Effects of Fe(III)-concentration, speciation, excitation-wavelength and light intensity on the quantum yield of iron(III)-oxalato complex photolysis

Weller, Christian E.; Horn, Sabrina; Herrmann, Hartmut

doi:10.1016/j.jphotochem.2013.01.014

Cited by 91 publications

(52 citation statements)

References 45 publications

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“…The photolysis of C 2 (and C 3 ) in the presence of iron species could cause an isotopic fractionation and enrichment of 13 C in the remaining C 2 (and C 3 ) diacids, because unidirectional reaction causes an enrichment of 13 C in the remaining reactant3436. Further the formation of Fe-oxalato (and malonato) complex and subsequent photolysis mainly depends on concentration ratios of Fe to oxalic (and malonic) acid rather than the UV light intensity344044. Pavuluri and Kawamura34 reported an enrichment of 13 C in authentic C 2 diacid upon its photolysis in the presence of Fe 3+ (and Fe 2+ ) in aqueous phase in a laboratory experiment.…”

Section: Discussionmentioning

confidence: 99%

Enrichment of 13C in diacids and related compounds during photochemical processing of aqueous aerosols: New proxy for organic aerosols aging

Pavuluri

Kawamura

2016

Sci Rep

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To investigate the applicability of compound specific stable carbon isotope ratios (δ13C) of organics in assessment of their photochemical aging in the atmosphere, batch UV irradiation experiments were conducted on two ambient (anthropogenic and biogenic) aerosol samples in aqueous phase for 0.5–120 h. The irradiated samples were analyzed for δ13C of diacids, glyoxylic acid (ωC2) and glyoxal. δ13C of diacids and related compounds became larger with irradiation time (i.e., aging), except for few cases. In general, δ13C of C2-C4 diacids showed an increasing trend with decreasing chain length. Based on δ13C of diacids and related compounds and their relations to their concentrations, we found that C2 and C3 are enriched with 13C during the photochemical decomposition and production from their higher homologues and oxoacids. Photochemical breakdown of higher (≥C3) to lower diacids is also important in the enrichment of 13C in C3-C9 diacids whereas their production from primary precursors causes depletion of 13C. In case of ωC2 and glyoxal, their photochemical production and further oxidation to highly oxygenated compounds both cause the enrichment of 13C. This study reveals that δ13C of diacids and related compounds can be used as a proxy to trace the aging of organic aerosols during long-range atmospheric transport.

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Section: Discussionmentioning

confidence: 99%

Enrichment of 13C in diacids and related compounds during photochemical processing of aqueous aerosols: New proxy for organic aerosols aging

Pavuluri

Kawamura

2016

Sci Rep

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“…This correlation did not change significantly after the passage of the air parcel through the cloud especially during the FCEs. Despite the fact that the photolysis of iron oxalate complexes in aqueous media is known (Weller et al, 2013) to lead to the destruction of oxalate, which may indirectly lead to a poor correlation between iron and oxalate after the air mass passes through the cloud, and also particulate matter loss due to droplet deposition, a significant change of the correlation was not observed. However, this could also be due to the fact that most of the cloud events were observed in the evening hours where photochemical processes such as photolysis are not significant.…”

Section: Other Correlationsmentioning

confidence: 95%

Trace metal characterization of aerosol particles and cloud water during HCCT 2010

et al. 2015

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Abstract. Trace metal characterization of bulk and sizeresolved aerosol and cloud water samples were performed during the Hill Cap Cloud Thuringia (HCCT) campaign. Cloud water was collected at the top of Mt. Schmücke while aerosol samples were collected at two stations upwind and downwind of Mt. Schmücke. Fourteen trace metals including Ti, V, Fe, Mn, Co, Zn, Ni, Cu, As, Sr, Rb, Pb, Cr, and Se were investigated during four full cloud events (FCEs) that fulfilled the conditions of a continuous air mass flow through the three stations. Aerosol particle trace metal concentrations were found to be lower than those observed in the same region during previous field experiments but were within a similar range to those observed in other rural regions in Europe. Fe and Zn were the most abundant elements with concentration ranges of 0.2-111.6 and 1.1-32.1 ng m −3 , respectively. Fe, Mn, and Ti were mainly found in coarse mode aerosols while Zn, Pb, and As were mostly found in the fine mode. Correlation and enrichment factor analysis of trace metals revealed that trace metals such as Ti and Rb were mostly of crustal origin while trace metals such as Zn, Pb, As, Cr, Ni, V, and Cu were of anthropogenic origin. Trace metals such as Fe and Mn were of mixed origins including crustal and combustion sources. Trace metal cloud water concentration decreased from Ti, Mn, Cr, to Co with average concentrations of 9.18, 5.59, 5.54, and 0.46 µg L −1 , respectively. A non-uniform distribution of soluble Fe, Cu, and Mn was observed across the cloud drop sizes. Soluble Fe and Cu were found mainly in cloud droplets with diameters between 16 and 22 µm, while Mn was found mostly in larger drops greater than 22 µm. Fe(III) was the main form of soluble Fe especially in the small and larger drops with concentrations ranging from 2.2 to 37.1 µg L −1 . In contrast to other studies, Fe(II) was observed mainly in the evening hours, implying its presence was not directly related to photochemical processes. Aerosol-cloud interaction did not lead to a marked increase in soluble trace metal concentrations; rather it led to differences in the chemical composition of the aerosol due to preferential loss of aerosol particles through physical processes including cloud drop deposition to vegetative surfaces.

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“…The reaction cell was a semi-cylindrical shape with an optically flat quartz window fused to the pyrex cell and at right angles to the collimated light beam as described previously [29]. The volume-averaged incident irradiance I 0 in the range of 480–550 nm was determined by ferrioxalate chemical actinometry [32,33,34]. It should be noted that the quantum yield and molar absorptivity of ferrioxalate actinometer are closed to zero beyond 550 nm.…”

Section: Methodsmentioning

confidence: 99%

Markedly Enhanced Surface Hydroxyl Groups of TiO2 Nanoparticles with Superior Water-Dispersibility for Photocatalysis

Deng

et al. 2017

Materials

161

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The benefits of increasing the number of surface hydroxyls on TiO2 nanoparticles (NPs) are known for environmental and energy applications; however, the roles of the hydroxyl groups have not been characterized and distinguished. Herein, TiO2 NPs with abundant surface hydroxyl groups were prepared using commercial titanium dioxide (ST-01) powder pretreated with alkaline hydrogen peroxide. Through this simple treatment, the pure anatase phase was retained with an average crystallite size of 5 nm and the surface hydroxyl group density was enhanced to 12.0 OH/nm2, estimated by thermogravimetric analysis, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Especially, this treatment increased the amounts of terminal hydroxyls five- to six-fold, which could raise the isoelectric point and the positive charges on the TiO2 surface in water. The photocatalytic efficiency of the obtained TiO2 NPs was investigated by the photodegradation of sulforhodamine B under visible light irradiation as a function of TiO2 content, pH of solution, and initial dye concentration. The high surface hydroxyl group density of TiO2 NPs can not only enhance water-dispersibility but also promote dye sensitization by generating more hydroxyl radicals.

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Effects of Fe(III)-concentration, speciation, excitation-wavelength and light intensity on the quantum yield of iron(III)-oxalato complex photolysis

Cited by 91 publications

References 45 publications

Enrichment of 13C in diacids and related compounds during photochemical processing of aqueous aerosols: New proxy for organic aerosols aging

Enrichment of 13C in diacids and related compounds during photochemical processing of aqueous aerosols: New proxy for organic aerosols aging

Trace metal characterization of aerosol particles and cloud water during HCCT 2010

Markedly Enhanced Surface Hydroxyl Groups of TiO2 Nanoparticles with Superior Water-Dispersibility for Photocatalysis

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