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

Qiang Hu; Yong Sik Ok; Chi Hwa Wang

doi:10.1021/acs.est.2c01645

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 journal › Article › peer-review

18 Citations (Scopus)

Abstract

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 Fe₂AlO_x-based chemical looping technology in a two-zone reactor. The Fe₂AlO_x-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 language	English
Pages (from-to)	8953-8963
Number of pages	11
Journal	Environmental Science and Technology
Volume	56
Issue number	12
DOIs	https://doi.org/10.1021/acs.est.2c01645
Publication status	Published - 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 ( www.shiyanjia.com ) 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.

Keywords

chemical looping
circular economy
cyclic performance
gasification
plastic pollution
redox cycle

ASJC Scopus subject areas

General Chemistry
Environmental Chemistry

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1021/acs.est.2c01645

Cite this

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title = "Sustainable and Highly Efficient Recycling of Plastic Waste into Syngas via a Chemical Looping Scheme",

abstract = "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.",

keywords = "chemical looping, circular economy, cyclic performance, gasification, plastic pollution, redox cycle",

author = "Qiang Hu and Ok, {Yong Sik} and Wang, {Chi Hwa}",

note = "Funding Information: This work was supported by the National Research Foundation (NRF), Prime Minister{\textquoteright}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 ( www.shiyanjia.com ) for the H-TPR analysis and Dr. He Li for the elemental analysis of the post-use catalyst. 2 Publisher Copyright: {\textcopyright} 2022 American Chemical Society. All rights reserved.",

year = "2022",

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doi = "10.1021/acs.est.2c01645",

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AU - Hu, Qiang

AU - Ok, Yong Sik

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N1 - 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 ( www.shiyanjia.com ) 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.

PY - 2022/6/21

Y1 - 2022/6/21

N2 - 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.

AB - 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.

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KW - circular economy

KW - cyclic performance

KW - gasification

KW - plastic pollution

KW - redox cycle

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SN - 0013-936X

VL - 56

SP - 8953

EP - 8963

JO - Environmental Science and Technology

JF - Environmental Science and Technology

IS - 12

ER -

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

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

UN SDGs

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