Preparation Of Magnetic Nano Catalyst And Performance Of Catalytic Fenton Oxidation To Degrade Dye

Dye wastewater has the characteristics of high chromaticity,consists of complex components and difficult biochemical degradation.It has the impact of teratogenesis,carcinogenesis and mutagenesis on organisms,which will cause the serious environmental pollution and health risk.Fenton oxidation process has got exensive attention in the treatment of dye wastewater because of its advantages.While,the application of traditional Fenton catalyst is limited by the disadvantages which include the narrow pH range of application,low utilization rate of hydrogen peroxide?H₂O₂?and bad reuse ability.Therefore,the study of efficient and segregative Fenton catalyst is particularly important.In this paper,three nano materials named Hollow Fe₃O₄,Fe₃O₄@SiO₂@KCC,Fe₃O₄@NiSiO₃ respectively were synthesized and characterized.Dyes that rodamine B,acid scarlet 3R,methyl orange,methylene blue,malachite green were used as target pollutants to study on the Fenton catalytic performance of these three nano-materials and the degradation kinetics.The results of experiments are as follow:1)The hollow Fe₃O₄ nano particles were synthesized by template method and catalyzed Fenton reaction whose optimal reaction conditions are initial reaction pH=3.0,1.00 g·L^-1 of catalyst dosage and 7.5%H₂O₂ dosage.After 5 h reaction,the degradation efficiency of all dyes reached over 85%.The H₂O₂ and pollutants could diffuse into the inside of hollow Fe₃O₄ through the unique holes in the structure of hollow Fe₃O₄ and Fenton reaction occurred both inside and outside of the catalyst.The degradation process matched with the first order reaction kinetics and the activation energy was 43.52 kJ·mol^-1.2)The Fe₃O₄@SiO₂@KCC nano particles were synthesized by solvothermal method and sol-gel method,and catalyzed Fenton reaction whose optimal reaction conditions are no adjusting pH,1.00 g·L^-1of catalyst dosage and 5.0%of H₂O₂ dosage.After 100 min reaction,the degradation efficiency of all dyes except the azo-dye reached over 90%.The degradation efficiency of rhodamine B was used as the evaluation index,and was stable at90%after reusing 5 times.The magnetic separability and recycling of Fe₃O₄@SiO₂@KCC were good.Comparing to the hollow Fe₃O₄,the heterogeneous Fenton system catalytic by yolk-shell Fe₃O₄@SiO₂@KCC broadens initial reaction pH,has better catalytic activity and faster reaction rate.3)The synthesized Fe₃O₄@NiSiO₃ nano particles were used as heterogeneous Fenton catalyst to degrade different kinds of dyes.The optimal reaction conditions are no adjusting pH,1.00 g·L^-1of catalyst dosage and 2.5%of H₂O₂ dosage.After 100min reaction,the degradation efficiency of all dyes except the azo-dye reached over 95%.The degradation efficiency of rhodamine B was used as the evaluation index,and was stable at95%after reusing 5 times.The Fe₃O₄@NiSiO₃ have good magnetic separability and recycling ability.Comparing to the Fe₃O₄@Si O₂@KCC,the heterogeneous Fenton system catalytic by yolk-shell Fe₃O₄@NiSiO₃ has higher reaction efficiency and better reaction activity.Indicating that the nickel element among the nano particles can promote the Fenton reaction.