中文摘要：

利用共沉淀法和巯基化表面修饰制备Fe3O4纳米吸附材料,并将其应用于海水中痕量汞检测的富集和分离前处理过程.所制备的巯基化Fe3O4纳米颗粒的粒径小于100 nm,饱和磁化强度达63.64 emu·g-1,巯基含量为3.11 mg·g-1.当巯基化Fe3O4的用量为0.5 mg·m L-1、吸附溶液p H值为7.5—8.0、吸附时间为20min时,吸附剂对汞的富集率可达95%以上,并且在外磁场作用下可快速分离.在优化的吸附条件下并借助原子荧光光谱法测定了实际海水样品中汞离子的含量,加标回收率在89.8%—107.3%之间,11次空白样品测量的检出限（3σ）为5.3 ng·L-1.该方法利用巯基化Fe3O4纳米材料具有高效富集的特点,可应用于海水中痕量汞的快速富集和分离,以实现对海水中痕量汞的准确测量.

英文摘要：

The nano-Fe3O4 particles were prepared through co-precipitation method,followed by surface thiolation. As an adsorbent they were employed in the enrichment and separation pretreatment for the trace analysis of mercury in seawater. The as-prepared thiol-functionalized nanoFe3O4particles（ nano-SH-Fe3O4）,with an average diameter below 100 nm and the content of mercapto group about 3. 11 mg·g- 1,show quick response to the external magnetic field for its saturation magnetization as high as 63. 64 emu·g- 1. Under the optimal conditions including the amount of 0. 5 mg·m L- 1adsorbent,the p H value of 7. 5—8. 0 and the adsorption time of 20 min,the nano-SH-Fe3O4 have an enrichment ratio up to 95% for mercury ions,Furthermore they are easily and rapidly separated by a magnet. We achieved the trace determination of mercury ions in seawater with atomic fluorescence spectrometry after the enrichment under the optimum adsorption condition. The recoveries are within 89. 8% —107. 3% and the detection limit（ 3σ） for 11 blank samples is 5. 3 ng·L- 1. In this method,nano-SH-Fe3O4 particles,with the ability of high efficient enrichment and rapid separation by external magnetic field,can be applied in the enrichment and separation of trace mercury ions in seawater for the subsequent accurate determination.