Development of Mesoporous Alumina-based Composites for CO2 Capture

by Fan Wang

Research Advisor: Dr. M. JaroniecGraduate Student: Chamila Gunathilake

OutlineIntroduction about CO2 emissionsModern approaches to control CO2 and disadvantagesCriteria for selecting Al-based compositesSynthesis Pathway (EISA)Determine characterization via TGA and N2 adsorptionMeasure the CO2 uptake through Temperature programmed desorption (TPD) Study

IntroductionMain CO2 Emission Sources:

Power PlantsGas Processing IndustryRefineries, Chemical and

Petrochemical IndustriesIron and Steel Industries, Cement

Industries

Modern Aqueous Amine-based Processes and their Disadvantages

MEA (monoethanolamine) and DEA [N-Methyl DEA,AMP(2-amino-2-methyl-1-propanol)] are usually used

1) Reduced power generation capacity by 1/32) Regeneration is expensive3) Corrosion problems4) Problems with scaling up Large volumetric flow rates of flue gas at 1atm pressure with

CO2 at low partial pressures Temperature range of 100-150 ∼ 0C The presence of impurities (SOx, NOx, and significant amounts

of oxygen)

A. Samanta, A. Zhao, G. K. H. Shimizu, P.Sarkar and R. Gupta, Post-Combustion CO2 Capture Using Solid Sorbents, J. Am. Chem. Soc.2011

Criteria for Selecting Al/Mg and Al/Zr as Solid Sorbents for CO2 Capture1 Adsorption capacity2 Selectivity 3 Adsorption Desorption 4 Mechanical strength of sorbent particles5 Chemical stability/tolerance to impurities6 Regeneration of sorbents7 Sorbent costs

ObjectivesSynthesize alumina-based composites with enhanced: Porosity by using block copolymer-assisted sol-gel

synthesis Basic properties by adding Mg oxide Thermal stability by adding Zr and Mg species as

structure promoters Examine CO2 capture at elevated temperatures (120oC)

to achieve high CO2 sorption capacity

template removal via calcination

Synthesis Pathway (involves Evaporation Induced Self-assembly)

calcination in tube furnace

Thermogravimetric (TGA) Study thermal analysis is used to monitor the changes in physical and chemical properties of materials as a function of temperature (usually with constant heating rate) in TGA the recorded mass loss or gain is due to desorption, decomposition, oxidation, or chemisorption, respectively

TGA study of Al/Mg solid sorbents: as-synthesized Al-Mg (green), sample after extraction (blue), and sample after calcination (red).

N2 Adsorption Studies of Alumina-based Sorbents

Adsorption Analyzer →

Sample SBET (m2/g)

Vsp(cm3/g)

Vmi(cm3/g)

wKJS(nm)

Alc 83 0.14 0.01 13Al-Zr10c 210 0.48 0.03 15Al-Zr30c 87 0.10 0.01 5Al-Mg10c 275 0.43 0.04 13Al-Mg30c 290 0.41 0.04 9Al-Mg50c 223 0.40 0.02 10Al-Mg70c 283 0.45 0.02 5

Time (minutes)0 20 40 60 80 100 120 140 160

TCD

Sig

nal (

a.u)

0.00

0.01

0.02

0.03

0.04

0.05

0.06

PretreatmentPulse CO2 CO2 TPD

123

2 3

1

Al-Mg50C

(120 0C)

TPD Instrument

TPD Graph

TPD Studies of CO2 Sorption

Time (minutes)0 20 40 60 80 100 120 140

TPD

Sig

nal (

a.u)

AlC

Al-Zr10C

Al-Zr30C

760 0C

Time (minutes)0 20 40 60 80 100 120 140

TPD

Sig

nal (

a.u)

0.000

0.002

0.004

0.006

0.008

0.010

Al-Mg10C

Al-Mg30C

Al-Mg50C

780 0C

TPD for Al-Mg(X) composites

TPD for Al-Zr(X) composites

Isotherm CO2 Uptake(mmol/g)

AlC 1.30Al-Zr10C 1.23Al-Zr30C 1.73Al-Mg10C 1.47Al-Mg30C 2.08Al-Mg50C 2.46Al-Mg70C 2.87

TPD Studies of CO2 Sorption

Conclusions MgO effect on the enhancement of CO2

capture by Al2O3-MgO composites at 120 oC is clearly shown

Further improvement of the surface area, porosity and chemical composition of the aforementioned composites is possible

Further studies are required to evaluate the long term stability and regenerability of the composites and to explore performance under flue gas conditions