In Situ-Generated Reactive Oxygen Species in Precharged Titania and Tungsten Trioxide Composite Catalyst Membrane Filters: Application to As(III) Oxidation in the Absence of Irradiation
Abstract
This study demonstrates that in situ-generated reactive oxygen species (ROSs) in prephotocharged TiO₂ and WO₃ (TW) composite particle-embedded inorganic membrane filters oxidize arsenite (As(III)) into arsenate (As(V)) without any auxiliary chemical oxidants under ambient conditions in the dark. TW membrane filters have been charged with UV or simulated sunlight and subsequently transferred to a once-through flow-type system. The charged TW filters can transfer the stored electrons to dissolved O₂, producing ROSs that mediate As(III) oxidation in the dark. Dramatic inhibition of As(V) production with O₂ removal or addition of ROS quenchers indicates an ROS-mediated As(III) oxidation mechanism. Electron paramagnetic spectroscopic analysis has confirmed the formation of the HO₂•/O₂•– pair in the dark. The WO₃ fraction in the TW filter significantly influences the performance of the As(III) oxidation, while As(V) production is enhanced with increasing charging time and solution pH. The As(III) oxidation is terminated when the singly charged TW filter is fully discharged; however, recharging of TW recovers the catalytic activity for As(III) oxidation. The proposed oxidation process using charged TW membrane filters is practical and environmentally benign for the continuous treatment of As(III)-contaminated water during periods of unavailability of sunlight.
Additional Information
© 2020 American Chemical Society. Received: March 12, 2020; Revised: June 3, 2020; Accepted: June 16, 2020; Published: June 16, 2020. This research was partly supported by the National Research Foundation of Korea (2019R1A2C2002602, 2018R1A6A1A03024962, and 2019M1A2A2065616). We are grateful to the Global Research Laboratory (GRL) Program (2014K1A1A2041044) through the National Research Foundation, Korea. This publication was made possible by a grant from the Qatar National Research Fund under its National Priorities Research Program (NPRP 10-1210-160019). Author Contributions: J.P. and J.L. contributed equally to this work. The authors declare no competing financial interest.Attached Files
Supplemental Material - es0c01550_si_001.pdf
Files
Name | Size | Download all |
---|---|---|
md5:34e6ffeb30c4e44c698c8dc0f96e57b5
|
466.2 kB | Preview Download |
Additional details
- Alternative title
- In-situ-generated reactive oxygen species in pre-charged titania and tungsten trioxide composite catalyst membrane filters: Application to As(III) oxidation in the absence of irradiation
- Eprint ID
- 103953
- Resolver ID
- CaltechAUTHORS:20200622-104137391
- 2019R1A2C2002602
- National Research Foundation of Korea
- 2018R1A6A1A03024962
- National Research Foundation of Korea
- 2019M1A2A2065616
- National Research Foundation of Korea
- 2014K1A1A2041044
- National Research Foundation of Korea
- NPRP 10-1210-160019
- Qatar National Research Fund
- Created
-
2020-06-23Created from EPrint's datestamp field
- Updated
-
2021-11-16Created from EPrint's last_modified field