scholarly journals Reductive Dechlorination of Chloroacetamides with NaBH4 Catalyzed by Zero Valent Iron, ZVI, Nanoparticles in ORMOSIL Matrices Prepared via the Sol-Gel Route

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 986
Author(s):  
Michael Meistelman ◽  
Dan Meyerstein ◽  
Amos Bardea ◽  
Ariela Burg ◽  
Dror Shamir ◽  
...  
Keyword(s):  
Reductive Dechlorination ◽  
Sol Gel ◽  
Reaction Medium ◽  
Zero Valent Iron ◽  
Catalyst Structure ◽  
Organically Modified ◽  
Plausible Mechanism ◽  
Zero Valent Iron Nanoparticles ◽  
Insight Into ◽  
Dechlorination Reaction

The efficient reductive dechlorination, as remediation of dichloroacetamide and monochloroacetamide, toxic and abundant pollutants, using sodium borohydride catalyzed by zero valent iron nanoparticles (ZVI-NPs), entrapped in organically modified hybrid silica matrices prepared via the sol-gel route, ZVI@ORMOSIL, is demonstrated. The results indicate that the extent of the dechlorination reaction depends on the nature of the substrate and on the reaction medium. By varying the amount of catalyst or reductant in the reaction it was possible to obtain conditions for full dechlorination of these pollutants to nontoxic acetamide and acetic acid. A plausible mechanism of the catalytic process is discussed. The present work expands the scope of ZVI-NP catalyzed reduction of polluting compounds, first reports the catalytic parameters of chloroacetamide reduction, and offers additional insight into the heterogeneous catalyst structure of M0@ORMOSIL sol-gel. The ZVI@ORMOSIL catalyst is ferromagnetic and hence can be recycled easily.

Zero-valent iron nanoparticles entrapped in SiO2 sol-gel matrices: A catalyst for the reduction of several pollutants

2020 ◽  
Vol 133 ◽  
pp. 105819 ◽  
Author(s):  
Neelam ◽  
Dan Meyerstein ◽  
Jaydeep Adhikary ◽  
Ariela Burg ◽  
Dror Shamir ◽  
...  
Keyword(s):  
Iron Nanoparticles ◽  
Sol Gel ◽  
Zero Valent Iron ◽  
Zero Valent Iron Nanoparticles

scholarly journals “Doing More with Less”: Ni(II)@ORMOSIL, a Novel Sol-Gel Pre-Catalyst for the Reduction of Nitrobenzene

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1391
Author(s):  
Michael Meistelman ◽  
Dan Meyerstein ◽  
Ariela Burg ◽  
Dror Shamir ◽  
Yael Albo
Keyword(s):  
Iron Nanoparticles ◽  
Color Change ◽  
Sol Gel ◽  
Solvent Mixtures ◽  
Hybrid Silica ◽  
Low Concentrations ◽  
Nitrobenzene Reduction ◽  
Organically Modified ◽  
Zero Valent Iron Nanoparticles

Reduction of nitrobenzene with NaBH4 using zero-valent iron nanoparticles (ZVI-NPs) and NiCl2∙6H2O incorporated in organically modified hybrid silica matrices as ZVI@ORMOSIL and Ni(II)@ORMOSIL catalysts is proposed as a remediation strategy. Ni(II)@ORMOSIL is prepared by ion-exchanging H+ of the ORMOSIL matrix with NiII. Ni(II)@ORMOSIL is a pre-catalyst that undergoes reduction by NaBH4 by an in-situ reaction and promotes nitrobenzene reduction by the unconsumed NaBH4, leading to sparing use of the catalyst. Ni(II)@ORMOSIL undergoes color change from green to black in this process, returning to a green hue after washing and drying. Nitrobenzene reductions were examined in aqueous acetonitrile solvent mixtures, and the reduction cascade produced the reaction end-products with catalytic implications. Plausible mechanisms of ZVI@ORMOSIL and Ni(II)@ORMOSIL catalyzed reductions of nitrobenzene are discussed. This work is the first to report M(II)@ORMOSIL pre-catalysts for in-situ reduction of nitrobenzene, and expands the scope of the ORMOSIL series of catalysts for the reduction of polluting compounds. This approach enables the development of catalysts that use very low concentrations of transition metal cations.

Microstructural characterization of sol-gel coating on PET films

1994 ◽  
Vol 52 ◽  
pp. 886-887
Author(s):  
R. T. Chen ◽  
R.A. Norwood
Keyword(s):  
Ion Beam ◽  
Sol Gel ◽  
Industrial Applications ◽  
Hard Coatings ◽  
Nanometer Scale ◽  
Ion Beam Sputtering ◽  
Process Technology ◽  
Refractive Index Measurement ◽  
Organically Modified ◽  
Pet Films

Sol-gel processing has been used to control the structure of a material on a nanometer scale in preparing advanced ceramics and glasses. Film coating using the sol-gel process was also found to be a viable process technology in applications such as optical, porous, antireflection and hard coatings. In this study, organically modified silicate (Ormosil) coatings are applied to PET films for various industrial applications. Sol-gel materials are known to exhibit nanometer scale structures which havepreviously been characterized by small-angle X-ray scattering (SAXS), neutron scattering and light scattering. Imaging of the ultrafine sol-gel structures has also been performed using an ultrahigh resolution replica/TEM technique. The objective of this study was to evaluate the ultrafine structures inthe sol gel coatings using a direct imaging technique: atomic force microscopy (AFM). In addition, correlation of microstructures with processing parameters, coating density and other physical properties will be discussed.The materials evaluated are organically modified silicate coatings on PET film substrates. Refractive index measurement by the prism coupling method was used to assess density of the sol-gel coating.AFM imaging was performed on a Nanoscope III AFM (by Digital Instruments) using constant force mode. Solgel coating samples coated with a thin layer of Ft (by ion beam sputtering) were also examined by STM in order to confirm the structures observed in the contact type AFM. In addition, to compare the previous results, sol-gel powder samples were also prepared by ultrasonication followed by Pt/Au shadowing and examined using a JEOL 100CX TEM.

scholarly journals Zero-Valent Iron Nanoparticles for Soil and Groundwater Remediation

2020 ◽  
Vol 17 (16) ◽  
pp. 5817
Author(s):  
Alazne Galdames ◽  
Leire Ruiz-Rubio ◽  
Maider Orueta ◽  
Miguel Sánchez-Arzalluz ◽  
José Luis Vilas-Vilela
Keyword(s):  
Contaminated Soils ◽  
Groundwater Remediation ◽  
Iron Nanoparticles ◽  
Environmental Issues ◽  
High Specific Surface Area ◽  
Zero Valent Iron ◽  
Pilot Studies ◽  
High Effectiveness ◽  
Nanosized Materials ◽  
Zero Valent Iron Nanoparticles

Zero-valent iron has been reported as a successful remediation agent for environmental issues, being extensively used in soil and groundwater remediation. The use of zero-valent nanoparticles have been arisen as a highly effective method due to the high specific surface area of zero-valent nanoparticles. Then, the development of nanosized materials in general, and the improvement of the properties of the nano-iron in particular, has facilitated their application in remediation technologies. As the result, highly efficient and versatile nanomaterials have been obtained. Among the possible nanoparticle systems, the reactivity and availability of zero-valent iron nanoparticles (NZVI) have achieved very interesting and promising results make them particularly attractive for the remediation of subsurface contaminants. In fact, a large number of laboratory and pilot studies have reported the high effectiveness of these NZVI-based technologies for the remediation of groundwater and contaminated soils. Although the results are often based on a limited contaminant target, there is a large gap between the amount of contaminants tested with NZVI at the laboratory level and those remediated at the pilot and field level. In this review, the main zero-valent iron nanoparticles and their remediation capacity are summarized, in addition to the pilot and land scale studies reported until date for each kind of nanomaterials.

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