Evidence for Fenton Photoassisted Processes Mediated by Encapsulated Fe ions at Biocompatible pH Values

Fernández, Jacqueline; Dhananjeyan, and M. R.; Kiwi, J.; and, Y. Senuma; Hilborn, J. W.

doi:10.1021/jp9943777

Cited by 86 publications

(52 citation statements)

References 11 publications

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“…The C-F species is the main component of the Nafion polymer, and it is the decomposition of H 2 O 2 over the Fe-ionic species in the Nafion cages that produces the oxidative radicals necessary for Orange II decomposition. [3][4][5][6] Furthermore, experiments following the sulfur enrichment of the C-Nafion/Fe-ion fabrics show that the topmost layers removed by Ar + -ion sputtering at 165/165 eV are within the same distance from the surface as the C-F layers observed for the Nafion sulfonate with a binding energy value (BE) of 1697/170 eV.…”

Section: Kinetics Of Orange II Decomposition As a Function Of Thementioning

confidence: 99%

Abatement of an Azo Dye on Structured C-Nafion/Fe-Ion Surfaces by Photo-Fenton Reactions Leading to Carboxylate Intermediates with a Remarkable Biodegradability Increase of the Treated Solution

et al. 2003

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A novel C-Nafion/Fe-ion structured fabric capable of mediating Orange II decomposition in Fenton-immobilized photoassisted reactions is presented. The catalyst preparation requires the right balance between the amount of the Nafion necessary to protect the C-surface and the minimum encapsulation of the Fe-cluster catalytic sites inside the Nafion to allow the photocatalysis to proceed. The C-Nafion/Fe fabric can be used up to pH 10 under light to photocatalyze the disappearance of Orange II in the presence of H2O2. The photocatalysis mediated by the C-Nafion/Fe-ion fabric increased with the applied light intensity and reaction temperature in the reaction needing an activation energy of 9.8 kcal/mol. This indicates that ion− and radical−molecule reactions take place during Orange II disappearance. The build up and decomposition of intermediate iron complexes under light involves the recycling of Fe2+ and was detected by infrared spectroscopy (FTIR). This observation, along with other experimental results, allows us to suggest a surface mechanism for the dye degradation on the C-Nafion/Fe-ion fabrics. The C-Nafion/Fe-ion fabric in the presence of H2O2 under solar simulated light transforms the totally nonbiodegradable Orange II into a biocompatible material with a very high BOD5/COD value. X-ray photoelectron spectroscopy (XPS) and sputtering by Ar+-ions of the upper surface layer of the C-Nafion/Fe-ion fabric allow us to describe the intervention of the photocatalyst down to the molecular level. Most of the Fe clusters examined by transmission electron microscopy (TEM) showed particle sizes close to 4 nm due to their encapsulation into the Gierke cages of the Nafion thin film observed by scanning electron microscopy (SEM) and optical microscopy (OM).

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Section: Kinetics Of Orange II Decomposition As a Function Of Thementioning

confidence: 99%

Abatement of an Azo Dye on Structured C-Nafion/Fe-Ion Surfaces by Photo-Fenton Reactions Leading to Carboxylate Intermediates with a Remarkable Biodegradability Increase of the Treated Solution

et al. 2003

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“…[35,36] This work evidenced the decolourisation of an azo dye (Direct Orange S) using economically effective INP based on the Fenton oxidation within 60 min. Sonolysis enhances the decolourisation rate further by increasing the catalytic activity of the semiconductor catalyst.…”

Section: Discussionmentioning

confidence: 77%

Decolourisation of Direct Orange S dye by ultra sonication using iron oxide nanoparticles

Karthikeyeni

Vijayakumar

Vasanth

et al. 2013

Journal of Experimental Nanoscience

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Biosynthesised iron oxide nanoparticles (INPs) less than 100 nm were used to decolourise the textile dye, Direct Orange S by the process of ultra sonication. The parameters tested for the decolourisation of the Direct Orange S dye were the INP concentration (0.2-1g/l), pH (3-11) and H 2 O 2 concentration (2-8 ml/l). The rate of decolourisation process was performed by both stirrer and ultra sonicator method using the first-order kinetics ln(c/c 0 ). The percentage of dye removal for the optimum conditions such as INP, 1g/l (87.2%); pH, 9 (85.5%) and H 2 O 2 concentration 8 ml/l (86.5%) were observed. The Direct Orange S dye was degraded efficiently by sonolysis (60 min) than by the magnetic stirrer method (120 min). High-performance liquid chromatography results showed that the peak for Direct Orange S dye was not present when the dye sample was treated by either H 2 O 2 þ INP or INP alone. Use of biosynthesised iron NPs in Direct Orange S dye (azo dye) decolourisation by a simple non-toxic Fenton reaction is a safe and novel approach. Industrialisation of this technique will be an economical way to decolorise the textile dyes present in water systems.

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“…However, considering the cost of Nafion on a large scale [16], various low cost polymeric materials, which have also the capability of adsorbing inorganic and organic pollutants, are being explored as support for heterogeneous photo-Fenton reactions [17,18]. For instance, Fe(III) ions have been immobilized onto modified polyacrylonitrile fibers [19,20] and alginate [21,21]. The latter, is a biopolymer exhibiting a sol-gel transition when exposed to different ionic environment (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…However, the low iron concentration in the natural clay has limited their use in photo-Fenton reaction [27]. Moreover, after some pioneering report [21], that underlined the effect of Fe-alginate beads to conduce the photo-Fenton reaction at neutral pH, the application of iron-containing alginate beads as heterogeneous Fenton catalysts for the degradation of the organic pollutants, due their "big fragility" [23] and high iron leaching, seems to be still in its embryonic stage [23,28]. Therefore, we decided to explore the possibility of using iron-enriched clay for the construction of stable hybrid alginate/clay beads as catalyst for heterogeneous photo-Fenton.…”

Section: Introductionmentioning

confidence: 99%

Neutral solar photo-Fenton degradation of 4-nitrophenol on iron-enriched hybrid montmorillonite-alginate beads (Fe-MABs)

Barreca

Colmenares

Pace

et al. 2014

Journal of Photochemistry and Photobiology A: Chemistry

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a b s t r a c tHybrid montmorillonite-alginate beads (MABs) were prepared by the ion-gelation method from alginate and montmorillonite clay suspension dropped in a calcium chloride solution. Similarly, iron-enriched beads (Fe-MABs) were prepared using iron-exchanged montmorillonite. All beads were characterized by atomic absorption and Fourier-transform infrared spectroscopy. The efficiency of Fe-MABs as catalysts for the solar photo-Fenton performed at initial pH = 7.0 was evaluated by varying the catalyst amount and hydrogen peroxide concentration, and monitoring the removal of 4-nitrophenol (4-NP) at initial concentration of 10 ppm. A kinetic analysis showed that the removal of 4-NP by Fe-MABs followed a pseudo first-order kinetics model (R 2 = 0.966). High 4-NP removal (75%) was achieved with 25 Fe-MABs by using 150 ppm of hydrogen peroxide and 40 min of irradiation, while total 4-NP removal was obtained by using 500 ppm of hydrogen peroxide. Moreover, preliminary studies about beads' recycling showed good removal efficiencies for the first three cycles.

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Evidence for Fenton Photoassisted Processes Mediated by Encapsulated Fe ions at Biocompatible pH Values

Cited by 86 publications

References 11 publications

Abatement of an Azo Dye on Structured C-Nafion/Fe-Ion Surfaces by Photo-Fenton Reactions Leading to Carboxylate Intermediates with a Remarkable Biodegradability Increase of the Treated Solution

Abatement of an Azo Dye on Structured C-Nafion/Fe-Ion Surfaces by Photo-Fenton Reactions Leading to Carboxylate Intermediates with a Remarkable Biodegradability Increase of the Treated Solution

Decolourisation of Direct Orange S dye by ultra sonication using iron oxide nanoparticles

Neutral solar photo-Fenton degradation of 4-nitrophenol on iron-enriched hybrid montmorillonite-alginate beads (Fe-MABs)

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