A New Generation of Catalytic Poly(vinylidene fluoride) Membranes: Coupling Plasma Treatment with Chemical Immobilization of Tungsten-Based Catalysts

Authors

  • L. C. Lopez,

    1. Department of Chemistry, University of Bari, Via Orabona 4, 70126 Bari, Italy
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  • M. G. Buonomenna,

    1. Institute on Membrane Technology, National Research Council of Italy, ITM-CNR, University of Calabria, Via P. Bucci cubo 17/C, 87030 Rende, Italy
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  • E. Fontananova,

    1. Institute on Membrane Technology, National Research Council of Italy, ITM-CNR, University of Calabria, Via P. Bucci cubo 17/C, 87030 Rende, Italy
    2. CEMIF.CAL, Department of Chemical Engineering and Materials, University of Calabria, Via P. Bucci, 87030 Rende, Italy
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  • G. Iacoviello,

    1. Department of Chemistry, University of Bari, Via Orabona 4, 70126 Bari, Italy
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  • E. Drioli,

    1. Institute on Membrane Technology, National Research Council of Italy, ITM-CNR, University of Calabria, Via P. Bucci cubo 17/C, 87030 Rende, Italy
    2. CEMIF.CAL, Department of Chemical Engineering and Materials, University of Calabria, Via P. Bucci, 87030 Rende, Italy
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  • R. d'Agostino,

    1. Department of Chemistry, University of Bari, Via Orabona 4, 70126 Bari, Italy
    2. Institute of Inorganic Methodologies and Plasmas IMIP-CNR, c/o University of Bari, Plasma Solution Srl., Via Orabona 4, 70126 Bari, Italy
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  • P. Favia

    1. Department of Chemistry, University of Bari, Via Orabona 4, 70126 Bari, Italy
    2. Institute of Inorganic Methodologies and Plasmas IMIP-CNR, c/o University of Bari, Plasma Solution Srl., Via Orabona 4, 70126 Bari, Italy
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  • The authors gratefully acknowledge Dr. A. Milella (Univ. Bari, Italy) for valuable scientific discussion on plasma treatments and Dr. L. Donato (ITM-CNR, Univ. of Calabria, Rende, Italy) for HPLC measurements. The Italian Ministry of Universities and Research is acknowledged for supporting this research through the Cofin 2002 2002033184_001 and CLAB01TYEF projects.

Abstract

A new generation of catalytically active membranes for secondary amine oxidation and phenol degradation has been developed by coupling the advantages of low-temperature plasma-modification processes with surface chemical immobilization reactions of catalysts. Poly(vinylidene fluoride) membranes have been modified with NH3 radiofrequency glow discharges in order to graft amino groups at their surface, providing active sites for stable immobilization of tungsten-based heterogeneous catalysts. Particular attention has been focused on tungstate, WO42–, and decatungstate, W10O324–, which act efficiently as catalysts for the oxidation of secondary amines and as photocatalysts for the degradation of organic pollutants, respectively. Plasma-modified membranes surface-tailored with WO42– have been used in catalytic membrane reactors to activate hydrogen peroxide for oxidizing secondary amines to nitrones; membranes modified with W10O324– have been used for the complete degradation of phenol. The obtained results, in terms of amine–nitrone conversion and phenol degradation, respectively, appear extremely promising; these modified membranes can be considered as a pioneering, successful example of heterogenization of W-based catalysts on plasma-treated membranes.

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