Polymers flocculation

Polymer electrolyte Polymer electrolytes Polymer emulsions Polymer flocculation Polymer gasoline... 

The carboxylated units, ionized, decrease adsorption on subterranean substrates (23), ia proportion to the number of units, an important parameter ia petroleum recovery processes. In waste treatment processes cationic acrylamide comonomer units are often used (31) to iacrease adsorption and thereby flocculation of soHds ia wastewater (see Acrylamide POLYMERS Flocculating agents). The favorable and characteristics of acrylamide facilitate the... 

Recent papers by a manufacturer of sodium borohydride, NaBH (145,146), have demonstrated that excellent removal of metals and color of acid, direct, and reactive dyes for textiles and paper can be achieved with bisulfite-catalyzed borohydride reduction in combination with polymer flocculation. 

With polymer flocculation of slurries, however, extended agitation after the addition of the polymer may be detrimental. The reagent should be added to the slurry under conditions which promote rapid... 

Mannich polymers Cationic, solution polymer flocculants with a MW of 5 to 8 M. Very high viscosity at only 4 to 8% active strength solution liquid. A hydrolyed polyacrylamide, it is very useful for general municipal waste water treatment. The dose rate normally is 200 to 300 ppm or more. 

A major advantage of the simple model described in this paper lies in its potential applicability to the direct evaluation of experimental data. Unfortunately, it is clear from the form of the typical isotherms, especially those for high polymers (large n) that, even with a simple model, this presents considerable difficulty. The problems can be seen clearly by consideration of some typical polymer adsorption data. Experimental isotherms for the adsorption of commercial polymer flocculants on a kaolin clay are shown in Figure 4. These data were obtained, in the usual way, by determination of residual polymer concentrations after equilibration with the solid. In general, such methods are limited at both extremes of the concentration scale. Serious errors arise at low concentration due to loss in precision of the analytical technique and at high concentration because the amount adsorbed is determined by the difference between two large numbers. 

Polymer flocculants are now used in a wide range of applications (1). Early interest in these materials was largely based on their ability to improve the dewatering rates (i.e. to increase the permeability) of suspensions. 

R.O. Keys and R. Hogg, Mixing Problems in Polymer Flocculation in Water - 1978, G.F. Bennett (ed.), AIChE Symposium Series, American Institute of Chemical Engineers, New York, 1979, Vol. 75, pp. 63-72. 

Samples prepared with 1-5% DVB were dissolved at 20 °C and fractionated (Figure 10). Precipitation is abrupt near n = 8-9. At n = 10, 90% of the polymer flocculates. 

Coagulants lower MW polymers. Flocculants higher MW polymers. 

Mannich polymers Cationic, solution polymer flocculants... 

Thus the ratio of the size of the particle to the root mean square end to end distance of the polymer is an important factor. With small particles, diameter ca.50 run, bridging occurs easily and since they are small, or similar in dimensions, to the polymers flocculation occurs easily moreover, the number concentration of particles is high and hence a large number of bridges are formed. With large particles, diameter > 1 ym, the polymer molecule is much smaller than the particle and hence it forms an adsorbed layer which often confers a degree of steric stability (48). 

Syrup Clarification. In some factories, a process known as syrup clarification is used to produce a higher-quality raw sugar and better yield. Evaporator syrup is treated with phosphoric acid, lime, and a polymer flocculent insoluble impurities are floated to the surface of the syrup with aeration and removed by skimming. The clarified syrup goes to the vacuum pan for crystallization. Syrup clarification reduces the color and turbidity of the sugar produced, and can also be used in conjunction with sulfitation to produce an off-white, edible sugar.30... 

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