Electrostatic-chemical theory

As pointed out earlier, a possible mechanism could be the chemical nature of the environment which is created after the application of CP in terms of increasing the local pH and inhibiting the bacterial reproduction of microbes [43] in such a high alkaline environment. But there are two seemingly rival theories in this respect, the electrostatic-chemical theory and the chemical bridge theory. We briefly explain these theories and interpretations below. 

Pratt, L. R., and Rempe, S. B. (1999). Quasi-chemical theory and implicit solvent models for simulations. In Simulation and Theory of Electrostatic Interactions in Solution. Computational Chemistry, Biophysics, and Aqueous Solutions (L. R. Pratt and G. Hummer, eds.), vol. 492 of AIP Conference Proceedings, pp. 172-201. American Institute of Physics, Melville, NY... 

While the use of an electrical or electrostatic theory of chemical affinity declined decade by decade in the nineteenth century, the theory began to experience a small revival on two fronts in the 1880s. One source of revival was the lecture that Helmholtz gave to a large audience at the Chemical Society of London in 1881. Helmholtz firmly associated himself with a theory of electrical "particles," namely, that the ions produced in electrolysis carry discrete and indivisible "atoms of electricity" that are independent of the elementary substance with which they combine. He further identified these atoms of electricity with indivisible units of chemical affinity "This is the modern chemical theory of quantivalence, comprising all the saturated compounds."Ill... 

For large separations, the force between two solid surfaces in a fluid medium can usually be described by continuum theories such as the van der Waals and the electrostatic doublelayer theory. The individual nature of the molecules involved, their discrete size, shape, and chemical nature was neglected. At surface separations approaching molecular dimensions continuum theory breaks down and the discrete molecular nature of the liquid molecules has to be taken into account. 

The basic approach of chemical theory to surface science is to model a surface with a cluster of a finite number of atoms, with one or more adsorbate atoms or molecules bonded to various sites on the cluster. In parallel with the chemical theory there is also the solid state physics approach. This starts from an extended surface surface model, where an array of atoms perfectly periodic in two dimensions represents both the substrate and any adsorbates. Many theoretical techniques have been developed for the extended-surface model. We can only refer the interested reader to the literature/87,88,89,90,91,92,93,94/ and remark that the relative merits of the cluster and extended-surface approaches are still very much under active debate. It is clear that certain properties, such as bonding, are very localized in character and are well represented in a cluster. On the other hand, there are properties that have a delocalized nature, such as adsorbate-adsorbate interactions and electrostatic effects, for which an extended surface model is more appropriate. 

Van Loosdrecht et al. (1990) have investigated systematically the adhesion of microorganisms to solid surfaces in aquatic environments and describe the initial adhesion process in terms of a colloid-chemical theory. These workers focus on the interplay of (1) electrostatic interactions between bacterial surfaces and solid surfaces and (2) on the hydrophobic and steric energies of these surfaces. Adsorbed polymers can influence bacteria-surface interactions in several ways (1) electrostatic repulsions, (2) steric hinderance caused by mono-... 

Hu, H., Lu, Z., and Yang, W. (2007). Fitting molecular electrostatic potentials from quantum mechanical calculations, youma/ of Chemical Theory and Computation 3, 3, pp. 1004-1013. 

There are two general situations in which the particles in a solution do not have the same identity as those that are put into the system when a component dissociates and when components can combine to form other species. The first case is commonly identified with salts forming ions with electrostatic charges. In both cases, the reactions need not be complete, so that the solution can have the original species (components) as well as the new species. Further, the speciation need not lead to detectable entities. Thus, the chemical theory of solutions and the solution of... 

Mechanical Theory Electrostatic (Electronic) Theory Diffusion Theory Wetting Theory Chemical Bonding 1.6.5.1 Acid-Base Theory Weak Boundary Layer Theory... 

The principal theories can be divided into five groups plus an additional one that is quite different (1) mechanical theories (2) adsorption theories (3) chemical theories (4) diffusion theories (5) electrostatic theories plus pressure sensitive theories. Each of these will... 

We extend our imderstanding of the concepts of chemical bonding and reactivity learned in Chapter 3 on metals and Chapter 4 on zeolites to catalysis over metal oxides and metal sulfides in Chapter 5. The featmes that lead to the generation of surface acidity and basicity are described via simple electrostatic bonding theory concepts that were initially introduced by Pauling. The acidity of the material and its application to heterogeneous catalysis are sensitive to the presence of water or other protic solvents. We explicitly examine the effects of the reaction medium in which the reaction is carried out. In addition, we compare and contrast the differences between liquid and solid acids. We subsequently describe the influence of covalent contributions to the bonding in oxides and transition to a discussion on the factors that control selective oxidation. 

Mains et al. [49], in trying to explain why applying CP to stainless and structural steel surfaces immersed in seawater can inhibit the settlement and attachment of aerobic bacteria to these surfaces, call the use of electrostatic repulsion theory in explaining such phenomena as being an oversimplification . Instead, they propose an alternative mechanism. We call their proposed mechanism the chemical bridge theory, or CB. 

Laino, T., Mohamed, F., Laio, A., 8c Parrinello, M. (2006). An efficient linear-Scaling electrostatic coupling for treating periodic boundary conditions in QM/MM simulations. Journal of Chemical Theory and Computation, 2,1370. 

Nam, K., Gao, J., 8c York, D. M. (2005). An efficient linear-scaling ewald method for long-range electrostatic interactions in combined QM/MM calculations. Journal of Chemical Theory and... 

The adhesion between two solid particles has been treated. In addition to van der Waals forces, there can be an important electrostatic contribution due to charging of the particles on separation [76]. The adhesion of hematite particles to stainless steel in aqueous media increased with increasing ionic strength, contrary to intuition for like-charged surfaces, but explainable in terms of electrical double-layer theory [77,78]. Hematite particles appear to form physical bonds with glass surfaces and chemical bonds when adhering to gelatin [79]. 

In this theory, the adhesion is due to electrostatic forces arising from the transfer of electrons from one material of an adhesive joint to another. Evidence in support of this theory includes the observation that the parts of a broken adhesive joint are sometimes charged [48]. It has been shown that peeling forces are often much greater than can be accounted for by van der Waals forces or chemical bonds. 

What Are the Key Ideas The central ideas of this chapter are, first, that electrostatic repulsions between electron pairs determine molecular shapes and, second, that chemical bonds can be discussed in terms of two quantum mechanical theories that describe the distribution of electrons in molecules. 

Debye-Huckel theory assumes complete dissociation of electrolytes into solvated ions, and attributes ionic atmosphere formation to long-range physical forces of electrostatic attraction. The theory is adequate for describing the behaviour of strong 1 1 electrolytes in dilute aqueous solution but breaks down at higher concentrations. This is due to a chemical effect, namely that short-range electrostatic attraction occurs... 

Clearly, then, the chemical and physical properties of liquid interfaces represent a significant interdisciplinary research area for a broad range of investigators, such as those who have contributed to this book. The chapters are organized into three parts. The first deals with the chemical and physical structure of oil-water interfaces and membrane surfaces. Eighteen chapters present discussion of interfacial potentials, ion solvation, electrostatic instabilities in double layers, theory of adsorption, nonlinear optics, interfacial kinetics, microstructure effects, ultramicroelectrode techniques, catalysis, and extraction. 

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