Colloid, organic

Many betterments provided by activated carbon can be correlated with effects caused by organic colloids (see Table 4 8). Colloidal phenomena are considered in Chapter 6 here we shall give but a brief simplified outline using familiar experiences with detergents for purpose of illustration. 

BETTERMENTS ASSOCIATED WITH USE OF CARBON FOR REMOVAL OF ORGANIC COLLOIDS 

Elimination of turbidity, haze, emulsions Improved filterability of process liquor and finished product Reduced tendency to foam during evaporation and distillation Faster rate of settling during clarification 

Improved performance at crystallization station greater yield of purer crystals having better form and higher melting point Greater stability of product, longer shelf life 

If air is passed through a column of water, bubbles will form, but they will break almost immediately. Shaking an oil-water mixture will cause the oil to form droplets in the water but the two liquids separate when the shaking ceases. Powdered sand will remain suspended in water only briefly. 

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Freshwater Muds—Dispersed Systems. The pH value of low-pH muds may range from 7.0 to 9.5. Low-pH muds include spud muds, bentonite-treated muds, natural muds, phosphate-treated muds, organic thinned muds (red muds, lignite muds, lignosulfate muds), and organic colloid-treated muds. The pH value of high pH muds, such as alkaline tannate-treated mud, is above 9.5. 

Saturated saltwater muds can be weighted to more than 19 Ib/gal. Saturated saltwater muds conditioned with organic colloids to control filtration can be... 

Sawadaishi, T. and Shimomura, M. (2005) Two-dimensional patterns of ultra-fine particles prepared by self-organization. Colloid. Surf. A, 257-258, 71-74. 

Gustafsson O, Buesseler KO, Gschwend PM (1996) On the integrity of cross-flow filtration for collecting marine organic colloids. Marine Chem 55 93-111... 

Grieser F, Ashokkumar M (2004) In Caruso F (ed) Sonochemical synthesis of inorganic and organic colloids, colloids and colloid assemblies. Wiley-VCH GmbH Co. KgaA, Weinheim, pp 120-149... 

Diffusion is characterized by a mass transfer coefficient U8 of 104 m/h, which can be regarded as a molecular diffusivity of 2 x 10 6 m2/h divided by a path length of 0.02 m. In practice, bioturbation may contribute substantially to this exchange process, and in shallow water current-induced turbulence may also increase the rate of transport. Diffusion in association with organic colloids is not included. The D value is thus given as Us AwZ2. 

Chin, Y.-R, Gschwend, P.M. (1992) Partitioning of polycyclic aromatic hydrocarbons to marine porewater organic colloids. Environ. Sci. Technol. 26, 1621-1626. 

Colloids Organic Colloids Inorganic Colloids iron oxyhydroxides... 

Organic colloids are particularly effective at binding metals. 

Fig. 102. Schematics of available sites for organizing colloidal semiconductors in single-bilayer surfactant vesicles [500]...

Estimate the Kh]0 values (Eq. 10-4) for PCB52 and PCB180 for Anabaena sp. and compare them to the apparent BAFt values given above. Assume that with a rather high lipid content of 5.3%, the role of proteins as sorbents in Anabaena sp. can be neglected for apolar compounds such as PCBs (see Illustrative Example 10.2, pentachlorobenzene). Could any discrepancy found between Klhui and BAF, be explained by the fact that the compounds associated with the organic colloids present in the culture medium ... 

The presence of organic colloids may give rise to a third fraction of the biphenyl molecules, the fraction sorbed to nonsettling microparticles and macromolecules. This fraction neither contributes to the air-water exchange equilibrium nor participates in the process of particle settling. By generalizing the notation introduced in Eq. 9-23 one can write ... 

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