Dr. Daisuke Aoki, Assistant Professor at Tokyo Institute of Technology, explained about his research on "a method to convert plastic into fertilizer" which can contribute to solving major global issues. He used this document for his presentation. For more information, please visit the Tokyo Tech News https://www.titech.ac.jp/english/news/2021/062681

1. School of Materials and Chemical Technology, Tokyo Institute of Technology • JST PRESTO
Daisuke Aoki
Developing a Recycling System to Convert Plastics into Fertilizers
Offering a Solution to Both Plastic Disposal and Food Problems
Plastics to Fertilizers: Chemical Recycling of a Bio-based Polycarbonate as a Fertilizer Source
T. Abe, R. Takashima, T. Kamiya, C. P. Foong, K. Numata, D. Aoki, and H. Otsuka

2. Chemical structure
n
n
n
R R R
R
X X X
X
R R Y
R Y
R Y
p
Topology (form)
Automobiles
Aquarium tanks
Source: Okinawa Churaumi Aquarium Source: JST ImPACT program (Ito)
Containers
X
Issues for polymers: functionality, quality improvement, toughness, degradability, recyclability
Plastics (Polymers) 1

3. The Microplastics Problem 2
Microplastics* drifting the seas and oceans
“The Problem of Plastics in the Seas and Oceans,” Ministry of the Environment (Government of Japan)
* Plastic particles 5 mm or smaller
The current state of the microplastics problem
Distribution and densities of microplastics
M. Eriksen et al., PloS ONE, 2014, 9(12)
Forecast of plastics volume in the seas and oceans
The New Plastics Economy: Rethinking the future of plastics, World Economic Forum, 2016
The microplastics problem is an
environmental problem on a global scale
Resolution is necessary as soon as
possible
—It is forecast that by 2050,
the weight of fish and plastics
in the seas and oceans will be equal

4. Measures in Japan against the Plastics Problem 3
Act on Promotion of
Resource Circulation for Plastics
Effective June 11, 2021
Environmentally Conscious Design
guideline
Rationalization of use
Sorted collection and recycled products by
municipalities
Voluntary collection by manufacturers and
retailers
Reduction of waste and reuse as
resources by waste-generating
businesses
For materials: using less volume,
simplifying, and increasing life span;
adding sortability and degradability; etc.
Reduction of unnecessary use
of
single-use plastics
Revision to the Containers and Packaging Recycling Law
Effective July 1, 2020
Charging for shopping bags made compulsory

5. Petroleum
(Buried underwater) Plastics Disposal by incineration
Biomass resources
Plastics Disposal by incineration
Raw
material
Biomass resources
Plastics Fertilizer
+CO2
-CO2 +CO2
-CO2
-CO2
Existing Systems and the New System 4
Raw
material
Raw
material

6. This Research
Biomass resources
Raw
material
Plastics Fertilizer
-CO2
-CO2
Degradation
Extraction
Conversion
Poly(isosorbide
carbonate)
Urea
Reuse
Isosorbide
NH3
Food
supply
Sugar
A solution to
the food problem
Fertilizer
synthesis
Use as
fertilizer
Plastics with plants
as the raw material
Bio-based raw
material
Use as glasses and goggles,
interiors and exteriors,
mobile phone housing, etc.
Raw material
5

7. PIC Degradation by Ammonia 6
Degradation by ammonia
PIC Urea
24 h, 30 ºC
GPC 1H NMR
Disappearance
Polymers disappeared after 24 hours
Signals from PIC disappeared after 24 hours
(RI, DMF)
(500 MHz, DMSO-d6)
Isosorbide

8. Use of Degradation Product as Fertilizer
PIC ISB Urea
Isosorbide = Sugar-based compound
May work as fertilizer
① Isosorbide only ② Urea only ③ Degradation product
Test on the growth of plants
③
②
①
Does isosorbide assist the fertilization effect of urea?
No problems with plant growth when the degradation product was used The degradation product itself was
also effective as fertilizer
7
No
fertilizer
10 7
Acknowledgments: Dr. Takehiro Kamiya (University of Tokyo)
Dr. Keiji Numata (Kyoto University)

9. Overview of this Research 8
Carbonate bonds react with amine
and can be converted to urea
bonds

10. Research Concept 9
Fritz Haber Carl Bosch
Ammonia synthesis process
The Haber-Bosch process
“Make bread out of air”
Used to
synthesize fertilizer
Use to
grow plants
“Make bread out of plastic”
This research
Bio-based
polycarbonate
Biomass-based
raw ingredient
Fertilizer
Use of biomass and recycling of materials
Fertilizer synthesis
Photos from the Nobel Foundation archive
https://www.nobelprize.org/prizes/chemistry/1918/summary/
https://www.nobelprize.org/prizes/chemistry/1931/bosch/facts/