Synthesis And Photocatalytic Properties Of Heteropoly Salt Doped Polyaniline

Six polyaniline hybrid material doped with mono-substituted Keggin structure heteropoly salt were prepared by solid-state synthesis method.The structure and appearance of doped materials were characterized by UV-Vis,IR spectroscopy,X-ray diffraction(XRD),fluor- escence spectrum, thermogravimetric analysis and scanning electron microscopy. Conductivity and water-soluble of materials were measured.The results showed that heteropoly acid doped polyaniline materials were constituted by positively charged polymer chain of polyaniline and negatively charged heteropolyanion. Synthetic doped materimals showed good thermal stability and conductivity. Conductivity of doped materials changed significantly,the best conductivity of the doped materials is 100 S/cm at room temperature(25℃). It meets the needs of the conductor.The images of scanning electron microscopy (SEM) show that the materials have flake, hollow sphere, microtube shape.In this paper,doped materials photocatalytic degradation of organic dyes had been investigated. The influence factors of photocatalytic degradation of congo red,gentian violet and methylene blue had been studied. Influence factors such as the amount of catalyst ,initial pH of solution, initial concentration of solution and light source.As a result,acidic conditions are conducive to the degradation of congo red,neutral conditions are favorable for the degradation of gentian violet,alkaline conditions are favorable for the degradation of methylene blue.Optimal condition of doped materials for degradation of dyes were found.Under optimal condition,the 30W UV lamp as light source,α-SiW₁₁Ti/PANI as photocatalyst, light 120min,9mg/L congo red decolorization rate was 91.18%;Respectivelyβ₂-SiW₁₁Ti/PANI(S),β₂-SiW₁₁Ti/PANI(L),SiMo11Ti/PANI,PW₁₁Ti/PANI,PMo11Ti/PANI as the catalyst, ultraviolet light 10mg/L congo red 150min,the decoloration rate of congo red were 73.51%,75.16%,85.7%,75.7%,82.8% . Sunlight exposure to 10mg/L congo red 150min, decolorization rates of congo red were 77.43%,77.64%,68.4%,77.0%,80.8% . Photocatalytic degradation of gentian violet in the best condition, respectivelyβ₂-SiW₁₁Ti/PANI(S),β₂-SiW₁₁ Ti/PANI(L) as the photocatalyst,UV light 150min,decolorization rates of gentian violet were 93.53% and 90.41%;after sunlight 150min, decolorization rates of gentian violet were 96.32% and 91.52% .Under optimal condition of photocatalytic degradation of methylene blue,β₂-SiW₁₁Ti/PANI(S) as photocatalyst,respectively sunlight and UV as light sourse,after irradiation 150min,decolorization of methylene blue were 98.47% and 93.98%.The photocatalytic decolorization of the dyes by heteropoly salt doped polyaniline were abided by secondary or tertiary kinetics. Photocatalytic possible mechanism was studied finally.