Unexpected electronic effects on benzotriazole UV absorber photostability: Mechanistic implications beyond excited state intramolecular proton transfer

Suhadolnik, Joseph C.; DeBellis, Anthony D.; Hendricks-Guy, Carmen; Iyengar, R.L.N.; Wood, M. G.

doi:10.1007/bf02720140

Cited by 18 publications

(32 citation statements)

References 20 publications

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“…For a horizontal CW with a large residence time (720 h), temperature was identified as important factor for BZT degradation (degradation during winter months: 0%, during summer months: 53%). From this comparison, it appears that detailed understanding of the mechanisms and physico-chemical variables that control UV degradation of BZT are still unclear [73].…”

Section: Resultsmentioning

confidence: 99%

Enhancement of Micropollutant Degradation at the Outlet of Small Wastewater Treatment Plants

et al. 2013

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The aim of this work was to evaluate low-cost and easy-to-operate engineering solutions that can be added as a polishing step to small wastewater treatment plants to reduce the micropollutant load to water bodies. The proposed design combines a sand filter/constructed wetland with additional and more advanced treatment technologies (UV degradation, enhanced adsorption to the solid phase, e.g., an engineered substrate) to increase the elimination of recalcitrant compounds. The removal of five micropollutants with different physico-chemical characteristics (three pharmaceuticals: diclofenac, carbamazepine, sulfamethoxazole, one pesticide: mecoprop, and one corrosion inhibitor: benzotriazole) was studied to evaluate the feasibility of the proposed system. Separate batch experiments were conducted to assess the removal efficiency of UV degradation and adsorption. The efficiency of each individual process was substance-specific. No process was effective on all the compounds tested, although elimination rates over 80% using light expanded clay aggregate (an engineered material) were observed. A laboratory-scale flow-through setup was used to evaluate interactions when removal processes were combined. Four of the studied compounds were partially eliminated, with poor removal of the fifth (benzotriazole). The energy requirements for a field-scale installation were estimated to be the same order of magnitude as those of ozonation and powdered activated carbon treatments.

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Section: Resultsmentioning

confidence: 99%

Enhancement of Micropollutant Degradation at the Outlet of Small Wastewater Treatment Plants

et al. 2013

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“…[1][2][3][4][5][6][7] This is also thought to be the decay mechanism for other photostabilizers such as hydroxyphenyl triazines. 4 Such molecules contain a strong intramolecular hydrogen bond in the ground state, which is believed to be essential for the photostability of these compounds.…”

Section: Introductionmentioning

confidence: 97%

Theoretical Study of Benzotriazole UV Photostability: Ultrafast Deactivation through Coupled Proton and Electron Transfer Triggered by a Charge-Transfer State

et al. 2004

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A theoretical CASSCF study of the reaction path for excited-state intramolecular proton transfer (ESIPT) for a model system derived from the UV absorber 2-(2'-hydroxyphenyl) benzotriazole without the fused benzo ring on the triazole has been carried out. A planar reaction path can be optimized but is shown to have no physical significance. The true reaction path involves twisted geometries. Adiabatic proton transfer is triggered by a charge-transfer from the phenol to the triazole group, and is followed by radiationless decay at the keto form. Along the nonplanar reaction path, there is a coupled proton and electron transfer in a manner similar to tryptophan. This rationalizes unexpected experimental results on the effect of electron withdrawing substituent groups on the photostability. The coupled proton and electron transfer is followed by a barrierless relaxation in the ground state to recover the enol form. An alternative photostabilization pathway from a phenyl localized state has also been documented and is similar to the channel 3 decay pathway in benzene photochemistry. Additionally, a long-lived intermediate for a twisted intramolecular charge-transfer (TICT) state has been identified as the species potentially responsible for the increase of blue fluorescence in strongly polar media.

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“…10 However, the corrosion resistance and mechanical properties of the copper film are poor, which limits its application. Aluminum is another kind of metal with high conductivity.…”

Section: Introductionmentioning

confidence: 99%

Optical Enhanced Transmission of Double Layer Ultrathin Metallic Films

Lang¹,

Du²,

Gao³

et al. 2015

j nanosci nanotechnol

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Double layer ultrathin metallic films composed of an aluminum film with thickness of 33 nm on copper films with thickness of 16 nm or 32 nm were deposited on polyester foil by cylindrical medium frequency magnetron sputtering in turn. Transmittance and reflectance of these films were measured and compared to each composite film, as well as absorptance, respectively. The results show that the reflectance increases, while both the transmittance and the absorptance decrease with the increase in copper film thickness. At the same time, the three optical parameters of the double layer film were calculated theoretically. Compared to theoretical results, there is an increase in transmittance, while a decrease in reflectance and absorptance for the double layer on experimental results. It is concluded that the optical properties of the double layer films are not simply the sum of the two composite films, there is an enhanced transmission effect to electromagnetic wave at the double layer metallic film.

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Unexpected electronic effects on benzotriazole UV absorber photostability: Mechanistic implications beyond excited state intramolecular proton transfer

Cited by 18 publications

References 20 publications

Enhancement of Micropollutant Degradation at the Outlet of Small Wastewater Treatment Plants

Enhancement of Micropollutant Degradation at the Outlet of Small Wastewater Treatment Plants

Theoretical Study of Benzotriazole UV Photostability: Ultrafast Deactivation through Coupled Proton and Electron Transfer Triggered by a Charge-Transfer State

Optical Enhanced Transmission of Double Layer Ultrathin Metallic Films

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