Distributed reactivity

Reactive MPC dynamics should prove most useful when fluctuations in spatially distributed reactive systems are important, as in biochemical networks in the cell, or in situations where fluctuating reactions are coupled to fluid flow. 

Huang W, Weber W (1997) A distributed reactivity model for sorption by soils and sediments. 10. Relationships between desorption, hysteresis, and the chemical characteristics of organic domains. Environ Sci Technol 31 2562-2569... 

In woody gymnosperms, there are significant differences in the distribution, reactivity and physical properties of protolignins found in the compound middle lamella and the secondary wall (1-3). Additionally, variations between lignins in vessels and fibers have also been noted (3). All of these... 

Weber, W.J., P.M. McGinley, and L.E. Katz. 1992. A distributed reactivity model for sorption by soils and sediments-1 Conceptual basis and equilibrium assessments. Environ. Sci. Technol. 26 1955-1962. 

The Hashimoto process (b) was formd to be infeasible for 99.9% purity. In fact, the process is thermodynamically infeasible for the production of pure A. The scheme achieves only low performance for 90% purity. This is in agreement with literature [2]. The hypothetical option of a fully integrated process with distributed reactivity (c) allows for a significant improvement of process performance. This holds in particular for component A, where SR and EC are strongly reduced. The main reason is that here the required 3 / -value is 16% lower than in case (a) m [ is even lower than the Henry constant of B. The explanation is that any B in the reactive zone I also reacts to produce A, which is desorbed more easily and transported towards the non-reactive zones. A similar benefical effect (which is somewhat less pronounced) is found for m [v, which is higher for the fully integrated schemes than for the flowsheet-integrated processes. 

The distributed reactivity models used by Burnham and Braun [92] in the kinetic analysis of complex materials (see Section 5.5.12.) deserve further consideration, particularly in view of the results obtained by Christy et ai, [93] for the kinetics of dehydration of calcium oxalate monohydrate. Water loss proceeds at different rates from different lattice sites in this monohydrate. 

Distributed Reactivity in the Sorption of Hydrophobic Organic Contaminants in Natural Aquatic Systems... 

Distributed Reactivity. Natural systems commonly are composed ol a variety of different solid phases and interfaces, each of which might well yield distinctly individual local sorption behavior with respect to a particula] solute and thus an identifiable local isotherm. Figure 3 is a schematic illustration of four different types of local sorption phenomena, ranging from a specific adsorption reaction of a solute molecule with a sorbent surface on the left to the absorption of the molecule into the matrix of a sorbing substance on the right. 

Distributed Reactivity Model. Isotherm relationships observed for natural systems may well be expected to reflect composite sorption behavior resulting from a series of different local isotherms, including linear and nonlinear adsorption reactions. For example, an observed near-linear isotherm might result from a series of linear and near-linear local sorption isotherms on m different components of soft soil organic matter and p different mineral matter surfaces. The resulting series of sorption reactions, because they are nearly linear, can be approximated in terms of a bulk linear partition coefficient, KDr that is... 

As illustrated in Figure 6, the influence of distributed reactivity on sorption becomes more significant with decreasing residual solution-phase con-... 

Figure 10. Distributed reactivity and resultant sorption behavior for various types of natural sorbents.

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