聚醚酰亚胺功能化磁性纳米微球吸附富集及测定水中痕量镉

Adsorption,concentration and determination of trace cadmium in water by polyetherimide modified magnetic microspheres

利用聚醚酰亚胺修饰纳米磁性微球,制备了一种磁性纳米吸附材料,将其作为固相萃取吸附剂用于富集水体中的痕量镉Cd（Ⅱ）离子,并通过等离子电感耦合发射光谱法测定.利用透射电子显微镜（TEM）、傅里叶变换红外光谱（FIIR）和热重分析仪（TGA）对材料进行了表征,并考察了吸附剂对Cd（Ⅱ）离子的吸附性能,研究了溶液pH值、吸附时间、饱和吸附量、干扰离子、洗脱条件等因素对吸附性能的影响.结果表明,当水样的pH值为5时,振荡吸附15 min达到平衡,饱和吸附容量为5.61 mg/g.吸附在磁性纳米材料上的Cd（Ⅱ）离子可用5 mL 1.0 mol/L盐酸溶液完全洗脱,然后用等离子电感耦合发射光谱法测定此洗脱液中Cd（Ⅱ）离子的含量.将该方法用于环境水样中痕量Cd（Ⅱ）离子的吸附富集和测定,加标回收率在95.3％ ～97.8％之间.

The polyetherimide（PEI） was chemically grafted on the suriace of magnetic mlcrospnere Fe3O4 @ SiO2 and the novel magnetic sorbent was used as a valuable solid-phase extraction adsorbent for the preconcen- tration of trace Cd （ Ⅱ ） ion prior to its determination by ICP-OES. The resulting material was characterized by FT-IR, TGA, and TEM. Various factors affecting the separation and preconcentration were investigated, such as pH of sample solution, adsorption time, adsorption capacity, interfering ions and eluent. In an aqueous medium of pH = 5 and after shaking for 15 min to achieve equilibrium of adsorption, the resulting material exhibited strong affinity to Cd（ Ⅱ ） ion and the maximum adsorption capacity of Cd（ Ⅱ ） ion was calculated to be 5.61 mg/g. The new adsorbent shows superior reusability and stability. The procedure was successfully applied to the determination of trace quantities of Cd（ Ⅱ ） in water samples, giving results of adding standard recovery in the range of 95.3% -97.8%.