Prepraration, Characterization And Eleccatalytic Performance Of FePMo₁₂

Dye wastewater has the characteristic of complicated composition, low biochemcial degradability, chromaticity and great toxicity, which ususlly have been considered as one of the problem of wastewater treatment. Polyoxometallates(POMs) with strong acidity can be used as bifuncational catalysts in the catalytic field. However, POMs suffer from some shortcomings, such as the small surface area and low thermal stability. These drawbacks greatly limit their applications in the industry field. Therefore, the experiment was designed to preparation of supported and efficient POMs catalyst. The POMs catalyst was used to enhance the electrochemical oxidation dye wastewater in this paper. The results are described as followings:1) Three-dimensional electrode catalytic oxidation system. FePMo12/APTES-4A was characterized by X-ray diffraction(XRD), Fourier transform infrared(FT-IR) spectroscopy and X-ray fluorescence(XRF). The heteropolyanion showed a Keggin structure. Orthogonal experimental design, univariate analysis and response surface methodology were used to optimize the technological conditions for decolorization of acid red 3R(AR3R). The decolorization efficiency reached 84.28% under the operating condition as the follows: electrolytic voltage 20.0V, air-flow 0.10m3?h-1, electrode span 3.0cm, initial pH 4.0. The sequence of significant factors to decolorization efficiency was: electrolytic voltage>air-flow>electrode span>pH. Significant interactions existed between electrolytic voltage and air-flow, electrolytic voltage and electrode span, air-flow and pH, electrode span and pH alternation. UV-vis and LC-MS were used to identify the degradation pathway and intermediate products.2) Electrocatalysis system. A FePMo12-SiO2 hollow sphere porous structure was fabricated using tea pollen as a biotemplate via an aqueous sol-gel soakage process followed by calcination. The as-prepared FePMo12-SiO2 was characterized by scanning electron microscopy(SEM), X-ray diffraction(XRD), Fourier transform infrared(FT-IR) spectroscopy and specific surface area test. The spectra of XRD and FT-IR illustrated that the Keggin-type structure of FePMo12-SiO2 was retained. Specific surface area test results showed that the specific surface area of FePMo12-SiO2 was 101.08m2?g-1 and 11 times than that of FePMo12. Subsequently, cyclic voltammetry and electrochemical impedance spectroscopy(EIS) techniques were used to investigate the electrochemical behavior of the FePMo12-SiO2/GCE. The results indicated that the electroactive coverage(Γc) of FePMo12-SiO2/GCE was 2.08×10-9 mol?cm-2. The property of FePMo12-Si O2/GCE exhibited a reversible process and a mainly surface-controlled process. The FePMo12-SiO2/GCE exhibited good long-term stability and high electrocatalytic activity toward AR3 R. Comparative experiments revealed that the FePMo12-SiO2 could enable better catalytic capability. Electrocatalytic oxidation of AR3 R underwent a three-step irreversible process.In this work, the three-dimensional electrochemcial system had good effect on degradation of dye wastewater. POMs catalytic material via biomimetic synthesis technology exhibited the higher performance. The modified electrode exhibited high electrocatalytic activity toward dye. In conclusion, POMs has the wide development prospect in the electochemisty field.