https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:55543 Wed 05 Jun 2024 09:36:43 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:46916 2) capture using reactive silicate-based mineral slurries exposed to a gas flow containing CO₂. The model is validated through experimentation using thermally conditioned or heat-activated serpentinite (hydrous metamorphic ultramafic rock) in a laboratory-scale bubble column reactor. The kinetic model developed advocates a holistic modeling approach, offering an expanded view of the dissolution of heat-activated serpentinite under lean CO₂ conditions, in which the gas–liquid–solid system and its influence on CO₂ dissolution and the coupled dissolution behavior of the material are considered in their entirety. Modeling incorporates the characteristics of the gas to liquid phase interaction, such as CO₂ composition of the gas phase and interfacial area, the composition of the aqueous phase and its temperature, and compositional and morphological features of the solid. We demonstrate that such an approach is essential when considering proton-limiting conditions that are especially relevant to mineral dissolution under dilute CO₂ conditions in short reaction timeframes. The model is of particular relevance to the use of reactive silicate-based minerals for the aqueous capture of CO₂ from dilute CO₂ gas streams. The model as developed can be used to predict CO₂ capture using heat-activated serpentinite slurries for a given set of operating conditions and should be adaptable for use with other alkaline materials of defined reactivity in similar or varying reaction settings by adequately specifying reaction conditions.]]> Thu 08 Dec 2022 08:53:04 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21318 Scenedesmus alga to the solution. Precipitation of nesquehonite occurred during both an accelerated degassing of CO₂ induced by sparging small nitrogen bubbles (representative diameter of 20 µm), and during slow degassing engendered by introducing large nitrogen bubbles (representative diameter of 5 mm). The response of the system during low rates of degassing closely approached quasi-thermodynamic predictions, which permitted an estimation of the level of supersaturation of nesquehonite, prior to the onset of precipitation. Small bubbles and CA significantly increased rates of degassing and indirectly the production of nesquehonite, as the rate of degassing can limit the precipitation process. The response of the system during rapid rates of degassing, prior to precipitation, was not entirely consistent with quasi-thermodynamic predictions. During precipitation, higher rates of degassing produced similar alkalisation and precipitation trends to that observed for lower rates of degassing. Our results agree with the formation of travertine deposits in nature, where the degassing of solutions enriched with inorganic carbon, and enhanced alkalisation by microorganisms, have been shown to influence carbonate formation. The results demonstrate a catalytic effect of CA on the rate limiting carbonate reactions, increasing CO₂ exchange between nitrogen and water, and indirectly accelerating the precipitation of carbonates for a system controlled by rate of degassing. The results of this study have applications to large-scale storage of CO₂ by mineralisation.]]> Sat 24 Mar 2018 07:52:52 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:35221 Mon 24 Aug 2020 18:00:51 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:41902 Mon 15 Aug 2022 14:15:27 AEST ]]>