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Oxygen-doped porous graphitic carbon nitride in photocatalytic peroxymonosulfate activation for enhanced carbamazepine removal: Performance, influence factors and mechanisms
被引:68
|作者:
Meng, Yuan
[1
]
Li, Zhifeng
[1
]
Tan, Jie
[1
]
Li, Jie
[1
]
Wu, Junxue
[2
]
Zhang, Tingting
[1
]
Wang, Xiaohui
[1
]
机构:
[1] Beijing Univ Chem Technol, Coll Chem Engn, Dept Environm Sci & Engn, Beijing 100029, Peoples R China
[2] Beijing Acad Agr & Forestry Sci, Inst Plant & Environm Protect, Beijing 100097, Peoples R China
基金:
中国国家自然科学基金;
关键词:
Oxygen-doping;
g-C3N4;
PMS activation;
Photocatalysis;
Non-radical pathways;
DISSOLVED ORGANIC-MATTER;
DEGRADATION;
WATER;
OXIDATION;
PRODUCTS;
G-C3N4;
PERSULFATE;
LIGHT;
PHARMACEUTICALS;
PHTHALOCYANINE;
D O I:
10.1016/j.cej.2021.130860
中图分类号:
X [环境科学、安全科学];
学科分类号:
08 ;
0830 ;
摘要:
Due to the effective removal of refractory organic pollutants, advanced oxidation technology based on sulfate radicals (SO4 center dot-) has attracted widespread attention. However, it is still a challenge to design an eco-friendly catalyst that efficiently activates persulfate. In this paper, oxygen-doped porous graphitic carbon nitride (OCN) was prepared by a simple thermal polymerization method to activate persulfate for removing the stubborn drug carbamazepine and showed a good removal effect. Compared with the pristine g-C3N4, the catalytic performance of OCN increased by 5.6 times under dark conditions and 4.1 time under visible light irradiation conditions, respectively. Under dark conditions, oxygen doping mainly modulated the electronic structure of the catalyst to provide more active sites to enhance persulfate activation. Under visible light conditions, oxygen doping reduced the band gap and introduced impurity defect energy level, so that the light absorption capacity was improved and photo-generated carriers were effectively separated. The results of electron paramagnetic resonance and active species trapping experiments showed that the combined action of free radicals and non radical oxidation pathways was the main mechanism of carbamazepine degradation. Therein, singlet oxygen (O-1(2)) was the main active species, followed by O-2(center dot-) and SO4 center dot-. In addition, environmental factor experiments showed that chloride ions, bicarbonate ions and humic acid all had significant promoting effects, and there were other interactions between humic acid and carbamazepine besides adsorption to promote the degradation reaction. Finally, high-resolution mass spectrometry identified that ring condensation, hydroxylation and carboxylation were the primary degradation pathways of carbamazepine. This work provides a feasible way for designing high-efficiency and pollution-free persulfate activators to remove refractory pollutants.
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页数:15
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