Investigation of the accelerated carbonation of a MgO-based binder used to treat contaminated sediment
| Autor: | Kyung-Yup Hwang, Inseong Hwang, Cheolyong Kim, Tae Yoo Kim, Jun-Young Ahn, Hoang Q. H. Phan |
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| Rok vydání: | 2017 |
| Předmět: |
Thermogravimetric analysis
Carbonation 0211 other engineering and technologies Soil Science chemistry.chemical_element Mineralogy 02 engineering and technology 010501 environmental sciences engineering.material 01 natural sciences chemistry.chemical_compound Reaction rate constant 021105 building & construction Environmental Chemistry Relative humidity 0105 earth and related environmental sciences Earth-Surface Processes Water Science and Technology Global and Planetary Change Magnesium Brucite Geology Pollution chemistry Chemical engineering Carbon dioxide engineering Magnesite |
| Zdroj: | Environmental Earth Sciences. 76 |
| ISSN: | 1866-6299 1866-6280 |
| DOI: | 10.1007/s12665-017-7115-6 |
| Popis: | A MgO-based binder developed to simultaneously solidify/stabilize contaminated sediment and store CO2 has been described previously. The objectives of the study presented here were to investigate the kinetics of the carbonation reactions of the binder and the extent to which carbonation occurred and to identify the optimal conditions for using the binder. The carbonation reaction was clearly faster and the degree of carbonation higher at CO2 concentrations of 50 and 100% than in the ambient atmosphere (which contains 0.04% CO2). A modified unreactive core model adequately described the kinetics. The rate constants were 0.0217–0.319 h−1 and were proportional to the degree of carbonation. A high degree of carbonation, 93.8%, was achieved at a CO2 concentration of 100%. The water to sediment ratio strongly affected carbonation, the optimal ratio being around 0.7. The relative humidity did not strongly affect the carbonation performance. The carbonation products were magnesite (MgCO3) and nesquehonite (MgCO3·3H2O). X-ray diffraction analysis showed that brucite (Mg(OH)2) was not present, suggesting that brucite was very quickly transformed into magnesium carbonates, the presence of which was confirmed by thermal gravimetric analysis. The results indicated that, in 7 d, 1 kg of binder could sequester up to 0.507 kg of CO2 in a 100% CO2 atmosphere. The results indicate that the MgO-based binder has great potential to be used to sequester CO2 under accelerated carbonation conditions. |
| Databáze: | OpenAIRE |
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