scholarly journals Preconcentration And Determination Of Precious Metals Using Silica Gel Chemically Modified With Products Of Interaction Of O- or p-Aminotiophenols With g-(Trietoxisilane)Propylisocyanate

2020 ◽  
Vol 15 (2) ◽  
pp. 53-56
Author(s):  
A.K. Trofimchuk ◽  
V.N. Losev ◽  
V.V. V.V. ◽  
E.V. Elsuf’ev ◽  
N.V. Gudymа
Keyword(s):  
Precious Metals ◽  
Silica Gels ◽  
Luminescence Spectroscopy ◽  
Surface Complexes ◽  
Chemically Modified ◽  
Gold Silver ◽  
Lower Oxidation ◽  
Sulfur Containing ◽  
Better Than

The synthesis of new complexing adsorbents with thiophenol (MPhS) and aminobenzthiazolpropyl (ABTS) groups grafted onto the surface of silica gels are considered. The extraction of precious metals (Au(III), Ag(I), Pd(II), Pt(II,IV), Rh(III), Ir(IV), Ru(IV), Os(IV)) from solutions of hydrochloric acid by MPhS and ABTS adsorbents. Contact time, acidity, temperature (25 – 95 °C), and the presence of a labilization agent tin(II) chloride is examined. It is shown that the adsorption properties of MPhS for precious metals are better than ABTS. It was proved by luminescence spectroscopy that gold, silver and platinum in the surface complexes with sulfur-containing groups are in lower oxidation states; and by the EPR method it was proved that ruthenium and osmium in surface complexes are in oxidation state +3. The formation of luminescent Ag(I), Au(I) and Pt(II) complexes on the surface of the MPhS, colored Ru(III) complexes on the surface of MPhS and ABTS, and mixed-ligand complexes of Pt(II) with surface aminobenzthiazole groups and Michler’s thioketone were used for developing methods of their adsorption luminescent, adsorption-photometric and test determinatio

scholarly journals Silicas Chemically Modified with Sulfur-Containing Groups for Separation and Preconcentration of Precious Metals Followed by Spectrometric Determination

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 481
Author(s):  
Vladimir Losev ◽  
Evgeney Elsuf’ev ◽  
Elena Borodina ◽  
Olga Buyko ◽  
Natalya Maznyak ◽  
...  
Keyword(s):  
Certified Reference Materials ◽  
Precious Metals ◽  
Substitution Reactions ◽  
Thiourea Derivatives ◽  
Chemically Modified ◽  
Dipropyl Disulfide ◽  
Separation And Preconcentration ◽  
High Concentrations ◽  
Precious Metal Ions ◽  
Sulfur Containing

Silicas chemically modified with a number of sulfur-containing groups (mercaptopropyl, mercaptophenyl, dipropyl disulfide, thiadiazole thiol, dithiocarbamate and thiourea derivatives) were proposed for the separation and preconcentration of precious metals. These adsorbents quantitatively extracted precious metals from 0.5 to 4 M solutions of hydrochloric acid. It allowed their separation from high concentrations of non-ferrous, alkaline earth, alkali and some other related metals. The selectivity of separation of kinetically labile precious metal ions in ligand substitution reactions from kinetically inert ones depended on the nature of sulfur atom within the functional group of adsorbents and increased when passing from thione to thiol sulfur. Approaches for the preconcentration of precious metals using silicas chemically modified with sulfur-containing groups prior to their AAS, ICP-OES, and ICP-MS determination in ores, concentrates and their processing products were proposed. The correctness of the developed methods was confirmed by the analysis of certified reference materials.

scholarly journals Separation and preconcentration followed by ICP-OES and ICP-MS determination of precious metals using silica gel chemically modified with dithiocarbamate groups

2019 ◽  
Vol 55 (15) ◽  
pp. 2659-2669 ◽  
Author(s):  
Vladimir N. Losev ◽  
Victoriya V. Parfenova ◽  
Evgeney V. Elsuf’ev ◽  
Elena V. Borodina ◽  
Segey I. Metelitsa ◽  
...  
Keyword(s):  
Silica Gel ◽  
Precious Metals ◽  
Icp Oes ◽  
Chemically Modified ◽  
Icp Ms ◽  
Separation And Preconcentration

Preconcentration and determination of osmium(VIII) using silicas chemically modified with sulfur-containing groups

2015 ◽  
Vol 70 (7) ◽  
pp. 781-787
Author(s):  
V. N. Losev ◽  
V. V. Parfenova ◽  
E. V. Elsuf’ev ◽  
A. K. Trofimchuk
Keyword(s):  
Chemically Modified ◽  
Sulfur Containing

scholarly journals Application of Silica Chemically Modified by Sulfur-Containing Groups to the Separation and Determination of Platinum and Rhenium in Catalysts Based on Aluminum Oxide

2018 ◽  
Vol 73 (4) ◽  
pp. 325-333 ◽  
Author(s):  
V. N. Losev ◽  
V. V. Parfenova ◽  
E. V. Elsuf’ev ◽  
O. V. Buiko ◽  
S. L. Didukh ◽  
...  
Keyword(s):  
Aluminum Oxide ◽  
Chemically Modified ◽  
Sulfur Containing

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

Selectivity coefficients of some simple and complex inorganic ions for Spheron DEAE

1984 ◽  
Vol 49 (10) ◽  
pp. 2349-2354 ◽  
Author(s):  
František Vláčil ◽  
Karel Koňák
Keyword(s):  
Ion Exchange ◽  
Mobile Phase ◽  
Dynamic Method ◽  
Precious Metals ◽  
Inorganic Ions ◽  
Chromatographic Determination ◽  
Chloride Ions ◽  
Chloro Complexes ◽  
Selectivity Coefficients

The selectivity coefficients of the nitrate and chloride ions and of anionic chloro complexes of Au(III), Rh(III), Pd(II), and Pt(IV) for ion exchange on Spheron DEAE in the chloride form are determined by the dynamic method. the complex anion species formed are identified and the ion exchange nature of the sorption of precious metals on this sorbent is confirmed based on the elution order of the precious metals as determined previously by the column chromatography on Spheron DEAE using hydrochloric acid as the mobile phase. The effect of the presence of perchlorate in the mobile phase during the liquid chromatography of precious metals and during the chromatographic determination of nitrate traces is explained.

Determination of trace concentrations of copper by FIA-FAAS after preconcentration on chelating sorbents

1989 ◽  
Vol 54 (7) ◽  
pp. 1785-1794 ◽  
Author(s):  
Vlastimil Kubáň ◽  
Josef Komárek ◽  
Zbyněk Zdráhal
Keyword(s):  
Sampling Frequency ◽  
Copper Determination ◽  
Flow Rates ◽  
Sample Injection ◽  
Injection Flow ◽  
Chelating Sorbents ◽  
Set Up ◽  
Trace Concentrations ◽  
Better Than

A FIA-FAAS apparatus containing a six-channel sorption equipment with five 3 x 26 mm microcolumns packed with Spheron Oxin 1 000, Ostsorb Oxin and Ostsorb DTTA was set up. Combined with sorption from 0.002M acetate buffer at pH 4.2 and desorption with 2M-HCl, copper can be determined at concentrations up to 100, 150 and 200 μg l-1, respectively. For sample and eluent flow rates of 5.0 and 4.0 ml min-1, respectively, and a sample injection time of 5 min, the limit of copper determination is LQ = 0.3 μg l-1, repeatability sr is better than 2% and recovery is R = 100 ± 2%. The enrichment factor is on the order of 102 and is a linear function of time (volume) of sample injection up to 5 min and of the sample injection flow rate up to 11 ml min-1 for Spheron Oxin 1 000 and Ostsorb DTTA. For times of sorption of 60 and 300 s, the sampling frequency is 70 and 35 samples/h, respectively. The parameters of the FIA-FAAS determination (acetylene-air flame) are comparable to or better than those achieved by ETA AAS. The method was applied to the determination of traces of copper in high-purity water.

Sign in / Sign up

Export Citation Format

Share Document