New Functionalized Mesoporous Silicas for Adsorption of Heavy Metal Ions

CTS-0086512“用于吸附重金属离子的新型功能化介孔二氧化硅”Mietek JaroniecKent State University这项研究项目致力于开发具有高负载能力、易于再生和重复使用的重金属离子吸附剂，而负载能力不会有任何明显的损失。更具体地说，这项工作是为了合成新的介孔二氧化硅基吸附剂，用于去除水溶液中的汞离子和其他重金属离子。多孔二氧化硅表面正在被1-benzoyl-3-[3-(triethoxysilyl)propyl]thiourea和1-烯丙基-3-[3-(三乙氧基硅基)丙基]硫脲等配体功能化，预计它们与汞和其他重金属离子的结合强度低于常用的3-巯基丙基配体。因此，应该可以在较温和的条件下(即不使用浓酸)再生这些新的吸附剂，从而防止再生时吸附能力的丧失。这些吸附剂是通过将自组装的二氧化硅/表面活性剂介孔结构材料直接官能化，以及通过高比表面积、大孔容和容易获得的孔结构的无表面活性剂的介孔二氧化硅功能化来制备的。对所得到的重金属离子吸附剂的性能进行了严格的评估，并正在寻找用于水处理的载体、官能化程序和配体的最佳组合。拟议研究的直接影响将是获得新的、易于再生的吸附剂，用于选择性地吸附水中有害的重金属离子。这项研究有望对限制几何形状和孔径对离子和分子物种的吸附的影响这一重要而又在很大程度上尚未解决的问题提供有价值的见解，并揭示键合层的结构和类型与其金属离子吸附性能之间的潜在有用的关联。拟议研究的跨学科性质为培养在学术界和工业界从事各种职业的研究生和本科生提供了一个独特的教育机会。此外，学生们还将有极好的机会参与PI在纳米结构材料的合成、功能化和应用领域建立的国际合作。

CTS- 0086512"New Functionalized Mesoporous Silicas for Adsorption of Heavy Metal Ions"Mietek JaroniecKent State UniversityABSTRACTThis research project is focused on the development of heavy-metal-ion adsorbents that would exhibit high loading capacities and could be readily regenerated and reused without any appreciable loss of the loading capacity. More specifically, the effort is to synthesize new mesoporous silica-based adsorbents for removal of mercury ions and other heavy-metal ions from aqueous solution. The porous silica surface is being functionalized with ligands such as 1-benzoyl-3-[3-(triethoxysilyl)propyl]thiourea and 1-allyl-3-[3-(triethoxysilyl)- propyl] thiourea, which are expected to bind mercury and other heavy metal ions less strongly than in the case of commonly used 3-mercaptopropyl ligands. Thus, it should be possible to regenerate these new adsorbents under milder conditions (i.e., without using concentrated acids), and consequently, to prevent the loss of adsorption capacity upon regeneration. These adsorbents are being prepared by a direct functionalization of self-assembled silica/surfactant mesostructured materials and by functionalization of surfactant-free mesoporous silicas of high specific surface areas, large pore volumes, and readily accessible porous structures. The performance of the resulting heavy-metal- ion adsorbents are critically evaluated, and the best combination of support, functionalization procedure, and ligand for water treatment is being sought. The immediate impact of the proposed research will be the availability of novel, easy-to- regenerate adsorbents for selective adsorption of harmful heavy-metal ions from waters. This study promises to provide valuable insight into important and yet largely unresolved problems of the influence of confined geometry and pore size on adsorption of ionic and molecular species and to reveal a potentially useful correlation between the structure and type of bonded layers with their performance in metal-ion adsorption. The interdisciplinary nature of the proposed research provides a unique educational opportunity for training graduate and undergraduate students for a range of careers in academia and industry. Also, students will have an excellent opportunity to participate in the international collaborations established by PI in the area of synthesis, functionalization, and application of nanostructured materials.