Synthesis and characterization of calcium oxide and magnesium oxide supported calcium oxide for carbon dioxide adsorbent
| dc.contributor.author | Farah Diana Mohd Daud | |
| dc.date.accessioned | 2021-05-06T03:46:22Z | |
| dc.date.available | 2021-05-06T03:46:22Z | |
| dc.date.issued | 2015-09-01 | |
| dc.description.abstract | Many studies reported that calcium oxide (CaO) used for CO2 removal suffer from structural instability, thus reduced the adsorption capacity and sorbent recyclability. Therefore, the ultimate aim of this work was to produce CaO with high surface area and good structural stability for widespread application of CaO as CO2 sorbents. The effect of solvent, time, temperature of the reaction and calcination for the formation of CaO from Ca(OH)2 phase via precipitation method was investigated. Then, the addition of MgO in CaO to delay sintering and consequently improved sorbent recyclability was studied. It was found that ethanol/deionized water (ethanol/DIW) and dimethylformamide/deionized water (DMF/DIW) with volume of 78 ml/02 ml for 30 minutes at 35 °C produces homogenous pods structure of Ca(OH)2 sorbent. Solvent with high amount of ethanol/DIW and DMF/DIW with volume (78 ml/ 2 ml and 80 ml/0 ml) acts as good capping agent to suppress the growth of Ca(OH)2 crystal at (1010) direction while induce anisotropic growth along (0001) direction. Comparatively, the sorbent produce in ethanol/DIW have highest surface area (30.45 m2/g), high pore volume (0.235 cm3/g) and small pore diameter (3.8 nm) than DMF/DIW which have surface area (20.66 m2/g), pore volume (0.111 cm3/g) and pore diameter (19.02 nm). The time of reaction determines the formation of homogeneous structure while temperature determines the solubility of the calcium ions. The adsorption capacity was 60% (16 mmol CO2/sorbent) subsequently reduced to 35% (8 mmol CO2/g sorbent) after 10 cyclic carbonation. This is due to sintering problem. However, the addition of MgO in the range of 5 to 30 wt% have improves the microstructure whereby demonstrated less sintering effect with high structural stability. The 5 and 10 wt% of MgO added CaO exhibited high specific surface areas and enhanced the sintering-resistant over multiple cycles for CO2 adsorption. Most importantly, 10 wt% MgO added CaO sorbent showed constant CO2 adsorption capacity (50%) over 10 carbonation cycles. Without MgO addition, the CO2 capacity of pure CaO decreases by 35 wt% but with 10 wt% MgO remained constant. In summary, the results of this research showed 10 wt% MgO is sufficient to form sorbents with high surface area with good structural stability for enhanced cyclic CO2 adsorption capacity. . | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/13326 | |
| dc.language.iso | en | en_US |
| dc.title | Synthesis and characterization of calcium oxide and magnesium oxide supported calcium oxide for carbon dioxide adsorbent | en_US |
| dc.type | Thesis | en_US |
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