M. ZGRZEBNICKI A.GĘSIKIEWICZ-PUCHALSKA R.J. WROBEL

B. MICHALKIEWICZ U. NARKIEWICZ A.W. MORAWSKI

Study of ash removal from activated carbon and its result

on CO2 sorption capacity

Presentation structure:

Introduction

Materials and methods

Experimental

Results

Conclusions

Acknowledgements

Supporting data

PRESENTATION OUTLINE

Introduction

Greenhouse effect

Fig. 1. Solar radiation – primary radiation. Fig. 2. IR radiation - secondary radiation.

http://www.esrl.noaa.gov/gmd/outreach/carbon_toolkit/basics.html

Temperature [°C]

Earth without greenhouse effect -18

Earth with greenhouse effect 15

Tab.1. Temperature on Earth with and without greenhouse effect.

Introduction

2015; 0.87

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1950 1960 1970 1980 1990 2000 2010

DIF

FE

RE

NC

E O

F A

VE

RA

GE

AN

NU

AL

TE

MP

ER

AT

UR

E [°C

]

YEAR

Fig. 3. Changes of carbon dioxide concentration. Fig. 4. Changes of average temperature.

http://www.esrl.noaa.gov/gmd/ccgg/trends/full.html

CO2 and temperature

Introduction

Fig. 5. Carbon Capture and Storage scheme.

http://www.sccs.org.uk/

Carbon Capture and Storage

Introduction

Acivated carbons:

microporous materials,

specific surface area up to 2500 m2/g,

support for noble metals,

cointain mineral matter,

used in purification of water and as

an adsorbent for SO2 or CO2.

Material

containing

carbon

Carbonization

Physical

activation

(CO2, H2O(g))

Chemical

activation

(KOH, K2CO3)

Combined

activation

Materials used for preparation activated carbon:

cherry stones,

wood,

palm shell,

coal,

peat.

Scheme 1. Preparation of activated carbon.

Materials and methods

Methods:

BET,

CO2 uptake,

XPS,

XRF,

XRD.

Materials:

• activated carbon BA11 (delivered by Carbon, Poland),

• 35-38% hydrochloric acid, 65% nitric acid, 40% fluoric acid

(Chempur, Poland).

Fig. 6. Activated carbon BA11.

Experimental

BA11

BA11_HCl

BA11_HNO3

BA11_H2O

BA11_HF

+HCl

+HNO3

+HF

+H2O

(B)(A)

1

2 3

4

5

6

78

Fig. 7. Synthesis apparature: (A) for acid treatment, (B) for

water treatment. 1 – filtering flask, 2 – Buchner funnel, 3 –

beaker, 4 –magnetic stirrer, 5 – condenser, 6 – Soxhlet

apparatus, 7 – round bottom flask, 8 – hot plate.

Scheme 2. Preparation of sorbents.

Results

0.0

2.0

4.0

6.0

8.0

10.0

12.0

Ca Fe Mg Al Si S K

CO

NC

EN

TR

AT

ION

[w

t%]

ELEMENTS

BA11

BA11_HCl

BA11_HNO3

BA11_H2O

BA11_HF

Fig. 8. XRF results of activated carbons.

Results

10 20 30 40

10 20 30 40 50

B

2°

10 20 30 40 50

F

BA11 HCl

10 20 30 40 50

D

BA11 HNO3

10 20 30 40 50

P1

O

20 40

L

BA11-HF

A

H

F

H

HH

H H

Q

Q

Q

Q(BA11)

AF

(BA11_HCl)

(BA11_HNO3)

(BA11_H2O)

(BA11_HF)

50

POSITION 2θ[°]

INT

EN

SIT

Y [

arb.

unit

s]

Fig 10. XRD results. Identified phases:

A – anhydrite, Q – quartz, H – hematite, F

– fluorite.

Fig 9. Mineral matter content.

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

0.00 0.20 0.40 0.60 0.80 1.00 1.20

PS

D [

cm3

g-1

nm

-1]

Pore width [nm]

BA11

BA11_HCl

BA11_HNO3

BA11_H2O

BA11_HF

Results

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

1.0 2.0 3.0 4.0 5.0

PS

D [

cm3g

-1nm

-1]

Pore width[nm]

BA11

BA11_HCl

BA11_HNO3

BA11_H2O

BA11_HF

Sample Vmicro [cm3/g] Vsubmicro [cm3/g] (<0.8 nm)

BA11 0.28 0.10

BA11_HCl 0.29 0.13

BA11_HNO3 0.30 0.14

BA11_H2O 0.30 0.14

BA11_HF 0.27 0.16

Fig. 11. Pore size distribution calculated from

CO2 adsorption/desorption isotherms at 0 °C.

Fig. 12. Pore size distribution calculated from N2

adsorption/desorption isotherms at -196 °C.

Tab. 2. Pore volumes of obtained samples.

Results

180.0

200.0

220.0

240.0

260.0

280.0

300.0

320.0

0.0 0.2 0.4 0.6 0.8 1.0

VO

LU

ME

AD

SO

RB

ED

[cm

3/g

]

RELATIVE PRESSURE P/P0

BA11

BA11_HCl

BA11_HNO3

BA11_H2O

BA11_HF0.0

0.5

1.0

1.5

2.0

2.5

3.0

0.0 0.2 0.4 0.6 0.8 1.0

SO

RP

TIO

N C

APA

CIT

Y [

mm

ol/

g]

RELATIVE PRESSURE P/P0

BA11

BA11_HCl

BA11_HNO3

BA11_H2O

BA11_HF

SampleSBET

[m2/g]

Sorption capacity

[mmol/g]

Vmicro

[cm3/g]

Vsubmicro [cm3/g]

(<0.8 nm)

BA11 967 2.01 0.28 0.10

BA11_HCl 997 2.50 0.29 0.13

BA11_HNO3 1001 2.73 0.30 0.14

BA11_H2O 1024 2.30 0.30 0.14

BA11_HF 960 2.88 0.27 0.16

Fig. 12. N2 adsorption/desorption isotherms at -196 °C.Fig. 13. CO2 adsorption isotherms at 0 °C.

Tab. 3. Results from volumetric methods for obtained samples.

Results

540 538 536 534 532 530 528

inte

nsity [a

rb. u

nits]

biding energy [eV]

experimental

C-O

C=O

COOH

H2O

Fe2O

3

SiO2

CaSO4

backgorund

envelope

Fig. 15. XPS results. Deconvolution of O 1s signal from

BA11 sample.

Fig. 17. XPS results. Composition

of the surface for BA11,

BA11_HCl, BA11_HNO3.

296 294 292 290 288 286 284 282

inte

nsity [a

rb. u

nits]

binding energy [eV]

experimental

graphite

C=O

C-O

COOH

satellite

keto-enolic

background

envelope

Fig. 16. XPS results. Deconvolution of C 1s signal from

BA11 sample.

BA11 BA11_HCl BA11_HNO3

0

20

40

60

80

100

Su

rfa

ce

co

mp

ositio

n [a

tom

ic %

]

O 1s

C 1s

1. Mineral matter behave like a ballast. Its removal leads to increased CO2 sorption

capacity.

2. Mineral matter may block access to pores. Its removal leads to increased specific

surface area and may provide access to additional submicropores crucial for CO2

adsorption.

3. The most effective compounds in removing mineral matter are:

• HCl/HF for removing Fe2O3,

• distilled water for removing CaSO4,

• HF for removing SiO2.

4. CaSO4 should be removed prior to HF treatment due to formation of fluorite.

5. The highest sorption capacity was achieved for activated carbon after HF treatment

(an increase of 44%).

6. Removing mineral matter reveals oxidized surface of the activated carbon.

CONCLUSIONS

The research leading to these results has received funding from the Polish-Norwegian

Research Programme operated by the National Centre for Research and Development

under the Norwegian Financial Mechanism 2009-2014 in the frame of Project Contract

No Pol-Nor/237761/98.

ACKNOWLEDGEMENTS

Improvement of CO2 uptake of activated carbons by treatment

with mineral acids

A. Gęsikiewicz-Puchalska, M. Zgrzebnicki, B. Michalkiewicz, U.

Narkiewicz, A.W. Morawski, R.J. Wrobel, Chemical Engineering

Journal, 309 (1 February 2017) p. 159-171

Thank you for your attention.

SUPPORTING DATA