Colloidal solutions coarsely dispersed systems

Сентябрь 9, 2022

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Colloidal solutions coarsely dispersed systems

Содержание

2. Disperse system is a system consisting of two or more phases. One of them which mass
3. Classification of disperse systems 1. According to a disperse phase dispersion degree : coarsely dispersed (particle
4. Classification of disperse systems 2. According to the aggregate state of the disperse phase and the
5. Methods of colloidal solutions preparation Dispergation methods (breaking up larger particles to the colloid dispersion degree)
6. Colloidal solutions purification methods Dialysis Electrodialysis Ultrafiltration
7. Structure of colloidal particles Each sol consists of micelles and intermicellar liquid. Micelle is an electrically
8. The main parts of a micelle structure : nucleus adsorbed layer diffuse layer
9. The process of settling of disperse phase particles under the action of forces of different nature
10. The process of colloidal particles combining into larger aggregates due to loss of aggregation stability is
11. Coarsely dispersed systems Aerosols are disperse systems with a gas disperse medium and a liquid or
12. Coarsely dispersed systems Pastes are coarsely dispersed systems with high concentration of a solid disperse phase
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Disperse system is a system consisting of two or more phases.

One of them which mass prevails is named
a disperse medium.
The other phase (or few phases) being in it in dispersed state in a form of fine particles is named a disperse phase.

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Classification of disperse systems
1. According to a disperse phase dispersion

degree :
coarsely dispersed (particle diameter is more than 10-7 m),
fine-grained (particle diameter is 10-7 - 10-9 m)
molecular dispersed (particle diameter is less than 10-9 m).

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Classification of disperse systems
2. According to the aggregate state of the

disperse phase and the disperse medium the disperse systems are classified into 8 types.
S/L/, L/L, G/L, S/S, L/S, G/S, S/G, L/G
3. According to the interphase interaction:
lyophobic
lyophilic

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Methods of colloidal solutions preparation
Dispergation methods (breaking up larger particles to

the colloid dispersion degree)
Condensation methods (association of atoms, molecules or ions to form colloidal particles).

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Colloidal solutions purification methods
Dialysis
Electrodialysis
Ultrafiltration

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Structure of colloidal particles Each sol consists of micelles and intermicellar liquid. Micelle

is an electrically neutral particle of a disperse phase with the double electrical layer surrounding it.

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The main parts of a micelle structure :
nucleus
adsorbed layer
diffuse

layer

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The process of settling of disperse phase particles under the action

of forces of different nature (gravitational, centrifugal, electrical) is called sedimentation.

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The process of colloidal particles combining into larger aggregates due to

loss of aggregation stability is called coagulation

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Coarsely dispersed systems
Aerosols are disperse systems with a gas disperse medium

and a liquid or solid disperse phase (mists, smokes or dusts, smogs).
Powders are coarsely dispersed systems with a solid disperse phase and a gaseous disperse medium. The disperse phase particles diameter is 10-8-10-4 m.
Suspensions are coarsely dispersed systems with a solid disperse phase and a liquid dispersion medium.

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Coarsely dispersed systems
Pastes are coarsely dispersed systems with high concentration of

a solid disperse phase in a liquid disperse medium. Mass fraction of the disperse phase is 25-75%.
Emulsions are micro-heterogeneous systems consisting of two liquids which do not mix with each other because of different polarity.