In this chapter, we will restrict our attention to the ferrites and a few other closely related materials. The great interest in ferrites stems from their unique combination of a spontaneous magnetization and a high electrical resistivity. The observed magnetization results from the difference in the magnetizations of two non-equivalent sub-lattices of the magnetic ions in the crystal structure. Materials of this type should strictly be designated as “ferrimagnetic” and in some respects are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present. We shall not adhere to this special nomenclature except to emphasize effects, which are due to the existence of the sub-lattices.

Ferromagnetic materials

Carbon capture and storage (CCS) is broadly recognised as having the potential to play a key role in meeting climate change targets, delivering low carbon heat and power, decarbonising industry and, more recently, its ability to facilitate the net removal of CO2 from the atmosphere. However, despite this broad consensus and its technical maturity, CCS has not yet been deployed on a scale commensurate with the ambitions articulated a decade ago. Thus, in this paper we review the current state-of-the-art of CO2 capture, transport, utilisation and storage from a multi-scale perspective, moving from the global to molecular scales. In light of the COP21 commitments to limit warming to less than 2 °C, we extend the remit of this study to include the key negative emissions technologies (NETs) of bioenergy with CCS (BECCS), and direct air capture (DAC). Cognisant of the non-technical barriers to deploying CCS, we reflect on recent experience from the UK's CCS commercialisation programme and consider the commercial and political barriers to the large-scale deployment of CCS. In all areas, we focus on identifying and clearly articulating the key research challenges that could usefully be addressed in the coming decade.

/pdf/carbon-capture-and-storage-ccs-the-way-forward-11rgsqyer0.pdf

Carbon capture and storage (CCS): the way forward

In view of the climate changes caused by the continuously rising levels of atmospheric CO2 , advanced technologies associated with CO2 conversion are highly desirable. In recent decades, electrochemical reduction of CO2 has been extensively studied since it can reduce CO2 to value-added chemicals and fuels. Considering the sluggish reaction kinetics of the CO2 molecule, efficient and robust electrocatalysts are required to promote this conversion reaction. Here, recent progress and opportunities in inorganic heterogeneous electrocatalysts for CO2 reduction are discussed, from the viewpoint of both experimental and computational aspects. Based on elemental composition, the inorganic catalysts presented here are classified into four groups: metals, transition-metal oxides, transition-metal chalcogenides, and carbon-based materials. However, despite encouraging accomplishments made in this area, substantial advances in CO2 electrolysis are still needed to meet the criteria for practical applications. Therefore, in the last part, several promising strategies, including surface engineering, chemical modification, nanostructured catalysts, and composite materials, are proposed to facilitate the future development of CO2 electroreduction.

Recent Advances in Inorganic Heterogeneous Electrocatalysts for Reduction of Carbon Dioxide

Although many methods for enzyme immobilization have been described in patents and publications, relatively few processes employing immobilized enzymes have been successfully commercialized. The cost of most industrial enzymes is often only a minor component in overall process economics, and in these instances, the additional costs associated with enzyme immobilization are often not justified. More commonly the benefit realized from enzyme immobilization relates to the process advantages that an immobilized catalyst offers, for example, enabling continuous production, improved stability and the absence of the biocatalyst in the product stream. The development and attributes of several established and emerging industrial applications for immobilized enzymes, including high-fructose corn syrup production, pectin hydrolysis, debittering of fruit juices, interesterification of food fats and oils, biodiesel production, and carbon dioxide capture are reviewed herein, highlighting factors that define the advantages of enzyme immobilization.

Industrial use of immobilized enzymes

The gradually increased concentration of carbon dioxide (CO2 ) in the atmosphere has been recognized as the primary culprit for the rise of the global mean temperature. In recent years, development of routes for highly efficient conversion of CO2 has received much attention. This Review describes recent progress on the design and synthesis of solid-state catalysts for the electrochemical reduction of CO2 . The significance of this catalytic conversion is presented, followed by the general parameters for CO2 electroreduction and a summary of the reaction apparatus. We also discuss various types of solid catalysts based on their CO2 conversion mechanisms. We summarize the crucial factors (particle size, surface structure, composition, etc.) determining the performance for electroreduction.

Nanostructured Materials for Heterogeneous Electrocatalytic CO2 Reduction and their Related Reaction Mechanisms

The separation and capture process of carbon dioxide from power plants is garnering interest as a method to reduce greenhouse gas emissions. In this study, aqueous alkanolamine solutions were studied as absorbents for CO2 capture. The solubility of CO2 in aqueous alkanolamine solutions was investigated with a continuous stirred reactor at 313, 333 and 353 K. Also, the heat of absorption (−ΔHabs) between the absorbent and CO2 molecules was measured with a differential reaction calorimeter (DRC) at 298 K. The solubility and heat of absorption were determined at slightly higher than atmospheric pressure. The enthalpies of CO2 absorption in monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), and 2-amino-2-methyl-1-propanol (AMP) were 88.91, 70.44, 44.72, and 63.95, respectively. This investigation showed that the heat of absorption is directly related to the quantity of heat for absorbent regeneration, and is dependent on amine type and CO2 loading.

http://koreascience.or.kr:80/article/JAKO201314358626727.pdf

Comparison of Carbon Dioxide Absorption in Aqueous MEA, DEA, TEA, and AMP Solutions

Electrochemical reduction of carbon dioxide at low overpotential on a polyaniline/Cu2O nanocomposite based electrode

This study examines a sequestration of CO2 using sterically hindered 2-amino 2-(hydroxymethyl)-1,3-propanediol in the presence and absence of the carbonic anhydrase enzyme to obtain a CaCO3 with a polymorphic crystal composition that depended on the pH, temperature, or mole ratio of the reactants in the reaction mixture. The CO2 loading capacity of amine absorbent was 8.5 fold higher than CO2 saturated in water. The amounts of CO2 and CaCO3 precipitated were quantified using ion-selective electrodes and ion chromatography, respectively. Interestingly, each of the three polymorphs of CaCO3 (calcite, aragonite, and vaterite) were obtained in pure form, regardless of the presence of the enzyme, and reaction parameters, or the presence of additives in the reaction medium. Mg2+ was found to promote the formation of one of the polymorphs, aragonite. The purities and characteristics of the three polymorphs were verified and quantified by XRD. The carbonization yield, surface morphologies and specific characteristics of the three phases were revealed by IC, FE-SEM, FT-IR, and XPS studies. This study suggests conversion of absorbed CO2 to three polymorphs of CaCO3 could be considered as a potential mineralization process.

Sung Chan Nam

Papers

Comparison of Carbon Dioxide Absorption in Aqueous MEA, DEA, TEA, and AMP Solutions

Electrochemical reduction of carbon dioxide at low overpotential on a polyaniline/Cu2O nanocomposite based electrode

CO2 mineralization into different polymorphs of CaCO3 using an aqueous-CO2 system

Solubility of carbon dioxide in amine-functionalized ionic liquids: Role of the anions

Immobilization of carbonic anhydrase on spherical SBA-15 for hydration and sequestration of CO2.