Loading presentation...

Present Remotely

Send the link below via email or IM

Copy

Present to your audience

Start remote presentation

  • Invited audience members will follow you as you navigate and present
  • People invited to a presentation do not need a Prezi account
  • This link expires 10 minutes after you close the presentation
  • A maximum of 30 users can follow your presentation
  • Learn more about this feature in our knowledge base article

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.

DeleteCancel

Make your likes visible on Facebook?

Connect your Facebook account to Prezi and let your likes appear on your timeline.
You can change this under Settings & Account at any time.

No, thanks

Molecular adsorption & molecular encapsulation

No description
by

Xavi Gironès

on 2 June 2014

Comments (0)

Please log in to add your comment.

Report abuse

Transcript of Molecular adsorption & molecular encapsulation

Molecular adsorption
&
molecular encapsulation
Xavier Gironès
Charlotte Girod
-
Adsorption
: is a physical or chemical process whereby atoms, ions or molecules are trapped or retained on the
surface
of a material.
-
Absorption
: is a physical or chemical process whereby atoms, ions or molecules pass from a first phase to another, by joining at the
volume
of the second phase.
attraction between the molecules present on the surface of an adsorbent solid and a fluid mixture.
ADSORPTION
PARTS
ADSORBENT
ADSORBATE
solid on which the transferable component of the liquid phase is retained
is the component transferred from the fluid phase to the surface of the adsorbent
- Big especific surface
(wich means high porosity)

- Good capacity of regeneration (desorption)

e.g.:
Activated Carbon
generic term that describes a family of highly crystalline carbonaceous adsorbents and with a highly developed internal porosity.
Adsorption types according to the interaction
By exchange
Chemisorption
Physisorption
electrostatic attraction on charged sites of the surface
- by Van der Waals forces

- the adsorbed specie retains its chemical nature

- is not fixed at a specific location of the surface
- by covalent bonds

- the adsorbed specie suffers a transformation to form a distinct specie

- the adsorbate forms strong bonds in the active centers of the adsorbent
COMPARISON
Physisorption - multilayers
Chemisorption - monolayer

- adsorption distance: where the energy of the system with respect to the molecule to be adsorbed is minimal
d(physisorption) < d(chemisorption)
- temperatures occurrence:
T(physisorption) < T(chemisorption)
because chemisorption needs an activation energy
Molecular potential energy evolution approaching at a surface.
OTHER INFORMATION
- adsorption is favored:

temperatures

pressures
- adsorption is an exotermic process:
G= H-T S
(-)
Pore types and methods of characterization of porous solids
- closed / opened
- cylindrical, slit, hollow, funnel, ink-bottle shaped...
- stereology
- radiation scattering
- pycnometry
- fluid flow
- calorimetric methods
- others...
THERMODYNAMICS
adsorbent - nanopores (activate centers)
admit that molecules of different nature are installed
e.g.: equilibums of adsorbent solids and gas mixture

- Adsorption isotherms - amount of gas adsorbed at the monopores on depending external gas pressure

the types depend on the porosity of the material, the adsorbate-adsorbent interaction...
APPLICATIONS
Adsorption is used to remove individually the
components of a gaseous or liquid mixture
The removed component can be the desired product but also an impurity
e.g.: cleaning of waste gases
- to remove humidity from compressed air

- to remove odors, flavors or colors unwanted (oils, sugar syrups...)

- gasoline dehumidification

- to obtain nitrogen
Gas Mask
NEW!
new nanopores materials with better gas adsorption properties...
VIDEO
ENCAPSULATION
DEFINITION: guest molecule captured in the cavity of a host molecule
One of the first examples of encapsulation was made by Cram and his coworkers

- carcerand molecule
-hemicarcerand molecule
Liposome
Microspheres
-glass, polymer, ceramic
Delivery mechanisms:
-Diffusion
-Erosion
-Osmosis
EXAMPLES OF CAPSULES USED FOR ENCAPSULATION

-Liposome bilayer
-Microspheres
-Micro-encapsulation
APPLICATION: DRUG DELIVERY
Advantages of encapsulation in drug delivery:
-Smaller effective doses of ingested drugs
-More efficient
-Reduced number of secondary effects

MICRO-ENCAPSULATION
Scratch-n-sniff
Examples of special drug delivery mechanisms:
Targeted drug delivery
: Increases the concentration of the medication in some parts of the body relative to other
Thin-film drug delivery
: Hydrophilic polymer film that rapidly dissolves on the tongue
Small particles surrounded by coating to create microcapsules, used to incorporate food ingredients, enzymes, etc. on a
micrometric scale
-Microcapsules that break easily when rubbed and release an aroma
-Perfume samples, scented stickers
-Detect anosmia (inability to perceive odor)
-Educate on methane gas leak
-diameters from 1µm to 1mm
APPLICATIONS OF ENCAPSULATION
PRINTING INDUSTRY
-Perfume samples in magazines

-Carbonless paper
TEXTILE INDUSTRY
-Fabrics with new functionality
-Hydrophobic and self-cleaning fabrics
-Coloration of fabrics
AGROCHEMICAL INDUSTRY
-Pesticides
FOOD INDUSTRY
-Improve performance of aromas, vitamins, etc.
-Hide bad taste in food products
COSMETICS INDUSTRY
-Skin care products
-Tanning creams
-Essential oils
PHARMACEUTICAL INDUSTRY
-Drug delivery
REFERENCES
http://www.mariogonzalez.es/2007/03/diferencia-entre-adsorcion-y-absorcion.html

http://www.gunt.de/download/absorption_spanish.pdf

http://es.wikipedia.org/wiki/Adsorci%C3%B3n#Aplicaciones

http://bibliotecadigital.ilce.edu.mx/sites/ciencia/volumen2/ciencia3/059/htm/sec_8.htm

http://www.agua.uji.es/pdf/leccionHQ17.pdf

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662008000500002

http://es.scribd.com/doc/81574156/aplicaciones-adsorcion

http://www.uco.es/~iq2sagrl/TranspAdsGases.pdf

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8917743

http://en.wikipedia.org/wiki/Molecular_encapsulation

http://en.wikipedia.org/wiki/Hemicarcerand

http://en.wikipedia.org/wiki/File:Liposome_scheme-en.svg

http://en.wikipedia.org/wiki/Liposome

http://en.wikipedia.org/wiki/Targeted_drug_delivery

http://www.eis.uva.es/~macromol/curso04-05/bio/encapsulacion.htm

http://en.wikipedia.org/wiki/Scratch-n-sniff
Full transcript