Recovery of Calcium from Waste Concrete and Fixation of Carbon Dioxide Gas by Carbonation Reaction

Steel slag and carbon dioxide were used as raw materials to prepare building material by carbonation. Effects of forming pressure on carbonation of steel slag and carbonated depth were studied by pore structural changes before and after carbonation and carbonated region. The results showed that these were visible pore structural changes between non-carbonated and carbonated steel slag, and after carbonation, the porosity of steel slag samples were decreased, the number of fine pore was increased and large pore was opposite. Carbon dioxide gas which was sequestrated by Ca(OH)2 and C3S were combined in CaCO3 crystal, and this process was form surface to interior. Clustered granular crystals were generated in the surface and 12 mm depth of samples, while none in the 20 mm depth of samples, no obvious granular crystal growth. The granular crystals which produced by carbonation filled the pores of the sample, in particular the arrangement of dense granular surface of crystal layer, which may impede the spread of CO2 gas to the depths, and carbonation reaction focused on the surface to 12 mm depth region.

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Formation and Dissociation of Carbon Dioxide Gas Hydrate in the Pore Space of Al2O3

Chemistry for Sustainable Development ◽

10.15372/csd20180110 ◽

2018 ◽

Keyword(s):

Carbon Dioxide ◽

Gas Hydrate ◽

Pore Space ◽

Carbon Dioxide Gas

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Atom Condensed Fukui Function for Condensed Phases and Biological Systems and Its Application to Enzymatic Fixation of Carbon Dioxide

10.26434/chemrxiv.9198770.v2 ◽

2019 ◽

Author(s):

Javier Oller ◽

David A. Sáez ◽

Esteban Vöhringer-Martinez

Keyword(s):

Carbon Dioxide ◽

Aqueous Solution ◽

Molecular System ◽

Chemical Reactivity ◽

Nucleophilic Attack ◽

Stable Conformation ◽

Fukui Functions ◽

Reactivity Descriptors ◽

Dynamics Simulations ◽

Fixation Of Carbon Dioxide

<div><div><div><p>Local reactivity descriptors such as atom condensed Fukui functions are promising computational tools to study chemical reactivity at specific sites within a molecule. Their applications have been mainly focused on isolated molecules in their most stable conformation without considering the effects of the surroundings. Here, we propose to combine QM/MM Born-Oppenheimer molecular dynamics simulations to obtain the microstates (configurations) of a molecular system using different representations of the molecular environment and calculate Boltzmann weighted atom condensed local reac- tivity descriptors based on conceptual DFT. Our approach takes the conformational fluctuations of the molecular system and the polarization of its electron density by the environment into account allowing us to analyze the effect of changes in the molecular environment on reactivity. In this contribution, we apply the method mentioned above to the catalytic fixation of carbon dioxide by crotonyl-CoA carboxylase/reductase and study if the enzyme alters the reactivity of its substrate compared to an aqueous solution. Our main result is that the protein en- vironment activates the substrate by the elimination of solute-solvent hydrogen bonds from aqueous solution in the two elementary steps of the reaction mechanism: the nucleophilic attack of a hydride anion from NADPH on the α, β unsaturated thioester and the electrophilic attack of carbon dioxide on the formed enolate species.</p></div></div></div>

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