Study of ash removal from activated carbon and its result on CO2 sorption capacity M. ZGRZEBNICKI B. MICHALKIEWICZ A.GĘSIKIEWICZ-PUCHALSKA U. NARKIEWICZ R.J. WROBEL A.W. MORAWSKI

PRESENTATION OUTLINE Introduction Materials and methods Presentation structure: Introduction Materials and methods Experimental Results Conclusions Acknowledgements Supporting data

Greenhouse effect Introduction 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

CO2 and temperature Introduction 1.0 2015; 0.87 0.8 0.6 0.4 0.2 0.0 -0.2 DIFFERENCE OF AVERAGE ANNUAL TEMPERATURE [°C] -0.4 1950 1960 1970 1980 1990 2000 2010 YEAR Fig. 3. Changes of carbon dioxide concentration. Fig. 4. Changes of average temperature. http://www.esrl.noaa.gov/gmd/ccgg/trends/full.html

Carbon Capture and Storage 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 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 Materials used for preparation activated carbon: cherry stones, wood, palm shell, coal, peat. Physical activation (CO2, H2O(g)) Chemical activation (KOH, K2CO3) 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, CO2 uptake, XPS, XRF,  XRD. Fig. 6. Activated carbon BA11.

Experimental BA11 2 3 1 5 +HCl +HNO3 BA11_HCl +HF 4 BA11_HNO3 6 BA11_H2O +H2O BA11_HF 7 8 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 CONCENTRATION [wt%] ELEMENTS 12.0 BA11 BA11_HCl BA11_HNO3 BA11_H2O BA11_HF 10.0 CONCENTRATION [wt%] 8.0 6.0 4.0 2.0 0.0 Ca Fe Mg Al ELEMENTS Si S K Fig. 8. XRF results of activated carbons.

Results Q Fig 10. XRD results. Identified phases: A – anhydrite, Q – quartz, H – hematite, F – fluorite. (BA11) A H H Q (BA11_HCl) Fig 9. Mineral matter content. Q INTENSITY [arb. units] (BA11_HNO3) H H Q (BA11_H2O) H H (BA11_HF) F A F 10 20 30 POSITION 2θ[°] 40 50

Vsubmicro [cm3/g] (<0.8 nm) Results 0.90 0.80 0.35 BA11 BA11_HCl BA11_HNO3 BA11_H2O BA11_HF 0.30 0.70 0.25 PSD [cm3 g-1nm-1] 0.60 0.50 PSD [cm3g-1nm-1] BA11 BA11_HCl BA11_HNO3 BA11_H2O BA11_HF 0.20 0.40 0.15 0.30 0.10 0.20 0.10 0.05 0.00 0.00 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.0 2.0 3.0 4.0 5.0 Pore width[nm] Pore width [nm] 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. 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 BA11_HF 0.27 0.16

Vsubmicro [cm3/g] (<0.8 nm) Results 3.0 320.0 SORPTION CAPACITY [mmol/g] 300.0 2.5 VOLUME ADSORBED[cm3/g] 280.0 2.0 260.0 BA11 BA11_HCl BA11_HNO3 BA11_H2O BA11_HF 0.0 0.2 0.4 0.6 0.8 1.0 1.5 BA11 BA11_HCl BA11_HNO3 240.0 1.0 220.0 BA11_H2O BA11_HF 0.5 200.0 0.0 180.0 0.0 0.2 0.4 0.6 0.8 RELATIVE PRESSURE P/P0 Fig. 13. CO2 adsorption isotherms at 0 °C. 1.0 RELATIVE PRESSURE P/P0 Fig. 12. N2 adsorption/desorption isotherms at -196 °C. Tab. 3. Results from volumetric methods for obtained samples. Sample SBET [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 BA11_HF 960 2.88 0.27 0.16

Results experimental C-O experimental graphite C=O C-O COOH satellite keto-enolic C=O COOH H O Fe O 2 SiO 2 3 intensity [arb. units] intensity [arb. units] CaSO 4 backgorund envelope background envelope 540 538 536 534 532 530 528 biding energy [eV] Fig. 15. XPS results. Deconvolution of O 1s signal from BA11 sample. 296 294 292 290 288 286 284 28 binding energy [eV] Fig. 16. XPS results. Deconvolution of C 1s signal from BA11 sample. 100 O 1s C 1s Surface composition [atomic %] 80 60 Fig. 17. XPS results. Composition of the surface for BA11, BA11_HCl, BA11_HNO3. 40 20 BA11 BA11_HCl BA11_HNO 3

CONCLUSIONS Mineral matter behave like a ballast. Its removal leads to increased CO2 sorption capacity. 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. The most effective compounds in removing mineral matter are: HCl/HF for removing Fe2O3, distilled water for removing CaSO4, HF for removing SiO2. CaSO4 should be removed prior to HF treatment due to formation of fluorite. The highest sorption capacity was achieved for activated carbon after HF treatment (an increase of 44%). 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.

Thank you for your attention. SUPPORTING DATA 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.