Loading...
Search for:
negatively-charged
0.005 seconds
Interactions between Rock/Brine and Oil/Brine interfaces within thin brine film wetting carbonates: A molecular dynamics simulation study
, Article Energy and Fuels ; Volume 33, Issue 9 , 2019 , Pages 7983-7992 ; 08870624 (ISSN) ; Badizad, M. H ; Kargozarfard, Z ; Ayatollahi, S ; Sharif University of Technology
American Chemical Society
2019
Abstract
The thin brine film that wets rock surfaces governs the wettability of underground reservoirs. The ionic composition and salinity of this nanosized brine film influence the wetting preference of the rock pore space occupied by hydrocarbons. Despite numerous investigations over the last decades, a unanimous fundamental understanding that concerns the contribution of ions in the original wetting state of the reservoir is lacking and hence the mechanisms responsible for the wettability reversal of the mineral are still unclear. This wettability reversal is the main consequence of ion-Tuned waterflooding. Although the method is widely accepted in practice, there is no universal consensus on the...
Experimental study on the influence of initial pH, ionic strength, and temperature on the selective adsorption of dyes onto nanodiamonds
, Article Journal of Chemical and Engineering Data ; Volume 64, Issue 4 , 2019 , Pages 1508-1514 ; 00219568 (ISSN) ; https://pubs.acs.org/doi/abs/10.1021/acs.jced.8b01091 ; Pourghaderi, A ; Shojaei, A ; Sharif University of Technology
American Chemical Society
2019
Abstract
In the current work, the performance of untreated nanodiamonds (UNDs) and thermally oxidized nanodiamonds (ONDs), as adsorbents for selective adsorption of methylene blue (MB) and methyl orange (MO) from aqueous media, was examined. The adsorption isotherm, initial pH, ionic strength, and thermodynamic study were investigated in batch experiments. The equilibrium adsorption data were analyzed by Langmuir and Freundlich isotherm models, which indicated that the isotherms were well fitted with the Langmuir model for both dyes. Thermodynamic parameters indicated that the adsorption operation was a feasible, spontaneous, and physisorption process in experimental conditions. Meanwhile, the...
Experimental study on the influence of initial pH, Ionic strength, and temperature on the selective adsorption of dyes onto nanodiamonds
, Article Journal of Chemical and Engineering Data ; 2019 ; 00219568 (ISSN) ; Pourghaderi, A ; Shojaei, A ; Sharif University of Technology
American Chemical Society
2019
Abstract
In the current work, the performance of untreated nanodiamonds (UNDs) and thermally oxidized nanodiamonds (ONDs), as adsorbents for selective adsorption of methylene blue (MB) and methyl orange (MO) from aqueous media, was examined. The adsorption isotherm, initial pH, ionic strength, and thermodynamic study were investigated in batch experiments. The equilibrium adsorption data were analyzed by Langmuir and Freundlich isotherm models, which indicated that the isotherms were well fitted with the Langmuir model for both dyes. Thermodynamic parameters indicated that the adsorption operation was a feasible, spontaneous, and physisorption process in experimental conditions. Meanwhile, the...
Experimental study on the influence of initial pH, ionic strength, and temperature on the selective adsorption of dyes onto nanodiamonds
, Article Journal of Chemical and Engineering Data ; 2019 ; 00219568 (ISSN) ; Pourghaderi, A ; Shojaei, A ; Sharif University of Technology
American Chemical Society
2019
Abstract
In the current work, the performance of untreated nanodiamonds (UNDs) and thermally oxidized nanodiamonds (ONDs), as adsorbents for selective adsorption of methylene blue (MB) and methyl orange (MO) from aqueous media, was examined. The adsorption isotherm, initial pH, ionic strength, and thermodynamic study were investigated in batch experiments. The equilibrium adsorption data were analyzed by Langmuir and Freundlich isotherm models, which indicated that the isotherms were well fitted with the Langmuir model for both dyes. Thermodynamic parameters indicated that the adsorption operation was a feasible, spontaneous, and physisorption process in experimental conditions. Meanwhile, the...
The impact of salinity on the interfacial structuring of an aromatic acid at the calcite/brine interface: an atomistic view on low salinity effect
, Article Journal of Physical Chemistry B ; Volume 124, Issue 1 , December , 2020 , Pages 224-233 ; Badizad, M. H ; Hartkamp, R ; Ayatollahi, S ; Ghazanfari, M. H ; Sharif University of Technology
American Chemical Society
2020
Abstract
This study aims to elucidate the impact of salinity on the interactions governing the adsorption of polar aromatic oil compounds onto calcite. To this end, molecular dynamics simulations were employed to assess adsorption of a model polar organic molecule (deprotonated benzoic acid, benzoate) on the calcite surface in NaCl brines of different concentration levels, namely, deionized water (DW), low-salinity water (LS, 5000 ppm), and sea water (SW; 45,000 ppm). Calcite was found to be completely covered by several well-ordered water layers. The top hydration layer is very compact and prevents direct adsorption of benzoates onto the substrate. Instead, Na+ ions form a distinct positively...
Multiway investigation of interaction between fluorescence labeled DNA strands and unmodified gold nanoparticles
, Article Analytical Chemistry ; Volume 84, Issue 15 , July , 2012 , Pages 6603-6610 ; 00032700 (ISSN) ; Kompany Zareh, M ; Hormozi Nezhad, M. R ; Sharif University of Technology
ACS
2012
Abstract
The single stranded DNA can be adsorbed on the negatively charged surface of gold nanoparticles (AuNPs), but the rigid structure of double stranded DNA prevents it from adsorption. Signal of a tagged single stranded DNA will be quenched by the plasmon effect of the AuNP surface after its adsorption. This phenomenon has been used to study the DNA hybridization and interactions of two complementary 21mer oligonucleotides each tagged with a different fluorescent dye in the presence of 13 nm gold nanoparticles. The DNA strands used in this study belong to the genome of HIV. The obtained rank deficient three-way fluorescence data sets were resolved by both PARAFAC and restricted Tucker3 models....
Effect of Cysteine Substitutions on the Structural and Magnetic Properties of Fe3O4–Cysteine/RGO and Fe3O4/RGO–Cysteine Nanocomposites
, Article Journal of Superconductivity and Novel Magnetism ; 2018 ; 15571939 (ISSN) ; Mehrani, K ; Madaah Hosseini, H. R ; Zare, K ; Sharif University of Technology
Springer New York LLC
2018
Abstract
We synthesized by electrostatic self-assembly route in basic solution Fe3O4–cysteine/RGO and Fe3O4/RGO–cysteine nanocomposites. In this method, electrostatic interaction was created via negatively charged surface of the reduced graphene oxide and reduced graphene oxide–cysteine sheets and positively charged surface of the Fe3O4 and Fe3O4–Cys nanoparticles in aqueous solution. The structural and magnetic properties of the prepared samples were analyzed by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM), respectively. The dependences of magnetization as a function of...
Effect of cysteine substitutions on the structural and magnetic properties of Fe3O4–Cysteine/RGO and Fe3O4/RGO–Cysteine nanocomposites
, Article Journal of Superconductivity and Novel Magnetism ; Volume 32, Issue 5 , 2019 , Pages 1299-1306 ; 15571939 (ISSN) ; Mehrani, K ; Madaah Hosseini , H. R ; Zare, K ; Sharif University of Technology
Springer New York LLC
2019
Abstract
We synthesized by electrostatic self-assembly route in basic solution Fe3O4–cysteine/RGO and Fe3O4/RGO–cysteine nanocomposites. In this method, electrostatic interaction was created via negatively charged surface of the reduced graphene oxide and reduced graphene oxide–cysteine sheets and positively charged surface of the Fe3O4 and Fe3O4–Cys nanoparticles in aqueous solution. The structural and magnetic properties of the prepared samples were analyzed by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM), respectively. The dependences of magnetization as a function of...
Electrochemical preparation of over-oxidized polypyrrole/multi-walled carbon nanotube composite on glassy carbon electrode and its application in epinephrine determination
, Article Electrochimica Acta ; Volume 57, Issue 1 , 2011 , Pages 132-138 ; 00134686 (ISSN) ; Saberi, R. S ; Sharif University of Technology
Abstract
A composite film constructed of surfactant doped over-oxidized polypyrrole and multi-walled carbon nanotube was prepared on the surface of glassy carbon electrode by the electro-polymerization method. Surface characterization of the modified electrode was performed by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectrometry. The investigations have been proved that the over-oxidation of the modifier film resulted in a porous thin layer that improves the interlayer diffusion mechanism for the electroactive species. On the other hand, the negative charge density on the surface of the electrode excludes the negative analytes (e.g. ascorbate and Fe(CN)63?/4?)...