介孔二氧化钛/煤系高岭土-氧化铁复合材料的合成及其对水中污染物的吸附性能研究

Coal-Series Kaolin (CSK) is one of the plentiful minerals in China, and its effective utilizations are extremely important from environment management. Especially, the development of an adsorbent with low-cost and high capacity using this material is urgent to address industrial waste materials and to water treatment. Therefore, the related study on the subject is considered as one of important research goals. In our recent studies, we have found that mesoporous TiO2 nanopowder has high adsorption abilities for various pollutants including heavy metal ions, organic dyes and fluoride, indicating that the material could be an excellent adsorbent. However, the high production cost of the mesoporous TiO2 may limit its usage for water treatment. Another problem is that the TiO2 powder cannot be efficiently recovered from treated water by traditional methods such as filtration and centrifugation due to high dispersivity of the TiO2 nanoparticles in water. Therefore, an inexpensive and readily available material is desired to be used as a support material for the mesoporous TiO2 adsorbent to decrease cost. CSK is a promising candidate because of its low cost. Considering these issues, the present research project will be carried out with the objective of exploring the possibility of using CSK, which is produced in Inner Mongolia Area, as one of the starting materials for the synthesis of magnetic mesoporous TiO2/kaolin-iron oxide composites and to investigate the adsorption properties of the synthesized composite materials for various pollutants, in view of application to water treatment.

煤系高岭土是我国独特的矿产资源，其综合开发利用是关系到资源的有效利用、环境保护、可持续发展的重大课题，利用其特有的结构及性质开发廉价、高效新型吸附剂的研究对解决工业废弃物和日益严重的水污染问题具有很重要的现实意义。最近我们课题组发现介孔二氧化钛(TiO2)粉体对水中的重金属离子、有机染料、氟化物等多种污染物具有超强的吸附能力，但其本身的生产成本较高，同时因其颗粒粒度极小而易分散于水中，极难回收，因此寻找一种廉价易得、容易回收的载体则是解决问题的有效途径。虽然煤系高岭土本身的活性及吸附性能相对有限，但它可以作为廉价的载体应用于环保领域。因此，本研究利用内蒙古自治区丰富的天然资源，以本地区煤系高岭土和氧化铁(γ-Fe2O3或Fe3O4)为载体，将高性能介孔TiO2负载在其表面，制备系列磁性介孔TiO2/煤系高岭土-氧化铁复合材料，研究合成材料对各种污染物的吸附性能。

内蒙古自治区已成为全国最大的煤炭基地，随着煤炭生产规模的加大煤系高岭土的排放量也不断增加，但其利用率远远跟不上排放速度，造成严重的社会问题。因此，煤系高岭土的研究不仅具有重要的学术意义，而且对解决我区固体废弃物的堆放和日益严重的环境污染问题具有很重要的现实意义。为充分发挥和利用内蒙古自治区资源优势，扩大煤系高岭土的利用范围，我们在本项目中以本地区煤系高岭土为主要原料合成了系列吸附材料，并系统地研究了其对主要污染物的吸附性能。主要研究成果如下:.（1）以改性煤系高岭土和尿素铁配合物为原料成功地制备出了高性能磁性γ-Fe2O3/煤系高岭土纳米复合材料，并系统地研究了该材料对次甲基蓝的吸附性能。结果表明，该复合材料对次甲基蓝显示出较好的吸附性能，并可用外加磁场很容易将其从溶液中分离出来。.（2）以改性煤系高岭土和硫酸钛为原料，合成了介孔TiO2/煤系高岭土纳米复合材料。发现将煤系高岭土与TiO2复合后其对阴离子型染料的吸附能力得到了大大提高。.（3）以改性煤系高岭土、硫酸钛和尿素铁配合物为原料，合成了磁性介孔TiO2/煤系高岭土-γ-Fe2O3复合吸附材料，解决了介孔TiO2/煤系高岭土纳米粉体材料分离回收难的问题。.（4）发现了采用浓硫酸以及尿素铁配合物直接活化煤系高岭土的新方法，为扩展煤系高岭土的应用范围提供了有力的科学依据，也为下一步的研究打下了基础。