TY - JOUR
T1 - Insight on the generation of reactive oxygen species in the CaO2/Fe(II) Fenton system and the hydroxyl radical advancing strategy
AU - Xue, Yunfei
AU - Sui, Qian
AU - Brusseau, Mark L.
AU - Zhang, Xiang
AU - Qiu, Zhaofu
AU - Lyu, Shuguang
N1 - Funding Information:
This study was financially supported by the grant from the Natural Science Foundation of Shanghai, China (16ZR1407200). The contributions of Mark Brusseau were supported by the NIEHS Superfund Research Program of United States ( PS 42 ES04940 ).
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/12/1
Y1 - 2018/12/1
N2 - Calcium peroxide (CaO2) is a stable hydrogen peroxide (H2O2) carrier, and the CaO2/Fe(II) system has been applied for treatment of various pollutants. It is commonly reported in the literature that hydroxyl radical (HO[rad]) and superoxide radical anions (O2 [rad]−) are the two main reactive oxygen species (ROSs) generated in the CaO2/Fe(II) system. However, many of the reported results were deduced from degradation performance rather than specific testing of radical generation. Thus, the specific generation of ROSs and the influence of system conditions on ROSs yield are still unclear. To our knowledge, this is the first study specifically focusing on the generation of HO[rad] and O2 [rad]− in the CaO2/Fe(II) system. Experimental conditions were optimized to investigate the production of HO[rad] and O2 [rad]−. The results showed the influences of CaO2, Fe(II), and solution pH on HO[rad] and O2 [rad]− generation, and the HO[rad] generation efficiency was reported for the first time. In addition, the ROSs generation pathways in the CaO2/Fe(II) system were elucidated. A strategy for enhancing HO[rad] yield is developed, based on the continuously dosing Fe(II). This proposed strategy has implications for the effective application of in situ chemical oxidation employing CaO2/Fe(II) for groundwater remediation.
AB - Calcium peroxide (CaO2) is a stable hydrogen peroxide (H2O2) carrier, and the CaO2/Fe(II) system has been applied for treatment of various pollutants. It is commonly reported in the literature that hydroxyl radical (HO[rad]) and superoxide radical anions (O2 [rad]−) are the two main reactive oxygen species (ROSs) generated in the CaO2/Fe(II) system. However, many of the reported results were deduced from degradation performance rather than specific testing of radical generation. Thus, the specific generation of ROSs and the influence of system conditions on ROSs yield are still unclear. To our knowledge, this is the first study specifically focusing on the generation of HO[rad] and O2 [rad]− in the CaO2/Fe(II) system. Experimental conditions were optimized to investigate the production of HO[rad] and O2 [rad]−. The results showed the influences of CaO2, Fe(II), and solution pH on HO[rad] and O2 [rad]− generation, and the HO[rad] generation efficiency was reported for the first time. In addition, the ROSs generation pathways in the CaO2/Fe(II) system were elucidated. A strategy for enhancing HO[rad] yield is developed, based on the continuously dosing Fe(II). This proposed strategy has implications for the effective application of in situ chemical oxidation employing CaO2/Fe(II) for groundwater remediation.
KW - CaO/Fe(II) oxidation
KW - Hydroxyl radical
KW - In situ chemical oxidation
KW - ROSs yield
KW - Superoxide radical anion
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U2 - 10.1016/j.cej.2018.07.124
DO - 10.1016/j.cej.2018.07.124
M3 - Article
AN - SCOPUS:85050777839
VL - 353
SP - 657
EP - 665
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
SN - 1385-8947
ER -