Insight into the role of charge carrier mediation zone for singlet oxygen production over rod-shape graphitic carbon nitride: Batch and continuous-flow reactor

Hyeseong Kim; Choe Earn Choong; Ihn Han; Chang Min Park; In Wook Nah; Jung Rae Kim; Byong-Hun Jeon; Yeomin Yoon; Min Jang

doi:10.1016/j.jhazmat.2021.127652

Insight into the role of charge carrier mediation zone for singlet oxygen production over rod-shape graphitic carbon nitride: Batch and continuous-flow reactor

J Hazard Mater. 2022 Feb 15;424(Pt C):127652. doi: 10.1016/j.jhazmat.2021.127652. Epub 2021 Nov 2.

Authors

Hyeseong Kim¹, Choe Earn Choong², Ihn Han³, Chang Min Park⁴, In Wook Nah⁵, Jung Rae Kim⁶, Byong-Hun Jeon⁷, Yeomin Yoon⁸, Min Jang⁹

Affiliations

¹ Department of Environmental Engineering, Kwangwoon University, 20 Kwangwoon-Ro, Nowon-Gu, Seoul 01897, Republic of Korea.
² Department of Environmental Engineering, Kwangwoon University, 20 Kwangwoon-Ro, Nowon-Gu, Seoul 01897, Republic of Korea; Plasma Bioscience Research Center, Kwangwoon University, 26 Kwangwoon-Ro, Nowon-Gu, Seoul 01899, Republic of Korea. Electronic address: cce_@live.com.
³ Plasma Bioscience Research Center, Kwangwoon University, 26 Kwangwoon-Ro, Nowon-Gu, Seoul 01899, Republic of Korea.
⁴ Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea.
⁵ Center for Energy Convergence, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea.
⁶ School of Chemical Engineering, Pusan National University, 63 Busandeahak-ro, Geumjeong-Gu, Busan 46241, Republic of Korea.
⁷ Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul 04763, Republic of Korea.
⁸ Department of Civil and Environmental Engineering, University of South Carolina, Columbia, 300 Main Street, SC 29208, USA.
⁹ Department of Environmental Engineering, Kwangwoon University, 20 Kwangwoon-Ro, Nowon-Gu, Seoul 01897, Republic of Korea; Plasma Bioscience Research Center, Kwangwoon University, 26 Kwangwoon-Ro, Nowon-Gu, Seoul 01899, Republic of Korea. Electronic address: minjang@kw.ac.kr.

PMID: 34775315
DOI: 10.1016/j.jhazmat.2021.127652

Abstract

As a new approach of creating the photo-exited electron (e^-) and hole (h⁺) mediation zone for highly selective singlet oxygen (¹O₂) production, the rod-type graphitic carbon nitride (NCN) has been synthesized from the nitric acid-modified melamine followed by the calcination. The NCN exhibited a higher surface area and surface oxygen adsorption ability than bulk graphitic carbon nitride (BCN). The increment of CO and NH_x groups on NCN corresponded to e^- and h⁺ mediation groups, respectively, resulting in higher production of ¹O₂ than BCN. Moreover, those mediation groups on NCN result in higher recombination efficiency and longer e^- decay time. As a result, the optimized NCN-0.5 (derived from 0.5 M of nitric acid-modified melamine) displayed 5.8 times higher kinetic rate constant of atrazine (ATZ) removal under UVA-LED irradiation compared to BCN. This study also evaluated the ATZ degradation pathways and toxicity effect of by-products. In addition, continuous flow experiments using NCN-0.5 showed superior ATZ removal performance with a hybrid concept between a slurry photocatalysis and a continuous stirred tank reactor system using actual effluent obtained from a wastewater treatment plant. Thus, this work provides an insight into the strategy for highly selective ¹O₂ production and the potential for water purification application.

Keywords: Continuous stirred tank reactor; Graphitic carbon nitride; Photocatalysis; Singlet oxygen.