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M S T, Naik L, Maridevarmath CV, Malimath GH. Interactions of Environmental Pollutant Aromatic Amines With Photo Excited States of Thiophene Substituted 1,3,4-Oxadiazole Derivative: Fluorescence Quenching Studies. J Fluoresc 2022; 32:1543-1556. [PMID: 35543794 DOI: 10.1007/s10895-022-02946-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 04/11/2022] [Indexed: 11/24/2022]
Abstract
In the present work, the fluorescence quenching of novel thiophene substituted1,3,4-oxadiazole derivative 2-(4-(4-vinylphenyl) phenyl)-5-(5-(4-vinylphenyl)thiophen-2-yl)-1,3,4-oxadiazole (TSO) by five different environmental pollutant aromatic amine derivatives like 2,4-dimethylaniline, 3-chloroaniline, 4-chloroaniline, o-anisidine, and m-toluidine has been studied at room temperature through steady-state and time-resolved methods. It is observed that, the quenching efficiency is highest in the case of o-anisidine and least in the case of 3-chloroaniline. The fluorescence quenching mechanism between TSO and aromatic amines is analysed through different quenching models. The results suggest that, the fluorescence quenching is due to diffusion assisted dynamic or collisional quenching according to the sphere of action static quenching model and according to the finite sink approximation model, the bimolecular quenching reactions are due to the collective effect of dynamic and static quenching. Further, cyclic voltammetry and DFT studies suggest that the fluorescence quenching is due to electron transfer. Binding equilibria analysis confirms the 1:1 stoichiometric ratio between fluorophore and the quencher.
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Affiliation(s)
- Thippeswamy M S
- Department of Physics, Government First Grade College, Harihara, 577601, Karnataka, India
| | - Lohit Naik
- Department of Physics and Electronics, CHRIST(Deemed to Be University), Bangalore, 560029, Karnataka, India
| | - C V Maridevarmath
- Department of Physics, Government First Grade College, Hubballi, 580032, Karnataka, India
| | - G H Malimath
- UG and PG Department of Physics, Karnataka Science College, Dharwad, 580001, Karnataka, India.
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Wu L, Zhang H, Xu Z, Wang C, Chen W, Ni J, Wei R. Biochar-mediated reduction of m-nitrotoluene: Interaction between reduction of m-nitrotoluene and sequestration of contaminants. Sci Total Environ 2021; 773:145662. [PMID: 33940750 DOI: 10.1016/j.scitotenv.2021.145662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 01/03/2021] [Accepted: 02/01/2021] [Indexed: 06/12/2023]
Abstract
Biochar is a highly effective adsorbent for nitroaromatic compounds (NACs), and acts as an electron shuttle that mediates the reduction of NACs. Hence, when biochar is used to mediate NAC reduction, adsorption and reduction will occur simultaneously and affect each other. However, the effect of biochar-mediated NAC reduction on sorption remains unknown. Eight biochars with different physicochemical properties were used to adsorb m-nitrotoluene and mediate its reduction. The results showed that the adsorption of m-nitrotoluene onto the various biochars facilitated its reduction, whereas biochar-mediated reduction retarded and weakened contaminant adsorption, which increased the environmental risk posed by m-nitrotoluene. Nevertheless, biochars with a high graphitization degree and developed porosity not only had a great catalytic ability, but also significantly alleviated the negative effect of reduction on adsorption. This was ascribed to the π-π interaction and pore-filling effect, which played more important roles than the hydrophobic effect in adsorbing the reduction product (m-toluidine) onto the studied biochars during reduction. Furthermore, the methanol extraction results indicated that the eight biochars presented significantly stronger sequestration abilities for adsorbed m-toluidine than for adsorbed m-nitrotoluene. This resulted from the hydrogen bonding and the Lewis acid-base effect between m-toluidine and each biochar, which were absent for m-nitrotoluene. These results suggest that biochars with a high graphitization degree and developed porosity are applicable for mediating reduction-enhancing sequestration of NACs, which could be a novel strategy for NAC remediation.
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Affiliation(s)
- Liang Wu
- College of geographical Science, Ministry of Education Key Laboratory of Humid Subtropical Eco-geographical Process, Fujian Provincial Key Laboratory for Plant Eco-Physiology, Fujian Normal University, Fuzhou, Fujian 350007, China
| | - Huiying Zhang
- College of geographical Science, Ministry of Education Key Laboratory of Humid Subtropical Eco-geographical Process, Fujian Provincial Key Laboratory for Plant Eco-Physiology, Fujian Normal University, Fuzhou, Fujian 350007, China
| | - Zhu Xu
- Yangzhou Haitong Electronic Co. Ltd, Yangzhou, Jiangsu 225001, China
| | - Caiting Wang
- College of geographical Science, Ministry of Education Key Laboratory of Humid Subtropical Eco-geographical Process, Fujian Provincial Key Laboratory for Plant Eco-Physiology, Fujian Normal University, Fuzhou, Fujian 350007, China
| | - Weifeng Chen
- College of geographical Science, Ministry of Education Key Laboratory of Humid Subtropical Eco-geographical Process, Fujian Provincial Key Laboratory for Plant Eco-Physiology, Fujian Normal University, Fuzhou, Fujian 350007, China.
| | - Jinzhi Ni
- College of geographical Science, Ministry of Education Key Laboratory of Humid Subtropical Eco-geographical Process, Fujian Provincial Key Laboratory for Plant Eco-Physiology, Fujian Normal University, Fuzhou, Fujian 350007, China
| | - Ran Wei
- College of geographical Science, Ministry of Education Key Laboratory of Humid Subtropical Eco-geographical Process, Fujian Provincial Key Laboratory for Plant Eco-Physiology, Fujian Normal University, Fuzhou, Fujian 350007, China
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Bornosuz NV, Gorbunova IY, Kireev VV, Bilichenko YV, Chursova LV, Svistunov YS, Onuchin DV, Shutov VV, Petrakova VV, Kolenchenko AA, Nguyen DT, Pavlov NV, Orlov AV, Grebeneva TA, Sirotin IS. Synthesis and Application of Arylaminophosphazene as a Flame Retardant and Catalyst for the Polymerization of Benzoxazines. Polymers (Basel) 2021; 13:263. [PMID: 33466828 DOI: 10.3390/polym13020263] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/08/2021] [Accepted: 01/10/2021] [Indexed: 01/01/2023] Open
Abstract
A novel type of phosphazene containing an additive that acts both as a catalyst and as a flame retardant for benzoxazine binders is presented in this study. The synthesis of a derivative of hexachlorocyclotriphosphazene (HCP) and meta-toluidine was carried out in the medium of the latter, which made it possible to achieve the complete substitution of chlorine atoms in the initial HCP. Thermal and flammability characteristics of modified compositions were investigated. The modifier catalyzes the process of curing and shifts the beginning of reaction from 222.0 °C for pure benzoxazine to 205.9 °C for composition with 10 phr of modifier. The additive decreases the glass transition temperature of compositions. Achievement of the highest category of flame resistance (V-0 in accordance with UL-94) is ensured both by increasing the content of phenyl residues in the composition and by the synergistic effect of phosphorus and nitrogen. A brief study of the curing kinetics disclosed the complex nature of the reaction. An accurate two-step model is obtained using the extended Prout–Tompkins equation for both steps.
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