Kinetics of competitive adsorption of polystyrene chains at a porous silica surface

Langmuir ◽  
1994 ◽  
Vol 10 (2) ◽  
pp. 538-541 ◽  
Author(s):  
Masami Kawaguchi ◽  
Yoshimasa Sakata ◽  
Sachio Anada ◽  
Tadaya Kato ◽  
Akira Takahashi
Keyword(s):  
Competitive Adsorption ◽  
Silica Surface ◽  
Porous Silica ◽  
Kinetics Of

Characteristics of the kinetics of exciplex formation between pyrene and N,N-dimethylaniline on a porous silica surface

1997 ◽  
Vol 33 (3) ◽  
pp. 157-160 ◽  
Author(s):  
V. P. Kondilenko ◽  
T. A. Kikteva ◽  
I. G. Tarasov ◽  
A. M. Eremenko
Keyword(s):  
Silica Surface ◽  
Porous Silica ◽  
Exciplex Formation ◽  
Kinetics Of

Ion specific effects of monovalent cations on deposition kinetics of engineered nanoparticles onto the silica surface in aqueous media

2019 ◽  
Vol 6 (9) ◽  
pp. 2712-2723 ◽  
Author(s):  
Ruixing Huang ◽  
Chengxue Ma ◽  
Qiang He ◽  
Jun Ma ◽  
Zhengsong Wu ◽  
...  
Keyword(s):  
Silica Surface ◽  
Aqueous Media ◽  
Engineered Nanoparticles ◽  
Monovalent Cations ◽  
Hydration Degree ◽  
Deposition Kinetics ◽  
Specific Effects ◽  
Kinetics Of

The cations decreased the deposition kinetics of different charged NPs onto silica with the decrease in the hydration degree of additive cations.

scholarly journals Removal Effect of Atrazine in Co-Solution with Bisphenol A or Humic Acid by Different Activated Carbons

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2558 ◽  
Author(s):  
Zhansheng Wu ◽  
Xinhui Wei ◽  
Yongtao Xue ◽  
Xiufang He ◽  
Xia Yang
Keyword(s):  
Humic Acid ◽  
Bisphenol A ◽  
Adsorption Kinetics ◽  
Competitive Adsorption ◽  
Activated Carbons ◽  
Second Order ◽  
Adsorption Behavior ◽  
Single Solution ◽  
Pseudo Second Order ◽  
Kinetics Of

Activated carbons (ACs) based on apricot shells (AS), wood (W), and walnut shells (WS) were applied to adsorb atrazine in co-solutions. To study the effect of Bisphenol A (BPA) on the adsorption behavior of atrazine, the adsorption performance of ACs for BPA in single solution was studied. The results demonstrated that the adsorption kinetics of BPA fitted the pseudo-second-order model, the adsorption isotherms of BPA followed the Langmuir model. Meanwhile, the adsorption kinetics of atrazine fitted the pseudo-second-order kinetics model and the isotherm was consistent with the Freundlich model both in single solution and co-solution. In addition, competitive adsorption was observed when atrazine coexisted with BPA or humic acid. For the adsorption capacity, the adsorption amount of ASAC, WAC, and WSAC for atrazine obviously decreased by 18.0%, 30.0%, and 30.3% in the presence of BPA, respectively, which was due to the π−π interactions, hydrophobic interactions, and H-bonds, resulting in the competitive adsorption between atrazine and BPA. This study contributes to the further understanding of the adsorption behavior for atrazine in co-solution.

scholarly journals Some Peculiarities of Silica Modification Under High Reagent Pressure. I. Methodological Aspects

1995 ◽  
Vol 12 (3) ◽  
pp. 231-238 ◽  
Author(s):  
V.V. Sidorchuk ◽  
V.A. Tertykh ◽  
R. Leboda ◽  
Z. Hubicki
Keyword(s):  
Thermal Analysis ◽  
Surface Reaction ◽  
Silica Surface ◽  
Porous Silica ◽  
Physicochemical Characteristics ◽  
Geometrical Parameters ◽  
Duration Of Treatment ◽  
Preparation Conditions ◽  
Modification Process ◽  
Methodological Aspects

The effect of the following factors on the chemical and geometrical modification of aerosilogel (prepared from aerosil) was studied: the physicochemical characteristics of the modifying reagent pressures, the preparation conditions for the silica surface, the reaction temperature, the reagent pressures, the duration of treatment and the method employed for the modification process. The course of the surface reaction was followed by IR spectroscopy, differential thermal analysis and adsorption. During high-pressure modification, the geometrical parameters of the porous silica structure may be changed.

Effect of Sodium Ions on the Dielectric Conductivity of Porous Silica in Humid Environments

1990 ◽  
Vol 195 ◽  
Author(s):  
Wanqing Cao ◽  
Rosario Gerhardt ◽  
John B. Wachtman
Keyword(s):  
Relative Humidity ◽  
Silica Surface ◽  
Porous Silica ◽  
Sodium Content ◽  
Silica Gels ◽  
Interfacial Region ◽  
Relaxation Processes ◽  
Sodium Ions ◽  
Frequency Range ◽  
Dielectric Conductivity

ABSTRACTPartially sintered silica gels were immersed in different NaCI solutions to deliberately introduce a small amount of sodium ions ranging from 387 to 9900 ppm. Dielectric measurements were carried out in the frequency range 12 to 107Hz under various relative humidity conditions. Two relaxation processes were observed in the impedance and modulus planes and were assigned to two separate regions in the hydrated silica surface. The top region is expected to be rich in hydrated sodium since its modulus relaxation time depends strongly on the relative humidity as well as the sodium content. The interfacial region is believed to be composed of structured water since its dielectric conductivity is affected mainly by the amount of water adsorbed on the pore surfaces.

scholarly journals Kinetics of atrazine degradation by photocatalytic process in aqueous solution

2003 ◽  
Vol 5 (2) ◽  
pp. 87-93 ◽  
Author(s):  
O. Zahraa ◽  
L. Sauvanaud ◽  
G. Hamard ◽  
M. Bouchy
Keyword(s):  
Aqueous Solution ◽  
Titanium Dioxide ◽  
Salicylic Acid ◽  
Photocatalytic Degradation ◽  
Competitive Adsorption ◽  
Initial Time ◽  
Photocatalytic Process ◽  
Herbicide Atrazine ◽  
Kinetics Of ◽  
Atrazine Degradation

The photocatalytic degradation of the herbicide atrazine has been studied using suspended titanium dioxide as catalyst. The Langmuir-Hinshelwood model is satisfactorily obeyed at initial time and in the course of the reaction. The rate of degradation is found to be enhanced by the addition of persulphate ions. Competitive degradation between atrazine and other pollutants is satisfactorily interpreted as monitored by a competitive adsorption of the reactants. As a consequence, efficient reactants such as salicylic acid and phenol delay atrazine degradation until these compounds are degraded.

Nitrogen Incorporation and Growth Kinetics of GaAsN/GaAs Epilayers Grown by MOVPE

2000 ◽  
Vol 616 ◽  
Author(s):  
Laurent Auvray ◽  
Hervé Dumont ◽  
Jacques Dazord ◽  
Yves Monteil ◽  
Jean Bouix
Keyword(s):  
Activation Energy ◽  
Phase Composition ◽  
Gas Phase ◽  
Competitive Adsorption ◽  
Nonlinear Function ◽  
Group V ◽  
Nitrogen Incorporation ◽  
Nitrogen Desorption ◽  
Kinetics Of ◽  
Growth Temperature Range

AbstractThe nitrogen incorporation behavior in GaAs was investigated in the growth temperature range 500-600°C. It was observed that the temperature-dependence of the nitrogen incorporation exhibits two regimes. At 530°C, the nitrogen content x is a nonlinear function of the gas-phase composition indicating a surface-controlled reaction mechanism. The N composition varies slowly with 500°C < T < 560°C with an activation energy of 0.6 eV. For T < 560°C, N decreases exponentially with Ea= 3.7 eV, interpreted in terms of nitrogen desorption. In light of experimental results, we propose a surface kinetic model based on the competitive adsorption of group V precursors.

scholarly journals Electron transfer processes of coadsorbed Anthracene and N,N-Dimethylaniline on titania-silica

2004 ◽  
Vol 6 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Anna Eremenko ◽  
Natalie Smirnova ◽  
Oksana Yakimenko ◽  
Galina Starukh ◽  
David R. Worrall ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Competitive Adsorption ◽  
Co Adsorption ◽  
Decay Kinetics ◽  
Electron Transfer Process ◽  
Adsorption Sites ◽  
Transfer Processes ◽  
Pure Silica ◽  
Electron Transfer Processes ◽  
Kinetics Of

The effect of titania-silica binaries on the processes of PET and the decay kinetics of the Anthracene (An) fluorescence and An radical cation in presence of the co-adsorbed electron donor N,Ndimethylaniline (DMA) has been studied. The fluorescence of excited An adsorbed on pure silica is quenched by the addition of DMA, while co-adsorption of DMA on Ti/Si binaries resulted in increase of fluorescence intensity of adsorbed An. We suggest that competitive adsorption between DMA and An results in DMA occupying more active “titania” sites causing the shift of An molecules to weaker adsorption sites located on the silica support. An and DMA molecules being adsorbed simultaneously on the surface, effectively produce reduced titanium ions due to an electron transfer process. These data appear to lend weight to the suggestion of a pre-exciplex An-DMA state on the surface and effective PET from the excited molecular pair to the acceptor sites on the surface. These sites may be titania aggregates, or titania ions when there is a low content of Ti in the binaries.

scholarly journals Quaternary Ammonium Borohydride Adsorption in Mesoporous Silicate MCM-48

2010 ◽  
Vol 1262 ◽  
Author(s):  
Michael Joseph Wolverton ◽  
Luc L. Daemen ◽  
Monika A. Hartl
Keyword(s):  
Organic Cation ◽  
Silica Surface ◽  
Inelastic Neutron Scattering ◽  
Porous Silica ◽  
Inelastic Neutron ◽  
Hydrogen Release ◽  
Hydrogen Density ◽  
Mesoporous Silicate ◽  
Bet Isotherm ◽  
Lower Temperature

AbstractInorganic borohydrides have a high gravimetric hydrogen density but release H2 only under energetically unfavorable conditions. Surface chemistry may help in lowering thermodynamic barriers, but inclusion of inorganic borohydrides in porous silica materials has proved hitherto difficult or impossible. We show that borohydrides with a large organic cation are readily adsorbed inside mesoporous silicates, particularly after surface treatment. Thermal analysis reveals that the decomposition thermodynamics of tetraalkylammonium borohydrides are substantially affected by inclusion in MCM-48. Inelastic neutron scattering (INS) data show that the compounds adsorb on the silica surface. Evidence of pore loading is supplemented by DSC/TGA, XRD, FTIR, and BET isotherm measurements. Mass spectrometry shows significant hydrogen release at lower temperature from adsorbed borohydrides in comparison with the bulk borohydrides. INS data from partially decomposed samples indicates that the decomposition of the cation and anion is likely simultaneous. These data confirm the formation of Si-H bonds on the silica surface upon decomposition of adsorbed tetramethylammonium borohydride.

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