Microwave-assisted Preparation Of Zirconium Phosphate Composites And Application In The Visible Photocatalysis Of Dyeing Wastewater

Photocatalytic technology can convert the sunlight into chemical energy and electricity,which can degrade kinds of pollutants in water directly.This technology has many advantages,such as low cost,no pollution,no selection,recyclingand so on.It is a simple and convenient method to degrade the dyeing wastewater by photocatalytic technology.However,the common photocatalysts are the wide bandgap semiconductor materials,which only have photocatalytic property under ultraviolet light.Importantly,the preparation of visible photocatalyst becomes the core issue in the field of photocatalysis.The preparation by microwave-assisted method and visible photocatalytic properties of nickel zirconium phosphate（Ni Zr P）and manganese zirconium phosphate（Mn Zr P）were investigated.In this paper,nickel zirconium phosphate and manganese zirconium phosphatewere successfully prepared with Zr OCl₂,NH₄ F,Na H₂PO₄,Ni Cl₂（or Mn Cl₂）and various surfactants in a certain reaction temperature and p H by microwave-assisted method.The influences of phosphorous source,ratios and concentration of reactants,reaction p H,reaction temperature and three kinds of surfactants（PVP-K30,CTAB and SDS）on the preparation of nickel zirconium phosphate and manganese zirconium phosphate were studied.The structure and morphology of the composites were characterized with various techniques,such as XRD,ICP,XPS,SEM（or FESEM）,TG and UV-Vis,etc.The reaction conditions of nickel zirconium phosphate were Zr OCl₂:Ni Cl₂:NH₄F:Na H₂PO₄ =1:1:6:20,[Zr4+]=0.005 mol/L,T=90℃ and t=30 min.Nickel zirconium phosphates with the better morphologies were prepared under the dosage of PVP-K30 at 0.59 g,CTAB at 0.04 g or SDS at0.29 g.The phosphorus source,ratios and concentration of reactants,reaction p H were the crucial factors of the preparation of nickel zirconium phosphate.When phosphorus source and p H changed,the morphologies of products were amorphous.The morphologies and compositions of products changed according to the molar ratios of Zr/Ni,Zr/P and F/Zr: the product was Ni Zr Pwith a spherical mixtureassembled from flakes at Zr/Ni>3;the morphologies of products were amorphous at Zr/P<10;the product was nickelphosphate at F/Zr>10.The morphologies of products were amorphous,when concentration of reactants was increased.The reaction temperature and surfactants affected the particle size,degree of uniform and the morphology of nickel zirconium phosphate.When reaction temperature was increased,the products had the better morphologies.After adding surfactants,the average size of particles decreased.Compared with SDS,PVP-K30 and CTAB had the stronger inhibition ability of growth of products.Manganese zirconium phosphates with different morphologies were prepared using PVP-K30,CTAB or SDS as template.The reaction conditions of manganese zirconium phosphate were Zr OCl₂:Mn Cl₂:NH₄F:Na H₂PO₄=1:1:6:20,T=90℃ and t=30 min,0.55 g PVP-K30,0.04 g CTAB or0.29 g SDS.With PVP-K30 as template,manganese zirconium phosphate was a sphere assembled from flakes.With CTAB as template,manganese zirconium phosphate was a aristate sphere.With SDS as template,manganese zirconium phosphate was a sphere assembled from flakes.The visible photocatalytic properties of nickel zirconium phosphate and manganese zirconium phosphate were carried out in wastewater of Rh B or MB under ligh.The UV/VIS absorbance was used to calculate the degradation rate of the dye.The results showed that the ratio of visible photocatalysis of MB was up to 49.0% using nickel zirconium phosphate as photocatalyst,while that of Rh B was up to 11.3%.Nickel zirconium phosphate has the better photocatalytic property to MB than that of Rh B,which might be because the difference of the molecule structure.The MB moleculeis smaller than Rh B,and this would benefit the adsorption of MB.Through catalytic mechanism discussion,·OH,h⁺ and ·O₂^-were the active substances that were involved in the degradation of dye.·OH was the key active substance in visible photocatalysis.As for manganese zirconium phosphate,the ratio of visible photocatalysis of Rh B was up to 18.0%.In short,both nickel zirconium phosphate and manganese zirconium phosphate had the visible photocatalytic properties.In conclusion,nickel zirconium phosphate and manganese zirconium phosphate were prepared by microwave-assisted method and were used to photocatalytic degradate Rh B and MB under visible light.The preparation of metal zirconium phosphate complex salt by microwave-assisted method would provide a reference for the synthesis of related materials.