• Resources Recycling
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• v.31 no.5
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• pp.34-41
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• 2022

Smelting reduction of spent lithium-ion batteries results in metallic alloys, slag, and dust containing Li(I). Precipitation of Li₂CO₃ was performed using the synthetic leachate of the dust. Herein, the effects of the precipitant and addition of non-aqueous solvents on the precipitation of Li(I) were investigated. Na₂CO₃ was a more effective precipitating agent than (NH₄)₂CO₃ owing to the hydrolysis reaction of dissolved ammonium and carbonate. The addition of acetone or ethanol improved the Li(I) precipitation percentage for both the precipitants. When using (NH₄)₂CO₃, the Li(I) precipitation percentage increased at a solution pH of 12. Under the same conditions, the Li(I) precipitation percentage using Na₂CO₃ was much higher than that using (NH₄)₂CO₃.

• Journal of Electrochemical Science and Technology
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• v.7 no.2
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• pp.91-96
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• 2016

Oxidation behaviours of ash free coal (AFC), carbon, and H₂ fuels were investigated with a coin type molten carbonate fuel cell. Because AFC has no electrical conductivity, its oxidation occurs via gasification to H₂ and CO. An interesting behaviour of mass transfer resistance reduction at higher current density was observed. Since the anode reaction has the positive reaction order of H₂, CO₂ and H₂O, the lack of CO₂ and H₂O from AFC results in a significant mass transfer resistance. However, the anode products of CO₂ and H₂O at higher current densities raise their partial pressure and mitigate the resistance. The addition of CO₂ to AFC reduced the resistance sufficiently, thus the resistance reduction at higher current densities did not appear. Electrochemical impedance results also indicate that the addition of CO₂ reduces mass transfer resistance. Carbon and H₂ fuels without CO₂ and H₂O also show similar behaviour to AFC: mass transfer resistance is diminished by raising current density and adding CO₂.

• Membrane Journal
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• v.30 no.3
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• pp.173-180
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• 2020

As the demand for fossil fuels continues to increase worldwide, carbon dioxide (CO₂) concentration in the air has increased over the centuries. The way to reduce CO₂ emissions to the atmosphere, carbon capture and sequestration (CCS) technology have been developed that can be applied to power plants and factories, which are primary emission sources. According to the climate change mitigation policy, direct air capture (DAC) in air, referred to as "negative emission" technology, has a low CO₂ concentration of 0.04%, so it is focused on adsorbent research, unlike conventional CCS technology. In the DAC field, chemical adsorbents using CO₂ absorption, solid absorbents, amine-functionalized materials, and ion exchange resins have been studied. Since the absorbent-based technology requires a high-temperature heat treatment process according to the absorbent regeneration, the membrane-based CO₂ capture system has a great potential Membrane-based system is also expected for indoor CO₂ ventilation systems and immediate CO₂ supply to smart farming systems. CO₂ capture efficiency should be improved through efficient process design and material performance improvement.

• Economic and Environmental Geology
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• v.56 no.3
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• pp.311-330
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• 2023

Development of Carbon Capture and Storage (CCS) technique is becoming increasingly important as a method to mitigate the strengthening effects of global warming, generated from the unprecedented increase in released anthropogenic CO₂. In the recent years, the characteristics of basaltic rocks (i.e., large volume, high reactivity and surplus of cation components) have been recognized to be potentially favorable in facilitation of CCS; based on this, research on utilization of basaltic formations for underground CO₂ storage is currently ongoing in various fields. This study investigated the feasibility of underground storage of CO₂ in basalt, based on the examination of the CO₂ storage mechanisms in subsurface, assessment of basalt characteristics, and review of the global research on basaltic CO₂ storage. The global research examined were classified into experimental/modeling/field demonstration, based on the methods utilized. Experimental conditions used in research demonstrated temperatures ranging from 20 to 250 ℃, pressure ranging from 0.1 to 30 MPa, and the rock-fluid reaction time ranging from several hours to four years. Modeling research on basalt involved construction of models similar to the potential storage sites, with examination of changes in fluid dynamics and geochemical factors before and after CO₂-fluid injection. The investigation demonstrated that basalt has large potential for CO₂ storage, along with capacity for rapid mineralization reactions; these factors lessens the environmental constraints (i.e., temperature, pressure, and geological structures) generally required for CO₂ storage. The success of major field demonstration projects, the CarbFix project and the Wallula project, indicate that basalt is promising geological formation to facilitate CCS. However, usage of basalt as storage formation requires additional conditions which must be carefully considered - mineralization mechanism can vary significantly depending on factors such as the basalt composition and injection zone properties: for instance, precipitation of carbonate and silicate minerals can reduce the injectivity into the formation. In addition, there is a risk of polluting the subsurface environment due to the combination of pressure increase and induced rock-CO₂-fluid reactions upon injection. As dissolution of CO₂ into fluids is required prior to injection, monitoring techniques different from conventional methods are needed. Hence, in order to facilitate efficient and stable underground storage of CO₂ in basalt, it is necessary to select a suitable storage formation, accumulate various database of the field, and conduct systematic research utilizing experiments/modeling/field studies to develop comprehensive understanding of the potential storage site.

• Membrane Journal
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• v.31 no.6
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• pp.404-416
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• 2021

In this study, a mixed matrix membrane was prepared by varying the contents of GO and PEI-GO synthesized in PEBAX2533, and the permeation characteristics of N₂ and CO₂ were studied. The N₂ and CO₂ permeability of the PEBAX/GO mixed membrane decreased as the GO content increased, and showed the highest CO₂/N₂ selectivity of 58.9 at GO 0.3 wt%. For the PEBAX/PEI-GO mixed membrane, the N₂ permeability decreased as the PEI-GO content increased, and the CO₂ permeability showed a different trend according to the PEI-GO content. Overall, the CO₂/N₂ selectivity was higher than that of the PEBAX/GO mixed membrane. In particular, PEI-GO 0.3 wt% showed the highest CO₂/N₂ selectivity of 73.5 among the mixed membranes, and a positive result was obtained as it was located above the Robeson upper bound. This is believed to be due to the molecular sieving channel effect resulting from the original GO structure, the functional groups present in the structure of GO having affinity for CO₂, and the effect of amine bound to PEI by modifying GO into PEI.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.47-48
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• 2016

Mineral carbonation technology is a process whereby CO₂ is chemically reacted with calcium-and/or magnesium-containing minerals to form stable carbonate materials. Add the Materials that could fix CO₂ as mineral admixture to concrete can improve the anti-carbonation properties of concrete. This paper has carried on the literature research on the carbonated mechanism of Material that could fix carbon dioxide. Such as Brucite, 𝜞-C₂S, Mg₂SiO₄, MgO, Ca₃MgSi₂O₈. And summarizes the development of the development of this field.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.6
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• pp.270-275
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• 2021

ZnO was synthesized according to the transformation behavior and crystallization conditions of Zn-intermediate obtained by zinc sulfate as a precursor and NaOH, Na₂CO₃ as a alkali agents. For ZnO crystallization, Zn₄(OH)₆SO₄·H₂O and Zn₅(OH)₆(CO₃)₂·H₂O as a Zn-intermediate were calcined at 400℃ and 800℃ for 1 h, respectively, based on decomposition temperature from TGA. Zn₄(OH)₆SO₄·H₂O was confirmed to have mixed Zn₄(OH)₆SO₄·H₂O and ZnO at 400℃, and was completely thermally decomposed at 800℃ to form ZnO phase. The prepared Zn₅(OH)₆(CO₃)₂·H₂O as a Zn-intermediate by the reaction with Na₂CO₃ was transformed to a complete ZnO crystallization over 400℃. Nano-sized ZnO can be synthesized at a relatively lower calcination temperature through the reaction with Na₂CO₃.

• Journal of The Korean Society of Clinical Toxicology
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• v.17 no.2
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• pp.86-93
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• 2019

Purpose: The objective was to determine the association between PaCO₂ and adverse cardiovascular events (ACVEs) in carbon monoxide (CO)-poisoned patients. Methods: This retrospective study included 194 self-breathing patients after CO poisoning with an indication for hyperbaric oxygen therapy and available arterial blood gas analysis at presentation and 6 hours later. The baseline characteristics and clinical course during hospitalization were collected and compared. The mean PaCO₂ during the first 6 hours after presentation was calculated. Results: The incidence rates of moderate (30 mmHg< PaCO₂ <35 mmHg) or severe (PaCO₂ ≤30 mmHg) hypocapnia at presentation after acute CO poisoning were 40.7% and 26.8%, respectively. The mean PaCO₂ during the first 6 hours was 33 (31-36.7) mmHg. The incidence of ACVEs during hospitalization was 50.5%. A significant linear trend in the incidence of ACVEs was observed across the total ranges of PaCO₂ variables. In multivariate regression analysis, mean PaCO₂ was independently associated with ACVEs (OR 0.798 (95% CI 0.641-0.997)). Conclusion: Mean PaCO₂ during the first 6 hours was associated with increased ACVEs. Given the high incidence of ACVEs and PaCO₂ derangement and the observed association between PaCO₂ and ACVEs, this study suggests that 1) PaCO₂ should be monitored at the acute stage to predict and/or prevent ACVEs; and 2) further study is needed to validate this result and investigate early manipulation of PaCO₂ as treatment.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.215-216
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• 2012

Emissions of CO₂ occur during the production of cement manufacturing process. During the production of clinker, limestone is mainly calcium carbonate, is heated to produce lime and CO₂ as a by-product. It has a major problem, CO₂ uptake is not considered in concrete carbonation, just focus in CO₂ emission. This study is to develop a simulation model for CO₂ uptakes in concrete structures based on carbonation reduction coefficient considering finishing materials. CO₂ uptakes unit of concrete cubic meter is calculated by CO₂ emissions unit of concrete materials and usage of concrete materials in mix proportion. From the simulation result, CO₂ uptake ratios is 2.04 percent in carbonation models of concrete structure during 40 years.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.43-45
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• 2012

As a part of recent CO₂ emission reduction studies in the concrete industry with active use of concrete admixtures with low basic unit of CO₂ emission such as blast furnace slag (BFS), basic unit of CO₂ emission by SBFS was computed in order to assess CO₂ emission by reinforced concrete building with smart blast furnace slag (SBFS). In addition, SBFS concrete was applied to the subject building for assessment of CO₂ emission during material production step among construction steps. Life cycle CO₂ emission assessment on the subject building was classified into 7cases according to mix ratio of BFS and SBFS.