title: Enhancing the reactivity of bimetallic Bi/Fe(0) by citric acid for remediation of polluted water.
abstract: In this study, the environmentally benign citric acid (CA) was utilized to improve the aerobic degradation of 4-chlorophenol (4-CP) over bismuth modified nanoscale zero-valent iron (Bi/Fe(0)). The characterization results revealed the existence of bismuth covering on the Fe(0) surface under zero-valent state. And, the Bi/Fe(0)-CA+O2 system performed excellent reactivity in degradation of 4-CP due to the generation of reactive oxygen species (ROS), which was confirmed by electron spin resonance (ESR) spectroscopy. After 30min of reaction, 80% of 4-CP was removed using Bi/Fe(0)-CA+O2 accompanying with high dechlorination rate. The oxidative degradation intermediates were analyzed by HPLC and LC-MS. We found that CA could promote the bismuth-iron system to produce much reactive oxygen species ROS under both aerobic and anaerobic conditions due to its ligand function, which could react with Fe(3+) to form a ligand complex (Fe(III)Cit), accompanying with a considerable production of Fe(2+) and H2O2. This study provides a new strategy for generating ROS on nZVI and suggests its application for the mineralization of many recalcitrant pollutants.
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea.
authors.forename: Jianyu
authors.initials: J
authors.lastname: Gong
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea.
authors.forename: Chung-Seop
authors.initials: CS
authors.lastname: Lee
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea.
authors.forename: Eun-Ju
authors.initials: EJ
authors.lastname: Kim
authors.affiliation: Department of Environmental Engineering, Kwangwoon University, Seoul 139-701, Republic of Korea.
authors.forename: Yoon-Young
authors.initials: YY
authors.lastname: Chang
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea. Electronic address: yschang@postech.ac.kr.
authors.forename: Yoon-Seok
authors.initials: YS
authors.lastname: Chang
keywords: Bismuth; Citric acid; Ligand complexes; Zero valent iron