Study On The Preparation And Property Of Minerals Supported-Nano TiO₂Composite Photocatalytic Materials

In recent years, because of increasing water shortage and pollution, it isextremely urgent to protect and restore water. As a kind of efficient photocatalyticmaterial, nano-TiO₂has broad application prospect in the field of water qualityrestoration, also faces some challenges. Owing to its nano-size, the problem ofseparation and recovery of nano-TiO₂photocatalyst from the reaction medium exists.An alternative method is immobilization of TiO₂powder on an inert and suitablesupporting matrix. Among various support materials, nature minerals have attractedmore interests due to their large specific surface area, pore volume, great adsorbability,steady chemical property and abundant storage. When using natural minerals ascarriers of nano TiO₂, the loading of TiO₂and targeted enrichment of water pollutantswere all carried out, which effectively improves the degradation efficiency. Therefore,systemic exploration of preparation and performance of natural mineralssupported-Nano TiO₂composite photocatalytic materials has significant actual andtheoretical value for their effective application in water restoration field.In this paper, mineral supported nano-TiO₂photocatalytic composites weresynthesized by an easily-operated powder sintering process using three kinds ofmineral with different pore structure-montmorillonite, sepiolite and zeolite as supportmatrix. The microstructure、morphologies and photocatalytic property of the meterialswere characterized and analyzed by scanning and transmission electron microscope（SEM, TEM）, X-ray diffraction spectrometer （XRD）, UV-Visible Spectrophotometer（UV-Vis）, Fluorescence spectrometer （FL）, et al. The results showed that mineralmatrix can reduce agglomeration of nano-TiO₂in photocatalytic composites andenhance absorption ability within UV-Vis response range, consequently boostphotocatalytic activity of the complex. The influence of mineral carrier type andnano-TiO₂load ratio on photocatalytic performance of the composites were explored,which showed that90%TiO₂/zeolite had optimal photocatalytic activity. And then, taking zeolite as the carrier, we systematically investigated theinfluencing law of sintering temperature and lapping mode in the synthesis process onphotocatalytic activity of nano-TiO₂/zeolite composite materials. It is revealed thatwhen using ball-milling mode and sintering at400℃in the powder sintering process,the yield zeolite supported nano-TiO₂photocatalytic composites have the bestphotocatalytic activityIn order to further judge the photocatalytic property of nano-TiO₂/mineralcomposite materials, photocatalytic degradation of methylene blue in solution by thecomposites was carried out. It was found that in single degradation test, after3h ofillumination, the composite materials with different load ratio all have gooddegradation effect on methylene blue. And90%nano-TiO₂/zeolite compositephotocatalytic material has the highest degradation rate, surpassing92%. After fivetimes of continuous loop degradation, the final degradation rate of90%nano-TiO₂/zeolite composite material to methylene blue can maintained above85%. It impliedthat nano-TiO₂/mineral composites has long working life, stable property and can berecycling used..