Suspension stability and mobility of Trap-Ox Fe-zeolites for in-situ nanoremediation

Gillies, Glenn; Raj, R. B. Amal; Kopinke, Frank‐Dieter; Georgi, Anett

doi:10.1016/j.jcis.2017.04.037

Cited by 18 publications

(8 citation statements)

References 54 publications

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“…These absorption bands can be deconvoluted into several peaks, which have been assigned to various iron species according to the literature. 31 − 33 0.52 Fe-BEA35 and 1.26 Fe-BEA35 demonstrate absorption bands around 200 and 280 nm, which are attributed to isolated ferric ions in tetrahedral and octahedral coordination, respectively. Three more absorption bands can be identified from the spectra of 1.61 and 2.36 Fe-BEA35.…”

Section: Resultsmentioning

confidence: 99%

“…As can be seen in Figure c, the spectra of 0.52 Fe-BEA35 and 1.26 Fe-BEA35 show strong absorption bands in the UV range (200–350 nm), while the spectra of 1.61 Fe-BEA35 and 2.36 Fe-BEA35 show broad absorption bands in the UV and visible range (200–550 nm). These absorption bands can be deconvoluted into several peaks, which have been assigned to various iron species according to the literature. − 0.52 Fe-BEA35 and 1.26 Fe-BEA35 demonstrate absorption bands around 200 and 280 nm, which are attributed to isolated ferric ions in tetrahedral and octahedral coordination, respectively. Three more absorption bands can be identified from the spectra of 1.61 and 2.36 Fe-BEA35.…”

Section: Resultsmentioning

confidence: 99%

“…Nevertheless, isolated iron species bound to ion-exchange sites (tetrahedral and octahedral coordination) are reported to be more active than other iron species in redox reactions catalyzed by Fe-zeolites. , We indeed observed the significant role of these isolated iron sites in PFOA photodegradation by relating PFOA photodegradation kinetics to iron speciation of the Fe-zeolites. The bands in UV–vis DR spectra were deconvoluted and analyzed in order to determine the different iron species semiquantitatively (Table ), following previously published strategies. ,− Compared to the sample with the lowest iron content, i.e., 0.52 Fe-BEA35, 1.26 Fe-BEA35 contains higher iron amounts in the form of isolated iron sites, in both tetrahedral and octahedral coordination, which contributed to a higher degradation rate of PFOA.…”

Section: Resultsmentioning

confidence: 99%

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A Deep Insight into Perfluorooctanoic Acid Photodegradation Using Metal Ion-Exchanged Zeolites

Qian,

Zhao,

Schierz

et al. 2024

ACS EST Eng.

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Treating perfluorooctanoic acid (PFOA) in an aqueous environment is problematic due to its low concentration and its high resistance to biological and chemical degradation. To tackle this challenge, combinations of pre-enrichment and photodegradation processes are promising solutions. In this work, we investigated metal ion-exchanged zeolites as adsorbents and photocatalysts for PFOA treatment. Among various transition metal ion-exchanged BEA zeolites, Fe-exchanged BEA (Fe-BEA) zeolites showed significant activity for the photodegradation of PFOA. The isolated iron species in Fe-BEA zeolite are responsible for PFOA photodegradation, whereas other iron species present from excess iron loading in the zeolite will lower its photocatalytic activity. Furthermore, it was proved via size exclusion tests using branched PFOA isomers that the photodegradation of PFOA took place on the internal surface rather than the external surface of Fe-BEA zeolite. Photodegradation of PFOA was also tested to be effective with Fe-exchanged BEA-type zeolites having various SiO 2 /Al 2 O 3 ratios, but ineffective with FAU-type zeolites. The optimal Fe-BEA zeolite showed a sorption coefficient K d of 6.0 × 10 5 L kg −1 at an aqueous phase PFOA concentration of 0.7 μg L −1 and a PFOA half-life of 1.8 h under UV-A irradiation. The presented study offers a deeper understanding of the use of metal ion-exchanged zeolites for photodegradation of PFOA.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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A Deep Insight into Perfluorooctanoic Acid Photodegradation Using Metal Ion-Exchanged Zeolites

Qian,

Zhao,

Schierz

et al. 2024

ACS EST Eng.

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“…The subsurface injection of water-based slurries containing nanoreagents (the so-called nanoremediation) has proved to be an effective technique for in-situ remediation of contaminated aquifers [1][2][3][4][5][6]. Typically, nanoreagents are injected directly close to the source of the contamination, thus improving the remediation performances and reducing the investment costs compared to more commonly applied techniques, such as permeable reactive barriers or pump and treat systems [7,8].…”

Section: Introductionmentioning

confidence: 99%

Injection of Zerovalent Iron Gels for Aquifer Nanoremediation: Lab Experiments and Modeling

Mondino

Piscitello

Bianco

et al. 2020

Water

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One of the main technical problems faced during field-scale injections of iron microparticles (mZVI) for groundwater nanoremediation is related to their poor colloidal stability and mobility in porous media. In this study, a shear-thinning gel, composed of a mixture of two environmentally friendly biopolymers, i.e., guar gum and xanthan gum, was employed to overcome these limitations. The slurry rheology and particle mobility were characterized by column transport tests. Then, a radial transport experiment was performed to mimic the particle delivery in more realistic conditions. The gel, even at a low polymeric content (1.75 g/L), proved effective in enhancing the mobility of high concentrated mZVI suspensions (20 g/L) in field-like conditions. The high radius of influence (73 cm) and homogeneous iron distribution were achieved by maintaining a low injection overpressure (<0.4 bar). Based only on the information derived from column tests, the MNMs 2018 software (Micro- and Nanoparticle transport, filtration, and clogging Model-Suite) was able to predict the particle distribution and pressure build-up measured in the radial domain. Experimental and simulated results showed good agreement, thus proving that a simplified experimental-modeling procedure based on 1D column tests could be used to effectively upscale the slurry behavior to more representative scales, e.g., radial domains.

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“…Modified and natural clay minerals have been widely studied and employed as adsorbents in water treatment because of their high cation exchange capacity, high specific surface area, and low toxicity and cost. − In cases where the pollutants are hydrophobic or anionic, the surface and the interlamellar/pore characteristics can be modified to facilitate specific, high-affinity, and extremely rapid adsorption of organic and inorganic pollutants. ,, In the past decade, the use of clays and iron oxides as catalysts for heterogeneous Fenton reactions has also been widely explored. ,− The structurally bound iron in the minerals is able to activate the oxidant at a wide range of pH values and produce reactive radicals that promote pollutant degradation without the precipitation of iron sludge . Still, slow activation rates inhibit the use of mineral catalysts in heterogeneous Fenton processes.…”

Section: Introductionmentioning

confidence: 99%

Iron–Montmorillonite–Cyclodextrin Composites as Recyclable Sorbent Catalysts for the Adsorption and Surface Oxidation of Organic Pollutants

Kundu

Manor

Radian

2020

ACS Appl. Mater. Interfaces

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Iron–clay–cyclodextrin composites were designed as sorbent catalysts to adsorb and oxidize pollutants from water. The clay–iron backbone served as a mechanical support and as a heterogeneous Fenton catalyst, and the cyclodextrin monomers or polymers cross-linked with polyfluorinated aromatic molecules were used to accommodate adsorption of the pollutants. The composite based on iron–clay–cyclodextrin–polymers (Fe–MMT−βCD–DFB) exhibited superior adsorption and degradation of the model pollutants, bisphenol A (BPA), carbamazepine (CBZ), and perfluorooctanoic acid (PFOA), compared to the monomer-based composite and the native iron clay. The variety of adsorption sites, such as the polyfluorinated aromatic cross-linker, cyclodextrin toroid, and iron–clay surface, resulted in high adsorption affinity toward all pollutants; BPA was primarily adsorbed to the cyclodextrin functional groups, CBZ showed high affinity toward the Fe–MMT surface and the Fe–MMT−βCD–DFB composite, whereas PFOA was adsorbed mainly to the βCD–DFB polymer. Degradation, using H2O2, was highly efficient, reaching over 90% degradation in 1 h for BPA and CBZ and ∼80% for PFOA. The composite also showed excellent degradation efficiency in a multicomponent system with all three model pollutants. Furthermore, the composite’s activity remained steady for five consecutive cycles of adsorption and degradation. The ability to remediate a broad range of pollutants, and the high overall removal exhibited by this novel material, demonstrates the potential for future application in water remediation technologies.

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Suspension stability and mobility of Trap-Ox Fe-zeolites for in-situ nanoremediation

Cited by 18 publications

References 54 publications

A Deep Insight into Perfluorooctanoic Acid Photodegradation Using Metal Ion-Exchanged Zeolites

A Deep Insight into Perfluorooctanoic Acid Photodegradation Using Metal Ion-Exchanged Zeolites

Injection of Zerovalent Iron Gels for Aquifer Nanoremediation: Lab Experiments and Modeling

Iron–Montmorillonite–Cyclodextrin Composites as Recyclable Sorbent Catalysts for the Adsorption and Surface Oxidation of Organic Pollutants

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