Study Of Treating Wastewater By Attapulgite Clay Immobilized Horseradish Peroxidase

Attapulgite clay immobilized horseradish peroxidase was successfully prepared,the effects of the vector formulation,immobilization conditions and reaction conditions are studied, the optimal conditions for the preparation of the carrier, enzyme immobilization and reaction conditions are determined through the orthogonal experiments. The optimal conditions for HRP immobilization, nitrophenol degradation reaction, the repeatability of immobilized HRP are also investigated through single factor parallel experiments. the kinetic parameter of degradation of aniline and nitrophenol by immobilized HRP, the maximum response velocity and michaelis constant (Km) by Lineweaver-Burk linear fitting between the initial concentration of nitrophenol and response velocity are investigated.The results shows when the amount of mass ratio of attapulgite clay : sodium silicate: soluble starch are 100:12:20,the calcination temperature of 550℃and the calcination time of 2 h, we can get carriers holding the best absorption properties. The optimal technological parameters for HRP immobilization are PH = 5.0,the volume of unit vector activity of the 1.5 mg/U and the immobilized 1.5 h at room temperature.When non-adjust PH, the reaction time is 1.5 h, 100 mg/L of aniline need 4.8 U enzyme activity, the molar ratio is H₂O₂ and aniline is 1.2, the immobilized HRP can be reused for 4 times and aniline degradation efficiency maintain over 90%.In the meantime, when non-adjust PH, the reaction time is 1.5 h, 100 mg/L of nitrophenol need 6.0 U enzyme activity, the molar ratio is H2O2 and nitrophenol is 1.2,t he immobilized HRP can be reused for 7 times and nitrophenol degradation efficiency maintain over 60%.The kinetic equation is 1/v = 1.403/[S] - 0.081, the Vmax and Km are 12.35 mg/L·min,and 17.32 mg/L, respectively.