1. Mekelle University
Ethiopian Institute of Technology-Mekelle
Department of Chemical Engineering
Process Engineering
Name: Etay Hailu
Id No:EITM/PR/81041/13
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3. Outline
Introduction
Sol and Gel
Sol-gel process
Factors influencing sol-gel process
Applications
Advantages
Limitations
Future
Reference
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6. Introduction
Sol-gel processing is one of the routes for the preparation of porous
materials by their solidification from a true solution phase.
Sol –gel processing designates a type of solid material synthesis
,performed in a liquid and at low temperature.
Dissolve the component in a liquid in order to bring it back as a
solid in a controlled manner.
It’s a typical nanotechnology because all gel products contain
nanoparticles or are nanocomposites.
7. Cont….
Figure 5.1 General scheme of sol-gel processing in the preparation of solid
materials: I – colloidization; II – flocculation; III – gelation;
IV – supercritical fluid processing; and V – drying by evaporation.
8. Sol and Gel
Sol is a stable dispersion of colloidal particles or polymers
in a solvent.
Consist of liquid with colloidal particles which are no
dissolved, but do not agglomerate or sediment.
Sol formation: hydrolysis of metal organic reactant in an
organic solvent that is miscible with water or inorganic salts in
water results in formation of sol.
Gel is a three dimensional continuous network which
encloses liquid phase.