Recycling CO2 to Achieve a Carbon Neutral Society

My specialty is polymer chemistry. When I was at the Kyoto Institute of Technology, I worked as an assistant professor in the laboratory of Professor Emeritus Yoshiharu Kimura to study polylactic acid (PLA), a biodegradable polymer derived from plants. Since then, I have been using Shimadzu's analytical instruments (Differential Scanning Calorimeter (DSC), Liquid Chromatograph-Mass Spectrometer (LC-MS), Scanning Probe Microscope (SPM), etc.). Currently, we are developing plastics made from CO₂ and biomass materials that can be recycled multiple times and will decompose in the natural environment. The plastics under development have three features that are good for the environment. First, they can be processed under pressure at near room temperature, which reduces the energy consumption during the molding process and, thus, reduces CO₂ emissions. Second, because they are made from CO₂ and biomass materials, it addresses the problem of oil depletion. Third, unlike conventional plastics, they can be molded without heating, meaning that they are not pyrolyzed, making them infinitely recyclable. Conventional plastics degrade due to thermal decomposition during material recycling, but the plastics we are currently developing are expected to become next-generation plastics that can be readily recycled. In our research and development project, Shimadzu's flow tester is used to evaluate the low-temperature flow of the plastics, and a gel permeation chromatography (GPC) system is used to measure their molecular weights. In addition, we are developing CO₂ capture and utilization technology that selectively separates CO₂ contained in the exhaust gas from thermal power plants. I have been conducting this research on the issue of CO₂ since joining the Research Institute of Innovative Technology for the Earth (RITE). How to use the separated CO₂ is essential to realize the goal of achieving a carbon-neutral society by 2050. Currently, we are conducting research to convert the separated and recovered CO₂ into raw materials for plastics and cement, as I mentioned earlier.

Currently, we are working with industry and academia to develop technology to recycle CO₂ emitted from cement plants, with the aim of implementing it in society by 2030. The cement industry is the third-largest source of CO₂ emissions in Japan after thermal power plants and steelworks. To address this, we are conducting research into reducing emissions and using CO₂ effectively in cement production.
In this project, CO₂ generated during the production of cement is separated as carbonate ions in an aqueous solution and combined with Ca₂+ extracted from Ca-containing waste to form calcium carbonate. This is then used again as a raw material for cement. In the conventional CO₂ capture process, which uses an alkaline aqueous solution, an enormous amount of energy is required when the separated CO₂ is recovered from the aqueous solution by heating. In our process, CO₂ is used directly without being recovered, so very little energy is required. The process is also characterized by its high recovery efficiency and rate. Shimadzu's Gas Chromatograph (GC) is used to determine the separation efficiency of CO₂ in the exhaust gas, and a Total Organic Carbon (TOC) analyzer is used to determine CO₂ in solution. We are now preparing a pilot demonstration of the technology.