TY - JOUR
T1 - Generation of Reactive Oxygen Species and Degradation of Pollutants in the Fe2+/O2/Tripolyphosphate System
T2 - Regulated by the Concentration Ratio of Fe2+and Tripolyphosphate
AU - Zhang, Chengwu
AU - Kong, Chuipeng
AU - Tratnyek, Paul G.
AU - Qin, Chuanyu
N1 - Funding Information:
This work was financially supported by the Scientific Research Project of Education Department of Jilin Province (Grant No. JJKH20221028KJ), the National Natural Science Foundation of China (42177049), the Fundamental Research Funds for the Central Universities of China, and the Graduate Innovation Fund of Jilin University.
Publisher Copyright:
© 2022 American Chemical Society.
PY - 2022/4/5
Y1 - 2022/4/5
N2 - Tripolyphosphate (TPP) has many advantages as a ligand for the optimization of the Fe2+/O2 system in environmental remediation applications. However, the relationship between remediation performance and the Fe2+/TPP ratio in the system has not been previously described. In this study, we report that the degradation mechanism of p-nitrophenol (PNP) in Fe2+/O2 systems is regulated by the Fe2+/TPP ratio under neutral conditions. The results showed that although PNP was effectively degraded at different Fe2+/TPP ratios, the results of specific reactive oxygen species (ROS) scavenging experiments and the determination of PNP degradation products showed that the mechanism of PNP degradation varies with the Fe2+/TPP ratio. When CFe2+ ≥ CTPP, the initially formed O2•- is converted to •OH and the •OH degrades PNP by oxidation. However, when CFe2+ < CTPP, the O2•- persists long enough to degrade PNP by reduction. Density functional theory (DFT) calculations revealed that the main reactive species of Fe2+ in the system include [Fe(TPP)(H2O)3]- and [Fe(TPP)2]4-, whose content in the solution is the key to achieve system regulation. Consequently, by controlling the Fe2+/TPP ratio in the solution, the degradation pathways of PNP can be selected. Our study proposed a new strategy to regulate the oxidation/reduction removal of pollutants by simply varying the Fe2+/TPP ratio of the Fe2+/O2 system.
AB - Tripolyphosphate (TPP) has many advantages as a ligand for the optimization of the Fe2+/O2 system in environmental remediation applications. However, the relationship between remediation performance and the Fe2+/TPP ratio in the system has not been previously described. In this study, we report that the degradation mechanism of p-nitrophenol (PNP) in Fe2+/O2 systems is regulated by the Fe2+/TPP ratio under neutral conditions. The results showed that although PNP was effectively degraded at different Fe2+/TPP ratios, the results of specific reactive oxygen species (ROS) scavenging experiments and the determination of PNP degradation products showed that the mechanism of PNP degradation varies with the Fe2+/TPP ratio. When CFe2+ ≥ CTPP, the initially formed O2•- is converted to •OH and the •OH degrades PNP by oxidation. However, when CFe2+ < CTPP, the O2•- persists long enough to degrade PNP by reduction. Density functional theory (DFT) calculations revealed that the main reactive species of Fe2+ in the system include [Fe(TPP)(H2O)3]- and [Fe(TPP)2]4-, whose content in the solution is the key to achieve system regulation. Consequently, by controlling the Fe2+/TPP ratio in the solution, the degradation pathways of PNP can be selected. Our study proposed a new strategy to regulate the oxidation/reduction removal of pollutants by simply varying the Fe2+/TPP ratio of the Fe2+/O2 system.
KW - concentration regulation
KW - ferrous-polyphosphate complex
KW - molecular oxygen activation
KW - oxidation/reduction
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U2 - 10.1021/acs.est.1c07467
DO - 10.1021/acs.est.1c07467
M3 - Article
C2 - 35275631
AN - SCOPUS:85126543559
SN - 0013-936X
VL - 56
SP - 4367
EP - 4376
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 7
ER -