Research On The Photocatalytic Ability Of Catalysts With Different Dimensions And Their Ultrafiltration Characters

The presented studies have focused on the photodegradation of azo dye with one-dimensional titanium dioxide nanotubes (TNTs) and its characters of separation and recovery in the process of ultrafiltration (UF), choosing zero-dimensional particle catalyst (P25) as reference. The TNTs with length of30～80nm and diameter of10nm, which appeared to be totally anatase by XRD analysis, were prepared by hydrothermal method at first. The effects of pH and catalyst loading on photocatalysis efficiency were then investigated in detail. The result showed that the optimal pH value and catalyst loading of this reaction system with application of TNTs were4.5and0.5g/L respectively. In this condition, the decolorization rate of X-3B with application of TNTs was up to94.6% after75min of irradiation, which was a little lower than that of P25with96.1%. In addition, the mineralization rate of X-3B with application of TNTs was up to66.5% after90min of irradiation.The PES ultrafiltration membrane was adopted to separate and recover the nano catalysts for reuse. In the process of separation, the differences between P25and TNTs in separation efficiency, recovery rate, membrane pollution characters and reuse efficiency were investigated. The retention rate of P25and TNTs were both100%. Due to unique one-dimensional structure, TNTs formed more porous cake layer on the membrane surface as compared to P25, and therefore the common membrane pollution can be effectively relieved. Furthermore, the recovery rate of TNTs were67%,46%and44%in the first, second and third recovery test respectively, which was higher than that of P25with49%,37%and21%. Based on the unique one-dimensional morphology and large surface area, TNTs showed a higher stability in three-time recycling use.