ENE190 Reviewer

Soil Formation

Soil is created through the weathering of rocks, exhibiting significant variability in chemical composition.

Primary Minerals

These are minerals like quartz and feldspar that remain chemically unaltered since their formation and have low reactivity.

Secondary Minerals

These are clay minerals with high reactivity and surface area, affecting chemical transport in soils.

Clay Mineral Formation

Includes layers like silica, gibbsite, and brucite, influencing the properties of clay minerals.

Specific Surface Area (SSA)

It represents the surface area of soil particles per unit mass and influences soil-water-contaminant interactions.

Cation Exchange Capacity (CEC)

Refers to the total quantity of exchangeable cations on clay surfaces, affecting soil fertility.

Flocculation and Dispersion

Describes the behavior of clay particles when they come close together or move apart due to surface forces.

Soil-Water Interaction

Involves different types of water in soil like free, held, structural, and adsorbed water, influencing soil properties.

Diffused Double Layer (DDL)

Refers to the charged clay surface and distributed ions adjacent to it, affecting cation distribution in soils.

Van der Waals Forces

These are weak attractive forces between atoms and molecules, influencing soil particle interactions.

Permittivity

Measure of the ease with which a molecule can be polarized and oriented in an electric field.

Helmholtz double layer

Model where surface charge of clays is neutralized by opposite sign counter ions placed at a distance away from the surface.

Gouy Chapman model

Model attributing interfacial potential at the charged surface to the presence of ions attached to the surface and in the solution.

Cation exchange capacity (CEC)

Sum of exchangeable cations soil can adsorb per 100 g of dry soil; easily replaced by incoming cations.

Boltzmann distribution

Group of cations diffused in a cloud surrounding the particle.

Exchangeable sodium percentage (ESP)

Normalized sodium in the adsorbed layer with respect to total exchange capacity.

Soil water potential

Total soil-water potential including gravitational, matric, pressure, and osmotic potentials.

Unsaturated soil mechanics

Study of soil behavior dependent on the relationship between suction and water content or saturation.

Soil-water characteristic curve (SWCC)

Relationship between suction and water content or saturation in unsaturated soil.

Attenuation

Reduction in contaminant concentration during fluid transport due to sorption, dissolution, precipitation, and other factors.