Some physicochemical and enzymic properties of selenium-containing abzyme

We successfully prepared the Se-containing abzyme (Se-abzyme) with glutathione peroxidase (GPX) activity and further studied its physicochemical and enzymic properties and stabilities. Data showed that the isoelectric point of the abzyme was 6.95-7.08, and its molecular weight was 158 KD. The ranges of optimum pH and temperature of the Se-abzyme were wider than the native GPX. The store stability of the abzyme was higher than the native GPX. The Se content in the abzyme was found to be 5 mol Se/mol abzyme by X-ray photoelectron spectrum, and binding constant 1.11 x 10(7)M-1 by using ELISA method. The Se-abzyme was inhibited competitively by dithiobis(2-nitrobenzoic acid) (DTNB), and inhibition constant was determined to be 1.25 x 10(-3)M-1.     

Relationship between the electromagnetic and physicochemical properties of carbonyl iron powder

Summary The relationship is examined between the electromagnetic properties of carbonyl iron powder and some factors involved in the manufacture of this powder. The electromagnetic properties depend on the onion skin structure of the powder particles and the chemical composition and particle size of the powder.Translated from Poroshkovaya Metallurgiya, No. 7 (43), pp. 38–44, July, 1966.     

The removal of iron from aluminum chloride leach liquors by ion exchange

The sorption behavior of iron onto two anion exchange resins from simulated aluminum chloride leach liquors was studied. Bench-scale sorption isotherm experiments were performed at room temperature. The initial chloride concentrations of the simulated leach liquors ranged from 1 M to 6 M. Iron loading for the Dowex SBR and Dowex MWA-1 resins increased with increasing chloride concentrations. Maximum capacities observed for both resins were approximately 0.95 meq Fe/g dry resin at an initial chloride concentration of 6 M. The Dowex SBR resin sorbed noticeably greater amounts of iron than the MWA-1 resin at initial chloride concentrations of 4 and 5 M. Computer programs were written to predict the equilibrium distribution of species in various aqueous electrolytes. Correlation of computer results with some published experimental data indicated good qualitative correlations. However, strict quantitative conclusions may be suspect due to an inability to predict activity coefficients accurately at the high ionic strengths of this work. Comparison of computer program predictions and sorption isotherm results indicate that the species FeCl_3(aq) may be involved in the sorption of iron from the simulated leach liquors.     

Some properties of reduced iron powder manufactured from Mill-scale

Conclusions Some key data are presented on the properties of iron powder reduced with a solid reducing agent from low-carbon steel mill-scale and on the mechanical characteristics of specimens pressed from this powder and sintered in hydrogen and dissociated ammonia atmospheres. The properties of iron powder manufactured by the process described meet the requirements of powder metallurgy.Translated from Poroshkovaya Metallurgiya, No. 3 (135), pp. 102–106, March, 1974.     

Preparation and properties of fine hematite powders by hydrolysis of iron carboxylate solutions

Submicrometer, crystalline hematite (α-Fe₂O₃) particles were prepared by hydrolysis of organic iron carboxylate solutions using water at 175 °C for 30 minutes. The particle size of hematite was significantly dependent on the liquid-phase stirring speed and the organic compositions. The precipitation rate of hematite from the organic solution followed first-order kinetics. The precipitation rate increased markedly with increasing temperature, and the activation energy for the process was 94.6 kJ mol⁻¹. At 220 °C, the hydrolysis of iron carboxylate solution led to a mixture of hematite and magnetite (Fe₃O₄). The iron oxides prepared at 175 °C to 220 °C were found to be free from organic contamination by the starting material.     

Mixed solvent systems for the extraction and stripping of iron(III) from concentrated acid chloride solutions

The extraction of concentrated iron(III) from acid chloride solutions has been investigated with methyl isobutyl ketone (MIBK), tri-n-butyl phosphate (TBP), di(2-ethylhexyl) phosphoric acid (D2EHPA), and their mixtures in various proportions, at different acid concentrations. On comparing the extraction of iron(III) with mixed and individual extractant, it was found that both D2EHPA-MIBK and D2EHPA-TBP mixtures exhibit synergism, the latter having better extraction ability. The synergistic coefficients, at different initial acid concentrations for each mixed extractant system, were evaluated and compared. An increase in the concentration of MIBK and TBP in the mixed organic resulted in higher synergistic coefficient. The stripping of iron(III) from loaded D2EHPA was found to increase with the strip feed acid concentration, while from loaded organic mixtures, it initially increased and then decreased. Stripping of iron(III) from D2EHPA-MIBK loaded solvent is better then D2EHPA-TBP. The extracted iron species formed and the stripping reactions have been proposed. Ultraviolet visible spectra of the stripped organic phase support the result and the proposed mechanisms.     

Some properties of components from iron powder alloyed with 6% chromium

Summary The process developed at the Institute for thermal diffusion impregnation from point sources is simple and reliable, and permits production of iron-chromium alloy powders of any desired composition. Compared with parts of pure iron, constructional components obtained from these powders exhibit higher strength, ductility, and oxidation resistance.Translated from Poroshkovaya Metallurgiya, No. 8(56), pp. 28–33, August, 1967.     

Electrical conductivity of acidic chloride solutions

The electrical conductivities of aqueous solutions in the system HCl-MCl_n (where M = K, Na, Mg, Ni, or Cd) were measured at different temperatures. The equivalent electrical conductivity of H⁺ was calculated on the basis of simple assumptions for these solutions, and show an inverse relationship with water activity in these solutions. The results obtained by varying temperatures, solute ratios, and ionic strength on the electrical conductivity were found to be consistent with a proton jump mechanism for the H⁺ ion, where the activity of water is the most significant parameter affecting its equivalent conductance, and a viscous (Stokes’ law) drag mechanism (i.e., Walden’s rule is obeyed) for other ions found in acidic solutions.