José Ortiz-Landeros

Analysis and perspectives concerning CO2 chemisorption on lithium ceramics using thermal analysis

CO2 removal from flue gas has been proposed as one of the most reliable solutions to mitigate global greenhouse emissions. Lithium ceramics are among several materials that have potential applications in CO2 removal. Lithium ceramics are able to chemisorb CO2 in a wide temperature range, presenting several interesting properties. All lithium ceramics present a similar CO2 chemisorption reaction mechanism that has been described at the micrometric scale. However, there are several issues that have not been fully elucidated. The aim of this study is to re-analyze different experiments related to the CO2 chemisorption on lithium ceramics and to propose how different factors control this process. This study focuses on diffusion controlled CO2 chemisorption, which has been shown to be the limiting step of the CO2 chemisorption process. Diffusion controlled CO2 chemisorption appears to be mainly influenced by the chemical composition of a product’s external shell.

Structural and Thermochemical Chemisorption of CO2 on Li4+x(Si1–xAlx)O4 and Li4–x(Si1–xVx)O4 Solid Solutions

Different Li(4)SiO(4) solid solutions containing aluminum (Li(4+x)(Si(1-x)Al(x))O(4)) or vanadium (Li(4-x)(Si(1-x)V(x))O(4)) were prepared by solid state reactions. Samples were characterized by X-ray diffraction and solid state nuclear magnetic resonance. Then, samples were tested as CO(2) captors. Characterization results show that both, aluminum and vanadium ions, occupy silicon sites into the Li(4)SiO(4) lattice. Thus, the dissolution of aluminum is compensated by Li(1+) interstitials, while the dissolution of vanadium leads to lithium vacancies formation. Finally, the CO(2) capture evaluation shows that the aluminum presence into the Li(4)SiO(4) structure highly improves the CO(2) chemisorption, and on the contrary, vanadium addition inhibits it. The differences observed between the CO(2) chemisorption processes are mainly correlated to the different lithium secondary phases produced in each case and their corresponding diffusion properties.

Synthesis of advanced ceramics by hydrothermal crystallization and modified related methods

The present article aims to give a brief overview about the advantages of the hydrothermal crystallization method for the synthesis of advanced ceramics. Emphasis is given, not only on the conventional hydrothermal crystallization, but also on some of its variants; such as ultrasound-assisted, electrochemical-assisted, microwave-assisted and surfactant-assisted hydrothermal methods which open up new opportunities for the synthesis of ceramic materials with novel properties demanded for advanced applications. In the current work the synthesis of barium titanate (BaTiO3), lithium metasilicate (Li2SiO3) and sodium-potassium niobate (Na, K)NbO3 powders are reported as cases of study.

Alkaline and Alkaline-Earth Ceramic Oxides for CO2 Capture, Separation and Subsequent Catalytic Chemical Conversion

The amounts of anthropogenic carbon dioxide (CO2) in the atmosphere have been raised dramatically, mainly due to the combustion of different carbonaceous materials used in energy production, transport and other important industries such as cement production, iron and steelmaking. To solve or at least mitigate this environmental problem, several alternatives have been proposed. A promising alternative for reducing the CO2 emissions is the separation and/ or capture and concentration of the gas and its subsequent chemical transformation. In that sense, a variety of materials have been tested containing alkaline and/or alkaline-earth oxide ceramics and have been found to be good options.

CO2 chemisorption in Li2CuO2 microstructurally modified by ball milling: study performed with different physicochemical CO2 capture conditions

Lithium cuprate (Li2CuO2) was obtained by a solid state reaction and a subsequent ball milling process; then, the samples were characterized structurally and microstructurally. Additionally, both the Li2CuO2 ball milled and the solid state samples, for comparison purposes, were tested in the CO2 chemisorption process at moderate and low temperatures under different reaction conditions: (i) at moderate CO2 pressure and (ii) in the presence of water vapor. In both cases, the textural and microstructural properties of the ball milled Li2CuO2 samples showed excellent CO2 chemisorption properties which are significantly enhanced due to CO2 pressure effects or the presence of water vapor. All these results were attributed to the textural and morphological changes evidenced in the samples. The observed surface area increments show preponderant effects during CO2 chemisorption at low and moderate temperatures.

Structure, thermal stability, and catalytic performance of MgO-ZrO2 composites

A composite constituted by zirconia supported on magnesia is thermally treated. Depending on temperature, several crystal sizes and crystalline zirconia structures are obtained. At low temperatures, cubic zirconia crystals are found to be deposited on the crystalline magnesia matrix. As temperature increases, the cubic zirconia phase transforms to the tetragonal and the monoclinic phases. They form clusters supported on the MgO matrix. All these results are supported by different analytical techniques and a catalytic test.