Treatment of landfill leachate using magnetically attracted zero-valent iron powder electrode in an electric field

Dongni Sun, Xiaoting Hong, Zhonghua Cui, Yingying Du, K. S. Hui, Enhao Zhu, Keming Wu, K. N. Hui

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This study combined electro-oxidation (EO) and electrocoagulation (EC) process (EO/EC) to treat landfill leachate by using RuO2-IrO2/Ti plate and microscale zero-valent iron powder composite anode. EO was achieved by direct oxidation and indirect oxidation on RuO2-IrO2/Ti plate, whereas EC was achieved using iron powder to lose electrons and produce coagulants in situ. The influences of variables including type of anode material, applied voltage, zero-valent iron dosage, interelectrode gap, and reaction temperature on EO/EC were evaluated. Results showed that at an applied voltage of 10 V, zero-valent iron dosage of 0.2 g, interelectrode gap of 1 cm, and non-temperature-controlled mode, the removal efficiencies were 72.5% for total organic carbon (TOC), 98.5% for ammonia, and 98.6% for total phosphorus (TP). Some heavy metals and hardness were also removed. Further analysis indicated that the removal of TOC, ammonia, and TP followed pseudo-first order, pseudo-zero order, and pseudo-second order kinetic models, respectively. Other characteristics were examined by scanning electron microscopy–energy dispersive spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy. Overall, our results showed that EO/EC can be used to efficiently remove organic matter, ammonia, TP, and heavy metals from landfill leachate.
Original languageEnglish
Article number121768
JournalJournal of Hazardous Materials
Early online date5 Dec 2019
Publication statusPublished - 15 Apr 2020

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