Temperature-Dependent Colloidal Stability of Hydrophobic Nanoparticles Caused by Surfactant Adsorption/Desorption and Depletion Flocculation

Langmuir ◽  
2009 ◽  
Vol 25 (18) ◽  
pp. 10501-10506 ◽  
Author(s):  
Thomas Dederichs ◽  
Martin Möller ◽  
Oliver Weichold
Keyword(s):  
Colloidal Stability ◽  
Surfactant Adsorption ◽  
Temperature Dependent ◽  
Depletion Flocculation ◽  
Adsorption Desorption

scholarly journals The Impact of Micelle Formation on Surfactant Adsorption–Desorption

ACS Omega ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 2248-2254 ◽  
Author(s):  
Dirk J. Groenendijk ◽  
Johannes N. M. van Wunnik
Keyword(s):  
Micelle Formation ◽  
Surfactant Adsorption ◽  
Adsorption Desorption ◽  
The Impact

Adsorption, desorption, and activity of glucose oxidase on selected clay species

1976 ◽  
Vol 22 (5) ◽  
pp. 684-693 ◽  
Author(s):  
H. W. Morgan ◽  
C. T. Corke
Keyword(s):  
Hydrogen Bonding ◽  
Protein Structure ◽  
Cation Exchange ◽  
Glucose Oxidase ◽  
Isoelectric Point ◽  
Active Form ◽  
Temperature Dependent ◽  
Specific Activities ◽  
Ph Dependent ◽  
Adsorption Desorption

The adsorption of the enzyme glucose oxidase (EC 1.1.3.4) to clays followed the pattern described for other proteins as being pH dependent. Maximum adsorption occurred at or below the isoelectric point of the enzyme. The amount of enzyme adsorbed to clay was influenced by the type of clay used, and also the saturating cations. Initially adsorbed enzyme showed low specific activities, and as amounts of enzyme adsorbed approached maximum saturation of clay, specific activities increased approaching that determined for free enzyme.The adsorption of glucose oxidase involved a temperature-independent cation-exchange mechanism, and enzyme adsorbed to surfaces of clay could be desorbed in active form by elevation of pH of suspending solution. This was followed by a slower temperature-dependent fixation, probably by hydrogen bonding, which resulted in protein being irreversibly adsorbed to clay surfaces.It is proposed that on adsorption of glucose oxidase to clay surfaces unravelling of the protein structure occurred, which allowed penetration of protein into the interlamellar spaces of montmorillonite. This proposal was based on the observed expansion of montmorillonite to 23 Å, and the decreases in amount of a second-protein lysozyme adsorbed with extended incubation times of glucose oxidase – clay complexes at pH 4.5.

scholarly journals Surfactant adsorption kinetics in microfluidics

2016 ◽  
Vol 113 (41) ◽  
pp. 11465-11470 ◽  
Author(s):  
Birte Riechers ◽  
Florine Maes ◽  
Elias Akoury ◽  
Benoît Semin ◽  
Philipp Gruner ◽  
...  
Keyword(s):  
Nonionic Surfactants ◽  
Adsorption Process ◽  
Surfactant Adsorption ◽  
Kinetic Measurement ◽  
Small Droplet ◽  
Kinetics Of Adsorption ◽  
Droplet Flow ◽  
Surfactant Interactions ◽  
Adsorption Desorption ◽  
Kinetics Of

Emulsions are metastable dispersions. Their lifetimes are directly related to the dynamics of surfactants. We design a microfluidic method to measure the kinetics of adsorption of surfactants to the droplet interface, a key process involved in foaming, emulsification, and droplet coarsening. The method is based on the pH decay in the droplet as a direct measurement of the adsorption of a carboxylic acid surfactant to the interface. From the kinetic measurement of the bulk equilibration of the pH, we fully determine the adsorption process of the surfactant. The small droplet size and the convection during the droplet flow ensure that the transport of surfactant through the bulk is not limiting the kinetics of adsorption. To validate our measurements, we show that the adsorption process determines the timescale required to stabilize droplets against coalescence, and we show that the interface should be covered at more than 90% to prevent coalescence. We therefore quantitatively link the process of adsorption/desorption, the stabilization of emulsions, and the kinetics of solute partitioning—here through ion exchange—unraveling the timescales governing these processes. Our method can be further generalized to other surfactants, including nonionic surfactants, by making use of fluorophore–surfactant interactions.

Temperature Dependent Adsorption–Desorption Behaviour of Pendimethalin in Punjab Soils

2017 ◽  
Vol 100 (1) ◽  
pp. 167-175 ◽  
Author(s):  
Pervinder Kaur ◽  
Amanpreet Makkar ◽  
Paawan Kaur ◽  
Shilpa
Keyword(s):  
Temperature Dependent ◽  
Adsorption Desorption

Modeling of Pyrolytic Laser-Assisted Chemical Vapor Deposition: Effects of Kinetics and Choice Of Substrate

1987 ◽  
Vol 101 ◽  
Author(s):  
D.C. Skouby ◽  
K.F. Jensen
Keyword(s):  
Gas Phase ◽  
Vapor Deposition ◽  
Laser Intensity ◽  
Chemical Vapor ◽  
Reaction Rates ◽  
Desorption Kinetics ◽  
Temperature Dependent ◽  
Finite Element Approach ◽  
Element Approach ◽  
Adsorption Desorption

ABSTRACTThe pyrolytlc laser-assisted deposition of metals Is modeled. A finite element approach is used to solve for temperatures and gas-phase concentrations In a transient calculation. The model accommodates the use of temperature-dependent physical properties as well as the occurrence of irregularly shaped deposits. Volcano-like deposits’ are predicted under certain conditions of gas pressure and laser intensity. The effect of using substrates with different thermal conductivities is investigated. Using adsorption-desorption kinetics such that the reaction rates have sharp maxima with respect to temperature, volcanoes of varying depths are modeled.

scholarly journals Time and temperature dependent sorption behaviour of dimethoate pesticide in various Indian soils

2014 ◽  
Vol 28 (4) ◽  
pp. 479-490 ◽  
Author(s):  
Sunita Rani ◽  
Dhiraj Sud Sant
Keyword(s):  
Adsorption Process ◽  
Driving Forces ◽  
Order Kinetic ◽  
Temperature Dependent ◽  
Sorption Behaviour ◽  
Enthalpy Of Adsorption ◽  
Indian Soils ◽  
Order Kinetic Model ◽  
Different Temperatures ◽  
Adsorption Desorption

Abstract Experiments were conducted to study the sorption behaviour of dimethoate in three Indian soils at different temperatures. A kinetic study showed that adsorption equilibrium was reached within 15 h at different initial levels of pesticide concentration. Applicability of the pseudo second order kinetic model suggested that the adsorption process was complex and several mechanisms were involved. The Freundlich model explained the adsorption behaviour adequately and the isotherms were of S-type. The adsorption process was found to be strongly affected by temperature. The Gibbs free energy change, ΔGº values (from -15.81 to -16.60 kJ mol-1) indicated that the process was spontaneous and exothermic in nature. The change in enthalpy of adsorption, ΔH° values (from -17.729 to -21.539 kJ mol-1) suggested that relatively weak H-bond forces were the main driving forces for adsorption. Desorption was found to be concentration- and temperature-dependent with higher desorption occurring at higher temperature and concentration levels. The results signify the importance of temperature in controlling the mobility of dimethoate in water bodies.

scholarly journals Correlation between Colloidal Stability and Surfactant Adsorption/Association Phenomena Studied by Light Scattering

2008 ◽  
Vol 112 (21) ◽  
pp. 6733-6733 ◽  
Author(s):  
Alessio Zaccone ◽  
Hua Wu ◽  
Marco Lattuada ◽  
Massimo Morbidelli
Keyword(s):  
Light Scattering ◽  
Colloidal Stability ◽  
Surfactant Adsorption
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