Applied Catalysis B: Environmental, Vol.104, No.1-2, 193-200, 2011
TiO2-encapsulating PVC capable of catalytic self-suppression of dioxin emission in waste incineration as an eco-friendly alternative to conventional PVC
Here, we describe the preparation of TiO2-encapsulating poly(vinyl chloride) (TEPVC). and demonstrate the potential applicability of the material as an eco-friendly alternative to conventional PVC. In particular, TEPVC shows lower emission of toxic chemicals upon waste incineration compared to PVC, owing to the catalytic oxidation and decomposition of such chemicals by the encapsulated TiO2 nanoparticles. Surface-modified TiO2 nanoparticles (M-TiO2) are used for the preparation of TEPVC to facilitate the uniform dispersion of monomeric TiO2 in the initial reaction mixture, which is the key to the preparation of a final TEPVC showing a high dispersion of functional TiO2 nanoparticles in the PVC matrix, without significant agglomeration. The content of encapsulated M-TiO2 in TEPVC was determined to be approximately 0.93 wt%, and the high dispersity of M-TiO2 minimizes PVC deterioration, as determined by examinations of morphology, and thermal and mechanical properties. The emission levels of toxic chemicals upon incineration of TEPVC and unmodified PVC samples were analyzed by gas chromatography with high-resolution mass spectrometric detection, using internal standards composed of C-13-labeled congeners of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls. The levels of toxic chemicals produced by incineration of TEPVC were 50% of those seen after unmodified PVC incineration; the sum of toxic equivalent values of all toxic chemicals generated from the incineration of TEPVC was thus only half that seen after incineration of unmodified PVC. (C) 2011 Elsevier B.V. All rights reserved.
Keywords:Titanium dioxide;Dioxin;Incineration;Poly(vinyl chloride);Chlorinated aromatic compounds;Encapsulation