多孔聚苯醚的合成及气体储存

通过厄尔曼缩合反应合成了一种具有dia-c5 拓扑结构的多孔聚苯醚JUC-Z6, 并对其结构进行了表征. 结果表明, 该化合物具有高热稳定性(214℃ 失重5%), 高化学稳定性、 高BET比表面积(192 m²/g)及窄孔径分布(1.36 nm). 低压气体吸附测试结果表明, JUC-Z6在多孔材料中具有较高的吸附焓(氢气4.1 kJ/mol, 二氧化碳33.7 kJ/mol, 甲烷4.1 kJ/mol).     

臭氧提高纳米TiO2光催化活性的ESR分析

以5,5-二甲基-1-吡咯啉-N-氧化物(DMPO)为自由基捕获剂,分别以去离子水和二甲基亚砜(DMSO)为溶剂,利用电子自旋共振(ESR)方法对UV、O₃、TiO₂/O₃、TiO₂/UV/O₂、UV/O₃和TiO₂/UV/O₃这6种体系中形成的羟基自由基(·OH)和超氧阴离子自由基(·O₂^-)进行了检测,同时考察了反应时间、催化剂投量以及体系溶解氧对TiO₂/UV/O₃体系形成·OH和·O₂^-的影响.结果显示,在纳米TiO₂光催化体系中加入臭氧,能显著增加反应体系中·OH和·O₂^-自由基的生成量,6种体系中DMPO-·OH和DMPO-·O₂^-加合物的ESR波谱峰信号强度分别为:TiO₂/UV/O₃>TiO₂/UV/O₂>UV/O₃>UV>TiO₂/O₃>O₃和TiO₂/UV/O₃≈TiO₂/UV/O₂>TiO₂/O₃>UV>UV/O₃>O₃,在TiO₂/UV/O₃体系中成功监测到·O₃^-自由基的存在.     

高效液相色谱-质谱联用法同步测定城市污水处理厂活性污泥中的多类抗生素残留

采用超声萃取、固相萃取及高效液相色谱-质谱联用技术(LC-MS),建立了活性污泥中3类共9种抗生素(包括5种磺胺类、3种四环素类及1种大环内酯类)的同时分析方法.样品经甲醇-Na2,EDTA/Mcllvaine缓冲液(1∶1,体积比)超声萃取,HLB固相萃取柱净化富集后,以Symmetry C18反相柱为分析柱,0.2...     

Impregnated Sulfur in Carbonized Nitrogen-containing Porous Organic Frameworks as Cathode with High Rate Performance and Long Cycle Life for Lithium-sulfur Batteries

The undesirable cycling performance caused by soluble poly sulfides shuttling between anode and cathode has been considered as the main challenge that has hindered its practical applications for lithium-sulfiir(Li-S) batteries. To solve tliis issue effectively, a nitrogen-containing porous carbon, namely JUC-Z2-900,developed from a porous organic framework, namely JUC-Z2, bearing a high surface area(805 m^2/g),small pore size(0.5 mil) and nitrogen doping(2.15%, mass fraction), has been used as a host material for Li-S batteries. The micropores of JUC-Z2-900 can confine the smaller sulfur molecules S2-4, which can essentially alleviate the critical problem of poly sulfide dissolution.Furthermore, nitrogen-containing JUC-Z2-900 can promote chemical adsorption of sulfur. The above two factors can improve the electrochemical performance of Li-S batteries effectively. To compare the eftects of sulfur contents and melt-difiusion strategy in JUC-Z2-900/S composites, a series of JUC-Z2-900/S composites was synthesized and tlieir electrochemical perfbnnances were explored, indicating good rate performance and excellent cycling stability of the composites contributed by both appropriate mass percentage of sulfiir and its confinement in the micropores.     

可控交联聚醚醚酮动态流变学行为的研究

聚芳醚酮类材料因其优异的综合性能在许多领域得到广泛应用 [1,2 ] .许多研究者通过提高聚芳醚酮分子链的刚性度来实现进一步提高其使用温度 ,但由于其在高温时流动性下降 ,熔体粘度增大 ,给加工及应用带来很大困难[3] .基于此 ,我们将可在高温或辐照条件下发生交联反应的硫醚结构作为交联点引入到聚醚醚酮主链中 ,合成了可控交联的聚醚醚酮[4 ,5] .聚合物的分子结构及其熔体中分子的内部作用可以用流变学进行研究 .因此 ,我们用动态流变学实验监测跟踪聚合物的交联反应过程 ,研究可控交联聚醚醚酮的交联反应动力学 ,为设计改造分子结构以满…