A Biogenerated Polymetallic Catalyst from Society's Wastes

Piccolo, Oreste and Paganelli, Stefano and Zanatta, Pietro and Tieuli, Sebastiano and Sperni, Laura and Baldi, Franco and Gallo, Michele and Arčon, Iztok and Vogel-Mikuš, Katarina (2019) A Biogenerated Polymetallic Catalyst from Society's Wastes. Chemical Science International Journal, 27 (1). pp. 1-12. ISSN 2456-706X

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Abstract

Aims: Preparation of the new metals-polymeric composite, Metx-EPS (I), to be used as a green catalyst in water or in two-phase aqueous conditions.

Study Design: Recovery and valorization of polymetallic wastes to obtain directly new catalysts using a microorganism to explore their application in removal of difficult and dangerous chemical pollutants present in aqueous environment.

Place and Duration of Study: Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia, Venezia Mestre, Italy; University of Nova Gorica, Nova Gorica, Slovenia, Institut Jozef Stefan, Ljubljana, Slovenia and Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia, between February 2018 and January 2019.

Methodology: For the preparation of Metx-EPS (I), the metals source was an exhausted catalytic converter that was grinded and treated with an acidic solution at 20-25°C. After filtration, the solution was concentrated, neutralized and added to a broth of Klebsiella oxytoca DSM 29614 to produce (I) where metals are embedded in a peculiar polysaccharide structure. The composite was easily recovered from the fermentation broth and purified. The process protocol was verified many times and was shown to be reproducible satisfactorily. The % recovery of metals, originally present in the converter, was good as determined by atomic absorption. The morphology and the chemical state of main metals in (I) were investigated by X-ray absorption spectroscopy methods (XANES and EXAFS). No metallic alloy seems to be evident.

Results: As first application of (I) as catalyst, the hydrodechlorination treatment of polychlorinated biphenyls (PCBs) was studied in water/methanol. A significant removal of higher chlorinated congeners was observed working at 1MPA of hydrogen and 60°C. This result improves significantly and surprisingly the methodology, previously studied by us using mono- or bi-metals embedded in the same polysaccharide moiety, indicating that positive synergies among the different metals were operating.

Conclusion: The preparation of this new polymetallic species embedded in a polysaccharide moiety starting from spent catalytic converters represents an alternative valorisation of metallic wastes. Moreover, a synergic effect was exerted by the different metals when the catalyst Metx-EPS (I) was used in the hydrodechlorination treatment of polychlorinated biphenyls (PCBs) in water/methanol. Finally, a promising preliminary proof of concept for the removal of polychlorinated aromatic pollutants even in contaminated aqueous sites was carried out.

Item Type: Article
Subjects: Science Global Plos > Chemical Science
Depositing User: Unnamed user with email support@science.globalplos.com
Date Deposited: 11 Apr 2023 07:47
Last Modified: 06 Mar 2024 04:23
URI: http://ebooks.manu2sent.com/id/eprint/449

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