Photophysics of Fe(III)–tartrate and Fe(III)–citrate complexes in aqueous solutions

Pozdnyakov, Ivan P.; Kolomeets, Alexander V.; Plyusnin, Victor F.; Melnikov, A. A.; Компанец, В. О.; Чекалин, С. В.; Tkachenko, Nikolai V.; Lemmetyinen, Helge

doi:10.1016/j.cplett.2012.01.051

Cited by 35 publications

(30 citation statements)

References 23 publications

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“…Fe III (Cit) has been measured in aqueous solution (Pozdnyakov et al, 2012), the corresponding quantum yield has not, which leaves the photolysis rate of Fe III (Cit), j, unknown. Also, there are no data reported of the diffusivity of O 2 in aqueous citric acid solutions, and the chemical reaction rate of the oxidation of the Fe II -citrate complex by O 2 is quite uncertain (Gonzalez et al, 2017).…”

Section: Development Of the Prad Modelmentioning

confidence: 99%

“…In this work we investigated iron(III)-citrate ([Fe III (OOCCH 2 ) 3 C(OH)], in short Fe III (Cit)), as a model species to better understand iron carboxylate photochemistry in atmospheric aerosol particles. Fe III (Cit) photochemistry is well established in both solution (Abida et al, 2012;Faust and Zepp, 1993;Pozdnyakov et al, 2012) and solid states (Abrahamson et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

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Photochemical degradation of iron(III)-citrate/citric acid aerosol quantified with the combination of three complementary experimental techniques and a kinetic process model

Dou¹,

Alpert²,

Arroyo³

et al. 2020

Preprint

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Abstract. Iron(III) carboxylate photochemistry plays an important role in aerosol aging, especially in the lower troposphere. These complexes can absorb light over a broad wavelength range, inducing the reduction of iron(III) and the oxidation of carboxylate ligands. In the presence of O2, ensuing radical chemistry leads to further decarboxylation, and the production of ·OH, HO2·, peroxides, and oxygenated volatile organic compounds, contributing to particle mass loss. The ·OH, HO2·, and peroxides in turn re-oxidize iron(II) back to iron(III), closing a photocatalytic cycle. This cycle is repeated resulting in continual mass loss due to the release of CO2 and other volatile compounds. In a cold and/or dry atmosphere, organic aerosol particles tend to attain highly viscous states. While the impact of reduced mobility of aerosol constituents on dark chemical reactions has received substantial attention, studies on the effect of high viscosity on photochemical processes are scarce. Here, we choose iron(III)-citrate (FeIII(Cit)) as a model light absorbing iron carboxylate complex that induces citric acid (CA) degradation to investigate how transport limitations influence photochemical processes. Three complementary experimental approaches were used to investigate kinetic transport limitations. The mass loss of single, levitated particles was measured with an electrodynamic balance, the oxidation state of deposited particles was measured with X-ray spectromicroscopy, and HO2· radical production and release into the gas phase was observed in coated wall flow tube experiments. To quantitatively compare these experiments and determine important physical and chemical parameters, a numerical multi-layered photochemical reaction and diffusion (PRAD) model that treats chemical reactions and transport of various species was developed. We observed significant photochemical degradation, with up to 80 % mass loss within 24 hours of light exposure. Interestingly, we also observed that mass loss always accelerated during irradiation, resulting in an increase of the mass loss rate by about a factor of 10. When we increased relative humidity, the observed particle mass loss rate also increased. This is consistent with strong kinetic transport limitations for highly viscous particles. The PRAD model was tuned to reproduce all experimental results and captured the essential chemistry and transport during irradiation. In particular, the photolysis rate of FeIII, the re-oxidation rate of FeII, HO2· production, and the diffusivity of O2 in aqueous FeIII(Cit)/CA system as function of relative humidity and FeIII(Cit) / CA molar ratio could be constrained. Photochemical degradation under atmospheric conditions predicted by the PRAD model shows that release of CO2 and re-partitioning of organic compounds to the gas phase may be very significant to accurately predict organic aerosol aging processes.

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Section: Development Of the Prad Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Photochemical degradation of iron(III)-citrate/citric acid aerosol quantified with the combination of three complementary experimental techniques and a kinetic process model

Dou¹,

Alpert²,

Arroyo³

et al. 2020

Preprint

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“…15 For [Fe(Lact)] + complex, a very weak long-lived component (A 3 (λ)) was observed, whose spectrum is in good agreement with the spectrum of [Fe II ⋯-O-CH(Me)-COO • ] + radical complex (ε 670 = 60 M −1 cm −1 ). 16 Therefore, the authors 16,26 concluded that the thermalized excited state decays with time constant τ 2 by two processes: internal conversion to the ground state and the formation of the long-lived Fe(II) radical complex in reaction (3a) or (3b). The competition among these processes determines the quantum yield of the photolysis of Fe(III)-ALCA complexes.…”

Section: Ultrafast Processes For Fe(iii)-alca Complexesmentioning

confidence: 98%

“…In some studies, 16,26 pump-probe spectroscopy (λ ex = 320 and 400 nm) was used to study ultrafast processes for Table 1.…”

Section: Ultrafast Processes For Fe(iii)-alca Complexesmentioning

confidence: 99%

Ultrafast photophysical processes for Fe(iii)-carboxylates

et al. 2014

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Photochemical reactions with the participation of iron(iii) carboxylates are important for environmental photochemistry and have a great potential of application in water purification (advanced oxidation processes, photo-Fenton and Fenton-like processes). In spite of this, information about excited states and primary intermediates in the photochemistry of Fe(iii) complexes with carboxylic acids is scarce. This mini-review presents and discusses the results of several recent publications in the field of ultrafast spectroscopy of natural Fe(iii) carboxylates.

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“…However, in the presence of other chelating agents, such as carboxylates, there could be another photochemical mechanism for generating • OH radicals (WANG et al, 2006). In this case, the reaction begins with an electron transfer from the complexed organic ligand (LL) to Fe(III) in the excited state of the Fe(III)-LL complex (POZDNYAKOV et al, 2012). This results in the generation of Fe(II) and a positive organic radical (LL •+ ) which can reduce molecular O 2…”

Section: Effect Of Chelated-fe(iii) On Ps/uva Systemmentioning

confidence: 99%

Degradation of persistent pesticides via advanced oxidation and reductive processes.

Graça¹

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Uma tese é pouco para agradecer a todos os que me ajudaram neste caminho. Em primeiro lugar agradeço aos meus Pais que, mesmo sofrendo com a minha partida, nunca deixaram de me incentivar a seguir os meus sonhos, mesmo sendo a 8000 km de casa e "por mares nunca d'antes navegados". Sem o vosso apoio incondicional não existiria esta tese, esta aventura, ou até mesmo nada do que conquistei até hoje. A vocês devo tudo. Ao Prof. Dr. Antonio Carlos Teixeira, pela oportunidade, orientação e compreensão ao longo dos últimos três anos. À Dr.ª Adriana Correia de Velosa por todos os ensinamentos, incentivos e "puxões de orelha", os quais me ajudaram a crescer na ciência e a olhá-la de um novo prisma. Ao Ricardo, por todo o amor, paciência (muita!) e companheirismo ao longo desta aventura, que sem os quais tudo teria sido mais difícil. Aos meus amigos e familiares de Portugal, que apesar da distância, sempre se fizeram sentir perto. À família portuguesa que encontrei no Brasil, por terem ajudado a levar tudo de forma mais leve e a sentir menos saudades de casa.

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Photophysics of Fe(III)–tartrate and Fe(III)–citrate complexes in aqueous solutions

Cited by 35 publications

References 23 publications

Photochemical degradation of iron(III)-citrate/citric acid aerosol quantified with the combination of three complementary experimental techniques and a kinetic process model

Photochemical degradation of iron(III)-citrate/citric acid aerosol quantified with the combination of three complementary experimental techniques and a kinetic process model

Ultrafast photophysical processes for Fe(iii)-carboxylates

Degradation of persistent pesticides via advanced oxidation and reductive processes.

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