Degradation of perfluorooctanoic acid adsorbed on Fe-zeolites with molecular oxygen as oxidant under UV-A irradiation

Qian, Lin; Georgi, Anett; Gonzalez-Olmos, Rafael; Kopinke, Frank‐Dieter

doi:10.1016/j.apcatb.2020.119283

Cited by 39 publications

(32 citation statements)

References 46 publications

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“…where C PFOS,free and C PFOS,total are the freely dissolved PFOS and total extractable PFOS concentrations, respectively. Similar to our previous study, 23 it is reasonable to hypothesize the complex formation as a prerequisite for photochemical PFOS degradation according to eqs 7 and 8:…”

Section: Resultssupporting

confidence: 77%

“…This is in accordance with our previous findings on PFOA degradation in the Fe-zeolite/ UV system. 23 Shorter-chain PFCAs (≤4 C) show a low adsorption degree at the applied zeolite concentration, i.e., they desorb into the solution phase instead of being further degraded. To confirm that a complete mineralization of PFOS can finally be obtained, the solution phase of the 96-h UV irradiated Fe-zeolite suspension was further treated by UV activation of sodium persulfate (Na 2 S 2 O 8 ), which was added in five steps (8.4 mM each) every 2 h. As shown in Figure S7, the remaining short-chain PFCAs were nearly completely decomposed (C2 > 93%, C3 and C4 > 98% removal degree) after 10 h. A nearly complete defluorination (d F − = 89%) of PFOS was achieved (Figure S8).…”

Section: Resultsmentioning

confidence: 99%

“…The Fe-BEA35 zeolite was characterized in detail and first applied for photochemical degradation of PFOA using UV-A light in our previous study. 23 Nevertheless, PFOS is known as more persistent than perfluorocarboxylic acids as it is, e.g., unreactive in e-transfer by sulfate radicals. In this study, we show for the first time that PFOS is degraded using these microscale Fe-zeolite particles when irradiated with UV-C light and identify the operation steps and conditions for its complete mineralization.…”

Section: Introductionmentioning

confidence: 99%

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Photodegradation of Perfluorooctanesulfonic Acid on Fe-Zeolites in Water

Qian

Kopinke

Georgi

2020

Environ. Sci. Technol.

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Perfluorooctanesulfonic acid (PFOS) decomposition in an aqueous environment remains a huge challenge because of its extreme chemical and biological inertness even when compared with other per-and polyfluoroalkyl substances (PFAS). In this work, we demonstrate for the first time a successful photochemical PFOS degradation by irradiation with 254 nm ultraviolet (UV) light after adsorption on μm-sized Fe(III)-loaded zeolites under ambient conditions with oxygen (O 2 ) as the terminal oxidant. Twenty μM PFOS loaded on 0.5 g L −1 Fezeolites in aqueous suspension was degraded up to 99% within 96 h under acidic conditions (pH ≤ 5.5) in the presence of oxygen. Besides fluoride and sulfate, short-chain perfluorinated carboxylic acids (PFCAs) were identified and quantified as products. In addition, the effects of initial pH, catalyst dosages, and operation temperature on the degradation of PFOS were investigated. We also successfully applied the system to real groundwater samples where trace PFOS was present. Our results indicate that PFOS degradation is initiated by electron transfer from sulfonate to iron. The presented experimental study offers an option for a novel water remediation technology, comprising first a zeolite-based adsorption step followed by a step for photochemical regeneration of the adsorbent.

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Section: Resultssupporting

confidence: 77%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Photodegradation of Perfluorooctanesulfonic Acid on Fe-Zeolites in Water

Qian

Kopinke

Georgi

2020

Environ. Sci. Technol.

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“…UV–vis diffuse reflectance spectroscopy (UV–vis DRS) was performed to analyze the coordination environment of metallic species in the materials, and the obtained spectra are displayed in Figures and S2. As shown in Figures a and S2a, an intense adsorption occurred in the patterns of 1Fe-SBA-15 and 2Fe-SBA-15 samples at around 250 nm, which is attributed to O → Fe 3+ ligand-to-metal charge-transfer transitions due to the doping of Fe. , In Figure S2b, the Cu(acac) 2 sample shows two adsorption peaks at 300 nm and 600 nm, corresponding to the π → π* transition of the acac ligand and the d–d transition of Cu in Cu(acac) 2 , respectively . In the case of 1Cu/1Fe-SBA-15 and 1Cu/2Fe-SBA-15 (Figures b and S2c), there are two identical adsorption peaks as that of the Cu(acac) 2 sample.…”

Section: Resultsmentioning

confidence: 99%

Synergistic Effect between Fe and Cu Species on Mesoporous Silica for Hydroxylation of Benzene to Phenol

Zhang

Wang

et al. 2021

Ind. Eng. Chem. Res.

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Direct hydroxylation of benzene to phenol is an effective and environment-friendly route to obtain phenol. Herein, Fe-doped and cupric acetylacetonate [Cu(acac)2]-grafted mesoporous silica (Cu/Fe-SBA-15) with highly dispersed metallic sites has been synthesized and used as a heterogeneous catalyst in the hydroxylation of benzene. The physiochemical properties of the synthesized materials as well as the reciprocity between iron and copper sites were analyzed by several characterization techniques including nitrogen adsorption–desorption, X-ray diffraction, transmission electron microscopy, UV–vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. In direct hydroxylation of benzene with H2O2 as the oxidant, the prepared Cu/Fe-SBA-15 material showed great catalytic activity. Moreover, the synergistic effect between doped Fe sites and grafted Cu sites was also investigated. In this catalyst, Fe and Cu species both played the role of active sites. Excessive activity of iron would lead to benzene peroxidation, while the presence of copper sites could effectively hinder benzene peroxidation.

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“… [ 76 ] Time = 12 h UV/NaHCO 3 pH = 8.8 100 82.3 0.37 h −1 PFOA UV-A/Fe-zeolites Hg UV-A light (4 W); Wavelength = 254 nm; Photon flux = 4.47 × 10 −6 mol/s −1 |PFOA| = 0.02 mg/L, |Cat| = 1 g/L Time = 24 h 100 38 0.38 h −1 PFOA is adsorbed by the catalyst and forms PFOA-Fe 3+ complex. Under irradiation the PFOA is oxidized through a ligand-to-metal charge transfer process [ 117 ] pH = 5.5 PFOA UV/β-Ga 2 O 3 Low-pressure Hg UV light (18 W); Wavelength = 254 nm |PFOA| = 0.05 mg/L |Cat| = 1.8 g/L Time = 2 h 70 30 0.44 h −1 A novel catalyst was developed with high activity for PFOA degradation. Activity was related primarily to the surface charge of the material and its charge carriers favorable redox potentials.…”

Section: Advanced Oxidation Processes For Pfas Degradationmentioning

confidence: 99%

Photo enhanced degradation of polyfluoroalkyl and perfluoroalkyl substances

Olatunde

Kuvarega

Onwudiwe

2020

Heliyon

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The increase in the presence of highly recalcitrant poly- and per- fluoroalkyl substances (PFAS) in the environment, plant tissues and animals continues to pose serious health concerns. Several treatment methods such as physical, biological and chemical processes have been explored to deal with these compounds. Current trends have shown that the destructive treatment processes, which offer degradation and mineralization of PFASs, are the most desirable process among researchers and policy makers. This article, therefore, reviews the degradation and defluorination processes, their efficiencies and the degradation mechanism of photon-based processes. It shows that high degradation and defluorination efficiency of PFASs could be achieved by photon driven processes such as photolysis, photochemical, photocatalysis and photoreduction. The efficiency of these processes is greatly influenced by the nature of light and the reactive radical generated in the system. The limitation of these processes, however, include the long reaction time required and the use of anoxic reaction conditions, which are not obtainable at ambient conditions.

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Degradation of perfluorooctanoic acid adsorbed on Fe-zeolites with molecular oxygen as oxidant under UV-A irradiation

Cited by 39 publications

References 46 publications

Photodegradation of Perfluorooctanesulfonic Acid on Fe-Zeolites in Water

Photodegradation of Perfluorooctanesulfonic Acid on Fe-Zeolites in Water

Synergistic Effect between Fe and Cu Species on Mesoporous Silica for Hydroxylation of Benzene to Phenol

Photo enhanced degradation of polyfluoroalkyl and perfluoroalkyl substances

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