Effects of added organosilanes on the formation and adsorption properties of silicates surface-imprinted with an organophosphonate
Effects of added organosilanes on the formation and adsorption properties of silicates surface-imprinted with an organophosphonate
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DOI：
10.1021/la000477o
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发表时间：
2000-07-25
期刊：
影响因子：
3.9
通讯作者：
Gaber, BP
中科院分区：
文献类型：
--
作者：
Markowitz, MA;Deng, G;Gaber, BP
二氧化硅颗粒表面印迹与梭曼水解产物甲基膦酸频哪醇酯（PMP）表现出结合选择性的水解产物超过其他膦酸单酯和二酯。在微粒形成过程中，通过将甲基膦酸频哪醇酯加入到由聚氧乙烯（5）壬基苯基醚（NP 5）、环己烷、氨化乙醇和水形成的微乳液中，对微粒表面进行印迹。在颗粒形成过程中，将一些具有末端官能团如伯胺、季胺、二氢咪唑和乙基吡啶的三烷氧基硅烷与四乙氧基硅烷（TEOS）混合，以增强所得表面印迹颗粒的结合性和选择性。硅酸盐的BET表面积取决于在颗粒形成期间添加的特定有机硅烷。此外，伯胺和二氢咪唑封端的有机硅烷产生高密度，低孔体积的胶体，而2-乙基吡啶和季胺封端的有机硅烷产生介孔硅酸盐。当在颗粒形成过程中加入甲基膦酸频哪醇酯时，观察到表面积减小。吸附等温线表明，表面印迹硅酸盐形成与添加季胺封端的有机硅烷具有最高的吸附容量每克硅酸盐。然而，更多的印迹网站每平方米形成时，二氢咪唑封端的有机硅烷用于颗粒合成。硅酸盐表面印迹与PMP显着更具选择性PMP比其他结构相似的有机膦酸酯。
Silica particles surface-imprinted with the soman hydrolysis product pinacolyl methylphosphonate (PMP) demonstrated binding selectivity for the hydrolysis product over other phosphonate mono- and diesters. Particle surfaces were imprinted during particle formation by adding pinacolyl methylphosphonate to the microemulsion formed from polyoxyethylene(5) nonylphenyl ether (NP 5), cyclohexane, ammoniated ethanol, and water. A number of trialkoxysilanes with terminal functional groups such as primary amine, quaternary amine, dihydroimidazole, and ethylpyridine were mixed with tetraethoxysilane (TEOS) during particle formation to enhance the binding and selectivity of the resulting surface-imprinted particles. The BET surface area of the silicates was dependent on the specific organosilane added during particle formation. The addition of primary amine- and dihydroimidazole-terminated organosilanes produced high-density, low-pore-volumes colloids while the addition of 2-ethylpyridine- and quatermnary amine-terminated organosilanes produced mesoporous silicates. When pinacolyl methylphosphonate was added during particle formation, a decrease in surface area was observed. Adsorption isotherms revealed that surface-imprinted silicates formed with added quaternary amine-terminated organosilanes had the highest adsorption capacity per gram of silicate. However, more imprinted sites per square meter were formed when the dihydroimidazole-terminated organosilane was used in particle synthesis. Silicates surface-imprinted with PMP were significantly more selective for PMP than for other structurally similar organophosphonates.