Adsorption dispersion

SCRAM (28) is a TDE dynamic, numerical finite difference soil model, with a TDE flow module and a TDE solute module. It can handle moisture behavior, surface runoff, organic pollutant advection, dispersion, adsorption, and is designed to handle (i.e., no computer code has been developed) volatilization and degradation. This model may not have received great attention by users because of the large number of input data required. 

Fig. 54. a A typical image of closely packed pZT plasmid DNA molecules adsorbed onto a cationic lipid membrane of dipalmitoyldimethyl ammoniumylpropane. The image was recorded in 20 mMNaCl [513]. b Height image of tobacco mosaic viruses on the mica surface modified with bovine serum albumin (BSA). In contrast, direct adsorption from a solution containing BSA led to disperse adsorption of the TMV rods [517]... 

In the three-dimensional advection-dispersion-adsorption equation, the adsorp-()S... 

Chapter 6 gives basic aspects about polymers, and Chapter 7 about proteins, the polymers often used in stabilizing food dispersions. Adsorption of surface active polymers is discussed in Section 10.3.2. 

BIOSCREEN (Newell et al., 1996) is an easy-to-use screening model that simulates remediation through natural attenuation (RNA) of dissolved hydrocarbons at petroleum fuel release sites. The software, programmed in a spreadsheet environment and based on the Domenico analytical solute transport model, has the ability to simulate advection, dispersion, adsorption, and aerobic decay as well as anaerobic reactions that have been shown to be the dominant biodegradation processes at many petroleum release sites. 

A core-flood for adsorption determination consists of injecting a measured volume of surfactant solution containing a nonadsorbing tracer into a brine-saturated core and collecting effluent fractions at the core outlet. Chemical analysis of the effluent samples allows the calculation of an adsorption level based on material balance considerations and also results in a set of effluent profiles for the surfactant and the tracer. In addition to the material balance, adsorption is evaluated by matching experimental effluent concentrations from the core-floods with a convection—dispersion—adsorption numerical model. The model parameters then allow calculation of a complete adsorption isotherm. 

Effluent profiles obtained from a core-flood performed with a mixture of two surface-active components (C12 and C18) separated from a commercially available sulfobetaine are shown in Figure 24 (115). The points represent experimental data, and the lines were obtained by simulating the core-flood with a convection—dispersion—adsorption model that is based on the surface excess concept and takes into account monomer—micelle equilibrium (115). Because the mixture contains different homologues of the same surfactant, the ideal mixed micelle model... 

Figure 11.102. Schematic representation of the dispersion process the polymer matrix is sheared and transported, whereby the agglomerates will be first distributed and destroyed, followed by dispersion (adsorption of a mono-molecular layer of matrix polymer onto the particle surface), and later phase separation. [Reproduced fiom ref 37 with kind permission of Elsevier.]...

Ismail, H.M. Fouad, N.E., and Zaki. M.I.. Nitrogen and pyridine adsorption on chromia-coated silica and alumina catalysts Probing the chromia dispersity. Adsorpt. Sci. Technol.. 8( 1). 34-43 (1992). 

By analogy with solid particle dispersions, adsorption isotherms can be determined as a function of the chemical potential of the solute. An indirect, but rapid and powerful, example is given by surface tension measurements, which can detect very low amounts of surface-active solute in the form of contaminant. This property is used to determine purity in easily hydrolysable surfactants such as SDS or sodium bis(2-ethylhexyOsulfosuccinate (AOT). A minimum in the surface tension near the CMC directly detects the presence of a surface-active contaminant such as dodecanol or octanol, which will desorb from the interface at high surfactant concentrations. This desorption is the origin of the a priori counter-intuitive increase of surface tension with surfactant content (16). 

Sparse Coatings by Disperse Adsorption of Cylindrical Brushes... 

Uses Softener, soil antiredeposition agent for detergents binder dispersant adsorption of llq. surfactants Lauramide 11 [Zohar Dalla]... 

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