The Combination of Nitrogen (N<sub>2</sub>) Pyrolysis and Carbon Dioxide (CO<sub>2</sub>) Activation for Regenerating Spent Activated Carbon

In line with the principles of the circular economy, this study aimed to develop a pyrolysis-activation regeneration process capable of producing highly porous carbon materials from spent granular activated carbon (GAC), which was generated by a high-tech electronics manufacturing company in Taiwan....

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Main Authors: Ya-Chen Ye, Wen-Shing Chen, Chi-Hung Tsai, Wen-Tien Tsai
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/10/5336
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author Ya-Chen Ye
Wen-Shing Chen
Chi-Hung Tsai
Wen-Tien Tsai
author_facet Ya-Chen Ye
Wen-Shing Chen
Chi-Hung Tsai
Wen-Tien Tsai
author_sort Ya-Chen Ye
collection DOAJ
description In line with the principles of the circular economy, this study aimed to develop a pyrolysis-activation regeneration process capable of producing highly porous carbon materials from spent granular activated carbon (GAC), which was generated by a high-tech electronics manufacturing company in Taiwan. Thermogravimetric analysis (TGA) and other thermochemical analyses were first conducted to investigate the thermal decomposition behavior of the spent GAC. Subsequently, the thermal regeneration system was employed to perform the N<sub>2</sub> pyrolysis and CO<sub>2</sub> activation experiments under various process conditions (i.e., 800, 850, and 900 °C for holding 0, 30, and 60 min, respectively). Analytical instruments included a surface area and porosimeter for pore property analysis, scanning electron microscopy (SEM) for porous texture observation, and energy dispersive X-ray spectroscopy (EDS) for surface elemental distribution analysis. The results revealed that the pore properties of thermally regenerated GAC were significantly improved compared to the spent GAC, indicating the effective removal or decomposition of adsorbed organics and deposited substances under the process conditions. Additionally, thermal regeneration via physical activation with CO<sub>2</sub> led to enhanced pore properties compared to simple pyrolysis. The maximum BET surface area achieved exceeded 720 m<sup>2</sup>/g, which was greater than those of spent GAC (approximately 425 m<sup>2</sup>/g) and N<sub>2</sub>-pyrolyzed GAC (approximately 570 m<sup>2</sup>/g) under the same regeneration conditions (i.e., 900 °C with a 30 min holding time).
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spelling doaj-art-6b596ee9c9434ac68fd1cfeff858572c2025-08-20T01:56:28ZengMDPI AGApplied Sciences2076-34172025-05-011510533610.3390/app15105336The Combination of Nitrogen (N<sub>2</sub>) Pyrolysis and Carbon Dioxide (CO<sub>2</sub>) Activation for Regenerating Spent Activated CarbonYa-Chen Ye0Wen-Shing Chen1Chi-Hung Tsai2Wen-Tien Tsai3Graduate Institute of Bioresources, National Pingtung University of Science and Technology, Pingtung 912, TaiwanDepartment of Chemical and Materials Engineering, National Yunlin University of Science and Technology, Yunlin 640, TaiwanDepartment of Resources Engineering, National Cheng Kung University, Tainan 701, TaiwanGraduate Institute of Bioresources, National Pingtung University of Science and Technology, Pingtung 912, TaiwanIn line with the principles of the circular economy, this study aimed to develop a pyrolysis-activation regeneration process capable of producing highly porous carbon materials from spent granular activated carbon (GAC), which was generated by a high-tech electronics manufacturing company in Taiwan. Thermogravimetric analysis (TGA) and other thermochemical analyses were first conducted to investigate the thermal decomposition behavior of the spent GAC. Subsequently, the thermal regeneration system was employed to perform the N<sub>2</sub> pyrolysis and CO<sub>2</sub> activation experiments under various process conditions (i.e., 800, 850, and 900 °C for holding 0, 30, and 60 min, respectively). Analytical instruments included a surface area and porosimeter for pore property analysis, scanning electron microscopy (SEM) for porous texture observation, and energy dispersive X-ray spectroscopy (EDS) for surface elemental distribution analysis. The results revealed that the pore properties of thermally regenerated GAC were significantly improved compared to the spent GAC, indicating the effective removal or decomposition of adsorbed organics and deposited substances under the process conditions. Additionally, thermal regeneration via physical activation with CO<sub>2</sub> led to enhanced pore properties compared to simple pyrolysis. The maximum BET surface area achieved exceeded 720 m<sup>2</sup>/g, which was greater than those of spent GAC (approximately 425 m<sup>2</sup>/g) and N<sub>2</sub>-pyrolyzed GAC (approximately 570 m<sup>2</sup>/g) under the same regeneration conditions (i.e., 900 °C with a 30 min holding time).https://www.mdpi.com/2076-3417/15/10/5336spent granular activated carbonthermal regenerationnitrogen pyrolysiscarbon dioxide activationpore property
spellingShingle Ya-Chen Ye
Wen-Shing Chen
Chi-Hung Tsai
Wen-Tien Tsai
The Combination of Nitrogen (N<sub>2</sub>) Pyrolysis and Carbon Dioxide (CO<sub>2</sub>) Activation for Regenerating Spent Activated Carbon
Applied Sciences
spent granular activated carbon
thermal regeneration
nitrogen pyrolysis
carbon dioxide activation
pore property
title The Combination of Nitrogen (N<sub>2</sub>) Pyrolysis and Carbon Dioxide (CO<sub>2</sub>) Activation for Regenerating Spent Activated Carbon
title_full The Combination of Nitrogen (N<sub>2</sub>) Pyrolysis and Carbon Dioxide (CO<sub>2</sub>) Activation for Regenerating Spent Activated Carbon
title_fullStr The Combination of Nitrogen (N<sub>2</sub>) Pyrolysis and Carbon Dioxide (CO<sub>2</sub>) Activation for Regenerating Spent Activated Carbon
title_full_unstemmed The Combination of Nitrogen (N<sub>2</sub>) Pyrolysis and Carbon Dioxide (CO<sub>2</sub>) Activation for Regenerating Spent Activated Carbon
title_short The Combination of Nitrogen (N<sub>2</sub>) Pyrolysis and Carbon Dioxide (CO<sub>2</sub>) Activation for Regenerating Spent Activated Carbon
title_sort combination of nitrogen n sub 2 sub pyrolysis and carbon dioxide co sub 2 sub activation for regenerating spent activated carbon
topic spent granular activated carbon
thermal regeneration
nitrogen pyrolysis
carbon dioxide activation
pore property
url https://www.mdpi.com/2076-3417/15/10/5336
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