Selective adsorption of the cationic dye rhodamine-6G from aqueous solution by phosphotungstic acid@MOF-199 composites

In this paper, H₃[ P(W₃O₁₀)₄]@MOF-199 composites ([email protected]) were successfully synthesized by a simple one-step reaction under solvothermal conditions and characterized by XRD, SEM, FT-IR and N₂ adsorption–desorption isotherms. Additionally, rhodamine-6G (Rh6G, a cationic dye) and methyl orange (MO, a anionic dye) as model dyes were employed to assess its adsorption performance. The adsorption capacity of MOF-199 towards Rh6G and MO were enhanced and weakened respectively after the introduction of PTA (from 8.6 mg/g to 41 mg/g; 11.4 mg/g to 2.6 mg/g) proving that the selective adsorption capacity for the cationic dye of porous MOF-199 could be improved through the modification of PTA. Moreover, in diverse initial concentrations of single Rh6G and MO aqueous solutions (10 mg/L, 25 mg/L, 50 mg/L and 100 mg/L), [email protected] exhibited much higher adsorbing capacity towards Rh6G (about 25, 30, 11 and 16 times higher than that of MO). In mixed dyes adsorption studies, the adsorption capacity of [email protected] towards Rh6G (2.871 mg) are nearly five times larger than that of MO (0.437 mg) even in a solution with a higher concentration of MO than Rh6G (5 mg/L of Rh6G and 10 mg/L of MO). The kinetic study indicated that the adsorption of the Rh6G and MO onto [email protected] followed the pseudo second-order model well. The isotherm obtained from experimental data fitted the Freundlich model (the linearly dependent coefficient are 0.99839 and 0.94845 for Rh6G and MO respectively) indicating multilayer adsorption mechanism. In summary, all these results implied that the as-prepared [email protected] is of great potential to be used as a cationic pollutants adsorbent with high efficiency and selectivity.     

铕基金属有机框架材料从混合染料中选择性分离亚甲基蓝

利用紫外-可见吸收光谱和粉末X射线衍射等技术, 通过染料吸附实验、 混合染料吸附实验、 吸附动力学实验和循环吸附实验, 研究了一种铕基金属有机框架材料从混合染料水溶液中选择性分离亚甲基蓝的性能与机理. 研究结果表明, 该材料对亚甲基蓝的最大吸附量为20 mg/g, 在12 h内可完成对亚甲基蓝的选择性吸附, 且可以循环使用3次以上. 混合染料吸附实验结果表明, 该材料的吸附选择性源于孔道的静电作用与尺寸排斥效应.     

反应速率和反应进度的辩证关系——以甲基丙烯酸甲酯自由基聚合为例

化学反应速率与化学反应进度是非常相似的概念和知识点,同时又密切相关。在宏观层面或者说表象层面上看,都描述了过程变化的程度,但二者确具有完全不同的性质,一个是动力学量、一个是热力学量;一个是微观性质、一个是宏观性质。通过甲基丙烯酸甲酯自由基聚合过程的分析,深入讨论和揭示反应速率与反应进度的内涵、意义,明确二者的辩证本质关系,以使学生进一步巩固如何提高聚合物产率、分子量等方面的理论知识,提高学生的学习能力,同时也促进在今后工作中的实践能力和创新能力的提高具有重要的意义。     

甲基异丁基甲酮萃取-火焰原子吸收光谱法测定氧化锑中的磷

研究了MIBK萃取-火焰原子吸收光谱法测定氧化锑中的磷。在盐酸介质中,磷酸根与钼酸铵形成磷钼物质的量之比为1∶12磷钼杂多酸,用酒石酸钾钠掩蔽锑,以甲基异丁基甲酮为萃取试剂,用火焰原子吸收光谱法测定有机相中磷钼杂多酸中的钼,据此建立了一种间接测定氧化锑中微量磷的新方法。在优化的实验条件下,当磷的含量在0.055~1.00 mg/L范围内时,其吸光度与浓度呈良好的线性关系;方法的检出限为0.011 mg/L;对4个样品进行测定的回收率在97.8%~106.2%之间;相对标准偏差为2.6%~4.2%。用于氧化锑中微量磷的测定,结果满意。     

PREPARATION AND PROPERTIES OF MMA/1-PROPYLMETHACRYLATE-POSS COPOLYMER WITH ATOM TRANSFER RADICAL POLYMERIZATION

The methyl methacrylate(MMA)/1-propylmethacrylate-polyhedral oligomeric silsesquioxane(PM-POSS) copolymers were synthesized via atom transfer radical polymerization with CuBr as catalyst.The unreacted PM-POSS monomer could be removed completely by washing the copolymerization product with n-hexane.The copolymers were characterized with ~1H-NMR,X-ray diffraction,differential scanning calorimetry,thermogravimetric analysis and gel permeation chromatography.With increasing PM-POSS feed ratio,the total conve...     

Liquid crystalline side chain polymer with a poly (Geraniol-co-MMA) backbone and phenylbenzoate mesogenic group: synthesis and characterization

A new side chain liquid crystalline polymers have been synthesized and characterized in which [geraniol-co-MMA] polymer are used as a backbone linked via polymethylene spacer to phenyl benzoate mesogenic group. The polymer exhibits enantiotropic liquid crystallinity with nematic phase and does not exhibit side chain crystallization .A clear difference between the nature of the mesophase is evidenced between [Geraniol-co-MMA] main chain and methacrylate polymers .The LC polymer exhibit glass transition at 40 °C. In a comparative analysis, we discuss the relevance of polymer backbone in the synthesis of side chain liquid crystalline polymers.     

铁系催化剂催化降冰片烯与丙烯酸甲酯共聚合

研究了Fe(acac)3-Al(i-Bu)3(acac=乙酰丙酮)催化降冰片烯(NB)与丙烯酸甲酯(MA)共聚反应条件影响、第三组份影响及催化剂铁铝比影响.并用核磁共振、红外光谱和元素分析方法研究了共聚物的组成,用热分析方法研究了共聚物的分解温度,并用电镜分析了共聚物的膜结构.结果表明,铁系催化剂在温和的反应条件下有较好的催化性能,并可获得能够形成有序多孔膜的共聚物.     

Separation and Assay of Cholecalciferol in Vitamin A + D Ointment

Summary. In this paper two methods are presented. One involves the separation of cholecalciferol from a topical ointment. The other involves the assay of cholecalciferol in this ointment. The study was performed with normal-phase high performance liquid chromatography using a NP-L3 column and UV detection. Applying a mobile phase mixture containing n-hexane:2-propanol (99:1) a total separation was achieved within 15 min. For isolation and assay of cholecalciferol from an ointment (vitamin A + D), dissolution in n-hexane gave the highest recovery (>95%). The isolation and assay process can be performed within 3.5 h.     

尖晶石型(Zn1-xCdx)2SnO4粉体的制备与光催化性能

运用化学共沉淀法,制备了尖晶石型(Zn1-xCdx)2SnO4(x=0.04,0.05,0.06,0.07,0.08)纳米粉体.通过X射线衍射分析(XRD)、光电子能谱分析(XPS)、扫描电镜(SEM)、比表面积分析(BET)及光度法等手段研究了粉体结构及不同掺杂量对光催化活性的影响,确定了最佳掺杂量和热处理温度.以波长λ=312nm的光源对甲基橙水溶液进行光催化降解实验,讨论了光催化剂用量、甲基橙浓度、催化剂烧结时间、试液的pH值、光照时间等与甲基橙脱色率的关系.结果表明,该复合氧化物粉体平均粒径小于30nm,属立方晶系.在实验条件下,Cd2 的加入使Zn2SnO4的光催化活性明显提高,甲基橙的脱色率可达到98%.