TY - JOUR
T1 - Electrochemical Aging and Halogen Oxides Formation on Multiwalled Carbon Nanotubes and Fe3O4@g-C3N4Coated Conductive Membranes
AU - Ma, Qingquan
AU - Gao, Jianan
AU - Potts, Courtney
AU - Tong, Xiao
AU - Tao, Yi
AU - Zhang, Wen
N1 - Funding Information:
The authors gratefully acknowledge funding support from the New Jersey Water Resources Research Institute (NJWRRI) Grant (Project Number: 2020NJ025B), NSF PFI grant (Award number: 2016472), NSF INTERN grant (Award number: 1836036), National Natural Science Foundation of China (52070117), and the United States Environmental Protection Agency (US EPA) P3 Program under Assistance Agreement No. (83945201). The NSF and the EPA have not formally reviewed this study. The views expressed in this document are solely those of authors and do not necessarily reflect those of the agencies. The NSF and EPA do not endorse any products or commercial services mentioned in this publication. This research used resources of the Center for Functional Nanomaterials (CFN), which is a U.S. Department of Energy Office of Science User Facility, at Brookhaven National Laboratory. The authors also thank the technical consultation and support from BRISEA Inc. High school intern Saachi Kuthari from Millburn High School contributed to the literature review.
Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.
PY - 2022/9/28
Y1 - 2022/9/28
N2 - Electrochemical membrane filtration is widely reported to enhance water contaminants' degradation or rejection via anodic oxidation or cathodic repulsion. Despite their advances, electrochemical membranes or electrocatalysts often suffer from corrosion or passivation, especially under strong electrode potentials or reactions. Moreover, the formation of toxic byproducts, such as chlorinated organic compounds and oxyhalides (e.g., ClO4-) is another major concern. This study investigated the membrane aging processes of two types of conductive membranes, multiwalled carbon nanotubes (MWCNTs) and ferrite/graphitic carbon nitride hybrids (Fe3O4@g-C3N4) coated on ceramic membranes. Under high current densities (∼20 mA·cm-2) with anodic potentials (∼10 V), MWCNTs and Fe3O4@g-C3N4catalysts underwent evident oxidation as indicated by an increase of the intensity ratio of the Raman spectral bands (ID/IG) and charge transfer resistance (Rct) of two electrochemical membranes. Under variations of electrode potentials, chloride or bromide were shown to be oxidized to bromate (BrO3-) and chlorate (ClO3-) at levels of 1-10 mmol·L-1. The formation of BrO3-and ClO3-was dependent on the solution pH, current densities (1-20 mA·cm-2), and initial concentrations of Br or Cl ions. To warrant a safe and rational design and operation of electrochemically reactive membrane processes, membrane aging and toxic byproduct's formation deserve careful characterization under relevant water filtration environments.
AB - Electrochemical membrane filtration is widely reported to enhance water contaminants' degradation or rejection via anodic oxidation or cathodic repulsion. Despite their advances, electrochemical membranes or electrocatalysts often suffer from corrosion or passivation, especially under strong electrode potentials or reactions. Moreover, the formation of toxic byproducts, such as chlorinated organic compounds and oxyhalides (e.g., ClO4-) is another major concern. This study investigated the membrane aging processes of two types of conductive membranes, multiwalled carbon nanotubes (MWCNTs) and ferrite/graphitic carbon nitride hybrids (Fe3O4@g-C3N4) coated on ceramic membranes. Under high current densities (∼20 mA·cm-2) with anodic potentials (∼10 V), MWCNTs and Fe3O4@g-C3N4catalysts underwent evident oxidation as indicated by an increase of the intensity ratio of the Raman spectral bands (ID/IG) and charge transfer resistance (Rct) of two electrochemical membranes. Under variations of electrode potentials, chloride or bromide were shown to be oxidized to bromate (BrO3-) and chlorate (ClO3-) at levels of 1-10 mmol·L-1. The formation of BrO3-and ClO3-was dependent on the solution pH, current densities (1-20 mA·cm-2), and initial concentrations of Br or Cl ions. To warrant a safe and rational design and operation of electrochemically reactive membrane processes, membrane aging and toxic byproduct's formation deserve careful characterization under relevant water filtration environments.
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U2 - 10.1021/acs.iecr.2c02847
DO - 10.1021/acs.iecr.2c02847
M3 - Article
AN - SCOPUS:85138831102
SN - 0888-5885
VL - 61
SP - 14260
EP - 14271
JO - Industrial and Engineering Chemistry Research
JF - Industrial and Engineering Chemistry Research
IS - 38
ER -