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

Hao Li,Roser Pleixats,Clarence Charnay,Laurence Raehm,Gulaim A Seisenbaeva,Ani Vardanyan,Jean‐Olivier Durand

doi:10.1002/cnma.202000383

Abstract

AbstractThe 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.

Highlights

The development of Mesoporous Organosilica Nanoparticles (MON) has grown a lot the last decade for different applications, mainly drug delivery, and catalysis
We present here the synthesis of BOC-protected bis(triethoxysilyl)-functionalized cyclen precursors through click reaction and their incorporation in Periodic Mesoporous Organosilicas (PMO) NPs with bis(triethoxysilyl)ethenylene (E)
Formation of the latter may be favored by local basic conditions in the pores induced by the presence of Cyclen ligands. It seems that chelation within a Cyclen ring is contributing to the mechanism of uptake. This indicates a considerable difference for the uptake in mesoporous nanoparticles compared to that of dense nanoparticles, where coordination of metal cations most often can be related to complexation in the monolayer on the surface.[14]

Summary

Introduction

The development of Mesoporous Organosilica Nanoparticles (MON) has grown a lot the last decade for different applications, mainly drug delivery, and catalysis. Hybrid organicinorganic mesoporous silica-based materials in bulk were first investigated. Carbon dots-modified mesoporous organosilica,[3] amino and thiol functionalized phenylenebridged Periodic Mesoporous Organosilicas (PMO),[4] or SBA-15 based mesoporous silica hybrid adsorbents[5] were reported. 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. After characterization of the materials and cleavage of BOC protecting groups, Ni(II) and Co(II) removal from model solutions and their separation from Rare Earth

Results and Discussion

Conclusion

Conflict of Interest