1. Preparation of activated carbon from hydrothermal carbonized bark M. Götz a *, A. Voglhuber-Slavinsky a, D. Wüst a,b, *, O. Sahin b, A. Kruse a,b a University of Hohenheim, Institute of Agricultural Engineering, Chair of Conversion Technology an Life Cycle Assessment of Renewable Resources, Stuttgart-Hohenheim, Germany b Karlsruher Institute of Technology, Institute of Catalysis Research and Technology, Eggenstein-Leopoldhafen, Germany * Contact: wuest.dominik@uni-hohenheim.de, markus_goetz@uni-hohenheim.de

2. Preparation of activated carbon from hydrothermal carbonized bark, November 13 th, 2015, slide 2 Motivation Bio-based charcoals and activated carbons for the chemical industry Bark as a suitable feedstock for activated carbons Use of residues Existing infrastructure and distribution channels Increasing the local added value of forestry (625 €/25 kg) (Agros Organics) Motivation  Methods  Results and Discussion  Conclusion 

3. Preparation of activated carbon from hydrothermal carbonized bark, November 13 th, 2015, slide 3 Basic Concept Fig. 1: Process chain from cork oak bark, poplar bark and robinia bark to hydrothermal carbonized charcoal (HTC) and activated carbon (Hepp, Gurk, 2014; own figures) ConversionActivation Motivation  Methods  Results and Discussion  Conclusion 

4. Preparation of activated carbon from hydrothermal carbonized bark, November 13 th, 2015, slide 4 Thermochemical transformation in liquid water under increased temperature and resulting pressure (closed system) Production of solid humus-like substances and porous lignite-like particles (Hydrochars) Reduction of the H/C and O/C ratio by dehydration t = 2 - 8 h, T = 180 – 220 °C, p max : 1.5 – 3.5 MPa Process parameters: T = 160/ 220 °C for t = 1 / 5 h, p max : 2.5 MPa, DM = 20 wt% Hydrothermal Carbonization (HTC) Motivation  Methods  Results and Discussion  Conclusion 

5. Preparation of activated carbon from hydrothermal carbonized bark, November 13 th, 2015, slide 5 Increase of the inner surface/pore volume with physical or chemical treatments Chosen methods: 2 different chemical treatments: 250 ml KOH-solution (c(KOH)= 0.5 mol L -1 ) g -1 hydrochar Stirred for 1 h, T = 30 °C (‘treatment’) Reaction at 450 °C in a muffle furnace with solid KOH t = 1 h (‘activation’) Activated Carbon Motivation  Methods  Results and Discussion  Conclusion 

6. Preparation of activated carbon from hydrothermal carbonized bark, November 13 th, 2015, slide 6 Coalification chart Motivation  Methods  Results and Discussion  Conclusion  Fig. 3: Coalification chart/ Van-Krevelen-Diagram of the feedstock poplar bark and the products hydrochar, activated carbon (activation) and activated carbon (treatment)

7. Preparation of activated carbon from hydrothermal carbonized bark, November 13 th, 2015, slide 7 FTIR-Spectra Motivation  Methods  Results and Discussion  Conclusion  Fig. 4: FTIR-Spectra of the Robinia products activated carbon ‘activation’ (left red curve) and activated carbon ‘treatment’ (left lower curve) and the fossil activated carbon Norit C Gran (right black curve) (own figure, Lai,2014)

8. Preparation of activated carbon from hydrothermal carbonized bark, November 13 th, 2015, slide 8 Scanning Electron Microscope Motivation  Methods  Results and Discussion  Conclusion  Fig. 5: SEM-image of the poplar product treatment (left side) and of fossil activated carbon ‘Silacarbon AK-K835’ Magnification: 30.000 times. (own figure, Lai, 2014)

9. Preparation of activated carbon from hydrothermal carbonized bark, November 13 th, 2015, slide 9 Inner Surface A Robinia HydrocharMeasurements failed (~ 20 – 40 m 2 g -1 ) Activation140 m 2 g -1 Treatment8 m 2 g -1 Cork oak Hydrochar895 m 2 g -1 Activation482 m 2 g -1 Treatment279 m 2 g -1 Poplar Hydrochar42 m 2 g -1 Activation222 m 2 g -1 Treatment11 m 2 g -1 Motivation  Methods  Results and Discussion  Conclusion  Tab. 1: Inner Surfaces in m 2 g -1 according to Brunauer, Emmet and Teller of all prepared products. Target value: Fossil coal ‘Norit C Gran’: 875 m 2 g -1

10. Preparation of activated carbon from hydrothermal carbonized bark, November 13 th, 2015, slide 10 Bark seems to be a interesting feedstock for conversion technologies HTC process and activation was successful, treatment less suitable Repetition of tests and analyses with more adapted methodology for this kind of biomass (currently in progress) Absorption tests (in the pipeline) More realistic tests with a bark mixture or wood chips Conclusion Motivation  Methods  Results and Discussion  Conclusion 

11. Preparation of activated carbon from hydrothermal carbonized bark, November 13 th, 2015, slide 11 We thank ELLS and the Czech University of Life Science for the opportunity to participate at this conference. Furthermore our thanks go to Dipl-Ing. Dominik Wüst, Dipl-Ing. Olga Sahin and Professor Dr. Andrea Kruse for their supervision. Acknowledgments

12. Preparation of activated carbon from hydrothermal carbonized bark, November 13 th, 2015, slide 12 GOETZ, M. and VOGLHUBER, A., 2014, Herstellung von Aktivkohlen aus hydrothermal karbonisierten Rinden, Projektarbeit, Stuttgart: Universität Hohenheim HEPP, C. and GURK, C., 2014-last update, Baumbestimmung leicht gemacht - Robinie. Available: http://www.baumkunde.de/Robinia_pseudoacacia/ [05/17, 2014]. http://www.baumkunde.de/Robinia_pseudoacacia/ LAI, M.Y., 2014. Herstellung von Aktivkohle mittels Hydrothermaler Karbonisierung (HTC). Bachelorthesis, Karlsruhe: K.I.T. Karlsruhe KIRSCHHÖFER, F., SAHIN, O., BECKER, G. C., MEFFERT, F., NUSSER, M., ANDERER, G., KUSCHE, S., KLAEUSLI, T., KRUSE, A. and BRENNER-WEISS, G., 2015. Wastewater treatment – adsorption of organic micropollutants on activated HTC-carbon derived from sewage sludge. Waste Science and Technology. JAIN, A., BALASUBRAMANIAN, R.,SRINIVASAN, M. P., 2015.Hydrothermal conversion of biomass waste to activated carbon with high porosity: A review. Chemical Engineering Journal. Source references