Center for Advanced Research of Energy and Materials
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Pore properties and CO₂ adsorption performance of activated carbon prepared from various carbonaceous materials
The production of activated carbon using biomass and coal as carbon sources, melamine as a nitrogen source, and K₂CO₃ as a chemical activator revealed that the lower carbon content and lower ash content of the carbon source resulted in better pore development, and that the surface area and micropore volume of activated carbon affected the CO₂ adsorption capacity. It was also shown that the optimal micropore size for CO₂ adsorption is 0.5 to 1.2 nm. These results are expected to lead to the establishment of production guidelines for activated carbon with high CO₂ adsorption capacity.
Yuuki Mochizuki, Javzandolgor Bud, Enkhsaruul Byambajav, and Naoto Tsubouchi
Selective separation of Li, Ni, Co and Mn from model spent Li ion battery cathode materials by dry processing using the combination of chlorination and oxidation
The present group has recently developed a technology to selectively recover valuable metals (Li, Ni, Co and Mn) from used lithium-ion battery cathode materials (LiNiO₂, LiCoO₂, LiMn₂O₄, and their composite composition). Specifically, we found that Li, Ni, Co and Mn can be selectively separated from LiNiO₂, LiCoO₂, and LiMn₂O₄ by chlorination up to 600℃ followed by air oxidation up to 1300℃. This research paper was selected as a Key Scientific Article by the selection committee of Advances in Engineering, Canada, and is highly evaluated.
Recovery of phosphate from carbonized sewage sludge by chlorination
The present research group has recently found a method to recover phosphorus, which is called “biological and technical nutrient”, from sewage sludge as phosphorus chloride forms. Specifically, we have developed a simple sewage sludge recycling technology that first carbonizes sewage sludge to improve handling, then chlorinates the resulting carbonized material at 500℃, and finally separates phosphorus chloride species and impurities by a cooled deposition method. This method can be applied to sewage sludge incineration ash, livestock manure, steelmaking slag, etc.
Unveiling the origin of diffusion suppression of hydrogen isotopes at the α-Al₂O₃(0001)/α-Cr₂O₃(0001) interfaces
Hydrogen in metallic materials causes degradation known as hydrogen embrittlement, which renders the materials brittle. Therefore, to promote the use of hydrogen energy in applications such as fuel cells and nuclear fusion reactors, strategies to prevent hydrogen permeation into structural materials are essential. In this study, we elucidated the mechanism by which coating multiple layers of different ceramic films on metal surfaces, which serve as hydrogen permeation barriers, can more effectively suppress hydrogen permeation than single-layer ceramic films. This research can contribute to extending the service life of metallic materials in a hydrogen environment.
Yuji Kunisada, Ryotaro Sano, and Norihito Sakaguchi
International Journal of Hydrogen Energy, Volume 97, Pages 1327-1334