Sustainable and Highly Efficient Recycling of Plastic Waste into Syngas via a Chemical Looping Scheme

Qiang Hu, Yong Sik Ok, Chi Hwa Wang

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


Converting plastic waste into valuable products (syngas) is a promising approach to achieve sustainable cities and communities. Here, we propose for the first time to convert plastic waste into syngas via the Fe2AlOx-based chemical looping technology in a two-zone reactor. The Fe2AlOx-based redox cycle was achieved with the pyrolysis of plastic waste in the upper zone, followed by the decomposition and thermal cracking of hydrocarbon vapors, and the oxidation and water splitting in the lower zone (850 °C) enabled a higher carbon conversion (81.03%) and syngas concentration (92.84%) when compared with the mixed feeding process. The iron species could provide lattice oxygen and meanwhile act as the catalyst for the deep decomposition of hydrocarbons into CO and the accumulation of deposited carbon in the reduction step. Meanwhile, the introduced water would be split by the reduced iron and deposited carbon to further produce H2and CO in the following oxidation step. A high hydrogen yield of 85.82 mmol/g HDPE with a molar ratio of H2/CO of 2.03 was achieved from the deconstruction of plastic waste, which lasted for five cycles. This proof of concept demonstrated a sustainable and highly efficient pathway for the recycling of plastic waste into valuable chemicals. 2022 American Chemical Society.

Original languageEnglish
Pages (from-to)8953-8963
Number of pages11
JournalEnvironmental Science and Technology
Issue number12
Publication statusPublished - 2022 Jun 21

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation (NRF), Prime Minister’s Office, Singapore, under its Campus for Research Excellence and Technological Enterprise (CREATE) program (grant number R-706-001-102-281). Y.S.O. was supported through a National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (no. 2021R1A2C2011734) and was partly supported by the OJEong Resilience Institute (OJERI) Research Grant from the OJERI, Korea University, Republic of Korea. The authors would like to thank Shiyanjia Lab ( ) for the H-TPR analysis and Dr. He Li for the elemental analysis of the post-use catalyst. 2

Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.


  • chemical looping
  • circular economy
  • cyclic performance
  • gasification
  • plastic pollution
  • redox cycle

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry


Dive into the research topics of 'Sustainable and Highly Efficient Recycling of Plastic Waste into Syngas via a Chemical Looping Scheme'. Together they form a unique fingerprint.

Cite this