Adsorptive removal of uranyl ions in aqueous solution using hydrothermal carbon spheres functionalized with 4-aminoacetophenone oxime group

Hydrothermal carbon spheres (HCSs) functionalized with 4-aminoacetophenone oxime group (HCSs-oxime) were prepared by a grafting method and explored to adsorption of uranyl ions from aqueous solution. The results of FT-IR, elemental analysis and zeta potential indicate a successfully modification with oxime group. The adsorbent shows an excellent adsorption capacity (Langmuir, q _m  = 588.2 mg g^?1) and quick adsorption kinetic (equilibrium time of approximately 60 min) at optimal pH of 6.0. The adsorptive selectivity for uranyl ions has been also great improved in present with various co-existing ions. Overall, HCSs-oxime is a potentially promising material for selective removal of uranium in the contaminated solution.     

手性离子液体在有机合成中的应用

近年来,手性离子液体的应用研究取得了重要进展,新的手性离子液体的不断涌现促使人们对其应用研究的兴趣不断提高.本文综述了手性离子液体在有机合成中应用研究的新进展.     

邻二取代苯电化学氧化聚合的实验及理论计算研究

用电化学阳极氧化方法尝试了一系列邻二取代苯衍生物的聚合反应,结果表明在三氟化硼乙醚(BFEE)溶液中邻苯二酚(oHDB)、邻二甲氧基苯(oDMOB)、1-羟基-2-甲氧基苯(HMOB)能够电化学聚合并获得聚合物,而其它邻二取代苯单体无法用此方法获得聚合物.NMR分析和理论研究证明oHDB、oDMOB、HMOB的聚合位点发生在(C4,C5)位.用密度泛函理论对单体进行分子轨道和负电荷密度分析,表明邻二取代苯单体进行电化学氧化聚合并获得聚合物满足至少两个条件,即聚合位点HOMO-LUMO满足轨道对称性匹配且能隙最小;负电荷密度绝对值高于某一临界值(估计为|0.09|).     

Adsorption of U(VI) onto the carboxymethylated chitosan/Na-bentonite membranes: kinetic,isothermic and thermodynamic studies

The carboxymethylated chitosan (CMC)/Na-bentonite (Na-Bt) composite membranes were prepared and throughly characterized. The Na-Bt/CMC mass ratio was optimized, and CB10 (membrane with Na-Bt/CMC mass ratio of 10%) was selected as the best membrane for U(VI) sorption. XPS analysis indicates that the main mechanism for UO₂²⁺ sorption onto CB10 is through inner-surface complexation. The sorption kinetics followed pseudo-second order model, indicating the chemisorption as the rate-controlling step. The U(VI) sorption on CB10 is endothermic and spontaneous, with the maximum mono-layer adsorption capacity of 115.6 mg/g at pH 5.0 and 298 K. Finally, the U(VI)-loaded CB10 can consecutively desorbed and reused for several cycles.     

Self-assembled micellar nanoparticles of a novel star copolymer for thermo and pH dual-responsive drug release

An amphiphilic star block copolymer comprised of a hydrophobic PMMA block and a hydrophilic tri-arm poly(NIPAAm-co-DMAEMA) block was synthesized by copolymerization of NIPAAm and DMAEMA, with Ce(4+) ions and tris(hydroxymethyl)methylamine as a redox initiatory system. The star copolymer undergoes self-assembly to the micellar nanoparticles with a core-shell structure and the thermo/pH dual-response, originated from the thermo-sensitivity of PNIPAAm and the pH-sensitivity of PDMAEMA. A fluorescence probe study showed the pH-dependent low CMCs (7.5 to 11.2 mg/L) of the micelles, confirming the formation of stable micelles. Morphological investigations showed that the blank and drug-loaded micelles both had spherical and uniform shapes. The sizes of the blank and drug-loaded nanoparticles were between 80 and 120 nm, depending on the given pH. The LCSTs of the star copolymer were determined to be 32 degrees C, 36.6 degrees C and 39.5 degrees C, corresponding to pH 5, pH 7.4 and pH 9, respectively, demonstrating a pH-dependent thermo-response. As a drug delivery, the micellar nanoparticles showed the dual-responsive release profiles in vitro, which were confirmed by the drug release studies. The obtained results showed the thermo-triggered accelerated release at pH 7.4, and the pH-triggered accelerated release at 37 degrees C, indicating the micelles nanoparticles would be a promising site-specific drug delivery for enhancing the accumulation of drug in targeting pathological areas.     

电喷雾萃取电离质谱在线监测 Friedl?nder 缩合反应

质谱在线监测有机化学反应能够实时捕捉反应过程中反应物、中间体、产物的信号及其变化情况,从而推测有机反应机理,并加深对反应本质的认识。本研究利用电喷雾萃取电离质谱(EESI-MS)技术在线监测草酸催化的邻氨基苯乙酮与乙酰丙酮间的Friedlnder缩合反应。在反应的不同时间点,分别捕捉到了反应物(m/z 136)、中间体(m/z 218、m/z 236)和产物(m/z 200)的准分子离子信号,并记录了它们的信号强度随反应时间的变化趋势,推测出了反应机理。