Amino-functionalized core-shell magnetic mesoporous composite microspheres for Pb(Ⅱ) and Cd(Ⅱ) removal

Amino-functionalized Fe3O4@mesoporous SiO/ core-shell composite microspheres NH2-MS in created in multiple synthesis steps have been investigated for Pb（Ⅱ） and Cd（Ⅱ） adsorption. The microspheres were characterized by transmission electron microscope （TEM）, scanning electron microscope （SEM）, N2 adsorption-desorption, zeta potential measurements and vibrating sample magnetometer. Batch adsorption tests indicated that NH2-MS exhibited higher adsorption affinity toward Pb（Ⅱ） and Cd（Ⅱ） than MS did. The Langmuir model could fit the adsorption isotherm very well with maximum adsorption capacity of 128.21 and 51.81 mg/g for Pb（Ⅱ） and Cd（Ⅱ）, respectively, implying that adsorption processes involved monolayer adsorption. Pb（Ⅱ） and Cd（Ⅱ） adsorption could be well described by the pseudo second-order kinetics model, and was found to be strongly dependent on pH and humic acid. The Pb（Ⅱ）- and Cd（Ⅱ）-loaded microspheres were effectively desorbed using 0.01 mol/L HC1 or EDTA solution. NH2-MS have promise for use as adsorbents in the removal of Pb（Ⅱ） and Cd（Ⅱ） in wastewater treatment processes.

F_(17)-Fe_3O_4@mSiO_2磁固相萃取GC-MS测定水中全氟羧酸

合成了全氟癸基功能化磁性介孔氧化硅微球(F_(17)-Fe_3O_4@mSiO_2),材料具有很好的水溶液分散性,能选择性富集全氟化合物,易分离、可重复使用等特点。以其为固相萃取材料、结合GC-M S方法建立了检测水中全氟羧酸的新方法。考察了磁性F_(17)-Fe_3O_4@m SiO_2用量、洗脱剂的类型和体积、萃取和洗脱的时间等参数的影响。在优化的实验条件下,方法的检出限为0.045~0.078μg/L,线性范围0.2~2000μg/L,相关系数大于0.998,相对标准偏差3.7%~7.2%。将方法应用于环境水中5种全氟羧酸的分析,回收率在95.6%~108.1%之间。