Preparation and properties of photocatalytic composites of nano TiO₂/polyester sea-island filament needle punched nonwoven

A series of nano TiO₂ photocatalytic dispersed solutions were prepared by using deionized water as a medium, sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (DBS), ployvinylpynolidone (PVP), cetyl trimethyl ammonium bromide (CTAB), polyacrylic acid sodium (PAAS) surfactant as the dispersant, respectively. The TiO₂ dispersed solutions were used as a finishing agent for the polyester sea-island filament needle punched nonwoven (PFN-NWF) to prepare TiO₂/PFN-NWF photocatalytic composites through the twice dip-padding technique. The morphology, structure and properties of TiO₂ solutions and TiO₂/PFN-NWF photocatalytic composites were investigated. The capsicol and formaldehyde solution was used as a model contaminant to evaluate the photocatalytic activity of the TiO₂/PFN-NWF composites. The results indicate that the dispersion system of TiO₂ significantly affected by acidity-basicity of solution and dispersant, and the dispersivity of TiO₂ solution can be effectively improved by addition of PAAS. The TiO₂ is well immobilized on the surface of PFN-NWF and has good load fastness, the load rate of TiO₂/PFN-NWF composites could be achieved 4.79%. The TiO₂/PFN-NWF composites also have excellent catalytic performance. The capsicol (2 mL) drops on the surface of TiO₂/PFN-NWF composites can be completely degraded under natural light irradiation for 60 min. The degradation ratio of formaldehyde is 95.98% under xenon lamp (300 W) irradiation for 3 h, and this ratio is remained above 90.19% after five cycles.