Flocculants, cationic

Two types of immobilization are used for immobilizing glucose isomerase. The intracellular enzyme is either immobilized within the bacterial cells to produce a whole-ceU product, or the enzyme is released from the cells, recovered, and immobilized onto an inert carrier. An example of the whole-ceU process is one in which cells are dismpted by homogenization, cross-linked with glutaraldehyde, flocculated using a cationic flocculent, and extmded (42). 

DETERMINATION OF THE RESIDUAL CONTENTS OF CATIONIC FLOCCULANTS IN WATERS... 

Cationic flocculants are widely used in clearing oil-water, waste, natural and drinking water. At the sarue time they ar e moderately toxic substances which have cumulative properties. For the majority of flocculants, prodused and used in Ukraine, limit admission concentration is 0,l-t-0,4 mg/dm for drinking water and 0,01 mg/dm and less - for natural waters. 

In practice, aeration towers using coke or volcanic lava tend not to be as efficient as spray ponds in facilitating the precipitation of ferrous hydroxide consequently, there is usually a requirement for a cationic flocculant to aid the precipitation of the insoluble materials into a larger floe or denser sludge that can be removed by clarification or sand filtration. 

Figure 5. Typical theoretical isotherm showing the experimental data for the cationic flocculant (see Figure 4) plotted on the same relative scales.

Preparation and Testing of Cationic Flocculants from Kraft Lignin... 

Pelton, R. H., Mcxlel cationic flocculant from Mannich reaction of polyacrylamide, J. Polym.. Sci. Polym. Utt. l-jL. 22. 3955, 1984. 

Properties Off-white granular powder. Den 47-53 Ib/f3, pH of 0.5% solution at 77F 6.5-8.5. TM for a dry polyacrylamide cationic, flocculated with controlled molecular weight distribution and varying charge densities. 

The adsorption of cationic flocculants on the minerals makes the negative zeta potential of quartz and scheelite move to positive. Charge reversal occurs at high concentrations. 

For the Agl-sol, for instance, the monovalent cations flocculate at a concentration of about 140 millimols/liter, the hi-... 

With the cations studied here the arabinate sol still remains perfectly stable, but with 4 and 6 valent cations flocculation or coacervation occurs. These higher valent cations have lower or even very low (true) reversal of charge concentrations (see p. 259 Chapter IX 1 and 2), that means ... 

As was already stated in Ch. VII, p. 223, hexol nitrate, a complex cobalt salt with hexavalent cation, flocculates or coacervates most biocolloids of acidic nature, thus also gum arabic and sodium arabinate sols. Here the remarkable situation is encountered, that the hexol nitrate concentration needed just to start coacervation is nearly proportional to the arabinate concentration, this fact already indicating that the expression hexol nitrate concentration is here of a doubtful value the hexol cations cannot be freely present in solution but must combine with the arabinate. 

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