摘要
通过溶胶-凝胶法制备了 NiFe2O4/硅藻土复合型催化剂(NFD),以甲基橙(MO)为目标污染物,研究NFD活化过硫酸盐(PMS)降解MO的机制,探究了 NFD解决NiFe2O4金属团聚与金属溶出问题.通过SEM、XRD、FT-IR、XPS表征了 NFD的结构与性能.探究了不同催化体系、NFD质量浓度、PMS质量浓度、pH、阴离子种类对NFD+PMS体系的影响.结果表明,硅藻土表面负载的颗粒为NiFe2O4且均匀分散,减少了 NiFe2O4团聚问题,且反应体系中Fe2+/Fe3+、Ni2+/Ni3+价态的循环转化参与了 PMS的活化;NFD+PMS体系在NFD质量浓度为0.10 g/L、PMS质量浓度为0.25 g/L、MO质量浓度为30 mg/L、pH为7、反应温度为30℃、反应时间为60 min的条件下,对MO的降解率为98.76％;NFD+PMS体系的pH适用范围为5～9,受无机阴离子影响小,且体系会产生·OH、SO4-·、1O2、·O2-4种活性物质;反应后金属溶出大幅减少.
Abstract
NiFe2O4/diatomite composite catalyst(NFD)is prepared via Sol-gel method.Taking methyl orange as the target pollutant,the mechanism for NFD activated peroxymonosulfate(PMS)in degrading methyl orange is studied,and it is explored to solve the problems of NiFe2O4 agglomeration and dissolution in NFD.The structure and performance of NFD are characterized by means of SEM,XRD,FTIR,and XPS.The influences of different catalytic systems,NFD mass concentration,PMS mass concentration,pH,and anion species on NFD+PMS system are explored.Results show that the particles loaded on diatomite surface are NiFe2O4 that disperses evenly,which reduces NiFe2O4 agglomeration problem.Moreover,the cyclic transformation of Fe2+/Fe3+,and Ni2+/Ni3+valence states in the reaction system involve in the activation of PMS.The degradation rate of methyl orange can reach 98.76％in NFD+PMS system when the mass concentrations of NFD,PMS and methyl orange are 0.10 g·L-1,0.25 g·L-1,and 30 mg·L-1,respectively,pH=7,reaction temperature is 30℃,and the reaction time is 60 min.The application scope of pH of NFD+PMS system is 5-9.The system is less affected by inorganic anions,and the system will generate 4 active substances including OH,SO4-·,1O2,and O2.Metal dissolution declines greatly after the reaction.
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