纤维基多齿配体重金属离子印迹材料的制备及在固相萃取中的应用

Heavy metal contamination has endangered the ecological environment and human health. It has played an important role in pollution control to determine the concentration of heavy metal at trace levels accurately and quickly. Although with the development of instrumental analysis method, the concentration of heavy metal ions can be determined accurately at trace or ultratrace levles. However, it is difficult for complex sample to analyze directly with the instrument due to the existence of matrix effects and interfering ions. Fiber-in-tube solid phase extraction(SPE) method, in which fibrous adsorbents was packed in a tube as SPE, can realize automatic operation combined with analysis instrument. It is an efficient, reliable and on-line sample preparation method. The extraction materials of SPE is the key issue in the sample preparation method. The objective of this project is to improve the adsorption quantity, selectivity and mass transfer rate of extraction materials, the design and preparation of extraction materials is the important portion. In view of the adsorption properties of fiber, the inorganic particals and iminodiacetic acid will introduce to the surface of PTFE fibers. The fibous surface ion imprinted materials will be prepared by coupling the cross-linking reaction with sol-gel technique using Pb(II) or Cd(II) as templet ions, the prepared organic-inorganic materials containg multidentate ligand as ligand. The mechanism of adsorption and selectivity will be studied, and the quick enrichment of heavy metal at trace levels in complex matrix will be realized. The implementation of this project will have better scientific significance on detection of heavy metal pollutants. It is the supplement in developing of extraction materials of heavy metals.

重金属污染已经严重危害到生态环境和人类的健康，如何快速准确的进行痕量重金属污染指示在污染控制上起着重要作用。尽管目前仪器分析方法的发展己经可以测定痕量甚至超痕量水平重金属，然而对于复杂样品，由于基体效应和干扰物质的存在，直接分析仍很困难。纤维管内固相萃取法是一种可以和仪器连用实现自动化操作的固相萃取技术，可高效、可靠、在线的进行样品前处理。本项目从该技术的核心萃取材料设计与合成入手，以提高材料的吸附量、选择性和传质速率为目标，拟以聚四氟乙烯纤维为基材，制备的含有多齿配体的有机-无机材料为功能配体，以重金属铅和镉为模板离子，采用醛基固定和溶胶-凝胶法相结合的两次成型工艺，制备具有较高吸附量和选择性的纤维基多齿配体重金属离子表面印迹材料，揭示其吸附及选择性机理，实现复杂基质中痕量重金属的快速富集。本项目的实现将对重金属污染物的检测有较强的科学意义，是发展重金属萃取材料的重要补充。

本项目针对水中痕量重金属直接分析困难，以纤维管内固相微萃取和仪器连用实现重金属的快速富集和检测。从纤维管内固相微萃取的核心萃取材料设计与合成入手，提高材料的吸附量、选择性和传质速率，实现高效、可靠的样品前处理。.通过高电子束辐射接枝聚合将甲基丙烯酸2-(二甲基氨基)乙酯接枝到聚丙烯纤维上，用环氧氯丙烷(ECH)官能化季铵，以Cr(VI)为模板离子，交联后洗脱制得纤维基Cr(VI)表面离子印迹聚合物Cr(VI)-IIPs。该化合物具有较宽的酸碱度工作范围，较大的吸附容量和较高选择性，在pH 2-7时，RE(%) > 91.5%； 在298 K时，最大吸附量为156.5 mg g-1；对Cr2O72-/HPO42-，Cr2O72-/NO3-和Cr2O72-/SO42-的选择性系数分别为36.7、39.9、1.49。同时，它表现出良好的稳定性和再生能力，在至少五次吸附循环后，对吸附能力不影响。.对于铅和镉阳离子表面印迹材料，分别采用聚丙烯和聚四氟乙烯纤维作为支撑材料，先在纤维表面接枝丙烯酸，再引入介孔硅胶，经过酸处理、氨基硅烷处理、氯代二乙酸取代反应等步骤合成含有氨基二乙酸型的多齿功能配体，再分别以铅、镉为金属模板并经交联，脱附后获得纤维状含多齿配体结构的表面离子印迹材料,用于快速吸附废水中重金属离子。pH值为4时，Pb(II)-IIPs纤维对Pb(II)的吸附量最大；在60分钟后达到吸附平衡；吸附符合Langmuir等温线模型在298 K，Pb(II)-IIPs纤维对Pb(II)的平衡吸附容量为49.9 mg g-1；印迹材料对Pb(II)的选择性好，选择性系数(K)的值远大于1。pH值为6时，Cd(II)-IIPs取得最大的Cd(II)吸附量；30分钟时达到吸附平衡；印迹材料对Cd(II)的选择性好，Cd(II)-IIPs对Cd(II)/Zn(II)、Cd(II)/Ni(II)、Cd(II)/Co(II)的选择性系数(K)的值为5.12-11.8。将此材料用于废水中铅和镉离子的富集和ICP-MS连用进行检测，可获得较好的测定结果。. 本项目制备的三种印迹材料的选择性好、在选择性去除、富集和检测重金属离子方面有较好的应用前景，为金属离子印迹材料用于固相微萃取检测重金属提供方法保证。