Unexpected discovery of superoxide radical generation by oxygen vacancies containing biomass derived granular activated carbon

Choe Earn Choong; Kien Tiek Wong; Hyeseong Kim; Seok Byum Jang; So Yeon Yoon; In Wook Nah; Wooyul Kim; Sang-Hyoun Kim; Byong-Hun Jeon; Yeomin Yoon; Min Jang

doi:10.1016/j.watres.2020.116757

Unexpected discovery of superoxide radical generation by oxygen vacancies containing biomass derived granular activated carbon

Water Res. 2021 Feb 15:190:116757. doi: 10.1016/j.watres.2020.116757. Epub 2020 Dec 16.

Authors

Affiliations

¹ Department of Environmental Engineering, Kwangwoon University, Seoul 01897, Republic of Korea.
² Center for Energy Convergence, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea.
³ Department of Chemical and Biological Engineering, Sookmyung Women's University, Seoul 04310, Republic of Korea.
⁴ Department of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea.
⁵ Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul 04763, Republic of Korea.
⁶ Department of Civil and Environmental Engineering, University of South Carolina, Columbia, 300 Main Street, SC, 29208, USA.
⁷ Department of Environmental Engineering, Kwangwoon University, Seoul 01897, Republic of Korea. Electronic address: minjang@kw.ac.kr.

PMID: 33360030
DOI: 10.1016/j.watres.2020.116757

Abstract

Herein, we discovered and reported oxygen vacancies in silicon oxycarbide containing granular palm shell activated carbon (Si-PSAC) as a photocatalyst under UV irradiation. A strong correlation between the atomic content of Si¹⁺, oxygen vacancies and photocatalytic performance of Si-PSAC was obtained. Based on the electron paramagnetic resonance and photoluminescence analyses, Si-PSAC under UVA₃₆₅ irradiation exhibited a higher donor density, better charge transfer and lower electron-hole recombination than that under the other light sources, leading to a higher O₂^· production efficiency. Si-PSAC exhibited effective removal performance for various anionic dyes and endocrine-disrupting chemicals under UVA₃₆₅ irradiation. Continuous-flow column tests revealed the life span of Si-PSAC under UVA₃₆₅ irradiation was extended by more than 16-fold compared to adsorption column. Since the oxygen vacancies can be created from the naturally present Si in the biomass derived Si-PSAC during the activation, this unexpected discovery of O₂^· production can extend commercially-available Si-PSAC into the full-scale photocatalysis.

Keywords: Adsorption; Granular palm shell activated carbon; Oxygen vacancies; Photocatalyst; Superoxide radical.

MeSH terms

Biomass
Charcoal*
Family Characteristics
Oxygen*
Superoxides

Substances

Superoxides
Charcoal
Oxygen