Microwave-assisted Preparation Of Zirconium Phosphate And Its Photocatalytic Performance

Zirconium phosphate is a kind of important tetravalent metal phosphates. It became a kind ofmulti-functional material studied in recent years, because of its stable physical-chemical propertiesand unique characteristics of inserting reaction. Traditional synthetic methods of zirconiumphosphate include sol reflux method, hydrothermal method, sol-gel method, direct precipitationmethod. But these methods are complicated. They need to be in the presence of high concentrationof phosphate to get zirconium phosphate, long reaction time (usually1-7days), and need hightemperature and pressure, even calcination.Microwave heating method is a new kind of materials synthesis method. Microwave energyimport mode can improve the efficiency of heating. Compared with the traditional method, it hasmany advantage, such as a short reaction time, lower reaction temperature, narrow distribution ofparticle size, good dispersibility, less reunion, good crystallinity. The microwave non-thermaleffect can also affect the formation of crystal shape. However, there is no research report onmicrowave-assisted synthesis of zirconium phosphate. In this paper, the preparation of zirconiumphosphate was carried on by microwave-assisted method. The preparation and application asphotocatalyst of α-ZrP were mainly discussed.Under low temperature (<100C) and normal pressure, hexagonal crystal zirconium phosphate(α-ZrP) was quickly prepared using ZrOCl2·8H2O, NH4F and H3PO4as raw materials bymicrowave-assisted method. The influence of molar ratio of NH4F and ZrOCl2·8H2O, molar ratioof H3PO4and ZrOCl2·8H2O, reaction time and microwave heating temperature on the crystal formof α-ZrP were studied. The result shows that the ratio of NH4F and ZrOCl2·8H2O, the molar ratioof H3PO4and ZrOCl2·8H2O, reaction time and microwave heating temperature have littleinfluence on the crystal form of α-ZrP. The crystallinity and morphology of α-ZrP were significantinfluenced by the mentioned condition. The result shows that hexagonal crystal α-ZrP can beprepared quickly by controlling the appropriate reaction conditions. Zirconium phosphate is a kind of semiconductor which has the photocatalytic activity. It canbe inserted to get the multi-functional composite materials. So it has good application prospect inthe photocatalytic degredation of dye. Photocatalytic activity of α-ZrP powder was evaluatedusing Rhodamine B as simulative dyeing wastewater. The α-ZrP powder exhibited goodvisible-light activity for photodegradation. In order to further improve the photocatalyticperformance of zirconium phosphate powder, it was succeed to get P25-doped α-ZrP namedP25-ZrP composite materials. P25doping ratio, catalyst dosage, pH, exposure time and the initialconcentration of dyes were studied to assess the activity of photocatalyst. It showed that the P25doping ratio, catalyst dosage, pH, exposure time and initial concentration of dyes had greatinfluence on the photocatalytic properties of P25-ZrP composite materials powder. Compared withundoped α-ZrP, the photocatalytic activity of P25-ZrP has increased significantly. P25-ZrP withdoping ratio of P251:6has the highest photocatalytic activity. The best degradation condition forRhodamine B (6×10-5mol/L) is: initial pH4, exposure time3h, and the dosage of P25-ZrP1:6powder3.6g/L.In conclusion, this eco-friendly microwave-assisted process could fast synthesize α-ZrP withsimple operation and low energy cost. The application of zirconium phosphate in the field ofphotocatalysis was further discussed. It would outlook that the microwave-assisted method wouldenlarge the application of α-ZrP and is possible to promote industrialization in the future.