Amino Group Surface-functionalized Ordered Mesoporous Materials: One-pot Synthesis, Heavy-metal Ion and CO2 Adsorption

Mesoporous materials have attracted more and more attention and shown great potentials in many fields, due to their outstanding properties including high surface areas, periodically arranged mesopore space, tunable pore sizes, alternative pore shapes and uniform nanosized frameworks. In this article, a simple one-pot hydrothermal strategy was applied to prepare periodic mesoporous amino group functionalized materials in the presence of nonionic block copolymer surfactant F127. Ordered hexagonal mesopores were observed from the TEM observations, with the high surface area and the uniform pore size distribution. FT-IR and MAS NMR could confirm that the functional groups were incorporated into the network of the mesoporous solids. Different experimental parameters including the adding amount of surfactant F127, the molar ratio of precursors, and the acidity of the reaction solution were investigated. And we found that the highly ordered hexagonal mesoporous materials could be prepared at pH approximate to 3, F127 adding amount of 1.5 similar to 2.5 g and 0.2<P/Ti<0.4. Heavy metal ions are proved to be highly toxic environmental pollutants, harmful to the health of human beings even at very low concentrations in the water. Thus the synthesized materials were used as efficient adsorbents for heavy metal ions such as Hg2+, Pb2+ and Cd(2+)ions, which followed Langmuir-type behavior. The synthesized adsorbents also had some selectivity for Hg(2+)and Pb(2+)over Cd(2+)ions. The adsorption capacity exhibited no obvious decrease after six multiple use cycles, showing well stability. With the increasing of carbon dioxide, undesirable consequence for the Earth's environment is caused by the alteration of the temperature of the atmosphere and the acidity of the oceans. The capture of CO2 and its storage may play a very important role for decreasing its emissions to the atmosphere. Therefore, the synthesized materials were also proved to be useful in CO2 capture benefiting from abundant amino and hydroxyl groups, showing the large adsorption capacity with high stability and selectivity. The present method is expected to open a new pathway to prepare amino group functionalized mesoporous adsorbents other than silica-based materials.