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-
Evaluation of Metal Organic Frameworks for Desulfurization
by
MORLA VYAS
Department of Chemical EngineeringIndian Institute of Technology, Guwahati
May, 2012
-
OUTLINE
INTRODUCTION
OBJECTIVES
LITERATURE REVIEW
EXPERIMENTAL WORK
RESULTS AND DISCUSSIONS
CONCLUSIONS
-
INTRODUCTION Environment
Air Pollution
Sulfur Emissions
Combustion of Fuels Combustion of Fuels
Gasoline and Diesel Fuels
Can`t we reduce these Emissions ????
Yes
-
Environmental Regulations
Euro III ( Concentration of [S] < 150 ppm) Euro IV ( Concentration of [S] < 25 ppm)
INDIA
BS III ( Concentration of [S] < 150 ppm) BS IV ( Concentration of [S] < 50 ppm)
Is there any methods to maintain these Sulfur concentrations ????
-
Methods Like
Oxidative and Bio Desulfurization
Ultra sound assisted Desulfurization
Extraction
Hydro Desulfurization Hydro Desulfurization
Adsorption
The first three methods are good at regulating the sulfur concentrations but these are not able to meet the present environmental regulations
-
HDS as an Conventional Technology
Principle: Converts Sulfur in to H2S
Advantages : Sulfur concentrations to less than 50 ppm very effectively Eliminates non aromatic sulfur compounds
Disadvantages : Requires high temperatures (~ 898 K) Requires high temperatures (~ 898 K) Requires high pressures (60 100 atm) High operating costs Frequent catalyst poisoning Ineffective in eliminating aromatic sulfur species like
Benzothiophene Dibenzothiophene 4,6-DMDBT
Decrease in octane ratings ( due to increase in temperature for the removal of organic sulfur species)
-
Here Comes Liquid Phase Adsorption
Advantages:
Requires Low temperature and low pressures (ambient conditions) Hydrogen is not required Low energy demands for the process Potential to regenerate the spent adsorbent Reduction of oil loss in the beds
Importance:
Selectively removes sulfur compounds from transportation fuels by the pi-complexation ( a weak chemica bond) adsorption. Refractory sulfur compounds bind strongly to the pi-complexation sorbents because of a better electron donation and back donation ability[01]
[01]Ralph T. Yang,Desulfurization of Transportation Fuels by Adsorption, Vol. 46, No. 2, pp. 111150, 2004
-
Adsorbents like :
Activated Carbon
Silica gel
Activated Alumina
Carbon Molecular sieves
Zeolites
Metal organic Frameworks
MOFs Consist of metal cations linked by polyfunctional organic linkers yielding porous three-dimensional networks.
Advantages:
High Surface Area
Easy Regeneration
Tunable structures
-
OBJECTIVE:
This Project focuses on
Synthesis and characterizing the adsorbents
Choosing the better adsorbent based on the effective removal of sulfur
species
Investigation of relationship between structures of the adsorbent
framework and sulfur adsorption
-
S. No Type of Adsorbent
Sulfur Species
removed
Work done Results at optimum
conditions
References
1. Cu-BTC-MOF
Thiophene and Tetra hydro thiophene (THT)
Investigated Zn containing MOF`s and Cu containing MOF`s (prepared by electro chemical methods) and found Cu containing MOF`s having higher potential towards the
78 wt% of the sulfur content was removed from the Thiophene based oils and 86 wt% for THT based oils
Sabine Achmann et.
al ,2010[2]
Literature Survey
potential towards the removal of thiophenes and THT in low sulfur gasoline and diesel fuels.
oils
2. Copper containing MOF
Benzothiophene, Thiopheneand tetra hydro thiophene
Investigated Al containing MOF`s ,Fe containing MOF`s and Cu containing MOF`s and observed C300 has high adsorption capacity.
The extent of DBT at temperatures close to ambient is eight times higher on C300 MOF`s
G.Blanco-Brieva et. al , 2011 [3]
-
S. No Type of Adsorbent
Sulfur species
removed
Work done Results at optimum
conditions
References
3. Ag+/Al-MSU-S
Benzo thiophenes and Di Benzo thiophenes (DBT)
Investigated Ag+ exchanged mesoporous material Al-MSU-S for gasoline containing 600 ppmw of BT and DBT
The sulfur species were brought to less than 10 ppmws
Chunmei Meng et. al 2010 [4]
Contd
4. Activated Carbon Fibre
BT,DBT before HDS and after HDS 4-MDBT;4-6 DMDBT; 2,4,6-
TMDBT
Activated carbon ber (ACF) was selected in this study asan adsorbent because it showed rather low pressure drop and
high performance among the activated carbon materials and the twice use of bed is possible
Removed the
sulphur content from 300 ppms to less than 10 ppms
Yosuke Sano et. al 2005 [5]
-
S. No Type of Adsorbent
Sulfur species
removed
Work done Results at optimum
conditions
References
5Activated
carbonImpregnated with CuCl and PdCl2
4,6-dimethyl di benzo
thiophene,BT,DBT
Considered JP-5, a jet fuel that has sulphur content of 1172 ppm and investigated metal impregnated oxides, zeolite 5A,13X,Y zeolites of various
65% sulphuradsorptioncapacity wasobserved forfirstregeneration
Hermen A. Zinnen 1999 [6]
Contd
of various metal cation forms..
regeneration and 54% for second regeneration
-
Sulfur Species
We have chosen Dibenzothiophene as our sulfur species
Why Dibenzothiophene????
Structure
Two benzene rings
Single sulfur atom (Hindered)
At very High temperatures (~900oC) DBT can At very High temperatures (~900oC) DBT can be removed
But at those temperatures the aromaticitywill be lost.
Hence, Liquid phase adsorption explored3 Dimensional structure of DBTSource : Ben mills et al.,
-
Metal organic Frameworks
We have chosen three different MOFs Cu-BTC Cr-BDC MIL-53 (Al)
What is the Importance of Choosing these MOFs????
Cu-BTC Coordinatively unsaturated metal center Stable structure Stable structure
Cr-BDC Open metal centers High surface area and large pore volume
MIL-53 (Al) Stable structure Partially saturated metal center Flexible framework
-
This Involves
Synthesis Characterization Adsorption Equilibrium Measurements
Synthesis:
Experimental Work
Adsorbent Reactants Temperature
(K)
Time
(h)
Product Recovery
Cu-BTC
[7]
[Cu3(BTC)2], [Cu
(NO3)2.3H2O ,
Ethanol, DMF,
Methanol and
Deionized water
373 10
Filtration and Soxhleted
with methanol, for
removal of excess DMF.
Product is dried in hot air
oven at 353 K
-
Adsorbent Reactants Temperature
(K)
Time
(h)
Product Recovery
Cr-BDC
[8]
Cr(NO3 )3.9H2O ,
BDC, Hydrofluoric
acid, DMF,ethanol
& Deionized water
493 8
Filtration and Washed
thoroughly with DMF
and dried in oven at 423
K in hot air oven for
overnight. For 200 mg of
373 20 the product,15 ml of
ethanol is added.
MIL 53(Al)
[9]
Al(NO3)2.9H2O,
Terephthalic acid,
DMF, and
Deionized water
493 72
Filtration and Washed
with Deionized water. For
removal of excess BDC
1 gm of product is added
with 25 ml of DMF and
keep for heating at 333 K
for 15 h
-
010
20
30
40
25 225 425
We
igh
t, m
g
Temperature , C
Characterization
Thermo Gravimetric analysis plot for Cu-BTC MOF
0
2
4
6
8
10
12
14
16
18
20
0 100 200 300 400 500 600
We
igh
t, m
g
Temperature C
Thermo Gravimetric analysis plot for Cr-BDC MOF
Thermo Gravimetric Analysis
0
2
4
6
8
10
12
14
16
0 200 400 600 800
We
igh
t, m
g
Temperature (oC)
Thermo Gravimetric analysis plot for MIL-53(Al) MOF
Metal Organic
Framework
BET Surface
Area (m2/gm)
Pore
volume
(cm3/gm)
Cu-BTC1668 0.828
Cr-BDC3300 1.38
MIL-53 (Al)1215 0.59
Textual Properties of Metal Organic frameworks
-
Adsorption Equilibrium Measurements:
To study the behavior of Metal organic Frameworks in Liquid phase adsorption, we followed a definite Protocol
Protocol Involves Six Steps:
Preparation of Synthetic Fuel mixtures
Synthesizing the Metal organic Framework Synthesizing the Metal organic Framework
Activating the Metal organic Framework
Loading the MOF to the fuel mixtures
Equilibrating the Fuel mixture
Analyzing the Fuel mixture
-
Equilibrium Experiments for Liquid phase adsorption
Allowed to distribute
Done by shaking at 200 rpm in an Incubator shaker
Time estimated for equilibration is 24 hrs
Adsorbent was filtered and the clear solution is collected
This unknown concentration (After adsorption) was analyzed in analyzing equipments This unknown concentration (After adsorption) was analyzed in analyzing equipments
Finally we will get the extent of adsorption done by measuring the removal of the subjected species on to the adsorbent.
Isotherms were plotted to understand the behavior of the adsorbents at different temperatures and to identify conditions for which high adsorption capacities can be obtained.
-
Sulfur Analysis
These can be carried out on
The fuel mixture need to be analyzed before and after the Adsorption, to know the extent of adsorption
We prepared Concentrations ranging from 100 ppm(S) to 6000 ppm(S) for our analysis
These can be carried out on
High Performance Liquid Chromatography
UV-Visible Spectrophotometer
GC/MS Spectroscopy
-
Determination of DBT concentrations in UFLC (Ultra Fast Liquid Chromatography):
Results and Discussion:
Column selected: C-18 (ZORBAX-ODS)
Wavelength range : 220 nm
Detector :UV-Visible
Stationary phase (A): Deionised water (HPLC grade)
Typical chromatogram for DBT+ n-heptane (500ppmw DBT) mixture using UFLC
Deionised water (HPLC grade)
Mobile phase (B): Methanol (HPLC grade)
Flow rate (A): 0.2 ml/min
Flow rate (B) : 0.8 ml/min
Pressure : 13.9 Mpa
Amount injected: 0.10 ml
Observation:
Compound of interest dibenzothiophene is detected at the retention time of 16-17.5 minutes( Retention Time) range.
-
Contd.Calibration Plot:
y = 1E-05x + 1.6411R = 0.998
0
100
200
300
400
500
600
700
800
900
1000
pp
mw
DB
T
Analysis:
50 ppmw DBT 950ppmw DBT
A plot of ppmw DBT verses these chromatogram areas gives the required calibration plot.
0
0 20000000 40000000 60000000 80000000 100000000
Area
Calibration plot of dibenzothiophene + n-heptane fuel mixture [11]
Observation:
From the trend line pattern it is obvious that analysing equipment is best suitable for the concentrations ranging upto around 900 ppmw DBT
[11]P.Poddar Adsorptive Desulfurization of Liquid Fuels, BTP thesis,Dept of chemical engineering,IITG
-
Contd.Dibenzothiophene on Cu-BTC:
0
20
40
60
80
100
120
Am
ou
nt
Ad
sorb
ed
( g
S/
kg M
OF)
298 K
313 K
328 K
Experiments were conducted at three different temperatures
298 K 313 K 328 K
0
0 1000 2000 3000 4000 5000
Concentration, ppmwS
Adsorption isotherms of DBT on Cu-BTC at 298 K, 313 K and 328 K
Observation:
It is evident that adsorption potential of this material is higher at 313 K than on 298 K and still lesser for 328 K
Reasons: At low temperatures, the adsorption process is basically governed by weak Van der Waals forces
At higher temperatures Chemisorption, and probably chemical reaction [12] is dominant showing in increase in adsorption potentials
[12] Zhang ZY, Adsorptive removal of aromatic organosulfur compounds over the modied NaY zeolites. Appl Catal B: Environ 2008;82:110
-
Contd.Dibenzothiophene on Cr-BDC:
0
20
40
60
80
100
120
Am
ou
nt
Ad
sorb
ed
(gS
/ kg
MO
F)
298 K
313 K
328K
Experiments were conducted at three different temperatures
298 K 313 K 328 K
0
0 1000 2000 3000 4000 5000
Concentration, ppmwS
Adsorption isotherms of DBT on Cr-BDC at 298 K, 313 K and 328 K
Observation:
It is evident that adsorption potential of this material is slightly higher at 313 K than on 298 K and still lesser for 328 K
Reasons: At low temperatures, the adsorption process is basically governed by weak Van der Waals forces
At higher temperatures Chemisorption, and probably chemical reaction [12] is dominant showing in increase in adsorption potentials
-
Contd.Dibenzothiophene on MIL-53 (Al):
0
20
40
60
80
100
120
140
0 1000 2000 3000 4000
Am
ou
nt
Ad
sorb
ed
( g
S/ k
g M
OF)
298 K
313 K
328 K
Reasons: At low temperatures, the adsorption process is
Experiments were conducted at three different temperatures
298 K 313 K 328 K
0 1000 2000 3000 4000
Concentration, ppmwS
Adsorption isotherms of DBT on MIL-53 (Al) at 298 K, 313 K and 328 K
adsorption process is basically governed by weak Van der Waals forces
Observation:
It is evident that adsorption potential of this material is slightly higher at 313 K than on 298 K and lesser for 328 K
Adsorption potentials at 298 K and 313 K haven`t shown significant changes, resembling that there is no effect of chemisorptions at 313K
-
Contd.Correlation of MOFs based on Temperature Kinetics:
0
20
40
60
80
100
120
140
0 1000 2000 3000 4000 5000Am
ou
nt
Ad
sorb
ed
(gS
/ kg
of
MO
F)
Concentration, ppmwS
Cu-BTC
Cr-BDC
MIL-53(Al)
Observation:
MIL-53 (Al) is having more adsorption capacity than other two mofs
Cu-BTC is competitive with MIL-53 (Al) because of its still adsorbing potentials
0
20
40
60
80
100
120
140
0 2000 4000 6000
Am
ou
nt
Ad
sorb
ed
( g
S/ k
g o
f M
OF)
Concentration, ppmwS
Cu-BTC
Cr-BDC
MIL-53 (Al)
Correlation among the adsorption isotherms of DBT on the three MOFs (Cu-BTC, Cr-BDC and MIL-53 (Al) ) at 298 K.
Correlation among the adsorption isotherms of DBT on the three MOFs (Cu-BTC, Cr-BDC and MIL-53 (Al) ) at 313 K.
Observation:
Same trend is observed at 313 K
-
Contd.Correlation of MOFs based on Temperature Kinetics:
0
20
40
60
80
100
120
140
Am
ou
nt
Ad
sorb
ed
( g
S /
kg o
f M
OF)
Cu-BTC
Cr-BDC
MIL-53 (Al)
0
0 1000 2000 3000 4000 5000
Concentration, ppmwS
Correlation among the adsorption isotherms of DBT on the three MOFs (Cu-BTC, Cr-BDC and MIL-53 (Al) ) at 328 K.
Observation:
MIL-53 (Al) is having more adsorption capacity than other two mofs
Cu-BTC is less competitive with MIL-53 (Al) at this temperature (328 K)
-
Contd.
0
20
40
60
80
100
120
140
290 300 310 320 330
Exte
nt
of
adso
rpti
on
( g
S/ k
g M
OF) MIL-53 (Al)
Cu-BTC
Cr-BDC
Variation of Adsorption amounts:
290 300 310 320 330
Temperature K
Variation of dibenzothiophene (DBT) adsorption capacity for Cr-BDC and MIL-53 (Al) at equilibrium concentration (3400 ppmwS) and Cu-BTC at 3400 ppmwS
Observation:
No distinct pattern is noticed
Extent of adsorption is maximum at 313 K for Cu-BTC and Cr-BDC
Extent of adsorption at 298 K , 313 K and 328K are more or less equal for MIL-53 (Al)
-
Contd.Comparison with existed Sorbents:
40
60
80
100
120
140
Exte
nt
of
Ad
sorp
tio
n (
g S
/ kg
So
rbe
nt)
Extent of DBT adsorption at 298 K (2500 ppmw S) for Cu-BTC, Cr-BDC,MIL-53 (Al), MOF-5, MOF-177, MOF-505 [13] , Y-Zeolites[03], Activated carbons[14]
[13] Adam J. Matzger, Liquid Phase Adsorption by Microporous Coordination Polymers: Removal of OrganosulfurCompounds, J. AM. CHEM. SOC. 2008, 130, 69386939[14]
0
20
MIL-53 (Al) Cu-BTC Cr-BDC MOF-5 MOF-505 MOF-177 Y-Zeolites Activated Carbon
Exte
nt
of
Ad
sorp
tio
n (
g S
/ kg
So
rbe
nt)
Sorbents
-
Why this higher and lower adsorption amounts ???
Factors effecting adsorption
Surface areas pore volumes
Liquid phase adsorption Impact of structure Impact of structure Role of metals Role of ligands Role of host-guest interactions
-
Comparison with existed Sorbents: Surface areas
SorbentsMetal
involvedLigand
BET
Surface
Area
(m2/gm)
Pore volume
(cm3/gm)
Amount Adsorbed
(g S / kg Sorbent)
Dibenzothiophene
Cu-BTC Copper
1,3,5-
benzenetricarboxylic
acid
1668 0.828 68.1
Cr-BDC Chromium
1,4-
benzenedicarboxyli
c acid
3300 1.38 57.3
1,4-
MIL-53 (Al) Aluminium
1,4-
benzenedicarboxyli
c acid
1215 0.59 118.6
MOF-5[13] Zinc
1,4-
benzenedicarboxyli
c acid
2900 1.04 40
MOF-177[13] Zinc1,3,5-
benzenetribenzoate4630 1.69 20
MOF-505[13] Copper
3,3,5,5-
biphenyltetracarbox
ylic acid
1830 0.71 35
[13] Adam J. Matzger, Liquid Phase Adsorption by Microporous Coordination Polymers: Removal of OrganosulfurCompounds, J. AM. CHEM. SOC. 2008, 130, 69386939
-
Contd.Reasons behind higher and lower adsorption:
Role of Cation on the S-M (Sulfur-Metal) interactions with alter in Ligand
40
60
80
100
Exte
nt
of
Ad
sorp
tio
n (
gS/
kg
of
MO
F)
298 K313 K
298 K 313 K 328 K
328 K Observation:
Here the Cation Copper ( Cu2+ ) is same for both the Materials
0
20
40
Cu-BTC Cu-DABCO Cu-BTC Cu-DABCO Cu-BTC Cu-DABCO
Exte
nt
of
Ad
sorp
tio
n (
gS/
kg
of
MO
F)
Metal organic frameworks
298 K 313 K 328 K
Possess greater (S-M) interactions and leads to higher adsorption for Cu-BTC than on Cu-DABCO
Extent of DBT adsorption at equilibrium (3500 ppmw S) for Cu-BTC andCu-DABCO [11]
[11]P.Poddar Adsorptive Desulfurization of Liquid Fuels, BTP thesis,Dept of chemical engineering,IITG
-
Contd.Reasons behind higher and lower adsorption: Role of Ligand on the S-M (Sulfur-Metal) interactions with alter in Cation
40
60
80
100
120
140
Exte
nt
of
adso
rpti
on
(g
S/ k
g o
f M
OF) Observation:
Here the CationAluminium (Al3+ ) and Iron (Fe2+) is different for both the Materials
But the ligands are identical
0
20
MIL-53 (Al) MIL-53 (Fe)
Exte
nt
of
adso
rpti
on
(g
S/ k
g o
f M
OF)
Metal organic frameworks
Extent of DBT adsorption at equilibrium (3500 ppmw S) for MIL-53(Al)and MIL-53(Fe) [03]at 313K
identical
Thus possess 6 times higher adsorption for MIL-53 (Al) than on MIL-53 (Fe)
[03] G.Blanco-Brievaa, Effectiveness of metalorganic frameworks for removal of refractory organo-sulfur compound present in liquid fuels, Fuel Vol:90, 2011
-
Conclusion:
In this study
The metal organic frameworks Cu-BTC, Cr-BDC and MIL-53 (Al) were synthesised and characterisation of these frameworks were also carried out.
The metal organic frameworks Cu-BTC, Cr-BDC and MIL-53 (Al) were synthesised and characterisation of these frameworks were also carried out.
Explored Sulfur adsorption measurements on these MOFs
Our studies explored that these MOFs have promising adsorption potentials than existing Sorbents employed for desulfurization of organosulfur compounds till yet
MIL-53 (Al) has higher adsorption potentials than Cu-BTC and Cr-BDC
Cu-BTC is more competitive with MIL-53 (Al) than Cr-BDC due to its still adsorbing capacities
-
It was explored that the structure of these organo sulfur compounds plays an important role along with the structure of MOF and other parameters like -Complexation and pore volumes and surface areas in deciding the adsorption potentials of these MOFs employed in this work
It has been demonstrated that the extent of dibenzothiophene (DBT) adsorption at temperatures close to ambient (304 K) is higher for all three mofs employed in this work
The very high adsorption capacity of these (MIL-53(Al)) and Cu-BTC) substrates makes it a potential candidate to be employed in the removal of remaining refractory S-compounds in
Contd.
potential candidate to be employed in the removal of remaining refractory S-compounds in previously desulfurized liquid fuels.
-
Future work
Evaluating these organo sulfur compounds like BT(benzothiophene) and DBT( dibenzothiophene) on mofs like MOF-74 with change in metal (w.r.t. Mg,Ni, and Co), which is showing higher adsorption potentials for CO2 adsorption till now.
Flow-through experiments and determination of the selectivity of these materials for BT and DBT in the presence of other aromatic compounds found in fuels are can be made to assess the practicality of desulfurization by adsorption to MOFs.
-
References[2] Sabine Achmann, Gunter Hagen, Martin Hmmerle, Itamar Malkowsky, Christoph Kiener, Ralf Moos, Sulfur Removal from Low sulphur Gasolineand Diesel Fuel by Metal Organic Frameworks, Chem. Eng. Technol. 2010, 33, No. 2, 275280
[3] G.Blanco-Brievaa, J.M. Campos-Martina, S.M. Al-Zahrani and J.L.G. Fierroa, Effectiveness ofmetalorganic frameworks for removal of refractory organo-sulfur compound present in liquidfuels, Fuel Vol:90, 2011
[4]Chunmei Meng, Yunming Fang, Lijun Jin, Haoquan Hu, Deep desulfurization of modelgasoline by selective adsorption on Ag+/Al-MSU-S , Catalysis Today 149 (2010) 138142
[5] Yosuke Sano, Kazuomi Sugahara, Ki-Hyouk Choi, Yozo Korai, Isao Mochida , Two-stepadsorption process for deep desulfurization of diesel oil , Fuel 84 (2005) 903910adsorption process for deep desulfurization of diesel oil , Fuel 84 (2005) 903910
[6] Hermen A. Zinnen Removal of organic sulphur compounds from FCC Gasoline usingRegenerable Adsorbents, US Patent number 5,935,422 Aug 10 1999
[7] Pradip C Ph.D. Thesis, Indian Institute of Technology, Guwahati, 2009
[8] Pradip chowdhury, Chaitanya Bikkina, and Sasidhar Gumma* Gas adsorption properties ofthe Chromium based Metal Organic Framework MIL 101 J.Phys.Chem.C 2009, 113, 6616-6621
[9] Rowsell, J. L. C., and Yaghi, O. M., Metalorganic frameworks: a new class of porousmaterials, Micropor. Mesopor. Mater., 73, 3-14 (2004)
-
Chemisorption:
-Complexation: The DewarChattDuncanson model is a model in organometallic chemistry , which
Chemisorption is a sub-class of adsorption , driven by a chemical reaction occurring at the exposed surface.
A new chemical species is generated at the adsorbent surface (e.g. corrosion, metallic oxidation).
The strong interaction between the adsorbate and the substrate surface creates new types of electronic bonds ionic or covalent, depending on the reactive chemical species involved
Back up
The DewarChattDuncanson model is a model in organometallic chemistry , which explains the type of chemical bonding between an alkene and a metal (pi-complex) in certain organometallic compounds.
The model is named after Michael J.S. Dewar , Joseph Chatt and L.A. Duncanson
The pi-acid alkene donates electron density into a metal d-orbital from -symmetry bonding orbital between the carbon atoms.
The metal donates electrons back from (a different) filled d-orbital into the empty antibonding orbital. Both of these effects tend to reduce the carbon-carbon bond order, leading to an elongated C-C distance and a lowering its vibrational frequency.[14]
[14] Olefin co-ordination compounds. Part III. Infra-red spectra and structure: attempted preparation of acetylene complexes J. Chatt and L. A. Duncanson, J. Chem. Soc., 1953,
-
Back up: for UFLC
ZORBAX-ODS: [10] Highly retentive reversed phase liquid chromatographic column packing based on the ZORBAX Microparticulate silica support This bonded phase packing is formed by the monomolecular bonding of octadecysilane groups to the surface of the particles Maximum surface area coverage is maintained to produce these columns with exceptional reproducibility of performance C-18 bonded phases are well established for the seperation of non polar and low polarity solutes Stronger retentive power for non polar compounds
Choice of Mobile phase: Methanol [10]
As our fuel mixture is basically a non polar mixture, we need our compound to be retended by the column So, we need a partially aqueous solvents to serve our purposeMethanol is a strong organic solvent and it is chosen as our mobile phase An increase in the retention is basically governed by increasing the water content of the mobile phase Hence we have chosen the binary mixture composition of flow as
Methanol : 0.8ml/min Deionised water : 0.2ml/min
[10] Instrumental Liquid chromatography: A practical manual on High performance liquid chromatography, by N.A Parris
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