Degradation pathways and mechanisms insight of indigo and shikonin with experiments and quantum chemical calculations

Zhou, Xudong; Guo, Yanju; Shi, Lei; Han, Qing; Lin, Chuhui; Zhang, Lingfan; Wu, Mengqi; Zhang, Wenqing

doi:10.1016/j.dyepig.2023.111455

Cited by 10 publications

(4 citation statements)

References 37 publications

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“…Knowing that the efficiency of IC degradation increases with increasing SnS 2 content (Figure ) and how ROS speciation and generation efficiency change across all the samples with their changing composition, the IC photodegradation pathways can be proposed (Figure ) in line with the representative literature. − Indigo carmine is classified as a donor–acceptor dye type, where heterocyclic amines (−NH– groups) are electron donors, and carbonyl groups (−CO) are electron acceptors. The color of IC in aqueous solutions (absorbance maximum at 610 nm , ) is related to the structural unit consisting of two −NH– and −CO groups that are “cross-conjugated” through >CC< bridge (H-chromophore). , Under light illumination, dye molecules can be converted into a higher-energy excited state (IC*).…”

Section: Resultsmentioning

confidence: 59%

“…Zhou et al analyzed the indigo photodegradation process (analogous molecule to IC, but without −SO 3 – groups). Based on DFT calculations, it was suggested that these radicals most probably can attack both >CC< bond and C atoms in benzene rings …”

Section: Resultsmentioning

confidence: 99%

“…Based on DFT calculations, it was suggested that these radicals most probably can attack both >C�C< bond and C atoms in benzene rings. 79 In the case of singlet oxygen interactions with various substances, this ROS can transfer energy to them without forming new products (physical quenching to the ground state 3 O 2 ) or undergo a chemical reaction, such as cycloaddition (chemical quenching). 89 Therefore, it can simply transfer energy to IC molecules without dye decolorization (the opposite reaction, IC* + 3 O 2 → IC + 1 O 2 , is also possible�see Figure 10b, "Pathway VI").…”

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confidence: 99%

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Tunable Generation of Reactive Oxygen Species in SnO₂/SnS₂ Nanostructures: Mechanistic Insights into Indigo Carmine Photodegradation

Michalec,

Mozgawa,

Kusior

et al. 2024

J. Phys. Chem. C

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In semiconductor-based photocatalysis, one of the most significant directions in future research is designing materials with improved activity for the targeted photodegradation of organic contaminants. However, obtaining such photocatalysts requires an in-depth mechanistic understanding of the involved interfacial processes. In this framework, a comprehensive knowledge of photocatalysts' ability to produce particular reactive oxygen species (ROS) and their interaction with contaminants is particularly crucial. This work aims to examine how the phase composition of SnO 2 /SnS 2 -based nanomaterials (from bare SnO 2 to SnS 2 ) affects their ability to generate various ROS and propose the corresponding photodegradation mechanism. To this end, we combined three methods: scavenger tests, electron paramagnetic resonance (EPR) spin trapping techniques, and UV−vis nitro blue tetrazolium (NBT) assay. To demonstrate the implications of different ROS involved in the photodegradation of a particular substance, indigo carmine (IC) dye was chosen as a model contaminant. The second purpose of this study was to reveal and explain side effects that appear during tests with commonly applied scavengers. The results demonstrate the possibility of tunable ROS generation (from • OH through 1 O 2 to O 2•− ) in SnO 2 / SnS 2 -based photocatalysts and the crucial role of superoxide radicals in the IC photodegradation. These findings were correlated with the band diagrams to rationalize the mechanisms of ROS formation and IC degradation. The applied experimental approach demonstrated the importance of using multiple techniques to examine ROS generation processes and elucidate their mechanistic roles.

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Section: Resultsmentioning

confidence: 59%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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Tunable Generation of Reactive Oxygen Species in SnO₂/SnS₂ Nanostructures: Mechanistic Insights into Indigo Carmine Photodegradation

Michalec,

Mozgawa,

Kusior

et al. 2024

J. Phys. Chem. C

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“…Indeed, sepiolite's strong UV resistance [51,79,80] was harnessed during the pigment's design to enhance the visual endurance of the Indigofera tinctoria L. extract, which is well known for its susceptibility to photofading of color induced by UV radiation [81,82], encompassing the cleavage of C=C double bonds [83].…”

Section: Outdoor Resistancementioning

confidence: 99%

Assessing the Impact of Sepiolite-Based Bio-Pigment Infused with Indigo Extract on Appearance and Durability of Water-Based White Primer

Calovi,

Rossi

2024

Materials

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The objective of this study is to evaluate how two varying amounts of sepiolite-based powder, infused with indigo extract, affect the appearance and durability of a water-based, white primer. To examine the influence of this eco-friendly pigment on the coatings’ overall appearance, assessments were performed for color, gloss, and surface roughness. Additionally, the coatings were investigated through optical and electron microscopic observations, to evaluate the distribution of the pigment within the polymer matrix. The effect of the pigment on the coating’s durability was assessed through accelerated tests, including exposure in a salt spray chamber and a UV-B chamber. These tests aimed to evaluate the emergence of defects and changes in the appearance of the samples over time. Furthermore, the impact of different quantities of sepiolite-based powder on the coating’s ability to act as a barrier was assessed using liquid resistance tests and contact angle measurements. These evaluations aimed to understand how the coating responded to various liquids and its surface properties concerning repellency or absorption. In essence, this study underscores the considerable influence of the eco-friendly pigment, demonstrating its capacity to introduce unique color and texture variations in the paint. Moreover, the inclusion of the pigment has enhanced the coating’s color stability, its ability to act as a barrier, and its overall durability when exposed to harsh environments.

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Degradation mechanism of methylene blue by heterogenous electro-Fenton with CeO2/rGO composite cathode

Sun,

Tu,

et al. 2024

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Degradation pathways and mechanisms insight of indigo and shikonin with experiments and quantum chemical calculations

Cited by 10 publications

References 37 publications

Tunable Generation of Reactive Oxygen Species in SnO₂/SnS₂ Nanostructures: Mechanistic Insights into Indigo Carmine Photodegradation

Tunable Generation of Reactive Oxygen Species in SnO₂/SnS₂ Nanostructures: Mechanistic Insights into Indigo Carmine Photodegradation

Assessing the Impact of Sepiolite-Based Bio-Pigment Infused with Indigo Extract on Appearance and Durability of Water-Based White Primer

Degradation mechanism of methylene blue by heterogenous electro-Fenton with CeO2/rGO composite cathode

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Degradation pathways and mechanisms insight of indigo and shikonin with experiments and quantum chemical calculations

Cited by 10 publications

References 37 publications

Tunable Generation of Reactive Oxygen Species in SnO2/SnS2 Nanostructures: Mechanistic Insights into Indigo Carmine Photodegradation

Tunable Generation of Reactive Oxygen Species in SnO2/SnS2 Nanostructures: Mechanistic Insights into Indigo Carmine Photodegradation

Assessing the Impact of Sepiolite-Based Bio-Pigment Infused with Indigo Extract on Appearance and Durability of Water-Based White Primer

Degradation mechanism of methylene blue by heterogenous electro-Fenton with CeO2/rGO composite cathode

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Tunable Generation of Reactive Oxygen Species in SnO₂/SnS₂ Nanostructures: Mechanistic Insights into Indigo Carmine Photodegradation

Tunable Generation of Reactive Oxygen Species in SnO₂/SnS₂ Nanostructures: Mechanistic Insights into Indigo Carmine Photodegradation