奎宁功能化聚乙烯咪唑修饰硅胶亲水相互作用色谱固定相的制备及应用

通过表面自由基链转移聚合和亲核取代反应制备了一种新型奎宁功能化聚乙烯咪唑修饰硅胶亲水色谱固定相(Sil-PIm-Qn)。通过元素分析和红外光谱对该固定相进行表征,并在亲水相互作用色谱(HILIC)模式下对其进行了色谱性能评价。结果表明,该固定相对5种氨基酸、9种磺胺以及10种碱基核苷有较好的分离选择性。实验考察了流动相中有机相乙腈体积分数和水相中乙酸铵浓度对待分离物质保留行为的影响,并进一步对固定相分离的重复性进行了考察,其保留时间的相对标准偏差(RSD)为0.08%~2.30%(n=10)。该亲水色谱固定相制备方法简单,并且表现出了优异的亲水色谱分离性能,有望在磺胺类药物及生物样品中碱基核苷等亲水性物质的分离分析中有一定应用。     

碳点在样品前处理及色谱分离中的应用

碳点（CDs）具有生物相容性好、毒性低、稳定性好等优点,目前已广泛应用于生物成像、传感、光催化等领域。近年来,以CDs为吸附剂和分离材料的样品前处理和色谱分离研究也引起了研究者的极大兴趣。该文对CDs在样品前处理和色谱分离中的应用进行了综述,并对其发展前景进行了展望。     

Simple fabrication of superhydrophobic PLA with honeycomb-like structures for high-efficiency oil-water separation

Polylactic acid(PLA) is one of the most suitable candidates for environmental pollution treatment because of its biodegradability which will not cause secondary pollution to the environment after application.However,there is still a lack of a green and facile way to prepare PLA oil-water separation materials.In this work,a water-assisted thermally induced phase separation method for the preparation of superhydrophobic PLA oil-water separation material with honeycomb-like structures is reported.The PLA material shows great ability in application and could adsorb 27.3 times oil to its own weight.In addition,it could also be applicated as a filter with excellent efficiency(50.9 m^3 m^-2 h^-1).     

碳酸钙纳米颗粒复合超分子凝胶润滑剂的摩擦学性能研究

采用碳酸钙纳米颗粒与全氟聚醚型超分子凝胶复合得到了一种新型的纳米颗粒复合超分子凝胶润滑剂. 超分子凝胶具有错综复杂的网络结构,有效地提高了碳酸钙纳米颗粒在全氟聚醚润滑油中的分散稳定性. 此外,碳酸钙纳米颗粒作为添加剂极大地提高了超分子凝胶的润滑性能,使其表现出较好的耐高温性能,以及较高的承载力. 采用差式扫描量热仪、热重分析仪和流变分析仪对该复合润滑剂的热力学性能进行表征,结果显示该复合润滑剂具有很好的热稳定性以及较好的力学性能. 最后,通过X射线光电子能谱(XPS)对其摩擦机理进行表征,结果表明碳酸钙纳米颗粒复合超分子凝胶润滑剂优异的摩擦学性能可归因于碳酸钙纳米颗粒在摩擦副表面形成了易剪切的薄膜,以及小尺寸的纳米粒子在摩擦过程中对摩擦表面进行的自修复效应.      

Effect of structure parameters on forces acting on baffles used in gas–solids fluidized beds

Effects of some important structural parameters, i.e. slat pitch, and layout position, on dynamic forces acting on the baffles were examined in the fluidized bed of FCC particles operating under different superficial gas velocities. The experimental baffles were made of multiple inclined slats. We found that the forces acting on the baffles decreased significantly with reducing pitch between the slats. For the baffles with a small slat pitch, the forces acting on the baffles increased slightly and then decreased with increasing superficial gas velocity, which is very different from the measured results of a single slat or tube immersed in fluidized beds. The different results are greatly related to the appearance of the “gas cushion” beneath the baffles, whose height increases with increasing superficial gas velocity. On the other hand, a region with stronger particle circulation induced by the inclined slat array was observed in the experiments. The slat near the wall and located below the region of downward-flowing particles was found to be subjected to the severest forces. Therefore, the slats located in similar locations of industrial baffles are suggested to be reinforced to increase their structural strength.     

C2H2/Ar流量比对a-C:H涂层结构及摩擦学性能的影响

a-C:H涂层因具有高硬度、低摩擦系数及良好的化学惰性等性能,使其作为表面防护材料具有广泛的应用前景,而涂层中的H含量和sp2C/sp3C比值是影响其力学及摩擦学性能的重要因素. 本研究中采用非平衡磁控溅射技术在9Cr18钢表面制备了a-C:H涂层,对比研究了前驱体组成对不同结构含H碳膜的氢含量、微观结构、力学性能和摩擦学性能的影响. 结果表明:增大C₂H₂/Ar流量比,涂层的生长率及H含量逐渐增大,但致密性降低. 由于涂层中C-H键及致密性的变化,a-C:H涂层的硬度和弹性模量随C₂H₂/Ar流量比的增大而逐渐减小,但结合强度却先增大后降低. 当C₂H₂/Ar流量比低于4:3时,涂层表现出良好的减摩耐磨性能,当C₂H₂/Ar流量比高于4:3时,涂层的摩擦系数和磨损率出现了急增的现象. 总体而言,a-C:H涂层的摩擦系数和磨损率随C₂H₂/Ar流量比的增加呈现先增大后降低的趋势. 由于H原子的钝化作用及涂层力学性能的变化,使a-C:H涂层的磨损机制由磨粒磨损和黏着磨损变为磨粒磨损. 当C₂H₂/Ar流量比为1:1时,a-C:H涂层具有最低的摩擦系数(约为0.1)和磨损率[8.0×10?8 mm3/(N·m)],表现出最佳的力学及摩擦学性能,这种性能的变化与涂层中的H含量和sp2C/sp3C比密切相关.      

Adsorption of U(VI) onto kaolin studied by batch method

Adsorption of U(VI) on purified kaolin was studied by batch methods under ambient conditions, including contact time, pH, fulvic acid, etc. Three kinetic models were used to model the kinetic adsorption which was very well described by the pseudo-second-order rate equation, and the activation energy of adsorption was 52.20 kJ/mol. The Freundlich and Dubinin–Radushkevich models fitted the experimental data better than the Langmuir model for the adsorption and desorption isotherms. The thermodynamic parameters indicated that the adsorption of U(VI) on kaolin was an endothermic and spontaneous process.     

可回收Fe3O4@SiO2-Ag磁性纳米微球对染料污染物的快速脱色处理

介绍了一种采用无毒廉价的前驱物制备Fe₃O₄@SiO₂-Ag磁性纳米微球的快捷方法,制备的Fe₃O₄@SiO₂-Ag纳米微球在NaBH₄存在下可以催化还原染料污染物.实验结果表明,Fe₃O₄@SiO₂-Ag磁性纳米粒子保持了Ag纳米粒子和Fe₃O₄纳米粒子的双重优点,不仅对染料罗丹明B和曙红Y具有良好的催化还原效率,而且可以在外加磁场作用下从溶液中快速有效的分离.催化还原反应速率与反应温度及Fe₃O₄@SiO₂-Ag催化剂用量有关,反应体系中表面活性剂和无机盐(Na₂SO₄)的存在也会影响催化剂的催化活性.该Fe₃O₄@SiO₂-Ag磁性纳米粒子在工业染料污染物处理方面具有应用前景.     

钯催化吲哚直接羰化合成吲哚-3-炔酮类化合物

以Pd(OAc)2为主催化剂,以Cu为助催化剂,以碘为氧化剂,高效地实现了吲哚与苯炔直接羰化合成吲哚-3-炔酮,并优化了反应条件. 结果表明,该催化剂体系对带有不同取代基的吲哚、端炔类化合物具有非常好的适用性,最高分离产率可达94%. 生成的吲哚-3-炔酮产物可进一步与叠氮化钠和溴苄一锅反应,高产率地得到3-甲酰三唑基吲哚类化合物. 由于原料来源简单,产率高,且两类产物都是重要的中间体,因此该方法具有一定的应用价值.     

Cr掺杂的丙烷选择氧化制丙烯酸高效催化剂

在丙烷选择氧化制丙烯酸催化剂MoVTeNbOx的活性相M1基础上掺杂一定量的Cr,当Cr/Nb摩尔比为0.002时,催化剂具有很高的丙烯酸选择性(78.3%)和收率(50.7%);并采用X射线衍射、X射线光电子能谱、程序升温还原、O2程序升温脱附、NH3程序升温脱附和异丙醇氧化等手段对催化剂的构效关系进行了探讨.结果表明,适量Cr的添加可调节催化剂表面Mo6+,V5+和Te4+等物种含量,提高催化剂的氧化能力,使丙烷转化率增加.同时,适量Cr的添加使得催化剂表面酸强度下降,酸性位点数量减少,从而抑制丙烯酸的深度氧化,提高了丙烯酸选择性.