磁性催化剂制备及其在臭氧催化氧化+磁分离工艺中的研究

Preparation of magnetic catalyst and its application in ozone catalytic oxidation combined with magnetic separation process

以粉末活性炭(PAC)为载体,通过改进一种简易、可大批量生产的方法,制备出新型磁性催化剂(Y_(x)Fe_(3-x)O_(4)/PAC)。采用SEM、XRD、BET、FT-IR、VSM等表征方法对新制备的磁性催化剂进行分析,结果显示,该类磁性催化剂具有微小颗粒状、质量轻、负载过渡金属元素均匀、比表面积大(624.33 m^(2)/g)、介孔结构(平均孔径为3.20 nm)、富含表面羟基基团以及超顺磁性易于磁回收(饱和磁化强度为13.26 emu/g)等特点。通过研究臭氧催化氧化结合磁分离工艺去除亚甲基蓝(MB)效果实验发现,当x=0.3时,磁性催化剂(Y_(0.3)Fe_(2.7)O_(4)/PAC)具有最佳的吸附、催化氧化效果,且重复性和稳定性好;当重复使用5次后,其MB吸附去除率稳定在37.9%,催化氧化去除速率约是单独臭氧氧化的1.7倍;同时,当外加磁场强度大于0.2 T时,磁性催化剂回收率可大于98%,利用超磁分离设备即可将其回收。

In this paper,a new type of magnetic catalyst(Y_(x)Fe_(3-x)O_(4)/PAC)was prepared by improving a simple and mass production method based on PAC.SEM,XRD,BET,FT-IR,VSM and other characterization methods were used to analyze the newly prepared magnetic catalyst.The results showed that the magnetic catalyst had the characteristics of small,granular,light weight,uniform load of transition metal elements,large specific surface area(624.33 m^(2)/g),mesoporous structure(average pore size 3.20 nm),rich in surface hydroxyl groups,and easy magnetic recovery(saturation magnetization 13.26 emu/g).By investigating the removal effect of MB by ozone catalytic oxidation combined with magnetic separation process,it was found that when x=0.3,the magnetic catalyst(Y_(0.3)Fe_(2.7)O_(4)/PAC)had the best adsorption and catalytic oxidation effect,and had good repeatability and stability.When the magnetic catalyst was repeated for 5 times,the MB adsorption removal rate was stable at 37.9%,and the catalytic oxidation removal rate was about 1.7 times that of ozonation alone.At the same time,when the applied magnetic field strength was greater than 0.2 T,the recovery rate of the magnetic catalyst could be more than 98%,which could be recovered by using the super-magnetic separation equipment.