Solutes diameters

If you watch a glass of muddy water, you will see particles in the water settling out. This is a heterogeneous mixture where the particles are large (in excess of 1000 nm), and it is called a suspension. In contrast, dissolving sodium chloride in water results in a true homogeneous solution, with solute particles less than 1 nm in diameter. True solutions do not settle out because of the very small particle size. But there are mixtures whose solute diameters fall in between solutions and suspensions. These are called colloids and have solute particles in the range of 1 to 1000 nm diameter. Table 131 shows some representative colloids. 

Critical solute diameter, nm Liquid volume space time, s Time on stream, s... 

Hydrodynamic. For a pressure driven process such as ultrafiltration the flow of solvent towards the membrane results in a drag which carries the solute in the same direction. This drag is a function of the distance of the solute from the pore entrance. At large distances it is equal to the isolated solute value (Stokes limit), but as the solute approaches and begins to enter the pore, the drag, for a constant filtration velocity, increases due to the restriction of solvent flow. This increase depends on the ratio of solute diameter to pore diameter. 

If a solute molecule penetrates into a narrow pore with a width only a few times larger lluin the solute diameter, it cannot be assumed that the... 

A typical curve relating inaccessible water to solute diameter is shown in Figure 3. The fiber saturation point corresponds to the plateau formed with very large diameter solute molecules while the median pore size is that value above and below which one-half the total volume of... 

Number of micellar droplets per kilogram of solution. Diameter of C02B particles. 

We recall that our main interest is focused on the properties of the solvent as a medium for the H4>0 interaction. Therefore, from a theoretical point of view, since the solute diameter o is a property of the solutes, there is no reason to restrict ourselves to R > (7 just because the two solutes repel each other at R < cr. 

In the previous subsections, we devised a measure of the HtpO interaction at some distance R < a a being the solute diameter), which was found to be useful for a comparison of various solvents. We also discussed the case R = 0. In both cases, it was argued that since our primary interest is the solvent rather than the solute, we can study the problem of the H0O interaction at any convenient distance for which we get a connection with experimental quantities. 

Figure 4.42 shows that when we vary the solute diameter ass, the height of the first maximum of gss(-R) is largest for ass/k T 0.75. Other results obtained for this model with parameters as in (4.10.1) are... 

Fig. 4.42 Variation of the solute-solute pair correlation function with the solute diameter as indicated next to each curve (see Sec. 4.10).

The solution was contained In each of two stainless-steel cylinders having 0.079-cm-thick walls the solution diameters weie 33>02 and 39.09 cm. The thickness of lateral steel reflectors adjacent to the solution ranged up to 5.08 cm and was surrounded by an infiiiitely thick wafer reflector. There was no top or bottom reflector. Similar eiq[>eriments using U(93.3)Oa(NO,), have been reported. Table I summarizes the data. 

In all cases, the tubes of the dissolver vessels were lined with S.5-mm-thick Kynar (polyvinylidene fluoride resin) for protection against the action of nitric and hydrofluoric adds used for dissolution. The vessels were S m high. Spacing between centers of the tubes in model 1 was 395.2 mm, in model 3, 533.4 mm, and in model 4, 549.3 and 457.2 mm (rectangular). The inner (solution) diameter in models 3 and 4 was 141.3 mm. 

For suspension polymerization the initial system is obtained by dispersion of an aqueous monomer solution in an organic liquid by mechanical stirring in the presence of stabilizers [402]. The dispersion medium may be represented by aromatic and aliphatic saturated hydrocarbons. The polymerization is initiated by water-soluble initiators, UV or y-radiation. The process occurs in droplets of an aqueous monomer solution (diameters 0.1-5.0mm) that act as microreactors [419,420]. 

Solution Estimate the solute diameter 2r,- from equation (3.3.90b). For NazSOi,... 

We next turn to diffusion of a solution held within an array of cylindrical pores. Normally, these large pores are assumed to span a thin film, and to all be perpendicular to the surfaces of the film. By large pores, we imply that the solvent acts as a continuum and that the solute diameter is much smaller than the pore diameter. Not surprisingly, this idealized geometry has been the focus of considerable theoretical effort. In spite of its idealizations, it does provide physical insight. 

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