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Effects of voltage on the migration of oxidant and activator and the removal of PAHs in soil during electrokinetic-enhanced in situ chemical oxidation |
Received:February 28, 2022 Revised:April 25, 2022 |
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KeyWord:electrokinetic remediation;PAHs;persulfate;ferrous citrate;voltage |
Author Name | Affiliation | E-mail | HUANG Qiao | Key Laboratory of Soil Environment and Pollution Remediation, Chinese Academy of Sciences(Institute of Soil Science), Nanjing 210008, China University of Chinese Academy of Sciences, Beijing 100049, China | | CANG Long | Key Laboratory of Soil Environment and Pollution Remediation, Chinese Academy of Sciences(Institute of Soil Science), Nanjing 210008, China | canglong@issas.ac.cn | ZHOU Mingzhu | Key Laboratory of Soil Environment and Pollution Remediation, Chinese Academy of Sciences(Institute of Soil Science), Nanjing 210008, China | | WANG Fan | Key Laboratory of Soil Environment and Pollution Remediation, Chinese Academy of Sciences(Institute of Soil Science), Nanjing 210008, China | |
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Abstract: |
To investigate the effects of voltage on the migration of oxidant and activator and the removal of pollutants in soil during electrokinetic-in situ chemical oxidation(EK-ISCO) , four voltages(5, 10, 20 V, and 40-30 V)were used to explore the removal of polycyclic aromatic hydrocarbons(PAHs)in soil via electrokinetic column experiments(adding sodium persulfate as an oxidant at the anode and ferrous citrate as an activator at the cathode) . The results showed that the current increased with an increase in voltage, and the highest current occurred in the 40-30 V treatment. However, the relationship between electroosmotic flow(EOF)and voltage was complex. The 10 V treatment had the highest EOF (981 mL) , followed by the 40-30 V and 20 V treatments, and the 5 V treatment had the lowest EOF. The 10 V treatment was beneficial to the migration of persulfate from the anode to the soil column, whereas higher voltages(20 V and 40-30 V) weakened the EOF, accelerated the alkalization of the catholyte and soil solution near the cathode, reduced the activity of ferrous citrate and was unfavorable for the migration of persulfate and ferrous citrate from the anode and cathode to the soil column. In terms of the PAH removal rate, in the 10 V treatment, the total removal rate reached 37.0%, which was higher than 21.3%-28.4% of the other treatments, and the energy consumption was relatively low(268.6 kWh·t-1) . In conclusion, the experiments showed that a 10 V treatment was favorable for the migration and reaction of oxidant and activator in the soil column and had the highest PAH removal rate and relatively low energy consumption, which indicated that 10 V was the appropriate voltage condition. |
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