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| Titel |
The effect of natural and anthropogenic factors on sorption of copper in chernozem |
| VerfasserIn |
Tatiana Bauer, Tatiana Minkina, Saglara Mandzhieva, David Pinskii, Vitaly Linnik, Svetlana Sushkova |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250122269
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| Publikation (Nr.) |
 EGU/EGU2016-1257.pdf |
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| Zusammenfassung |
| The aim of this work was to study the effect of the attendant anions and particle-size
distribution on the adsorption of copper by ordinary chernozem. Solutions of HM nitrates,
acetates, chlorides, and sulfates were used to study the effect of the chemical composition of
added copper salts on the adsorption of copper by an ordinary chernozem. Samples of the soil
sieved through a 1-mm sieve in the natural ionic form and soil fraction with different particle
size (clay - the particle with size < 1μm and physical clay < 10 μm) were treated with
solutions of the corresponding copper salts at a soil : solution ratio of 1:10. The
concentrations of the initial copper solutions were 0.02, 0.05, 0.08, 0.1, 0.3, 0.5, and 1.0
mM/L. The range of Cu2+ concentrations in the studied system covers different geochemical
situations corresponding to the actual levels of soil contamination with the metal
under study. The suspensions were shaken for 1 h, left to stand for 24 h, and then
filtered. The contents of the HM in the filtrates were determined by atomic absorption
spectrometry (AAS). The contents of the adsorbed copper cations were calculated
from the difference between the metal concentrations in the initial and equilibrium
solutions.
The isotherms of copper adsorption from the metal nitrate, chloride, and sulfate solutions
have near linear shapes and, hence, can be satisfactorily described by a Henry or Freundlich
equation:
Cads = KH •Ceq.(1)
Cads = KF •Ceqn,(2)
where Cadsis the content of the adsorbed cations, mM/kg soil;Ceq is the concentration of
copper in the equilibrium solution, mM/L; KH and KF denote the Henry and Freundlich
adsorption coefficients, respectively, kg/L.
The isotherm of Cu2+ adsorption by ordinary chernozem from acetate solutions is
described by the Langmuir equation:
Cads = C∞ÊLC / (1 + ÊLC), (3)
where Cadsis the content of the adsorbed cations, mM/kg soil;C∞ is the maximum
adsorption of the HM, mM/kg soil; ÊL is the affinity constant, L/mM; C is the concentration
of the HM in the equilibrium solution, mM/L.
According to the values of KH, the binding strength of the copper cations adsorbed
from different salt solutions decreases in the series: Cu(Ac)2(1880,5± 76,2) >
CuCl2(1442,8±113,5) > Cu(NO3)2(911,4 ± 31,1) >> CuSO4(165,3 ± 12,9). Thus, copper
is most strongly adsorbed from the acetate solution and least strongly from the sulfate
solution.
The adsorption of copper by clay and physical clay fractions from the ordinary
chernozem was of limited character and followed the (3) equation. In the particle-size
fractions separated from the soils, the concentrations of copper decreased with the decreasing
particle size. The values of ÊL and C∞characterizing the HM adsorption by the chernozem
and its particle-size fractions formed the following sequence: clay (80,20±20,29 and
28,45±0,46 > physical clay (58,20±14,54 and 22,15±1,22) > entire soil (38,80±12,33 and
17,58±3,038).
This work was supported by the Russian Ministry of Education and Science, project no.
5.885.2014/K, Russian Foundation for Basic Research, projects no. 14-05-00586 À |
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