Efficiency Of Catalytic Ozonation For Removal Of Organotin Compounds In Drinking Water

Among the currently known endocrine disruptors,Organotin compounds are the only metal compounds one,and also be one of the most poisonous chemicals that artificially introduces into the water environment.They have been polluting our environment for more than 50 years.The existing water treatment process is difficult to effectively remove them,so the catalytic ozonation process was applied to treat organotin compounds in drinking water.In this paper,MBT,DBT and TBT were chosen as the research objects,and the organotin was detected by liquid-liquid extraction and gas chromatography-mass spectrometry.Zero valent iron and iron oxyhydroxide were investigated as catalysts The main factors affecting the ozone oxidation of organic tin,the main work and research results are as follows:First,iron oxyhydroxide is prepared,and then the zero-valent iron and iron oxyhydroxide are respectively used as catalysts to catalyze ozone oxidation to remove organotin in water.In the process of catalyzing,the removal efficiency of organotin is mainly affected by such factors as catalyst dosage,ozone dosage,solution p H,reaction temperature and radical inhibitor,and the related kinetic parameters are determined.In the process of zero valent iron as the catalyst,the ozone dosage was 2.0mg / L and 4.0mg / L,respectively at the initial concentration of three organotin were 500?g / L,p H value was6.8 and the temperature was 20 ± 1 ?.L,4.0mg / L,zero-valent iron dosage 100 mg / L,125 mg / L and75 mg / L,the removal efficiency of three organotin was the best,MBT,DBT,TBT removal rates were 95.86%,78.05 % and 63.72%,respectively.During the course of using iron oxyhydroxide as catalyst,the dosage of ozone was 2.0mg / L and the dosage of iron oxyhydroxide was 100 mg / L.The removal efficiency of three kinds of organotin was the best,MBT,The removal rates of DBT and TBT were 98.19%,97.31% and 99.95%respectively.(1)The temperature in the reaction solution can affect the reaction activation energy and the solubility of ozone in water,so there is the most suitable reaction temperature for the removal of organotin compounds by catalytic ozonation..(2)Through the study of p H value and · OH radical inhibitor tert-butanol,it was found that zero valent iron and iron oxyhydroxide respectively catalyzed the ozone oxidation to remove organotin by the action of · OH radical.(3)Although HCO3-improve the pH value in water,the role of HCO3-inhibiting free radical generation is dominant.(4)Catalytic ozone oxidation Degradation of Organotins are achieved by demethylation.The removal efficiency of TBT is the worst,which may be due to the TBT with a larger number of butyl than MBT and TBT,the structure is relatively stable,so TBT is difficult to be degraded.(5)The reaction rate constants of OH radicals with MBT,DBT and TBT were 3.68 ×1010,2.91 × 1010 and 1.79 × 1010,respectively.