Synthesis of Cyclen-Functionalized Ethenylene-Based Periodic Mesoporous Organosilica Nanoparticles and Metal-Ion Adsorption Studies

Abstract

The preparation of two cyclens both possessing two triethoxysilyl groups through click chemistry is described. These two cyclens were incorporated into bis(triethoxysilyl)ethenylene-based periodic mesoporous organosilica nanoparticles (PMO NPs) at different proportions of bis(triethoxysilyl)ethenylene/cyclens (90/10, 75/25). The obtained nanorods were analyzed with different techniques and showed high specific surface areas at low proportion of cyclens. The nanorods containing free amino groups of cyclen were then used for Ni(II) and Co(II) removal from model solutions. The kinetics and isotherms of adsorption of Ni(II) and Co(II) were determined, and the materials showed high uptake of metals (up to 3.9 mmol ⋅ g−1). They demonstrated pronounced selectivity in separation of rare earth elements from late transition metals, e. g. Ni(II) and Co(II) by adsorption and even more so by controlled desorption.