A kind of silica-coated magnetic nanomaterials modified with l-octyl-3-methylimidazolium hexafluorophosphate([OMIM] PF6 ) was prepared, and characterized by scanning electron micro-scope (SEM), Fourier transform infrared spectroscopy (FT - IR), vibrating sample magnetometer (VSM) and thermogravimetric analyzer(TGA). The synthetic material(Fe3O4 - SiO2 - IL) showed a good acid resistance. The adsorption behavior of cadmium ion onto Fe3O4 - SiO2 - IL was tested, and it was found that the equilibrium adsorption followed Langmuir isotherms well. Based on this, a new method for separation and preconcentration of Cd2+ in aqueous solution was developed by using modified silica-coated magnetic nanoparticle as the sorbent and flame atomic absorption spectrometry (FAAS) as detector. Effects of some factors on recovery of Cd2+ were investigated. The optimum conditions were as the follows: pH 6. 0; eluent: 1 mol/L HC1; oscillation time: 10 min; standing time; 20 min. Under the optimized conditions, the limit of detection(LOD) for Cd2+ was 0.2 μg/ L, and relative standard deviation( RSD, n =6) for 15μg/L Cd2+ was 2. 5% . The proposed method was applied in the determination of Cd2+ in river and lake water with spiked recoveries of 84% -100% .%以四氧化三铁( Fe3O4)为载体包覆二氧化硅涂层,用1-辛基-3-甲基咪唑六氟磷酸盐([OMIM] PF6)负载修饰,制备了一种功能化磁性纳米材料,采用扫描电镜、傅立叶变换红外光谱仪、振动样品磁强计和热重分析仪对材料进行表征.材料显示出良好的耐酸性,其对镉离子的吸附符合Langmuir方程.将该材料用作固相萃取吸附剂萃取富集水中的痕量镉离子,之后用火焰原子吸收法测定,建立了一种分离富集和检测Cd2的新方法.实验考察了水样酸度、吸附剂用量、振荡和静置时间、洗脱剂及共存离子等对Cd2+回收率的影响.结果显示,在pH6.0、振荡10 min、静置20 min条件下,该材料对Cd2具有较好的吸附性,用1 mol/L盐酸可完全洗脱.在优化实验条件下,方法对Cd2+的检出限为0.2 μg/L,对15μg/L Cd2+测定结果的相对标准偏差( RSD,n=6)为2.5％.对河水和湖水样品中的Cd2+进行检测,加标回收率为84％～100％.
展开▼
