Synthesis of mesoporous silica-tethered phosphonic acid sorbents for uranium species from aqueous solutions

Abstract

One-pot synthesis of highly ordered SBA-15 type silica-tethered phosphonic acid at weakly acidic pH (3.75) allows for higher loading of phosphonic functionality (up to 33%) without significant deterioration of the mesostructure. In this synthesis sodium metasilicate was used instead of tetraethylorthosilicate. The resulting samples featured high specific surface areas (362-533 m 2 /g) and well developed mesoporosity. The hexagonal structure and high concentration of phosphonic acid groups (1.0-3.0 mmol/g) in the synthesized samples were established by XRD, TEM, EDS and elemental analysis methods. Since inexpensive sodium metasilicate was used as a source of silica, these materials can be of interest for large scale applications.Experimental studies of the synthesized materials showed that they are effective for extraction of trace uranium species under weak basic conditions (pH 8.3), which are relevant for practical use such as uranium extraction from seawater.

Synthesis of enhanced phosphonic functional groups mesoporous silica for uranium selective adsorption from aqueous solutions

“…Then, the final mixture, which is a kind of suspension, was left in the oil bath for 1 h at 40 °C. Finally, the resulting mixture was placed in the conventional oven for 2 h at 40 °C with magnetic stirring and 10 h at 100 °C without stirring 30 . The subsequent process included the treatments to remove the template.…”

“…synthesized different MSs with various molar ratios of the sodium metasilicate and DPTS. They reported the highest uranium adsorption capacity of 54.5 mg/g for 10:2 molar ratio 30 .…”

Synthesis and characterization of sulfur-containing hybrid materials based on sodium silicate

“…22 Positive experience in the synthesis of SBA-15 type materials based on metasilicate without a functional layer was described in papers, [23][24][25][26][27][28][29] and those with different types of functional groups in papers. [30][31][32][33][34][35] Based on the analysis of the literature data, the main conclusions about sulfonic acid catalysts can be summarized as follows: (a) the acidic and catalytic properties of materials synthesized in different ways are similar; (b) there is a relationship between the specic activity of the attached sulfonic acid groups and the concentration of these groups on the substrate surface. It is also possible to form clusters of interacting acid groups, with increasing concentration on the substrate.…”

Phosphonic acid functionalized siloxane crosslinked with 3‐glycidoxyproyltrimethoxysilane grafted polybenzimidazole high temperature proton exchange membranes

“…In addition, the phosphoric or phosphonic acids have excellent thermal stability and low vapor pressure at high temperature. Study on phosphonic acid functionalized silica has aroused increasing attention in recent years because the silica component has excellent thermostability and good hydrophilicity . At early time, Tadanaga et al .…”