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Yu P, Guo Z, Wang J, Guo Y, Wang T, Zhang L. Insight into the photodegradation of methylisothiazolinone and benzoisothiazolinone in aquatic environments. WATER RESEARCH 2024; 265:122301. [PMID: 39173356 DOI: 10.1016/j.watres.2024.122301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 07/29/2024] [Accepted: 08/18/2024] [Indexed: 08/24/2024]
Abstract
Methylisothiazolinone (MIT) and Benzisothiazolinone (BIT) are two widely used non-oxidizing biocides of isothiazolinones. Their production and usage volume have sharply increased since the pandemic of COVID-19, inevitably leading to more release into water environment. However, their photochemical behaviors in water environment are still unclear. Therefore, this study investigated photodegradation properties of MIT and BIT in natural water under simulated sunlight. The results demonstrated that direct photolysis was mainly responsible for their photodegradation which occurred through their excited singlet states rather than triplet states. The quantum yields of MIT and BIT photodegradation were 11 - 13.6 × 10-4 and 2.43 - 5.79 × 10-4, respectively. pH had almost no effect on the photodegradation of MIT, while the photodegradation of BIT was significantly promoted under alkaline condition due to abundance of BIT in its deprotonated form (BIT-N-). Cl-, NO3- and dissolved organic matter (DOM) in natural water inhibited the photodegradation of both MIT and BIT, with the light screening effect of DOM being the most significantly inhibitory factor. The addition of other isothiazolinones, which possibly coexisted with MIT and BIT in actual condition, slightly inhibited the photodegradation of MIT and BIT. The estimated half-life under natural sunlight at a 30°N latitude was estimated to be approximately 1.1 days. The photodegradation pathways of MIT and BIT are similar, primarily initiated from the ring-opening at the N-S bond, with Frontier electron densities (FED) calculations suggesting the likelihood of oxidation and ·OH addition reactions at the O, N, and S sites. While the photodegradation products exhibited significantly reduced acute toxicity compared to their parent compounds, they nonetheless posed substantial chronic toxicity. These insights are vital for assessing the ecological impacts of MIT and BIT in aquatic environments.
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Affiliation(s)
- Pengfei Yu
- Key Laboratory of Three Gorges Reservoir Region's Eco-environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China
| | - Zhongyu Guo
- Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-Ku, Tokyo, 152-8552, Japan
| | - Jieqiong Wang
- College of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China
| | - Yuchen Guo
- College of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China
| | - Tingting Wang
- RIKEN-Center for Computational Science, Kobe, Hyogo, 650-0047, Japan
| | - Lilan Zhang
- Key Laboratory of Three Gorges Reservoir Region's Eco-environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China
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de Araújo BB, Gonçalves PFB. From skin sensitizers to wastewater: the unknown photo-deactivation process of low-lying excited states of isothiazolinones. A non-adiabatic dynamics investigation. Phys Chem Chem Phys 2024; 26:12799-12805. [PMID: 38619871 DOI: 10.1039/d4cp00998c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Isothiazolinones represent a class of heterocyclic compounds widely used in various applications, including as biocides in cosmetics, detergents, and paints, as well as in industrial wastewater treatment. Indeed, the presence of isothiazolinones in the environment and their associated potential health hazards have raised significant concerns. In this study, a non-adiabatic dynamics investigation was conducted using state-of-the-art methodologies to explore the photochemistry of isothiazolinones. A simplified model, isothiazol-3(2H)-one (ISO), was employed to represent this compound class. The study validated the model and demonstrated that ISO can return to its ground state through the cleavage of the S-N or S-C bonds, with no significant energy barrier observed. Non-adiabatic dynamics simulations provided insights into the time scales and detailed processes of isothiazolinone photodissociation. The preferred route for deactivation was found to be the cleavage of the S-N bond. This research enhances our understanding of the photodeactivation processes of isothiazolinones and their potential environmental impact.
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Affiliation(s)
- Bruno Bercini de Araújo
- Grupo de Química Teórica, Universidade Federal do Rio Grande do Sul - Instituto de Química, Avenida Bento Gonçalves 9500, CP 15003, CEP 91501970, Porto Alegre, Brazil.
| | - Paulo Fernando Bruno Gonçalves
- Grupo de Química Teórica, Universidade Federal do Rio Grande do Sul - Instituto de Química, Avenida Bento Gonçalves 9500, CP 15003, CEP 91501970, Porto Alegre, Brazil.
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Wang W, Cao G, Zhang J, Qiao H, Li H, Yang B, Chen Y, Zhu L, Sang Y, Du L, Cai Z. UV-induced photodegradation of emerging para-phenylenediamine quinones in aqueous environment: Kinetics, products identification and toxicity assessments. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133427. [PMID: 38185090 DOI: 10.1016/j.jhazmat.2024.133427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/11/2023] [Accepted: 01/01/2024] [Indexed: 01/09/2024]
Abstract
Substituted para-phenylenediamine quinones (PPD-quinones) are a class of emerging contaminants frequently detected in the aqueous environment. One of them, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone (6PPD-Q), was found to cause acute toxicities to aquatic species at extremely low environmental levels. The ubiquitousness and ecotoxicity of such pollutants underscore the importance of their transformation and elimination. In this work, we demonstrated effective removals of five PPD-quinones in aqueous environments under UV irradiation, with up to 94% of 6PPD-Q eliminated after a 40-min treatment. By applying high-resolution mass spectrometry (HRMS) non-targeted screening in combination with isotope labeling strategies, a total of 22 transformation products (TPs) were identified. Coupling with the time-based dynamic patterns, potential transformation mechanisms were identified as an •OH-induced photocatalysis reaction involving bond cleavage, hydroxylation, and oxidation. Computational toxicity assessment predicted lower aquatic toxicity of the TPs than their parent PPD-quinones. Our results in parallel evidenced an obvious reduction of PPD-quinones accompanied by the presence of their TPs in the effluent after UV disinfection in real municipal wastewater. This work builds a comprehensive understanding of the fate, transformation products, and related toxicological characteristics of emerging PPD-quinone contaminants in the aqueous environment.
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Affiliation(s)
- Wei Wang
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, 999077, Hong Kong Special Administrative Region of China
| | - Guodong Cao
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, 999077, Hong Kong Special Administrative Region of China
| | - Jing Zhang
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, 999077, Hong Kong Special Administrative Region of China
| | - Han Qiao
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, 999077, Hong Kong Special Administrative Region of China
| | - Huankai Li
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, 999077, Hong Kong Special Administrative Region of China
| | - Biwei Yang
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, 999077, Hong Kong Special Administrative Region of China
| | - Yanyan Chen
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, 999077, Hong Kong Special Administrative Region of China
| | - Lin Zhu
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, 999077, Hong Kong Special Administrative Region of China
| | - Yuecheng Sang
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, 999077, Hong Kong Special Administrative Region of China
| | - Lei Du
- Huangpu Hydrogen Energy Innovation Center/School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, China
| | - Zongwei Cai
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, 999077, Hong Kong Special Administrative Region of China.
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