Study of ash removal from activated carbon and its result on CO 2 sorption capacity M. ZGRZEBNICKI A.GĘSIKIEWICZ-PUCHALSKA R.J. WROBEL B. MICHALKIEWICZ U. NARKIEWICZ A.W. MORAWSKI
PRESENTATION OUTLINE Presentation structure: Introduction Materials and methods Experimental Results Conclusions Acknowledgements Supporting data
Introduction Greenhouse effect Fig. 1. Solar radiation primary radiation. Fig. 2. IR radiation - secondary radiation. Tab.1. Temperature on Earth with and without greenhouse effect. Temperature [ C] Earth without greenhouse effect -18 Earth with greenhouse effect 15 http://www.esrl.noaa.gov/gmd/outreach/carbon_toolkit/basics.html
DIFFERENCE OF AVERAGE ANNUAL TEMPERATURE [ C] Introduction CO 2 and temperature 1.0 0.8 2015; 0.87 0.6 0.4 0.2 0.0-0.2 Fig. 3. Changes of carbon dioxide concentration. -0.4 1950 1960 1970 1980 1990 2000 2010 YEAR Fig. 4. Changes of average temperature. http://www.esrl.noaa.gov/gmd/ccgg/trends/full.html
Introduction Carbon Capture and Storage Fig. 5. Carbon Capture and Storage scheme. http://www.sccs.org.uk/
Introduction Acivated carbons: microporous materials, specific surface area up to 2500 m 2 /g, support for noble metals, cointain mineral matter, used in purification of water and as an adsorbent for SO 2 or CO 2. Material containing carbon Materials used for preparation activated carbon: Carbonization cherry stones, wood, palm shell, coal, peat. Physical activation (CO 2, H 2 O (g) ) Chemical activation (KOH, K 2 CO 3 ) Combined activation Scheme 1. Preparation of activated carbon.
Materials and methods Materials: activated carbon BA11 (delivered by Carbon, Poland), 35-38% hydrochloric acid, 65% nitric acid, 40% fluoric acid (Chempur, Poland). Methods: BET, CO 2 uptake, XPS, XRF, XRD. Fig. 6. Activated carbon BA11.
Experimental BA11 +HCl BA11_HCl +HNO 3 BA11_HNO 3 +HF BA11_H 2 O +H 2 O BA11_HF Scheme 2. Preparation of sorbents. (A) 1 2 3 4 5 6 7 8 (B) 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.
Results CONCENTRATION [wt%] 12.0 10.0 8.0 6.0 BA11 BA11_HCl BA11_HNO3 BA11_H2O BA11_HF 4.0 2.0 0.0 Ca Fe Mg Al Si S K ELEMENTS Fig. 8. XRF results of activated carbons.
Results INTENSITY [arb. units] Fig 10. XRD results. Identified phases: A anhydrite, Q quartz, H hematite, F fluorite. B (BA11) Q A H H (BA11_HCl) Q 10 20 30 40 50 2 F Fig 9. Mineral matter content. (BA11_HNO 3 ) Q 10 20 30 40 50 BA11 HCl D H H (BA11_H 2 O) Q 10 20 30 40 50 BA11 HNO3 P1 H H (BA11_HF) 10 20 30 40 50 A F O F L 10 20 30 40 20 40 BA11-HF POSITION 2θ[ ] 50
PSD [cm 3 g -1 nm -1 ] Results PSD [cm 3 g -1 nm -1 ] 0.90 0.35 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 BA11 BA11_HCl BA11_HNO3 BA11_H2O BA11_HF 0.30 0.25 0.20 0.15 0.10 0.05 BA11 BA11_HCl BA11_HNO3 BA11_H2O BA11_HF 0.00 0.00 0.20 0.40 0.60 0.80 1.00 1.20 Pore width [nm] Fig. 11. Pore size distribution calculated from CO 2 adsorption/desorption isotherms at 0 C. 0.00 1.0 2.0 3.0 4.0 5.0 Pore width[nm] Fig. 12. Pore size distribution calculated from N 2 adsorption/desorption isotherms at -196 C. Tab. 2. Pore volumes of obtained samples. Sample V micro [cm 3 /g] V submicro [cm 3 /g] (<0.8 nm) BA11 0.28 0.10 BA11_HCl 0.29 0.13 BA11_HNO 3 0.30 0.14 BA11_H 2 O 0.30 0.14 BA11_HF 0.27 0.16
SORPTION CAPACITY [mmol/g] Results VOLUME ADSORBED[cm 3 /g] 3.0 320.0 2.5 2.0 1.5 BA11 1.0 BA11_HCl BA11_HNO3 0.5 BA11_H2O BA11_HF 0.0 0.0 0.2 0.4 0.6 0.8 1.0 RELATIVE PRESSURE P/P 0 Fig. 13. CO 2 adsorption isotherms at 0 C. 300.0 280.0 260.0 BA11 240.0 BA11_HCl 220.0 BA11_HNO3 200.0 BA11_H2O 180.0 BA11_HF 0.0 0.2 0.4 0.6 0.8 1.0 RELATIVE PRESSURE P/P 0 Fig. 12. N 2 adsorption/desorption isotherms at -196 C. Tab. 3. Results from volumetric methods for obtained samples. Sample S BET [m 2 /g] Sorption capacity [mmol/g] V micro [cm 3 /g] V submicro [cm 3 /g] (<0.8 nm) BA11 967 2.01 0.28 0.10 BA11_HCl 997 2.50 0.29 0.13 BA11_HNO 3 1001 2.73 0.30 0.14 BA11_H 2 O 1024 2.30 0.30 0.14 BA11_HF 960 2.88 0.27 0.16
Results intensity [arb. units] experimental C-O C=O COOH H 2 O Fe 2 O 3 SiO 2 CaSO 4 backgorund envelope intensity [arb. units] experimental graphite C=O C-O COOH satellite keto-enolic background envelope 540 538 536 534 532 530 528 296 294 292 290 288 286 284 282 biding energy [ev] Fig. 15. XPS results. Deconvolution of O 1s signal from BA11 sample. binding energy [ev] Fig. 16. XPS results. Deconvolution of C 1s signal from BA11 sample. 100 O 1s C 1s Fig. 17. XPS results. Composition of the surface for BA11, BA11_HCl, BA11_HNO 3. Surface composition [atomic %] 80 60 40 20 0 BA11 BA11_HCl BA11_HNO 3
CONCLUSIONS 1. Mineral matter behave like a ballast. Its removal leads to increased CO 2 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 CO 2 adsorption. 3. The most effective compounds in removing mineral matter are: HCl/HF for removing Fe 2 O 3, distilled water for removing CaSO 4, HF for removing SiO 2. 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.
ACKNOWLEDGEMENTS 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.
SUPPORTING DATA Improvement of CO 2 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.