Mechanisms of Water Interaction with Pore Systems of Hydrochar and Pyrochar from Poplar Forestry Waste
| Autor: | Pellegrino Conte, Valentina Marsala, Giuseppe Alonzo, Bruno Glaser, Giulia Cimo, Ulrich M. Hanke |
|---|---|
| Přispěvatelé: | Conte, P, Hanke, UM, Marsala, V, Cimò , G, Alonzo, G, Glaser, B, University of Zurich, Conte, Pellegrino |
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Magnetic Resonance Spectroscopy
Water flow Settore AGR/13 - Chimica Agraria 1600 General Chemistry 1100 General Agricultural and Biological Sciences Hydrothermal carbonization Adsorption Biochar medicine 910 Geography & travel Porosity Waste Products Chemistry Temperature Water Forestry General Chemistry 10122 Institute of Geography Populus Agronomy Chemical engineering Charcoal General Agricultural and Biological Sciences Porous medium Saturation (chemistry) fast field cycling NMR relaxometry hydrochar pyrochar biochar water dynamics Activated carbon medicine.drug |
| Popis: | The aim of this study was to understand the water-surface interactions of two chars obtained by gasification (pyrochar) and hydrothermal carbonization (hydrochar) of a poplar biomass. The two samples revealed different chemical compositions as evidenced by solid state (13)C NMR spectroscopy. In fact, hydrochar resulted in a lignin-like material still containing oxygenated functionalities. Pyrochar was a polyaromatic system in which no heteronuclei were detected. After saturation with water, hydrochar and pyrochar were analyzed by fast field cycling (FFC) NMR relaxometry. Results showed that water movement in hydrochar was mainly confined in very small pores. Conversely, water movement in pyrochar led to the conclusion that a larger number of transitional and very large pores were present. These results were confirmed by porosity evaluation derived from gas adsorption. Variable-temperature FFC NMR experiments confirmed a slow-motion regime due to a preferential diffusion of water on the solid surface. Conversely, the higher number of large pores in pyrochar allowed slow movement only up to 50 °C. As the temperature was raised to 80 °C, water interactions with the pore surface became weaker, thereby allowing a three-dimensional water exchange with the bulk liquid. This paper has shown that pore size distribution was more important than chemical composition in affecting water movement in two chemically different charred systems. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|