Extraction of chlorinated hydrocarbons from fish with sulphuric acid

A method is described for extraction of chlorinated hydrocarbons (DDTs and PCBs) from fish samples with sulphuric acid of various concentrations. The results are better than those obtained by an official method using Soxhiet extraction with n-hexane, especially with 9.5-13M sulphuric acid. The relative standard deviation is about 12% for analysis of portions of a homogenized single sample taken from the dorsal flesh of the same fish. Drawbacks and advantages in comparison with other methods are discussed.     

Extraction of plutonium from sulphuric acid by TOA in toluene

The extraction of plutonium(VI) and plutonium(III) from sulphuric acid by TOA in toluene has been studied as a function of the acid and tri-octyl amine concentration. A comparison of the extraction properties of plutonium with those of uranium(VI) and uranium(IV) has been made. It was found that the extraction properties of plutonium(VI) are very similar to those of uranium(VI) and that TOA is a relatively poor extractant for plutonium(III). Uranium(IV) shows better extraction properties than plutonium(III). The results obtained are considered in the light of the stabilities of the complexes formed by these elements in the organic and aqueous phase. A method of separation of both elements by solvent extraction based on changing their oxidation states is suggested.     

Continuous dialysis of sulphuric acid in the presence of zinc sulphate

Transport of sulphuric acid in the presence of zinc sulphate through the anion-exchange membrane Neosepta-AFN (Astom Corporation, Japan) was studied in a two-compartment counter-current dialyzer with single passes at steady state. The following characteristics were used to characterize the dialysis process: recovery yield of acid, rejection coefficient of salt, and permeability coefficient of the membrane. In case of the H₂SO₄ + ZnSO₄ mixture, permeability of the membrane was quantified by four phenomenological coefficients which are functions of acid and salt concentrations in the feed. They were determined by numerical integration of differential equations describing the concentration profiles of both components in both compartments, which was combined with an optimizing procedure.     

Determination of sodium in spent sulphuric acid solution

Summary Sodium, sometimes present in spent sulphuric acid, may interfere with the intended re-use of the acid. Traditionally, sodium content is monitored by sample evaporation and analysis of the ash. It is proposed that by chemical oxidation of organic material present and a known addition technique, using a flame photometer, sodium concentration can be easily monitored with equal satisfaction. Sodium in g ml^–1 concentration is determined.The authors thank Edwin L. Spackey for assisting with the experimental measurements.     

Iodometric determination of persulphate in sulphuric acid solution

Summary A method for the iodometric determination of persulphate has been described, which consists in taking 25 ml distilled water and 15 ml cone. sulphuric acid (sp.gr. 1.84) in a 250 ml conical flask, immediately followed by the addition of 10 ml of solution of persulphate. The mixture is kept for about five minutes, diluted by 100 ml of distilled water and then are added 10–15 ml of 10% solution of potassium iodide. The liberated iodine is titrated against a standard solution of thiosulphate. 5 ml aliquots of persulphate solution may also be used. The results are satisfactory and the error lies within permissible limits.     

Fast and continuous isolation of short-lived mercury isotopes from diluted sulphuric acid solution

The seconds living mercury isotopes have been isolated from nuclear reaction products arising in the bombardment of ¹⁴⁷Sm target with ⁴⁰Ar ions at the U-400 cyclotron of JINR-Dubna.     

The investigation of the solvent extraction of molybdenum from concentrated solution of sulphuric acid

The solvent extraction of molybdenum(VI) from sulphuric acid solutions with di-(2-ethylhexyl)-phosphoric acid (HDEHP) and monododecylphosphoric acid (HDDP) in n-heptane has been studied (a) as a function of the concentration of sulphuric acid, molybdenum and the extractant; (b) in the presence of copper and zinc in the aqueous phase and (c) in the presence of tri-n-butylphosphate (TBP) in the organic phase. The distribution of the sulphuric acid between aqueous and organic phase has also been studied.     

Extraction behavior of yttriuí with diisodecylphosphoric acid from nitric acid solution

Extraction of yttrium and some of the lanthanoids by diisodecylphosphoric acid (DIDPA) has been studied as a function of nitric acid concentration in the aqueous phase and concentration of the DIDPA in n-dodecane. The distribution ratio of yttrium was found to increase with the second power of concentration of the extractant and decrease with the third power of concentration of nitric acid. As the concentration of yttrium in the organic phase increased, an amorphous solid was found to precipitate and the composition of the solid was determined to be Y(DIDP)₃. To dissolve Y(DIDP)₃ into n-dodecane, a 14-fold molar excess of DIDPA was required over Y(DIDP)₃. The distribution ratio of yttrium was found to be too high to back-extract this element by nitric acid of medium concentration.     

Complex fluorescence decay of quinine bisulphate in aqueous sulphuric acid solution

Fluorescence of quinine bisulphate is shown to be two-component. In 1.0 N H₂SO₄ solution the major component has a decay time ≈20 ns, but there is a minor component with decay time ≈2 ns with a different fluorescence spectrum. It is recommended that the compound not be used as a standard for decay-time measurements.     

Effect of polyacrylic acid on the corrosion behaviour of aluminium in sulphuric acid solution

Electrochemical techniques using both ac and dc as well as surface analyses approach were used to investigate the corrosion inhibition characteristics of polyacrylic acid (PAA) for pure cast aluminium in 0.5 M H₂SO₄ at 30 ± 1 °C. The effect of iodide ion additives was also studied. The results obtained indicate that PAA inhibited the corrosion of pure cast aluminium in the acid medium by adsorption onto the metal surface following Frumkin adsorption isotherm model. Inhibition efficiency increases with an increase in PAA concentration and synergistically enhanced by the addition of iodide ions. A mixed inhibition mechanism is proposed for the inhibitive effects of PAA as revealed by potentiodynamic polarisation technique. Synergism parameter evaluated was found to be greater than unity, indicating that the enhanced inhibition efficiency of PAA on addition of iodide ions was synergistic in nature. Fourier transform infrared analyses revealed that the synergistic effect of iodide ions and PAA is due to co-adsorption of iodide ions and PAA molecules which is cooperative in nature.     

Extraction behavior of moybdenum and zirconium with diisodecylphosphoric acid from nitric acid solution

This study was performed mainly from the viewpoint of consumption of diisodecylphosphoric acid (DIDPA) by the extracted Mo and Zr to estimate extraction capacities. The number of DIDPA molecules consumed per one extracted Mo atom was four when the concentration of Mo in the aqueous phase was less than 10^–3M and it decreased with increasing Mo concentration. Two molecules of DIDPA were consumed per one extracted Zr atom when the Zr concentration was high. Dependencies of the distribution ratio of Mo on the concentrations of Mo, DIDPA and HNO₃ are also described.     

Thin-layer chromatography of inorganic ions on sulphoethyl cellulose in sulphuric acid and ammonium sulphate media

Summary Thin-layer chromatographic (TLC) behaviour of 51 inorganic ions on a strongly acidic cation-exchanger, sulphoethyl (SE) cellulose, has been studied systematically in sulphuric acid and ammonium sulphate media (0.01–0.2 mol dm⁻³). Some aspects of the adsorption behaviour of the inorganic ions on the SE-cellulose are compared with those on other cation-exchangers in the same eluent systems. The possibilities for TLC separations of analytical interest are also proposed on SE-cellulose in sulphuric acid and acid ammonium sulphate media.     

Kinetics and mechanism of the reaction between biacetyl and hydroxylamine in acid solution

The kinetics and mechanism of formation of dimethylglyoxime from biacetyl and hydroxylamine in acid solution have been studied. Unprotonated hydroxylamine was found to react with the hydrogen-bonded carbonyl group to give the conjugate acid of the oxime. Detectable quantities of carbinolamine intermediates were not found in the acid concentration range studied.     

Extraction of uranium (VI) from sulfuric acid solution with TOPO

The extraction of uranium(VI) from sulfuric acid medium with tri-octylphosphine oxide (TOPO) in n-heptane was studied. Accompanied with the increase in the concentration of H₂SO₄, the distribution coefficient of uranium(VI) increased in the region of dilute sulfuric acid. When the concentration of H₂SO₄ surpassed 3.5 mol·dm⁻³, the distribution coefficient of uranium(VI) was at maximum. This result was due to the competition extraction between uranium(VI) and H₂SO₄. From the data, the composition of extracted species and the equilibrium constant of extraction reaction have been evaluated, which were (TOPOH)₂UO₂(SO₄)₂ (TOPO) and 10^7.6±0.15, respectively.     

海沙钛铁矿在硫酸溶液中的电化学溶解研究

采用电化学技术研究了孟加拉国海沙里钛铁矿在硫酸溶液中不同温度下的溶解行为. 循环伏安研究表明,在没有添加碳粉的条件下钛铁矿的溶解非常困难. 为了探明钛铁矿的溶解过程,考察了钛铁矿-碳比例、硫酸浓度和温度对钛铁矿电化学溶解行为的影响. 结果显示,钛铁矿在低还原电位和低温下的溶解速率较慢. 施加更负的还原电位和在较高的温度下溶解速率加快. 增加硫酸浓度（最大浓度到1 mol?dm^-3）也可提高溶解速率. 但是,在较高的硫酸浓度和还原电位下,由于氢气析出导致钛铁矿的溶解速率降低,且气体吸附最后使得钛铁矿的活性表面积减小. 计算得到活化能数值在高温区间为50±10 kJ•mol^-1, 而低温区间为?15±5kJ•mol^-1, 说明低温区间为扩散控制过程,而高温区间为化学控制过程.     

A note on the distillation of permanganic acid from sulphuric acid solutions

1. If solutions which contain XXX periodic acid and sulphuric acid are boiled, permanganic acid is found in the XXX concentration of permanganate in the steam is negligibly small until the sulphuric acid concentration of the solution exceeds about 6 M. It is at a maximum when the sulphuric acid is to M and then rapidly decreases as the sulphuric acid concentration further increases. 2.The'distillation of permanganic acid from nitric acid solutions is inappreciable even from the concentrated acid. 3. A brief account is given of the analytical application of the distillation from IoM sulphuric acid.