Most of the chemical products around us are artificially synthesized based on fossil fuels such as coal and petroleum. To date, these products have been repeatedly mass-produced, mass-consumed, and mass-discarded. However, we are now in an era where we should reconfirm that the reserves of fossil resources are finite, and the recycling of waste and the application of renewable resources are extremely important research issues. Our laboratory regards waste plastics as a raw material at the same level as fossil fuels, and applies chemical recycling using supercritical fluids with the major purpose of producing high-value-added compounds from waste plastics. We are also focusing on waste biomass residues such as tea leaves, and aim to apply them to the collection and removal of heavy metal ions contained in water as one of the effective uses of these.
Basic Information
Faculty name/Affiliation
Naohisa Yanagihara / Department of Biosciences Faculty of Science and Engineering
Specialized Fields
Polymer chemistry, Complex chemistry
Research theme
Applied research using supercritical fluids, basic research on effective use of biomass
Research keywords
Spercritical fluids, Chemical recycling, Plastics, Biomass, Adsorption of Metal ions
Chemical recycling of plastics using supercritical fluids In general, pure substances change into three states, solid, liquid, and gas, depending on the temperature and pressure. However, above the critical points (critical temperature and pressure), a fourth state develops. Substances above this critical point are called supercritical fluids, and have the advantages of both liquids and gases. Since supercritical fluids have characteristics equal to or better than those of ordinary liquid solvents, chemical reactions proceed favorably in this fluid. In our laboratory, we work on chemical recycling of various polycondensation and addition polymerization plastics, focusing on supercritical carbon dioxide, supercritical methanol, and supercritical water, which have special properties for chemical reactions.
Collection and removal of heavy metal ions in water by tea leaves and coffee bean husks Usually, a solvent extraction method, a coprecipitation separation method, an ion exchange separation method, a collector surface-modified with silica gel or a polymer, or activated charcoal is used to collect and remove metal ions in water. However, the collectors used in these methods are all artificially synthesized compounds made from crude oil. On the other hand, it is known that organisms actively work on specific essential elements to maintain their lives and concentrate and accumulate specific elements in their bodies. In order to protect the global environment, our laboratory uses metal ions [lead (II), zinc (II), copper (II), cadmium (II), etc.］ for waste biomass residues (tea husks, coffee bean husks, etc.) while considering the resource recycling function. We are aiming to utilize it as a new functional material for collection and removal.
Papers and Conferences Presentation
Paper presentation
Title
Laboratory
Contents
Studies on the Oxidative Degradation of Nylons by Nitrogen Dioxide in Supercritical Carbon Dioxide.
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