05 powder charzterization 3

05 powder charzterization 3 - Monolayer...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Monolayer Adsorption (Langmuir-Isotherm) A d sorbed a mount V Relative pressure
Background image of page 2
Implications of the specific surface area: uantifying colloidal material in a (complex) Quantifying colloidal material in a (complex) particle system that is not or only poorly accessible y particle size analysis. by pa c e s e a a ys s. Measurement of adsorption capacity of a powder to estimate the influence of a surface modification. The difference in surface area/surface energy from powder to a monolith is the main driving force for t i sintering
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Gas adsorption techniques (e.g. BET) • Nitrogen adsorption at -196 o C olecule can penetrate into all ores: N 2 molecule can penetrate into all pores: meso, macro and micropores urface area accessible to the itrogen • Surface area accessible to the nitrogen molecule is being measured
Background image of page 4
N 2 -Adsorption isotherm on kaolinite and calculation using the linear relationship
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
as adsorption techniques (e g BET) Gas adsorption techniques (e.g. BET)
Background image of page 6
BET-Method Brunauer, Emmett and Teller use isothermal sorption in the relative pressure range 0,05 < p/p 0 < 0,35 So-called BET-equation: ( ) ( ) 0 1 1 p p p p p m C C V V + = V : Adsorbed volume of gas 0 0 0 p p p C : Constant (depending on amount adsorped) p 0 : Equilibrium pressure of the specific gas used V m : Volume of an adsorbed monomolecular layer
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Transforming the equation yields a linear equation 1 1 p C p + = a+ b ( ) 0 0 p C V C V p p V m m y = a + b x with x = p/p 0 . 1 C 1 and sing a and b the monolayer adsorbed volume and constant C C V a m = C V b m = Using a and b the monolayer adsorbed volume and constant C can be calculated.
Background image of page 8
Note the digits after the point!
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Specific surface area measurements Sorption methods V N F S m A = F : Area per adsorbed molecule e.g. for N 2 (0.0154 (M/ ρ ) 2/3 nm 2 , 162 0 0
Background image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/04/2010 for the course MSE 6448 taught by Professor Sigmund during the Spring '10 term at University of Florida.

Page1 / 29

05 powder charzterization 3 - Monolayer...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online