Lecture 17 Flashcards
what are the different classifications of colloids:
- hydrophilic colloids 2. hydrophobic colloids 3. association colloids
colloids play a role in what?
transport
reducing conditions leads to high reactivity which means what in water?
leaching of products back into the water
what are associaton colloids?
consist of special aggregates of ions and molecules called micells. Has to have CH3(CH2)16
Coagulation:
reduction of electrostatic repulsion of individual particles, this causes them to aggregate by addition of salt
properties of a hydrophilic colloids:
consist of macromolecues such as proteins and synthetic polymers. In a sense, hydrophilic colloids are solutions of very large molecules or ions. Less affected by salts compared to hydrophobic
polyelectrolytes:
are polymers that cause colloids to form.
with a high pE environment, this means an oxidizing conditions. Soluble Fe 2 and Mn 2 are oxidized to form colloids. what happens to these?
may remain suspended or gradually settle to form sediment
why is FA adsorbed less versus Ha?
FA and is hydrophilic and small whereas HA is large and hydrophobic
with a low pE environments it is a reducing condition (anoxic) where are these conditions found? what happens to Fe 2 and Mn 2 ?
usually found in deep water sediments of sea water. insoluble Fe and Mn hydrous oxides reduced to more soluble Fe2 and Mn 2 species. Collidal FeS(s) and MnS(s) are found in anoxic sediments
examples of hydrophobic colloids:
clay particles, petroleum droplets, and very small gold particles
properties of hydrophobic colloids:
interact less with water compared to hydrophilic because of their positive or negative electrical charges. They have an electrical double layer which causes the particles to repel each other. Hydrophobic colloids are usuall caused to settle from suspension by the addition of salts.
