur. The precise mechanisms by which these agents treat hyperkeratosis are not known. Presumably, a common property is the ability to denature keratin, the major structural protein of the epidermis. Other beneficial effects vary among the different drugs. All of them have antimicrobial or... 

It is convenient to classify sols into three types (I) tvophilii (solvent loving) colloids, for example, are solutions or gelatin or starch in water (2 association colloids, of which a solution of Soap in water at moderate concentration is an example and (3) Iwphohic (solvent repelling) colloids, for example, sulfur in water. Both lyophilic and association colloids can be prepared in thermodynamic equilibrium, so that when solvent is removed and then returned to the system, the original properties of the system are regained. 

Characterization of DOM according to molecular size, polarity, or other structure-based properties include often the demand for element specific information. Questions to be answered might concentrate, for example, on the phosphorous, nitrogen, or sulfur distribution in the different molecular size ranges. From the point of view of transport processes, the heavy metal content in the different fractions might be important for the interactions between inorganic or geogenic colloids and DOM. 

Modified hard-core RMs by phosphosulfurized compound. Improved extreme-pressure and antiwear properties have also been obtained with the introduction of some chemical species, such as sulfur, phosphorus or boron derivatives, into the colloidal core (Delfort et al., 1998 Inoue, 1993 Inoue and Nose, 1987). Welding loads, load wear index and wear scar diameter at 5 wt% of a CaC03 core surrounded by a calcium alkylaryl-sulfonate surfactant shell, and modified by phosphosulfurized calcium carbonate core were evaluated for calcium dialkyl dithiophosphate (CaDTP) and calcium trithiophosphate (CaTTP) with the four-ball extreme-pressure test (ASTM D2783 standard method). Both modified products exhibit improved extreme-pressure performances (welding load and load wear index), while their antiwear properties (wear scar diameter) compared to those of the original micellar substrate remain at least at the same level. 

Therefore, the suggested equation (2.19) reflects adequately a variation in the properties of luminescence quenchers and describes well the experimental data as a whole. In addition, the data suggest that for the colloids obtained with an excess of the sulfide ions, the quencher adsorption site is represented most likely by the negatively charged surface sulfur atoms, on which the cations adsorb readily while the anions adsorb poorly. Actually, in this case, the dominant surface defects are either the vacancies of the cadmium ions, or... 

Sorption of various gases (02, N2, C02, and He) on wheat flour, soybean flour, potato starch, and wheat starch has been investigated in order to study the effect of those gases on the functional properties of processed food products. Results indicate that such properties improved only after flour and starch were treated with chlorine.455,456 The adsorptivity of various gases by starch has been reexamined.457 Liquid ammonia quickly forms a gelatinous paste with starch.458 Tomasik et al.459 attempted to prepare inclusion complexes of starch with colloidal sulfur. A key result was that inclusion inside the starch matrix was only possible in small amounts because of the large relative size of the sulfur micelles. 

X-ray diffraction of sulfur particles excreted by Thiobacillus sp. showed the presence of orthorhombic sulfur crystals. The solubility of crystalline orthorhombic sulfur in water is known to be only 5 /tg 1 [42]. In the solubility test shown in Fig. 7 it was seen that the biologically produced sulfur particles can be dispersed in water but not in hexadecane, whereas crystalline orthorhombic sulfur is soluble in hexadecane but not in water. The reason for the observed hydrophilicity of the biologically produced sulfur particles has to be attributed to the hydrophilic properties of the surface of the sulfur particles. Because of the relatively high stability of the biologically produced sulfur particles at high salt concentrations, it is concluded that the colloidal stability is not merely based on electrostatic repulsion. It is known that hydrophobic sulfur can be wetted by Thiobacillus thiooxidans bacteria due to formation of organic surface-active substances [43, 44]. 

Cellulose nitrate is produced in essentially the same way as it was (albeit accidentally) by Christian Schonbein in 1845. A mixture of nitric acid and sulfuric acid are added to cellulose in one of various forms (as wood pulp, powder, flakes, or a colloidal mixture with water, for example). The properties of the product formed depend on the relative quantities of each reagent used and the conditions under which the reaction is carried out. One of the most important variables is the amount... 

Kenyon, A. S., and V. K. LaMer Light Scattering Properties of Monodispersed Sulfur Sols. I. Monochromatic Ultraviolet Angular Scattering. II. Effect of the Complex Index of Refraction Upon Transmittance. J. Colloid Sci. 4, 163—184 (1949). 

LaMer, V. K., and M. D. Barnes Monodispersed Hydrophobic Colloidal Dispersions and Light Scattering Properties. I. Preparation and Light Scattering Properties of Monodispersed Colloidal Sulfur. J.Colloid Sci. 1, 71—77(1946). 

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