Porozni materijali

5/21/2018 Porozni materijali

1/67

POROZNI MATERIJALITeksturalne osobine

Silica Carbon Zeolite

V. Dondur 2011.


2/67

Important properties are:

Surface area - determined by BETPore structureChemical composition of the surface.

Techniques for studying composition of surface include

IR and Raman

X-ray fluorescence (XRF)Low energy electron diffraction (LEED)X-ray photoelectron spectroscopy (ESCA)Auger-electron spectroscopy (AES)


3/67

Porosi ty is usually defined as the ratio of thevolume of pores and voids to the volume occupied

by the solid.

In many cases the internal sur face area ismuch larger than the externalsu rface area andthe agglomerate then possesses a well-definedpore structure.


4/67

Texture and morphology of poroussystems pore size

pore shape pore-size distribution (same size or

various sizes?)

pore volume specific surface area of adsrbent


5/67

0.5nm

Pore diameters micropores (< 2 nm)

mesopores (2 - 50 nm)

macropores (> 50 nm)

Pore Size and Shape

0.5nm


6/67

Table 1. Definitions: porous solidsTerm DefinitionPorous solid Solid with cavities or channels which are deeper than they are wideopen pore Cavity or channel with access to the surface

Interconnected pore Pore which communicates with other poresBlind pore' Pore with a single connection to the surface (Deadend pore)Closed pore Cavity not connected to the surfaceVoid Space between particlesMiclopore Pore of internal width less than 2 nmMesopore Pore of internal width between 2 and 50 nmMacropore Pore of internal width greater than 50 nm

Pore size Pore width (diameter of cylindrical porc or distance between oppositePore volume Volume of pores determined by stated methodPorosity Ratio of total pore volume to apparent volume of particle or powderTotal porosity Ratio of volume of voids and pores (open and closed) to volume occuOpen porosity Ratio of volume of voids and open pores to volume occupied by solidSurface area Extent of total surface area as determined by given method under

conditionsExternal surface area Area of surface outside poresIntemal surface area Area of pore wallsDensity Density of solid, excluding pores and voids

Apparent density Density of material including closed and inaccessible pores, as deter stated method


7/67

ACTIVATED Carbon pores consist of:1. Micro pores with a radius of less than 1 nm (small pores)

2. Meso pores with a radius of 1-25 nm (medium pores)3. Macro pores with a radius larger than 25 nm (largepores)

Large pores are used for the transport of liquid throughthe carbon, and absorption occurs in the medium andsmall pores. Pores are formed during themanufacturing process, when the carbon is activated.

The activation basically means that pores are created ina non-porous material by means of chemical reactions.


8/67

AFM image of a typical nanoporousalumina template (dark areas arepores and the surrounding lightareas are aluminum oxide aroundthe pores (pore diameter is ~50nm)

SEM image of a typical nanoporousalumina (dark areas are pores and

the surrounding light areas arealuminum oxide around the pores(pore diameter is ~25nm)


9/67

SILICATE / ALUMINOSILICATE POROUS MATERIALS

Macroporous(>500)

Mesoporous(20-500)

Microporous(


10/67

Figure 1 Microporo us polym er.

These polymers are formed bycross-linking linear chains ofmonomer. Cross-links (shown asheavy lines above) create verysmall pores within the threedimensionalmatrix.

Figure 2. Macroporou s

polymer.

These materials have a highdegree of cross-linking,

preventingthem from swelling in solvents.Pores are larger than gels,but are irregular and terminateinside the matrix. Total porevolumes are typically 50%.

Figure 3. High in ternal phase

emuls ion. HIPE polymers,

illustratedabove, contain extremelylarge cavities that areinterconnected.Cavities are of micrometerdimensions, rather than angstromdimensions of conventional

polymers. Total pore volumecan exceed 90%.

polymers


11/67

Bro ken sph ere of Cavi l ink polym er.

This is interiorof polymer type shown in Fig. 9and shows cavities and poresfully communicating with spheresurface.

Cavi l ink polym er with fu l ly open surface.

This SEMphoto shows distinctive regularityof cavities in Cavilink polymers.

Cavities have diameters greaterthan 10,000 . Higher magnificationsreveal characteristic interconnectedstructure, (see Fig. 7).

Cavi l ink polym er with fu l ly open

surface.

Higher magnifications

reveal characteristic interconnectedStructure.


12/67

Pore Shapes

Slit

Ink-bottle

Cylindrical

Wedge

a b

dc


13/67

Pore Diameters and MeasurementTechniques

Experimental techniques

capillary condensation Hg intrusion

microscopy


14/67

Pore Shape Selectivity

Reactant selectivity

+

Product selectivity

CH3OH +

Restricted transition-state selectivity


15/67

Why is it important? It dictates the diffusion process through thematerial.

Pore Size and Diffusion Regimes

Configurationaldiffusion

Surfacemigration

1000 100 10 1 0.1

10-4

10-8

10-12

10-16

1000 100 10 1 0.1

100

50

0

Ea(kJ/mol)

D(m2/s)

Pore diameter (nm)

Pore diameter (nm)

Moleculardiffusion Knudsen

diffusion

Surfacemigration

Knudsen number: Kn = /d

= molecular free path length

d= characteristic pore diameter

Kn> 1 Knudsen diffusion

Types of diffusion

Molecular Knudsen

Surface

Cylindrical pore

dpdm


16/67

Volumetric Adsorption Measurement

N2(77.3 K) or

Ar, He, CH4, CO

2, Kr

adsorbate

adsorbent

pressuregauge

P V1

V2

high vacuum

PV=nRT


17/67

Adsorption Isotherms

0

5

10

15

20

25

0 0.2 0.4 0.6 0.8 1p/p

0

n

ad(mmol/g)1

Adsorption

Desorption

p is gas pressure

po is vapour pressure


18/67

Adsorption Isotherms

III

nad

p/p0

VI

nad

p/p0

V

nad

p/p0

I

nad

p/p0 p/p

II

nad

0

B

IV

nad

p/p0B


19/67

Langmuir AdsorptionIsotherm (Type I)

Assumptions:

homogeneous surface(all adsorption sites energetically identical)

monolayer adsorption (so no multilayer adsorption)

no interaction between adsorbed molecules

pK

pKnnn mmad

1

I

nad

p /p 0


20/67

LANGMUIR ISOTHERM

Assumptions

all adsorption sites equivalent

ability of adsorbate to bind is independent ofwhether the adjacent sites are occupied or not.adsorbate behaves as an ideal gas in gas phaseonly monomolecular adsorption takes place

adsorbed molecules occupy fixed sitesheat of adsorption is independent of surfacecoverage.


21/67

Type II and IV Isotherms

Multilayer adsorption (starting at B)

Common for pore-free materials

Similar to II at low p

Pore condensation at high p

p/p

II

nad

0

B

IV

nad

p /p0

B


22/67

Type III and V Isotherms

III

nad

p/p0

V

n

ad

p/p0

Strong cohesion force betweenadsorbed molecules, e.g. whenwater adsorbs on hydrophobicactivated carbon

Similar to III at low p

Pore condensation at high p


23/67

Surface Area & Monolayer Capacity

S =nmAmN

monolayercapacity (mol/g)

specific surfacearea (m2/g)

area occupied by onemolecule (m2/molecule)

Avogadros number

(molecules/mol)

BET model: SBET

t model: St


24/67

Properties of Adsorbates for PhysisorptionMeasurements

Adsorbate Boiling Point (K) Am (nm2/molecule)

N2 77.3 0.162

Ar 87.4 0.142CO2 194.5 0.17

Kr 120.8 0.152


25/67

N2Adsorption Isotherm in ZSM-5

0

1

2

3

4

5

6

0 0.2 0.4 0.6 0.8 1

p/p0

nad(m

mol/g)1

Langmuir Adsorption?

strong adsorption at low pdue to condensation inmicropores

at higher psaturation due to finite (micro)pore volume

Adsorption and Desorption Isotherms

BET (B E tt T ll ) M th d


26/67

BET (Brunauer, Emmett, Teller) Method

Modification of Langmuir isotherm

Both monolayer and multilayer adsorption

Layers of adsorbed molecules divided in:

First layer with heat of adsorption Had,1

Second and subsequent layers with Had,2= Hcond

BET isotherm:

BET equation does not fit entire adsorption isotherm

different mechanisms play a role at low and at highp

0mm0ad11pp

CnC

Cnppnp

RTHH

C condadexp


27/67

BET ADSORPTION ISOTHERMS

Assumptions:

Multiple layers form and langmuir model applies toeach layer.

Heat of adsorption, Hads for first layer has a valuedetermined by properties of surface and adsorbate,but for second and all subsequent layers, it is equalto heat of vapourization H vap.

Evaporation (or desorption) only occurs fromexposed surfaces.Rate of evaporation is equal to rate of condensationon preceding layer.

BET Model


28/67

reality model5

43

21

0

...321 210mad nni

1-nn1-n1

0

nn1-n

1

0101

0

11

1

0

0

pKp

k

kkpk

pKpk

kkpk

d

an

d

n

a

d

ada1stlayer

nthlayer

For every layer

Langmuir model

Assume

RT

H

RT

H

RT

H

KKK

KKcondn

ads

ee

e

0,n0,nn

0,11

0

0

0

m

ad

111 p

p

C

p

p

p

p

C

n

n

RT

HH

C

condads

e

BET Model

BET Equation


29/67

x1c1x1cx

V

v

m

BET Equation

p is gas pressurepo is vapour pressure

Vm is monolayervolumeV is volume measuredof gas adsorbed

Step 1: Plot x / [V(1-x)] vs x

Step 2: Determine from the plotIntercept 1 / (cVm)Slope (c-1) / (cVm)

Step 3: Calculate c, Vm

Vm= 1/ (slope + intercept)

o

mm

ppxwhere

cV

xc

cVxV

x

/

,11

1

Vmcan be used tocalculate Specific SurfaceArea,

SBET= VmAmwhereAmis area per adsorption sitenumber of gas molecules /

cm3


30/67

p/p0

nad/nm

(B) (A)

Low p/p0:

filling of micropores

favoured adsorption atmost reactive sites(heterogeneity)

High p/p0:

capillary condensation

Range 0.05 < p/p0

< 0.3 is used to determine SBET

BET equation

Porous Silica and Alumina

Adsorption at Pore Wall


31/67

Adsorption at Pore Wall

Cylindrical pore

Ink-bottle pore

Pore with shape of intersticebetween close-packed particles

Adsorbed layert

dpdm


32/67

t-method BET

only valid in small pressure interval

interpretation not very easy

thickness (t) of adsorbed layer can be calculated

plot of tversus pfor non-porous materials is thesame (has been checked experimentally)

t-plot helps in interpretation

0.354nm


33/67

t-method

nm354.0m

ad nn

t

tnS

NAt

nS

NAnS

ad6t

m

9adt

mmt

1073.5

10354.0

nad

t

Proportional to St


34/67

Shape of t-plots

nm354.0m

ad n

nt

t

nad

t

nad

t

nad

Non-porous Microporous Micro- and

mesoporous

St

Smesopores

p

nad

Adsorption isotherm

t= f(p)

Pore Size Distribution


35/67

Kelvin Equation for Nitrogen

m

012lnrRT

Vpp L

micro meso macro

VL= 34.6810-6m3/mol molar volume

= 8.88 mN/m surface tension

r is surface radius

dm(nm)

Relativepressurep/p0

0

0.2

0.4

0.6

0.8

1

0.1 1 10 100 1000 10000

Pore filling Model

Cylindrical Pore Channel

Pore Size DistributionCharge in vapor pressure for a curved surface


36/67

Hysteresis Loops

HI

na

d

p/p0

H2

na

d

p/p0

H3

na

d

p/p0

Information on pore shape


37/67

t-curves

p/p0

Ads

orbed-layerthicknesst(nm)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 0.2 0.4 0.6 0.8 1

a

bHalsey

Harkins-Jura-de Boer

333.0

0/ln

00.5354.0

ppt

5.0

0/log034.0

99.131.0

ppt

Interpretation of t Plot


38/67

t-plot of -alumina

0

2

4

6

8

10

0.0 0.2 0.4 0.6 0.8 1.0 1.2

t( nm)

nad(mmol/g)

St,micro= 0 m2

/gVt,micro = 0 ml/g

mesopores

macropores

St,micro = 0 m2/g

Vt,micro = 0 ml/g

St= 200 m2/g

Interpretation of t-Plot

nm354.0

m

ad

n

nt

Dubinin-Radushkevich equation


39/67

Dubinin Radushkevich equation

Where xrepresents the work done by the adsorption

forces when adsorbate is brought up to a distance lfrom surface

p

pRT ox lne

For porous solids Vo is taken to be the pore volume,and V, the volume adsorbed at given po/p value.

pp

ERTVV oo lnlnln

2

Volume of micropores

)exp( 2ebVV o

Pore Size Distribution n


40/67

Pore Size Distribution

alumina

0.0

0.1

0.2

0.3

0.4

0.5

1 10 100 1000

dp(nm)

dV/dd(ml/g/nm)

tr o

o

p

pRT

Vtr

ln

2

nm354.0m

ad n

nt

p

p

E

RTVV oo lnlnln

2


41/67

t-plot of N2Physisorption onZSM-5

t (nm)

0 0.5 1

n2

n1

n1 = liquid N2

n2 = solid N2

nad

(mmol/g

)

6

3

0


42/67

Mercury Intrusion Curve of -Alumina

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.1 1 10 100 1000

p(MPa)

V(ml/g)

Texture Data of Commercial Catalysts


43/67

Texture Data of Commercial CatalystsMaterial Mean dp(nm) SBET(m

2/g)

Catalyst supports

Silica gel 10 200

6 400

4 800

-Al2O3 10 150

5 500

Zeolite 0.6-2 400-800

Activated carbon 2 700-1200

TiO2 400-800 2-50

Aerosil SiO2 - 50-200

CatalystsMeOH synthesis (Cu/ZnO/Al2O3) 20 80

NH3synthesis (Fe/Al2O3/K2O) 100 10

Reforming (Pt/Re/Al2O3) 5 250

Epoxidation (Ag/-Al2O3) 200 0.5


44/67

Mercury Intrusion Porosimetry

pd

14860p

Hg does not wet surfaces; pressure is needed toforce intrusion

From a force balance:

(d in nm, pin bar)

Convenient method for determining pore volumeversus pore size


45/67

Discrepancy SHgand SBETfor Microporous Materials

Hg cannot penetrate small (micro)pores,N2can

Uncertainty of contact angle andsurface tension values

Cracking or deforming of samples


46/67

Surface Areas - SHgand SBET

Adsorbent SHg SBET

m2/g m2/g deg

Iron Oxide 14.3 13.3 130

Tungsten Oxide 0.11 0.10 130

Anatase 15.1 10.3 130

Hydroxy Apatite 55.2 55.0 130

Carbon Black (Spheron-6) 107.8 110.0 130

0.5 % Ru/-Al2O3 237.0 229.0 140

0.5 % Pd/-Al2O3 115.0 112.0 140

TiO2Powder 31.0 25.0 140

Sintered Silica Pellets 20.5 5.0 140

Zeolite H-ZSM-5 39.0 375.0 140

Norit Active Carbon R1 Extra 112.0 915.0 140


47/67

Texture PropertiesN2-physisorption Hg-porosimetry

SBET St Vp dp SHg Vp dp

m2/g m2/g ml/g nm m2/g ml/g nm

Wide Pore Silica 78 52 0.91 47 80 0.92 54

-Alumina 196 202 0.49 10 163 0.49 10

-Alumina 9 8 0.12 112 12 0.48 150

Active Carbon 1057a 28 0.51 2 0.6 0.46 106

Raney Ni 76 - 0.14 5.80 - - -

ZSM-5 345 344 0.19 0.58 11 1.1 820b

ap/p0range of 0.01-0.1 was used in the calculation.

bintraparticle voids.

N Adsorption Isotherms & Pore Volume


48/67

N2Adsorption Isotherms & Pore VolumeDistributions

0

5

10

15

20

25

0 0.2 0.4 0.6 0.8 1p/p

0

nad(mmol/g)1

wide-pore silica -alumina

0

5

10

15

20

25

0 0.2 0.4 0.6 0.8 1p/p

0

nad(mmol/g)1

0.00

0.02

0.04

0.06

0.08

0.10

1 10 100 1000dpore(nm)

dV/dd(ml/g/nm)

0.0

0.1

0.2

0.3

0.4

0.5

1 10 100 1000dpore(nm)

dV/dd(ml/g/nm)



49/67


-alumina activated carbon

0

5

10

15

20

25

0 0.2 0.4 0.6 0.8 1

p/p0

nad(mmol/g)1

0

5

10

15

20

25

0 0.2 0.4 0.6 0.8 1

p/p0

nad(mmol/g)1

0.000

0.002

0.004

0.006

0.008

0.010

1 10 100 1000dpore(nm)

dV/dd(ml/g/nm)

0.0

0.1

0.2

0.3

0.4

0.5

1 10 100 1000dpore(nm)

dV/dd(ml/g/nm)

} Tensile strength effect



50/67


Raney Ni ZSM-5

0

5

10

15

20

25

0 0.2 0.4 0.6 0.8 1p/p

0

nad(mmol/g)1

0

5

10

15

20

25

0 0.2 0.4 0.6 0.8 1p/p

0

nad(mmol/g)1

0.00

0.02

0.04

0.06

0.08

0.10

1 10 100 1000dpore(nm)

dV/dd(ml/g/nm)

0

2

4

6

8

10

0.0 0.5 1.0 1.5 2.0dpore(nm)

dV/dd(ml/

g/nm

Hg Intrusion Curves & Pore Volume


51/67

Hg Intrusion Curves & Pore VolumeDistributions


0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.1 1 10 100 1000p (MPa)

V(

ml/g)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.1 1 10 100 1000

p (MPa)

V(

ml/g)

0

0.02

0.04

0.06

0.08

1 10 100 1000 10000

dpore(nm)

dV/dd(ml/g/nm)

0.0

0.1

0.2

0.3

0.4

0.5

1 10 100 1000 10000dpore(nm)

dV/dd(ml/g/nm)



52/67



0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.1 1 10 100 1000

p (MPa)

V(

ml/g)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.1 1 10 100 1000p (MPa)

V(

ml/g)

0.000

0.001

0.002

0.003

0.004

0.005

1 10 100 1000 10000dpore(nm)

dV

/dd(ml/g/nm)

0.000

0.002

0.004

0.006

0.008

0.010

1 10 100 1000 10000dpore (nm)

dV/dd(ml/g/nm)



53/67


Raney Ni ZSM-5

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.1 1 10 100 1000

p (MPa)

V(

ml/g)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.1 1 10 100 1000p (MPa)

V(

ml/g)

0.00

0.02

0.04

0.06

0.08

0.10

1 10 100 1000 10000

dpore(nm)

dV/dd(m

l/g/nm)

0

0.001

0.002

0.003

0.004

0.005

1 10 100 1000 10000 100000

dpore(nm)

dV/dd(ml/g/nm)


54/67

BET- & t-plots


0.0

0.1

0.2

0.3

0.4

0.5

0.00 0.05 0.10 0.15 0.20 0.25 0.30

p/p0

p/[nad(p0-p)](g/mmol)

SBET= 78 m2/g

C= 146

0.0

0.1

0.2

0.3

0.4

0.5

0.00 0.05 0.10 0.15 0.20 0.25 0.30

p/p0


SBET= 196 m2/g

C = 97

0.0

0.5

1.0

1.5

2.0

2.5

0.0 0.2 0.4 0.6 0.8 1.0 1.2t( nm)

nad

(m

mol/g)

St,micro=28 m2/g

Vt,micro= 0.013 ml/g

0

2

4

6

8

10

0.0 0.2 0.4 0.6 0.8 1.0 1.2

t( nm)

nad

(m

mol/g)

St,micro= 0 m2/g

Vt,micro = 0 ml/g


55/67


0.0

0.1

0.2

0.3

0.4

0.5

0.00 0.05 0.10 0.15 0.20 0.25 0.30

p/p0

p/[nad(p

0-p)](g/mmol)

SBET= 9.3 m2/g

C= 142

0.0

0.1

0.2

0.3

0.4

0.5

0.00 0.05 0.10 0.15 0.20 0.25 0.30

p/p0

p/[nad(p

0-p)](g/mmol)

SBET= 1057 m2/g

C = 1057/p

0 = 0.01 - 0.1

0.00

0.05

0.10

0.15

0.20

0.25

0.0 0.2 0.4 0.6 0.8 1.0 1.2t ( nm)

nad

(mm

ol/g)

St, micro= 1.4 m2/g

Vt,mcro = 0.001 ml/g

0

5

10

15

0.0 0.2 0.4 0.6 0.8 1.0 1.2t( nm)

nad

(mm

ol/g)

St,micro= 856 m2/g

Vt,micro= 0.42 ml/g

BET- & t-plots


56/67

Raney Ni ZSM-5

0.0

0.1

0.2

0.3

0.4

0.5

0.00 0.05 0.10 0.15 0.20 0.25 0.30

p/p0


SBET= 76 m2/g

C= 46

0.0

0.1

0.2

0.3

0.4

0.5

0.00 0.05 0.10 0.15 0.20 0.25 0.30

p/p0

p/[nad(p

0-p)](g/mmol)

SBET= 345 m2/g

C = -245

/p0: 0.01 -0.1

0

1

2

3

4

5

0.0 0.2 0.4 0.6 0.8 1.0 1.2

t ( nm)

nad

(mm

ol/g)

St,micro= 0 m2/g

Vt,micro= 0 ml/g

0

2

4

6

0.0 0.2 0.4 0.6 0.8 1.0 1.2t ( nm)

nad(mm

ol/g)

St,micro= 344 m2/g

Vt,micro= 0.18 ml/g

BET- & t-plots

Sintering of Alumina upon


57/67

Sintering of Alumina uponHeating

Tcalc(K)

SBET

(m2/g)

Sintering

Reduction of surface area


58/67


59/67

COMMERCIAL SORBENTS AND APPLICATIONSOnly four types of generic sorbents havedominated the commercial use of adsorption:

activated carbon, zeolites, silica gel, and activatedalumina. Estimates of

worldwide sales of these sorbents are (Humphreyand Keller, 1997)

Activated carbon $1 billionZeolites $100 million

Silica gel $27 millionActivated alumina $26 million


60/67

Table 2. Examples of commercial adsorption processes and sorbents

usedSeparation AdsorbentGas Bulk SeparationsNormal paraffins/isoparaffins, aromatics Zeolite

N2/O2 Zeolite

O2/N2 Carbon molecular sieveCO, CH4, CO2, N2, Ar, NH3/H2 Activated carbonfollowed by zeolite (inlayered beds)

Hydrocarbons/vent streams Activated carbon

H2O/ethanol Zeolite (3A)Chromatographic analytical separations Wide range of inorgani and polymer resin agen

Gas Puri f icat ion


61/67

H2O/olefin-containing cracked gas,

natural gas, air, synthesis gas, etc. Silica, alumina, zeolite (3A)

CO2/C2H4, natural gas, etc. Zeolite, carbon molecularsieve

Hydrocarbons, halogenated organics,

solvents/vent streams Activated carbon, silicalite,others

Sulfur compounds/natural gas, hydrogen,

liquefied petroleum gas (LPG), etc. Zeolite, activated alumina

SO2/vent streams Zeolite, activated carbon

Odors/air Silicalite, others

Indoor air pollutantsVOCs Activated carbon, silicalite,resins

Tank-vent emissions/air or nitrogen Activated carbon, silicalite

Hg/chlor-alkali cell gas effluent Zeolite


62/67

Liquid Pur i fications

H2/organics, oxygenated organics,halogenated organics, etc., dehydration Silica, alumina, zeolite, corn grits

Organics, halogenated organics,

oxygenated organics,etc./H2Owater purification Activated carbon, silicalite, resins

Inorganics (As, Cd, Cr, Cu,

Se, Pb, F,Cl, radionuclides, etc.)/H2Owaterpurification Activated carbon

Odor and taste bodies/H2O Activated carbon

Sulfur compounds/organics Zeolite, alumina, others

Decolorizing petroleum fractions, syrups,vegetable oils, etc. Activated carbon

Various fermentation products/fermentor effluent Activated carbon, affinity agents

Drug detoxification in the body Activated carbon


63/67

Liquid Bu lk Separat ions

Normal paraffins/isoparaffins, aromatics Zeolite

p-xylene/o-xylene, m-xylene Zeolite

Detergent-range olefins/paraffins Zeolitep-Diethyl benzene/isomer mixture Zeolite

Fructose/glucose Zeolite

Chromatographic analytical separations Wide range of

inorganic, polymer,and

affinity agents

Pore Structures of Zeolites


64/67

Pore Structures of Zeolites

a b

ZSM-5 Mordenite


65/67

Figure 3: Nano-porous materials are generated after etching mesomorphic blockcopolymers selectively.


66/67


67/67

Documents

Porozni materijali