Details
| Original language | English |
|---|---|
| Pages (from-to) | 91-100 |
| Number of pages | 10 |
| Journal | Applied clay science |
| Volume | 120 |
| Early online date | 11 Dec 2015 |
| Publication status | Published - Feb 2016 |
Abstract
The work presents experimental and molecular modeling study of the anion diffusion with nitrate as a model probe in the organically modified bentonite. Organoclay samples with different loadings of the two cations Hexadecyltrimethylammonium (HDTMA+) and Hexadecylpyridinium (HDPy+) were prepared. The diffusivity of NO3- in the interfacial area of the organo-bentonite is strongly affected by the packing density of the organic coating. Through-diffusion experiments verified that the retardation capacity of the organoclays increases with the increasing amount of both organic cations on the clay surface. Observed NO3- diffusion in HDTMA+- and HDPy+-bentonite is in a similar range. Further, classical molecular dynamics studies, performed on sets of HDTMA+- and HDPy+-montmorillonite models, explained a molecular mechanism of the diffusion process of the nitrate anion at the organoclay-water interface. The molecular simulations showed comparable trends of the dependence of the NO3- diffusion coefficient on the content of organic cations on the surface as observed in experiment. Calculations explained how the organic cations are arranged on the surface and revealed that the positively charged head groups of the organic cations play a key role in the decreasing of the diffusivity of nitrate ions.
Keywords
- Anion diffusion, FTIR-spectroscopy, Molecular dynamics, Organoclay
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geology
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
In: Applied clay science, Vol. 120, 02.2016, p. 91-100.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Experimental and molecular dynamics study on anion diffusion in organically modified bentonite
AU - Schampera, B.
AU - Šolc, R.
AU - Tunega, D.
AU - Dultz, S.
N1 - Funding information: This study was supported within the frame of the D-A-CH collaboration by Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under the contract number SCHA 1732/1-1 and the FWF (Austrian Science Fund, Austria) under the contract number I880-N21 . The computational results presented have been achieved using the Vienna Scientific Cluster (VSC).
PY - 2016/2
Y1 - 2016/2
N2 - The work presents experimental and molecular modeling study of the anion diffusion with nitrate as a model probe in the organically modified bentonite. Organoclay samples with different loadings of the two cations Hexadecyltrimethylammonium (HDTMA+) and Hexadecylpyridinium (HDPy+) were prepared. The diffusivity of NO3- in the interfacial area of the organo-bentonite is strongly affected by the packing density of the organic coating. Through-diffusion experiments verified that the retardation capacity of the organoclays increases with the increasing amount of both organic cations on the clay surface. Observed NO3- diffusion in HDTMA+- and HDPy+-bentonite is in a similar range. Further, classical molecular dynamics studies, performed on sets of HDTMA+- and HDPy+-montmorillonite models, explained a molecular mechanism of the diffusion process of the nitrate anion at the organoclay-water interface. The molecular simulations showed comparable trends of the dependence of the NO3- diffusion coefficient on the content of organic cations on the surface as observed in experiment. Calculations explained how the organic cations are arranged on the surface and revealed that the positively charged head groups of the organic cations play a key role in the decreasing of the diffusivity of nitrate ions.
AB - The work presents experimental and molecular modeling study of the anion diffusion with nitrate as a model probe in the organically modified bentonite. Organoclay samples with different loadings of the two cations Hexadecyltrimethylammonium (HDTMA+) and Hexadecylpyridinium (HDPy+) were prepared. The diffusivity of NO3- in the interfacial area of the organo-bentonite is strongly affected by the packing density of the organic coating. Through-diffusion experiments verified that the retardation capacity of the organoclays increases with the increasing amount of both organic cations on the clay surface. Observed NO3- diffusion in HDTMA+- and HDPy+-bentonite is in a similar range. Further, classical molecular dynamics studies, performed on sets of HDTMA+- and HDPy+-montmorillonite models, explained a molecular mechanism of the diffusion process of the nitrate anion at the organoclay-water interface. The molecular simulations showed comparable trends of the dependence of the NO3- diffusion coefficient on the content of organic cations on the surface as observed in experiment. Calculations explained how the organic cations are arranged on the surface and revealed that the positively charged head groups of the organic cations play a key role in the decreasing of the diffusivity of nitrate ions.
KW - Anion diffusion
KW - FTIR-spectroscopy
KW - Molecular dynamics
KW - Organoclay
UR - http://www.scopus.com/inward/record.url?scp=84949498806&partnerID=8YFLogxK
U2 - 10.1016/j.clay.2015.11.026
DO - 10.1016/j.clay.2015.11.026
M3 - Article
AN - SCOPUS:84949498806
VL - 120
SP - 91
EP - 100
JO - Applied clay science
JF - Applied clay science
SN - 0169-1317
ER -