A recycling system has been developed that decomposes plant-based plastics with aqueous ammonia to convert them into fertilizers (urea) that promote plant growth.Joint achievements with Tokyo Institute of Technology, University of Tokyo, and Kyoto University.
Currently, more than 70% of plastics are discarded and less than 15% are recycled.Under these circumstances, the researchers focused on the fact that plastics with carbonate bonds (polycarbonate) can be converted to urea, which is a chemical fertilizer, when they react with ammonia and are completely decomposed.Among them, polycarbonate obtained by linking isosorbide, which is a biomass resource derived from glucose (sugar), can be decomposed into urea and isosorbide, so in addition to "chemical recycling" in which plastic is returned to the starting material and reused, it is used as fertilizer. Can also be recycled.
In the demonstration experiment of the idea of this recycling system, finally, by optimizing the conditions such as ammonia concentration and reaction temperature, it became possible to completely decompose the sugar-derived polycarbonate into urea and isosorbide within 6 hours.In the growth experiment of Arabidopsis thaliana using the obtained decomposition product (mixture of urea and isosorbide), it was demonstrated that urea acts as a fertilizer and promotes the growth of plants.
Another advantage of this recycling system is that the reaction can be promoted simply by heating ammonia water, and it is a simple process that does not require an expensive catalyst.If it becomes widespread, it will have a great ripple effect on the industrial world.
This recycling system is expected to be an innovative system that simultaneously solves the "plastic disposal problem" and the "food problem due to population growth."
Paper information:[Green Chemistry] Plastics to Fertilizers: Chemical Recycling of a Bio-based Polycarbonate as a Fertilizer Source
