Porous Titanium Dioxide/Calcium Alginate Composite Hydrogel for Photocatalytic Degradation of Wastewater

Nano-titanium dioxide (TiO2) is one of the most promising photocatalysts. It has the advantages of low cost, non-toxicity, high photocatalytic activity, etc.            However, the nano-titanium dioxide has a problem in difficult to recycle and reuse. If it cannot be recycled, nano-titanium dioxide dispersed in water will cause secondary pollution. Since the material that used for current approach for recycling TiO2- steel wire, glass beads, ceramic, cotton fabric and other materials- would absorb or block light, the photocatalytic efficiency of titanium dioxide nanoparticles is drastically reduced. In order to improve the photocatalytic efficiency of titanium dioxide nanoparticles, we decided to prepare a titanium dioxide/sodium alginate mixed solution and prepared titanium dioxide/calcium alginate composite hydrogel spheres by calcium chloride cross-linking. The size of a single particle is about 20nm. By using the spectrometer, under the irradiation of ultraviolet lamp, the photocatalytic efficiency of titanium dioxide nanoparticles can be determined by the rate of the degradation of methyl orange which is the simulation of pollutant. The result of experiment showed that the porous titanium dioxide/calcium alginate composite hydrogel beads have a higher photocatalytic activity, approximately about an increase of 20% in the degradation of methyl orange after 120 minutes. This experiment has a good reference value for the preparation of high activity and easy recovery photocatalysts in large quantities.