Large Pore Mesostructured Organosilica-Phosphonate Hybrids as Highly Efficient and Regenerable Sorbents for Uranium Sequestration
Large Pore Mesostructured Organosilica-Phosphonate Hybrids as Highly Efficient and Regenerable Sorbents for Uranium Sequestration
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DOI：
10.1021/cm3023709
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发表时间：
2012-11-13
影响因子：
8.6
通讯作者：
Kleitz, Freddy
中科院分区：
文献类型：
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作者：
Lebed, Pablo J.;Savoie, Jean-Daniel;Kleitz, Freddy
放射性/核事件对人口和环境的潜在后果已促使科学界重新考虑其基于放射化学分离的监测方法。在这方面，非常需要设计放射性分析系统，以便在发生事故和核事件时迅速评价环境影响。研究了磷酸盐功能化大孔三维（3-D）立方（KIT-6）和二维（2-D）六方（SBA-15）二氧化硅作为酸性介质中高效的铀萃取吸附剂。在这两种情况下，功能化是通过在二氧化硅载体的介孔表面接枝（2-二乙基磷酸乙酯）三乙氧基硅烷（DPTS）来实现的。特别注意了不同孔径和孔结构的比较及其对放射性核素提取的影响，主要是通过铀吸附等温线和吸附动力学研究。所有的杂化材料都表现出非常快的吸附动力学，在不到60s的时间内达到平衡。计算参数。Langmuir模型的结果表明，与其他同类材料相比，3-D立方基kit -6吸附剂的性能明显优越，特别是在铀平衡浓度低于50 mg L-1的情况下。此外，观察到在每克吸附剂54-56毫克U的范围内具有优越的最大吸附容量，与市售产品的容量相比，它几乎增加了3倍。在动态萃取实验中，用小于25mg的功能化介孔树脂模拟物进行了高效萃取。重要的是，再生介孔吸附剂的重复使用的可能性是在几个循环中建立的，而铀提取能力没有损失，这表明新的吸附剂材料具有足够的化学和结构稳定性。
Potential consequences of radiological/nuclear events on the population and the environment have led the scientific community to rethink its approach toward a monitoring based on radiochemical separation. In this context, there is a great need to design radioanalytical systems for quickly evaluating environmental impacts in case of incidents and nuclear events. Phosphonate-functionalized large pore three-dimensional (3-D) cubic (KIT-6) and two-dimensional (2-D) hexagonal (SBA-15) silicas have been studied as highly efficient uranium extracting adsorbents in acidic media. In both cases, functionalization was performed by grafting (2-diethylphosphatoethyl) triethoxysilane (DPTS) on the mesopore surface of the silica supports. Particular attention was given to comparison of different pore sizes and pore structures and impact on radionuclide extraction, principally through uranium adsorption isotherms and sorption kinetics studies. All hybrid materials demonstrated very fast adsorption kinetics, reaching equilibrium in less than 60 s. Calculated parameters. from the Langmuir model revealed a clearly superior performance of the 3-D cubic KIT-6-based sorbents compared to other equivalents, especially for uranium equilibrium concentrations below 50 mg L-1. Furthermore, a superior maximum adsorption capacity in the range of 54-56 mg of U per gram of sorbent was observed for which it represents almost a 3-fold increase compared to the capacity of commercially available products. High extraction efficiency is demonstrated through dynamic extraction experiments using less than 25 mg of functionalized mesoporous resin analogue. Importantly, the possibility of reusing regenerated mesoporous sorbents is established over several cycles with no loss in uranium extraction capacity suggesting adequate chemical and structural stability of the new sorbent materials.