TY - JOUR
T1 - Quantification of perfluorooctanoic acid decomposition mechanism applying negative voltage to anode during photoelectrochemical process
AU - Zhou, Yongyue
AU - Lee, Yonghyeon
AU - Ren, Yangmin
AU - Cui, Mingcan
AU - Khim, Jeehyeong
N1 - Funding Information:
This work was supported by the Basic Science Research Program through a National Research Foundation of Korea (NRF) grant funded by the Korean government (No. 2019R1A2C2087439 ) and the Korean Ministry of the Environment as a Subsurface Environment Management (SEM) project (No. 2019002480001 ).
Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/12
Y1 - 2021/12
N2 - Perfluorooctanoic acid (PFOA) is a carcinogen with a high binding energy between fluorine and carbon and is symmetrically linked, making it difficult to treat. In this study, a self-doped TiO2 nanotube array (TNTA) was used as the anode and platinum as the cathode to quantify the PFOA removal mechanism using a photoelectrochemical (PEC) system. The external voltage was negative compared to that of the anode. In addition, NO3− and t-BuOH were used as scavengers to quantify the PFOA oxidation/reduction mechanism in the PEC system. As a result of the study, TNTA crystals are TiO2 anatase, and the band gap energy was 3.42. The synergy index of PEC was 1.25, and the best electrolyte was SO42−. The PFOA decomposition activation energy corresponds to 70.84 kJ mol−1. Moreover, ΔH# and ΔS# correspond to 68.34 kJ mol−1 and 0.190 kJ mol−1 K−1, respectively. When the external negative voltage was 1 V, the contributions of the oxidation/reduction reaction during PFOA decomposition were 60% and 40%, and when the external negative voltage was 5 V, the contributions of the redox reaction were 45% and 55%. As the external negative voltage increased, the contribution of the reduction reaction increased as the number of electrons applied to the anode increased. When PFOA was decomposed, the by-products were C7F13O2H, C6F11O2H, C5F9O2H, and C4F7O2H, respectively. This study is expected to be used as basic data for research on the effects of other factors on the oxidation/reduction as well as the selection of anode and cathode materials on the decomposition of pollutants other than PFOA when using a PEC system.
AB - Perfluorooctanoic acid (PFOA) is a carcinogen with a high binding energy between fluorine and carbon and is symmetrically linked, making it difficult to treat. In this study, a self-doped TiO2 nanotube array (TNTA) was used as the anode and platinum as the cathode to quantify the PFOA removal mechanism using a photoelectrochemical (PEC) system. The external voltage was negative compared to that of the anode. In addition, NO3− and t-BuOH were used as scavengers to quantify the PFOA oxidation/reduction mechanism in the PEC system. As a result of the study, TNTA crystals are TiO2 anatase, and the band gap energy was 3.42. The synergy index of PEC was 1.25, and the best electrolyte was SO42−. The PFOA decomposition activation energy corresponds to 70.84 kJ mol−1. Moreover, ΔH# and ΔS# correspond to 68.34 kJ mol−1 and 0.190 kJ mol−1 K−1, respectively. When the external negative voltage was 1 V, the contributions of the oxidation/reduction reaction during PFOA decomposition were 60% and 40%, and when the external negative voltage was 5 V, the contributions of the redox reaction were 45% and 55%. As the external negative voltage increased, the contribution of the reduction reaction increased as the number of electrons applied to the anode increased. When PFOA was decomposed, the by-products were C7F13O2H, C6F11O2H, C5F9O2H, and C4F7O2H, respectively. This study is expected to be used as basic data for research on the effects of other factors on the oxidation/reduction as well as the selection of anode and cathode materials on the decomposition of pollutants other than PFOA when using a PEC system.
KW - Applying negative voltage to anode
KW - Mechanism
KW - Pathway
KW - Photoelectrochemical
KW - Scavenger
KW - TiO nanotube arrays anode
UR - http://www.scopus.com/inward/record.url?scp=85108626753&partnerID=8YFLogxK
U2 - 10.1016/j.chemosphere.2021.131311
DO - 10.1016/j.chemosphere.2021.131311
M3 - Article
C2 - 34182283
AN - SCOPUS:85108626753
SN - 0045-6535
VL - 284
JO - Chemosphere
JF - Chemosphere
M1 - 131311
ER -
