Activation of Persulfates Using Alkali-Modified Activated Coke to Promote Phenol Removal

Coke (AC) was modified and activated with sodium hydroxide (NaOH) and potassium hydroxide (KOH) to produce AC-Na and AC-K, respectively, and applied as a persulfate (PS) activator to promote phenol (Ph) removal in water. Under the given experimental conditions, compared to AC/PS (Ph removal effect w...

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Main Authors: Yan Zhang, Shuang Shi, Jianxiong Wei, Qiang Ma, Xiaoxue Wang, Xingyu Zhang, Huarui Hao, Chen Yang
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Nanomaterials
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Online Access:https://www.mdpi.com/2079-4991/15/10/744
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author Yan Zhang
Shuang Shi
Jianxiong Wei
Qiang Ma
Xiaoxue Wang
Xingyu Zhang
Huarui Hao
Chen Yang
author_facet Yan Zhang
Shuang Shi
Jianxiong Wei
Qiang Ma
Xiaoxue Wang
Xingyu Zhang
Huarui Hao
Chen Yang
author_sort Yan Zhang
collection DOAJ
description Coke (AC) was modified and activated with sodium hydroxide (NaOH) and potassium hydroxide (KOH) to produce AC-Na and AC-K, respectively, and applied as a persulfate (PS) activator to promote phenol (Ph) removal in water. Under the given experimental conditions, compared to AC/PS (Ph removal effect was 77.09%), the Ph removal effects were 94.46% and 88.73% for AC-K/PS and AC-Na/PS, respectively. AC-K proved to be a more effective activator than AC-Na and was used for all the subsequent experiments. When PS/phenol molar ratio was 6.26:1:00, the initial system pH was 7 and the system temperature was 25 °C; the AC-K/PS system could effectively remove Ph (98.75%) from the simulated wastewater. After that, the stability of AC-K was verified. Electron paramagnetic resonance (EPR) and quenching analysis confirmed the hydroxyl free radical (•OH) to be predominant within this system. EPR combined with X-ray photoelectron spectroscopy (XPS), Fourier-transformed infrared (FTIR) spectroscopy, and Raman spectroscopy indicated that the sulfate radical (SO<sub>4</sub><sup>•−</sup>) and •OH were generated due to the defects in AC-K, thereby enhancing the PS activation potency of AC-K. Additionally, the radical quenching experiments showed that the superoxide (O<sub>2</sub><sup>−</sup>) radical is a key intermediate product promoting SO<sub>4</sub><sup>•−</sup> and •OH, which aided Ph removal. Both radical (SO<sub>4</sub><sup>•−</sup> and •OH) and non-radical (<sup>1</sup>O<sub>2</sub>) pathways were found to co-exist during the removal process. The Ph removal rate of the AC-K/PS system could still reach 29.50%, even after four repeated cycles. These results demonstrate that the unique AC-K/PS system has a potential removal effect on organic pollutants in water.
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spelling doaj-art-b95b7ca7b69c4b598b30c7c39bfbbadd2025-08-20T03:48:01ZengMDPI AGNanomaterials2079-49912025-05-01151074410.3390/nano15100744Activation of Persulfates Using Alkali-Modified Activated Coke to Promote Phenol RemovalYan Zhang0Shuang Shi1Jianxiong Wei2Qiang Ma3Xiaoxue Wang4Xingyu Zhang5Huarui Hao6Chen Yang7School of Chemistry and Chemical Engineering, Yulin University, No. 51 Chongwen Road, Yulin 719000, ChinaSchool of Chemistry and Chemical Engineering, Yulin University, No. 51 Chongwen Road, Yulin 719000, ChinaYulin Innovation Institute of Clean Energy, Science and Technology Innovation 4th Road, Science and Technology Innovation New City, Yulin 719199, ChinaChina Coal Shaanxi Energy & Chemical Group Co., Ltd., Yuheng Industrial Park, High-Tech Zone, Yulin 719099, ChinaSchool of Chemistry and Chemical Engineering, Yulin University, No. 51 Chongwen Road, Yulin 719000, ChinaSchool of Materials Science and Engineering, Xi’an University of Technology, No. 5, Jinhua South Road, Xi’an 710048, ChinaSchool of Chemistry and Chemical Engineering, Yulin University, No. 51 Chongwen Road, Yulin 719000, ChinaSchool of Chemistry and Chemical Engineering, Yulin University, No. 51 Chongwen Road, Yulin 719000, ChinaCoke (AC) was modified and activated with sodium hydroxide (NaOH) and potassium hydroxide (KOH) to produce AC-Na and AC-K, respectively, and applied as a persulfate (PS) activator to promote phenol (Ph) removal in water. Under the given experimental conditions, compared to AC/PS (Ph removal effect was 77.09%), the Ph removal effects were 94.46% and 88.73% for AC-K/PS and AC-Na/PS, respectively. AC-K proved to be a more effective activator than AC-Na and was used for all the subsequent experiments. When PS/phenol molar ratio was 6.26:1:00, the initial system pH was 7 and the system temperature was 25 °C; the AC-K/PS system could effectively remove Ph (98.75%) from the simulated wastewater. After that, the stability of AC-K was verified. Electron paramagnetic resonance (EPR) and quenching analysis confirmed the hydroxyl free radical (•OH) to be predominant within this system. EPR combined with X-ray photoelectron spectroscopy (XPS), Fourier-transformed infrared (FTIR) spectroscopy, and Raman spectroscopy indicated that the sulfate radical (SO<sub>4</sub><sup>•−</sup>) and •OH were generated due to the defects in AC-K, thereby enhancing the PS activation potency of AC-K. Additionally, the radical quenching experiments showed that the superoxide (O<sub>2</sub><sup>−</sup>) radical is a key intermediate product promoting SO<sub>4</sub><sup>•−</sup> and •OH, which aided Ph removal. Both radical (SO<sub>4</sub><sup>•−</sup> and •OH) and non-radical (<sup>1</sup>O<sub>2</sub>) pathways were found to co-exist during the removal process. The Ph removal rate of the AC-K/PS system could still reach 29.50%, even after four repeated cycles. These results demonstrate that the unique AC-K/PS system has a potential removal effect on organic pollutants in water.https://www.mdpi.com/2079-4991/15/10/744alkali-modified activated cokephenolpersulfateremovalremoval mechanism
spellingShingle Yan Zhang
Shuang Shi
Jianxiong Wei
Qiang Ma
Xiaoxue Wang
Xingyu Zhang
Huarui Hao
Chen Yang
Activation of Persulfates Using Alkali-Modified Activated Coke to Promote Phenol Removal
Nanomaterials
alkali-modified activated coke
phenol
persulfate
removal
removal mechanism
title Activation of Persulfates Using Alkali-Modified Activated Coke to Promote Phenol Removal
title_full Activation of Persulfates Using Alkali-Modified Activated Coke to Promote Phenol Removal
title_fullStr Activation of Persulfates Using Alkali-Modified Activated Coke to Promote Phenol Removal
title_full_unstemmed Activation of Persulfates Using Alkali-Modified Activated Coke to Promote Phenol Removal
title_short Activation of Persulfates Using Alkali-Modified Activated Coke to Promote Phenol Removal
title_sort activation of persulfates using alkali modified activated coke to promote phenol removal
topic alkali-modified activated coke
phenol
persulfate
removal
removal mechanism
url https://www.mdpi.com/2079-4991/15/10/744
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