Solutes and colloids

Matsuoka, H. and Ise> N. Small-Angle and Ultra-Small Angle Scattering Study of the Ordered Structure in Polyelectrolyte Solutions and Colloidal Dispersions. VoL 114, pp. 187-232. 

K. S. Schmitz, Macroions in Solution and Colloid Suspension, VCH Publishers, New York, 1993. 

For ultrafiltration, the macromolecular solutes and colloidal species usually have insignificant osmotic pressures. In this case, the concentration at the membrane surface (C ) can rise to the point of incipient gel precipitation, forming a dynamic secondary membrane on top of the primary structure (Figure 7). This secondary membrane can offer the major resistance to flow. 

Equation 3 Indicates that a semilog plot of flux against concentration should be a straight-line intercepting the horizontal axis at the gel concentration (C ). When the bulk-stream concentration (C ) equals the gel concentration (C ) there is no driving force for removal of solute from the membrlne. The gel layer increases in thickness until the flux is zero. Figure 10 provides experimental confirmation for a number of protein solutions and colloidal suspensions ( ). The Intercepts with the horizontal axis are reasonable values for the gel concentration. 

Syntheses were run in modified Morey-type autoclaves of 15-ml capacity at autogenous pressure. For mordenite synthesis, the reactants were mixed in a mortar and pestle into a homogeneous mix and loaded into the autoclaves. For zeolite A and X synthesis, separate sodium aluminate solutions and colloidal silica sols were prepared and mixed in the autoclaves. 

In dealing with solutions and colloidal dispersions, the following quantities are often used ... 

Dialysis against DzO buffers can be speeded, and the quantity of expensive D20 reduced, if a multistep approach is taken. For most dilute solutions and colloids, the rate of dialysis exchange is unlikely to depend on the macromolecular sample... 

Schmitz KS (1993) Macroions in solution and colloidal suspension, VCH, New York... 

In fact, the SFA was initially developed for practically probing the DLVO theory, and DLVO forces were successfully measured in electrolyte solutions and colloidal systems [4,22]. However, the applications of the apparatus were not restricted to this. Detailed and accurate information was obtained on thickness and refractive index profiles of thin films [6], simple liquid molecular structuring... 

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