|dc.description.abstract||Here we report synthesis of two kinds of materials functionalized with tunable content of phosphonic acid groups, to adsorb Erbium ions and Paraquat.
One is bifunctional materials, synthesized by co-condensation of two different organosilane precursors, that is, 1,4-bis(triethoxysilyl)benzene (BTEB) and sodium 3-(trihydroxysilyl)propyl methyl phosphate (SPMP), under acidic condition using nonionic surfactant Brij-76 as template. These materials were periodic mesoporous organosilicas (PMOs) with benzene bridging groups in the silica wall, and denoted as BS-x, where x is the mole ratio of phosphonic acid groups.
The other is synthesized by co-condensation of tetraethyl orthosilicate (TEOS) and SPMP under same condiction like BS-x, and is called TS-x.
Materials were characterized by powder X-ray diffraction (XRD), nitrogen sorption measurements, solid-state 13C and 29Si MAS NMR spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM).
In adsorption experiment, first, we used BS-x and TS-x to adsorb erbium ions.
The adsorption process was carefully studied with differernt factors.The results reveal that the adsorption of erbium ion on mesoporous silica is strongly dependent on the content of phosphonic acid (PA) groups, and increases with the PA content increases.Theses materials retained more than 99 % metal removal efficiency after use for four consecutive cycles.
The second adsorption experiment suggested that there is a benefit for the use of aromatic groups as the enhanced π-π interaction between the aromatic groups of the BS-x materials and paraquat increase the adsorption in comparison to TS-x.The synthesized materials are promising for adsorption of herbicides.