https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:41382 Tue 02 Aug 2022 15:48:24 AEST ]]> https://nova.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://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:12448 Sat 24 Mar 2018 08:17:52 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:10414 Sat 24 Mar 2018 08:12:38 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:21380 2. A simplified rate law based on the known elementary reaction mechanism provides an excellent fit to the experimental data. The rate constant, 1.34 × 10^–6 M^–1 s^–1, is thought to be of higher accuracy than those in the literature as it does not depend on the rate of parallel reaction pathways or on the rate of interphase mass transfer of gaseous reaction products. The activation energy for the simplified rate law was established to be 107 kJ mol^–1. Quantum chemistry calculations indicate that the majority of the large activation energy results from the endothermic nature of the equilibrium 2HNO₂ ⇄ NO + NO₂ + H₂O. The rate constant for the reaction between nitrate ions and nitrous acid, which inhibits HNO₂ decomposition, was also determined.]]> Sat 24 Mar 2018 08:04:59 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:17893 – ion selective electrode. The reaction results in the formation of nitric oxide and thiocyanogen, the latter decomposing to sulfate and hydrogen cyanide in aqueous solution. The rate of consumption of ONSCN depends strongly on the concentration of SCN^– ions and is inhibited by nitric oxide. We have developed a reaction mechanism that comprises three parallel pathways for the decomposition of ONSCN. At high thiocyanate concentrations, two reaction pathways operate including a second order reaction to generate NO and (SCN)₂ and a reversible reaction between ONSCN and SCN^– producing NO and (SCN)₂^–, with the rate limiting step corresponding to the consumption of (SCN)₂^– by reaction with ONSCN. The third reaction pathway, which becomes significant at low thiocyanate concentrations, involves formation of a previously unreported species, ONOSCN, via a reaction between ONSCN and HOSCN, the latter constituting an intermediate in the hydrolysis of (SCN)₂. ONOSCN contributes to the formation of NO via homolysis of the O–NO bond and subsequent dimerization and hydrolysis of OSCN. Fitting the chemical reactions of the model to the experimental measurements, which covered a wide range of reactant concentrations, afforded estimation of all relevant kinetic parameters and provided an excellent match. The reaction mechanism developed in this contribution may be applied to predict the rates of NO formation from ONSCN during the synthesis of azo dyes, the gassing of explosive emulsions, or nitrosation reactions occurring in the human body.]]> Sat 24 Mar 2018 07:56:25 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:25335 Sat 24 Mar 2018 07:30:24 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:35221 Mon 24 Aug 2020 18:00:51 AEST ]]>