Colloidal components

Organic compounds interact with each other and with the inorganic, macro, micro, and colloidal components in soil. Complex and simple organic molecules form complexes with inorganic cations and anions and with colloidal... 

Milk is a dilute emulsion consisting of an oil/fat dispersed phase and an aqueous colloidal continuous phase. The physical properties of milk are similar to those of water but are modified by the presence of various solutes (proteins, lactose and salts) in the continuous phase and by the degree of dispersion of the emulsified and colloidal components. 

The water phase is, of course, complementary to the oil phase in that its hydro-colloidal components tend to provide a protective buffer zone around each oil droplet. 

Figure 8.5 Nature and size domain of the most important inorganic and organic freshwater colloidal components (redrawn from Buffle, 1988).

Buffle, J. Wilkinson, K.J., Stoll, S., Filella, M. and Zhang, J. (1998) A generalized description of aquatic colloidal interactions the three-colloidal component approach. Environ. Sci. Technol. (in press). 

Figure 5.6 Schematic drawing illustrating the removal of deposited negatively charged colloidal components from the surface of an anion-exchange membrane by reversing the electric field.

Once formed, these colloids may be used for further processing. For example, they can be mixed with paints.22 The products formed are as conductive as those obtained when carbon black is added to paints. However, they are also electroactive and presumably (at least the colloidal component) retain the unique chemical properties of the conducting polymer. 

It seems reasonable to suppose that the construction of the nucleus of a zeolite crystal may involve a more complex assembly process than is necessary for simpler substances whose unit cells are smaller and contain far fewer atoms, although there should be no difference in basic principles. The nature of the nucleation process in zeolite systems is also complicated by the nature of zeolite synthesis sols. These contain observable solid phases (amorphous gel, crystals) and components (cations, anions) in true solution. However, there is frequently also a colloidal component, invisible to the naked eye, which itself may be amorphous or crystalline. 

Both herbicides are adsorbed extensively by the organic colloidal components of the soil, but the adsorptive bond is weak, particularly in the case of prophan, so leaching by soil moisture does take place. Adsorption on the clay minerals of the soil is insubstantial (Freed, 19S1). 

Buffle J, Wilkinson KJ, Stoll S, Filella M, Zhang J (1998) A generalized description of aquatic colloid interactions The three-colloidal component approach. Environ Sci Technol 32 2887-2899 Bugaev LA, Ildefonse Ph, Flank AM, Sokolenko AP, Dmitrienko HV (2000a) Aluminum K-XANES spectra in minerals as the source of information on their local atomic structure. J Phys Condensed Matter 10 5463-5473... 

---