The increase in atmospheric carbon dioxide is linked to climate changes; hence there is an urgent need to reduce the accumulation of CO2 in the atmosphere. The utilization of CO2 as a raw material in the synthesis of chemicals and liquid energy carriers offers a way to mitigate the increasing CO2 buildup. This review covers six important CO2 transformations namely: chemical transformations, photochemical reductions, chemical and electrochemical reductions, biological conversions, reforming and inorganic transformations. Furthermore, the vast research area of carbon capture and storage is reviewed briefly. This review is intended as an introduction to CO2, its synthetic reactions and their possible role in future CO2 mitigation schemes that has to match the scale of man-made CO2 in the atmosphere, which rapidly approaches 1 teraton.

The teraton challenge. A review of fixation and transformation of carbon dioxide

Sequestration of CO2 in geological media: criteria and approach for site selection in response to climate change

The most recent IPCC assessment has shown an important role for negative emissions technologies (NETs) in limiting global warming to 2 °C cost-effectively. However, a bottom-up, systematic, reproducible, and transparent literature assessment of the different options to remove CO2 from the atmosphere is currently missing. In part 1 of this three-part review on NETs, we assemble a comprehensive set of the relevant literature so far published, focusing on seven technologies: bioenergy with carbon capture and storage (BECCS), afforestation and reforestation, direct air carbon capture and storage (DACCS), enhanced weathering, ocean fertilisation, biochar, and soil carbon sequestration. In this part, part 2 of the review, we present estimates of costs, potentials, and side-effects for these technologies, and qualify them with the authors' assessment. Part 3 reviews the innovation and scaling challenges that must be addressed to realise NETs deployment as a viable climate mitigation strategy. Based on a systematic review of the literature, our best estimates for sustainable global NET potentials in 2050 are 0.5–3.6 GtCO₂ yr⁻¹ for afforestation and reforestation, 0.5–5 GtCO₂ yr⁻¹ for BECCS, 0.5–2 GtCO₂ yr⁻¹ for biochar, 2–4 GtCO₂ yr⁻¹ for enhanced weathering, 0.5–5 GtCO₂ yr⁻¹ for DACCS, and up to 5 GtCO2 yr⁻¹ for soil carbon sequestration. Costs vary widely across the technologies, as do their permanency and cumulative potentials beyond 2050. It is unlikely that a single NET will be able to sustainably meet the rates of carbon uptake described in integrated assessment pathways consistent with 1.5 °C of global warming.

https://iopscience.iop.org/article/10.1088/1748-9326/aabf9f/pdf

Negative emissions-Part 2 : Costs, potentials and side effects

Polymeric CO2/N2 gas separation membranes for the capture of carbon dioxide from power plant flue gases

Aquifer disposal of CO2: Hydrodynamic and mineral trapping

Subterranean Containment and Long-Term Storage of Carbon Dioxide in Unused Aquifers and in Depleted Natural Gas Reservoirs

Calculation methods for the single-stage permeation of a multicomponent gas mixture are presented for five flow patterns: cocurrent flow, countercurrent flow, cross flow, perfect mixing, and one-side mixing. The derivations are cast in a form suitable for computer calculation. The calculation methods presented are appropriate for systems with any number of components. Calculation results are shown for the separations of a NH3, H2, and N2 gaseous mixture by means of a polyethylene membrane, and for a H2, CH4, CO, N2, and CO2 mixture through a microporous glass membrane.

Calculation methods for multicomponent gas separation by permeation

A diffusion equation for gas permeation through microporous media in the Knudsen regime was obtained theoretically, considering the potential energy between a gas molecule and the solid surface of pores. The equation as a function of temperature contains four parameters, all of which have physical meanings. The most significant of these parameters is the effective potential energy e*, by which the gas diffusion equation as a function of temperature is characterized. Permeabilities of He, H2, CO, N2, O2, Ar, and CO2 through a microporous Vycor glass membrane were measured in the temperature range from 300 K to 950 K. The validity of the diffusion equation obtained was verified experimentally and was shown to express well the previous data. For helium in particular, diffusion is almost gas-phase flow, with no adsorbed flow except at very low temperature. However, the diffusion is affected by the interaction energy between the gas molecules and the solid surface in the pores.

/pdf/gas-diffusion-in-microporous-media-in-knudsen-s-regime-p3f2i7qyyn.pdf

Gas diffusion in microporous media in knudsen''s regime

A membrane reactor, which is a double-tubular reactor equipped with a selective membrane tube as the inner tube, was proposed Such a reactor makes it possible to obtain a product yield of a reversible reaction beyond its equilibrium value by continuous removal of the products during reaction A microporous glass tube was employed as the selective membrane, through which gases permeate almost according to Knudsen''s law Experiments in the dehydrogenation of cyclohexane to benzene as a model reaction were carried out, using the membrane reactor under atmospheric pressure in the range of 453-493 K It was shown experimentally and theoretically that a marked increase in conversion over that at equilibrium can be achieved

Yuji Shindo

Papers

Subterranean Containment and Long-Term Storage of Carbon Dioxide in Unused Aquifers and in Depleted Natural Gas Reservoirs

Calculation methods for multicomponent gas separation by permeation

Gas diffusion in microporous media in knudsen''s regime

A membrane reactor using microporous glass for shifting equilibrium of cyclohexane dehydrogenation

Kinetics of the catalytic decomposition of hydrogen iodide in the thermochemical hydrogen production