Study On Adsorption And Photocatalytic Performance Of Functional Nanocomposites

TiO₂has attracted much attention for its application in decomposition of dye.However, its efficiency of utilizing sunlight is limited by the restricted absorbance ofvisible light. Moreover, TiO₂particles are difficult to recovery from the processingmedium. In order to solve the above problems, easily recovery one-dimensionalnanoscale TiO₂was fabricated and then couple with a narrower band gap semiconductorCu₂O, which greatly enhanced the decoloration efficiency of dye. The photocatalysis ofTiO₂in combination with the typical porous structure of paper, carbon fiber wasselected as the support for TiO₂loading, a photocatalytic paper was prepared in order tobroaden the range of photocatalysis application.One-dimensional titanium dioxide was obtained by simple hydrothermal treatment.Surface-coarsening TiO₂nanobelts and GX@TiO₂heterostructure composites wereprepared by the acid-assisted hydrothermal method and photo-light reduction method,respectively. Neither the cationic dye nor the anionic dye, GX@TiO₂composites exhibita enhanced decolorization activity than TiO₂nanobelts. The enhancement ofdecolorization activity is attributed to the large specific surface of grapheme and thesimilar benzene ring structure to adsorb with the dye molecules through π-π bonds.Cu₂O@TiO₂and Cu₂O@GX@TiO₂composites were synthesized by wet-chemicalprecipitation method. The former have more regular morphology and uniform sizedistribution. Compare to TiO₂and GX@TiO₂nanobelts, introducing Cu₂O nanoparticlesto the composites lead to a much higher decolorization efficiency, especially for theanionic dye methyl orange. The improved decolorization activity is attributed toexposure of {111} facets of Cu₂O. The decolorization performance of methyl orange forCu₂O@TiO₂composites is emphatically studied. The FTIR results proved that thecomposites could photodegrade methyl orange molecules under visible light irradiation.So the decolorization mechanism is proposed: fast capture and slow photodegradationprocess.Cellulose-based photocatalytic paper with TiO₂particles loaded on PAN-carbonfiber was prepared with a papermaking technique. The influence of pH value of methylorange （MO）, fixatives of TiO₂nanoparticles, carbon fiber to cellulose fiber ratio andcharge amount of wet strength agent （PAE） on the decolorization activity wereinvestigated. The optimization of preparation conditions are: TiO₂loaded carbon fiber: cellulose fiber=1:1, the charge level of Na₂SiO₃is2.5%based on TiO₂, the chargelevel of PAE is0.4%based on oven-dry fibers. The decoloration rate of photocatalyticpaper is higher than commercial TiO₂particles and directly loading TiO₂particles oncellulose fibers. In addition, the as-prepared photocatalytic paper can be repeatedly usewhile there is obvious reduced fraction at the sixth time. The prepared photocatalyticpaper has promising application due to the low cost and can be recycled for further use.