Research On The Effect Of Using MgMn₂O₄ Spinel To Catalyze Sodium Periodate For The Degradation Of Bisphenol A In Water

In order to degrade bisphenol A effectively,which is the endocrine disrupting compound pollutant in water,and to provide a theoretical basis for the future removal of other possible inorganic and organic pollutants in the water,a novel method of activating periodate oxidation in advanced oxidation processes was used in this research.In this study,we used spinel oxide catalyst to activate periodate,established a catalytic oxidation system,explored influencing factors and oxidation mechanism,clarified usage efficiency,stability of catalyst,and practical application capabilities.Firstly,a variety of different spinel-phase and non-spinel-phase catalysts were synthesized to explore their catalytic efficiency in the degradation of bisphenol A by periodate,and the leaching metal ion was tested by ICP-AES metal ion dissolution concentration test.The materials were characterized by XRD,XPS,FT-IR,SEM,TEM,BET,p Hzpc,etc.MgMn₂O₄ containing Mn³⁺could degrade bisphenol A most efficiently.The doping of Mg element suppresses the growth of crystal grain size,improves the dispersibility of Mn and increases the specific surface area.The pure MgMn₂O₄ spinel oxide prepared under the condition of Mg:Mn=1:4 has higher efficiency,less metal leaching and the best catalytic performance.The average particle size is 33.87±5.31 nm,showing a mesoporous structure.The BET specific surface area is 36.1775 m²/g and the p H_zpc is 3.632.Secondly,the MgMn₂O₄/Na IO₄ catalytic oxidation system was established to degrade bisphenol A from water.We discussed the effects of different factors on the performance of above-mentioned system for bisphenol A degradation.As for confirming radicals and non-radicals,ESR,radical quenching experiment,DO control and other methods were applied to analyze the main oxidation active substances in the system and speculate the mechanism of activating periodate via heterogeneous catalysis.It is clear that MgMn₂O₄ has the ability to activate periodate.The MgMn₂O₄/Na IO₄ system can degrade 96.17±0.97%of bisphenol A and remove 31.35±3.16%of TOC with 0.1 g/L catalyst and 1 mmol/L sodium periodate.And the reaction conforms to the Arrhenius formula.It was found that PO₄^3-,HCO₃^-,CO₃^2-have an inhibitory effect on BPA degradation,SO₄^2-has a slight increase on system efficiency.It is identified that the system contains ¹O₂ as a highly oxidizing active substance and there must be other oxidizing active substances involved in the degradation of bisphenol A.Finally,the stability of the MgMn₂O₄ catalyst was tested by 10 times recycle experiments under different conditions.We used XRD,XPS and ICP-AES metal ion dissolution test to investigate the structural stability of the material and combined tap water and river water to carry out the bisphenol A degradation in real water.Besides,we took out and dried the MgMn₂O₄ catalyst to regenerate the catalyst.The degradation of bisphenol A can be maintained above 92%after repeating use for 10 times,which is much higher than the degradation of 78.95%after 10 times of continuous use.After 10 times repeating experiments,the material maintains a good spinel crystal phase,and the leaching of Mg and Mn is less than that of 10 times of continuous use.The degradable bisphenol A in tap water is 53.42±2.70%and the removal of TOC is 12.92±3.30%.The degradable bisphenol A in river water is 44.59±3.98%and the removal of TOC is 9.09±2.33%.The efficiency of the system will be inhibited in real water bodies because the natural TOC substances in real water bodies will become competitive pollutants of bisphenol A,and there are substances in the complex system of real water bodies that inhibit the catalytic oxidation system.The research provides new ideas for the advanced oxidation method of activating periodate,explores the mechanism between periodate and spinel,and offers a theoretical basis for the application in actual water bodies.