摘要详情
842 / 2024-09-19 16:12:18
Study on degradation of polycyclic aromatic hydrocarbons in water by g-C3N4-based photocatalysts coupled with immobilized lignin peroxidase
Graphitic carbon nitride; Photocatalysis; Immobilized lignin peroxidase; Polycyclic aromatic hydrocarbons; Degradation
摘要待审
Polycyclic aromatic hydrocarbons (PAHs) are a kind of persistent organic pollutants in water environment. Immobilized lignin peroxidase (LiP) can effectively degrade PAHs in the presence of hydrogen peroxide (H2O2). In this paper, fluoranthrene and benzo [a] pyrene were used as research objects to investigate the concentration of H2O2 produced by four g-C3N4-based photocatalysts under visible light irradiation and their degradation rates to PAHs, and to screen out g-C3N4-based photocatalysts suitable for activating immobilized LiP with good degradation performance. The ratio of Fe2O3/g-C3N4 coupled immobilized LiP composite catalytic system was optimized.The effects of initial PAHs concentration and pH on the degradation rate and kinetics were investigated. The activity of immobilized LiP enzyme, the changes of H2O2 and ·OH under different conditions were analyzed, and the mechanism of degradation of PAHs by Fe2O3/g-C3N4 coupled immobilized LiP was preliminarily discussed. The main findings are as follows:
(1)When the concentration of H2O2 increased to 8 μmol/L, the immobilized LiP was activated and its enzyme activity was enhanced. Among the four photocatalysts, Fe2O3/g-C3N4 produced the highest H2O2 concentration, reaching 18.62 μmol/L, and the degradation rates of fluoranthrene and benzo [a] pyrene were 69.63% and 69.96%, respectively.
(2) When Fe2O3/g-C3N4 and immobilized LiP were added at the ratio of 0.5:0.5(w:w), the highest degradation rates of fluoranthrene and benzo [a] pyrene were 80.88% and 79.50%, respectively. The degradation rate decreased with the increase of initial PAHs concentration. When pH=7, both of them showed the best performance. The highest value was also reached at 400 W light intensity. In addition, at 30 ℃, both of them also perform well. However, when Cl-, NO3-, SO42-, Ca2+ ,Mg2+ plasma is present in the system, its degradation rate decreases, which indicates that these ions have an inhibitory effect on it. However, the degradation efficiency of isopropyl alcohol significantly decreased, indicating that ·OH was the main active group.
(3) When Fe2O3/g-C3N4 and immobilized LiP are 0.5:0.5(w:w) and the temperature is 30 °C, the activity of solid LiP enzyme is the strongest. When the concentration of PAHs is 1-5 mg/L, the addition of ions or masking agents will lead to the decrease of LiP enzyme activity and the concentration of H2O2 and ·OH. Therefore, these three factors jointly affect the concentration of different pollutants and the removal efficiency of PAHs after addition. When the pH is neutral or alkaline, and the concentration of ·OH is significantly increased at 400 W light intensity.
(1)When the concentration of H2O2 increased to 8 μmol/L, the immobilized LiP was activated and its enzyme activity was enhanced. Among the four photocatalysts, Fe2O3/g-C3N4 produced the highest H2O2 concentration, reaching 18.62 μmol/L, and the degradation rates of fluoranthrene and benzo [a] pyrene were 69.63% and 69.96%, respectively.
(2) When Fe2O3/g-C3N4 and immobilized LiP were added at the ratio of 0.5:0.5(w:w), the highest degradation rates of fluoranthrene and benzo [a] pyrene were 80.88% and 79.50%, respectively. The degradation rate decreased with the increase of initial PAHs concentration. When pH=7, both of them showed the best performance. The highest value was also reached at 400 W light intensity. In addition, at 30 ℃, both of them also perform well. However, when Cl-, NO3-, SO42-, Ca2+ ,Mg2+ plasma is present in the system, its degradation rate decreases, which indicates that these ions have an inhibitory effect on it. However, the degradation efficiency of isopropyl alcohol significantly decreased, indicating that ·OH was the main active group.
(3) When Fe2O3/g-C3N4 and immobilized LiP are 0.5:0.5(w:w) and the temperature is 30 °C, the activity of solid LiP enzyme is the strongest. When the concentration of PAHs is 1-5 mg/L, the addition of ions or masking agents will lead to the decrease of LiP enzyme activity and the concentration of H2O2 and ·OH. Therefore, these three factors jointly affect the concentration of different pollutants and the removal efficiency of PAHs after addition. When the pH is neutral or alkaline, and the concentration of ·OH is significantly increased at 400 W light intensity.
重要日期
-
会议日期
01月14日
2025
至01月17日
2025
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09月27日 2024
初稿截稿日期
-
12月14日 2024
注册截止日期
主办单位
State Key Laboratory of Marine Environmental Science, Xiamen University
联系方式
- JKejing GU
- xm******@xmu.edu.cn
- +86*********
