ENVS 2060 Lecture Notes - Lecture 8: Flocculation, Unit, Nitrification
26 Jul 2020
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Document Summary
Soil colloids: very small particles with electrically charged surfaces. Colloidal material will have a very large amount of surface area. Clay is particles smaller than 0. 002mm in diameter and has large surface area. Most clays in canada fall into the mineralogical group of the layer silicates. The layer silicates: has crystal structure that results in particles that are charged due to isomorphous substitution and edge control. Charges on particle surface are satisfied by attraction of oppositely charged ions in particle surface. Examples of layer silicate clays: kaolinite, vermiculite, smectite, and fine grained mica and chlorite. Consists of layers of silicon tetrahedral and aluminum/magnesium octahedral sheets. 1:1 silicates clays: non explandings and have low surface area and low charge. 2:1 silicate clays: larger surface area, some shrink some do not. Soil organic matter reps 1-5% of soil but has significant effects. Only the humus portion of organic matter is colloidal in nature and contributes to total charge in sol.
