排序方式: 共有6条查询结果,搜索用时 0 毫秒
1
1.
2.
Chugaev A. V. Chernyshev I. V. Budyak A. E. Mandzhieva G. V. Sadasyuk A. S. Gareev B. I. 《Doklady Earth Sciences》2019,484(2):167-172
Doklady Earth Sciences - The isotopic composition of uranium is a new geochemical indicator that facilitates reconstruction of the redox conditions of geological processes. In this paper the... 相似文献
3.
Chugaev A. V. Chernyshev I. V. Pokrovsky B. G. Mandzhieva G. V. Gareev B. I. Sadasyuk A. S. Batalin G. A. 《Doklady Earth Sciences》2019,485(1):336-340
Doklady Earth Sciences - Abstract—This article is devoted to a study of variations in the U isotopic composition (238U/235U) in the section of clastic–carbonate Ediacaran sediments... 相似文献
4.
I. V. Chernyshev V. N. Golubev A. V. Chugaev G. V. Mandzhieva 《Doklady Earth Sciences》2016,470(2):1097-1099
The variations in 238U/235U values accompanying mobilization of U by fracture waters from uranium-bearing rocks, in which U occurs as a fine impregnation of oxides and silicates, were studied by the high-precision (±0.07‰) MC–ICP–MS method. Transition of U into the aqueous phase in the oxidized state U(VI) is accompanied by its isotope fractionation with enrichment of dissolved U(VI) in the heavy isotope 238U up to 0.32‰ in relation to the composition of the solid phases. According to the sign, this effect is consistent with the tendency of the behavior of 238U and 235U upon interaction of river waters with rocks of the catchment areas [11] and with the effect observed during oxidation of uraninite by the oxygen-bearing NaHCO3 solution [12]. 相似文献
5.
New approaches to studying heavy metals in soils by X-ray absorption spectroscopy (XANES)) and extractive fractionation 总被引:2,自引:0,他引:2
T. M. Minkina A. V. Soldatov D. G. Nevidomskaya G. V. Motuzova Yu. S. Podkovyrina S. S. Mandzhieva 《Geochemistry International》2016,54(2):197-204
A comprehensive approach to studying the nature of interaction between heavy-metal ions and the organic–mineral matrix of soils involves application of modern physical analytical techniques and chemical methods of extractive fractionation. XANES was used to obtain the first data on the near-edge fine structure of X-ray spectra for a number of heavy-metal species in ordinary chernozem. Data on the structure of soil samples saturated with Zn2+ and Cu2+ obtained by XANES (X-ray absorption near-edge structure) make it possible to elucidate the interaction mechanisms of the metals and the types of chemical bonds formed thereby. As contamination doze of with Cu and Zn is increased (from 2000 to 10 000 mg/kg soil), particularly if the metals are introduced in the form of readily solubility salts, bonding between the metals and soil components weakens. Data of extractive fractionation of metal compounds from samples saturated with Cu and Zn compounds testify that the Cu2+ ion is preferably retained in the organic matter of the soil, whereas the Zn2+ ion is bound mostly to silicates, carbonates, and Fe and Mn (hydro)oxides. 相似文献
6.
D. L. Pinskii T. M. Minkina T. V. Bauer D. G. Nevidomskaya S. S. Mandzhieva M. V. Burachevskaya 《Geochemistry International》2018,56(3):266-275
Laboratory data in Cu2+ adsorption by chernozems and parent rocks in Rostov region show that adsorption isotherms can be approximated by the Langmuir equation, whose parameters (Kl and C∞) were calculated for all of the samples. The values of C∞ show a strong negative correlation with the values of cationexchange capacity (CEC) (r =–0.88 at Р = 0.95), and Kl is correlated with the content of physical clay (particles <0.01 mm) (r = 0.78) and with clay (particles <0.001 mm) content in ordinary chernozem and southern chernozems of various particle size distribution (r = 0.80). Even stronger correlations were detected between these parameters in southern chernozems (r = 0.89 for the physical clay (PC) and r = 0.91 for the silt). However, none of the samples displays a significant correlation of C∞ and Kl with the contents of physical clay and silt. This led us to conclude that the composition of the samples, for example, their organic matter, can affect Cu2+ adsorption by the soils and parent rocks. Acidification mechanisms of the equilibrium solutions during the Cu2+ adsorption by soils are discussed, as also are the reasons for the absence of balance between Cu2+ adsorbed by soils and exchangeable cations transferred into solution. Analysis of the fine structures of the XANES and EXAFS spectra suggests that Cu2+ can form coordinated chelate complex compounds with humic acids (HA) of soils and can substitute Al3+ at octahedral sites when interacting with clay minerals in soils. 相似文献
1