壳聚糖及其衍生物对金属离子的吸附研究(上)

壳聚糖是一种天然高分子,在其分子结构的重复单元中有-NH2和-OH,因而对金属离子有较好地吸附和配位能力.本文较全面地综述了壳聚糖及其衍生物对金属离子的吸附性能,简述了它们与金属离子形成配合物的结构及吸附机理,并对其发展前景作了展望.其中上篇主要讲述了壳聚糖及其衍生物对金属离子吸附性能的研究进展.     

壳聚糖衍生物对Zn(Ⅱ)的吸附动力学及机理研究

利用吸附体系研究了Zn(Ⅱ)与壳聚糖衍生物的吸附行为。评价了Zn(Ⅱ)在壳聚糖衍生物上的吸附能力。探讨了壳聚糖衍生物对Zn(Ⅱ)的吸附动力学行为,动力学实验数据与二级动力学模型相吻合,表明化学吸附过程为速率控制步骤。通过红外光谱和X射线光电子能谱,研究了壳聚糖衍生物与Zn2 的配位机理。结果表明,配合物中Zn2 与α-酮戊二酸缩壳聚糖中羧基氧原子和氨基氮原子配位,与羟胺α-酮戊二酸缩壳聚糖配位的配位原子为—NH—中的氮原子、羟肟酸中的氧原子及羰基中的氧原子。     

壳聚糖及其衍生物对重金属离子的吸附

壳聚糖的结构中含有大量的—NH₂和—OH,因此其对重金属离子有优良的吸附作用。但是作为天然高分子物质,壳聚糖的吸附性能又受到其自身物理形态、原料来源、脱乙酰度及体系pH值的影响,因此,对其进行物理和化学改性是提高壳聚糖吸附性能、扩大应用范围的必要手段。本文综述了壳聚糖的改性方法及其衍生物对重金属离子吸附作用的研究进展,并对其在重金属污染废水处理方面的前景作了展望。     

Cu~(2 )壳聚糖螯合物及壳聚糖吸附Cu~(2 )机理的XPS研究

壳聚糖能选择性地吸附Ｍｇ2 、Ｎｉ2 、Ａｌ3 、Ａｇ 、Ｐｂ2 等金属离子[1],在环境保护、水处理、贵金属精制和回收等领域有广泛的应用前景[2 ].目前对壳聚糖吸附金属离子尤其是对Ｃｕ2 吸附的研究十分活跃 ,对壳聚糖吸附了Ｃｕ2 后形成的螯合物的研究也有报道[3,4 ].Ｉｎａｋｉ等[5]认为壳聚糖吸附Ｃｕ2 的机理是通过其表面—ＮＨ2 及其邻近的—ＯＨ与Ｃｕ2 进行络合反应从而吸附了Ｃｕ2 .本文用Ｘ射线光电子能谱 (ＸＰＳ)研究了壳聚糖及吸附Ｃｕ2 后形成的Ｃｕ2 壳聚糖螯合物表面的元素组成及其结合能的变化 ,根据结合能的变…     

壳聚糖与尿素的相互作用及其应用研究进展

尿素能够显著破坏甲壳素/壳聚糖分子氢键结构和疏水相互作用,增加其临界胶束浓度,促进多糖大分子的溶解,并能减少其在溶液中的自聚集现象.碱-尿素水溶液可以作为一种新型的甲壳素/壳聚糖绿色溶剂,有望用于对刺激性要求较为苛刻的食品、生物医学等领域.壳聚糖衍生物特别是其与过渡金属离子的配合物具有良好的尿素吸附功能,可用于尿毒症患者血液中小分子毒物的吸附,对机体刺激性小且不吸附血清蛋白等生物大分子.有望成为血液灌流治疗法中清除尿素等小分子毒性物质的良好吸附剂.壳聚糖还可以作为包膜材料,制备壳聚糖包膜尿素,与普通的包膜尿素相比性能更为优越.     

新型席夫碱基杯[4]芳烃-壳聚糖衍生物的合成及其对金属离子的吸附性能

交替利用微波、超声技术使杯[4]芳烃-1,3-二醛衍生物与预处理的壳聚糖发生缩合反应,合成了新的席夫碱基杯[4]芳烃-壳聚糖衍生物(4),其结构经IR和SEM表征.离子吸附实验表明,4对金属离子具有良好的吸附能力.     

3,5-二(2-吡嗪基)-4-氨基-1,2,4-三唑的水热合成及晶体结构

1,2,4-三唑及其衍生物作为配体与中过渡金属离子能形成多种配合物,这些配合物可表现出良好的生物活性或特殊的电磁性能.因此,过渡金属的三唑配合物的结构和物理特性引起了人们的广泛关注[1-6].     

基于壳聚糖及其衍生物的金属离子吸附剂的研究进展

综述了近年来以壳聚糖和壳聚糖衍生物为原料的金属离子吸附剂的研究进展．重点介绍了壳聚糖及其衍生物的交联和功能化反应，以及交联后的树脂对多种金属离子的吸附情况．常用的交联剂包括戊二醛、甲醛及环氧氟丙烷，(聚)乙二醇双缩水甘油醚等，壳聚糖树脂的功能化主要包括向其中引入冠醚、羧甲基等功能团，其中羧甲基化是最常用最有效的方法．另外，还介绍了金属离子模板壳聚糖树脂以及基于壳聚糖衍生物的蛇笼树脂的合成。     

N,N′-二(对甲基苯磺酰基)-3-甲氧亚胺基-1,5-二氮环辛烷的合成

多氮杂大环及其衍生物能够与金属离子形成多齿配合物 ,而中环二胺则是一种重要的双齿配体 ,能够与金属离子形成“夹心状”配合物[1] 。氮杂环化合物能够与许多重金属离子形成稳定配合物 ,该性质使其具有很有意义的应用前景 ,如在医药、诊断方面具有实用性 ,也可用于金属离子的分离和回收[2 ] 。本文合成了环上含有羟亚胺基烷氧亚胺基取代的八元环二胺衍生物 ,该化合物中亚胺基中的氮原子带有一对孤电子 ,可参与形成氢键或配位键 ,该化合物可用于有机合成中的中间体 ,其合成路线如下 :1　实验部分1 .1　仪器与试剂熔点仪为Ｂ櫣ｃｈｉ 5 1 0 ,…     

一维链状2-氧-1(4H)-吡啶乙酸桥联钙配位聚合物[Ca(2-OPA)_2(H_2O)_2]_n的合成、晶体结构及热稳定性研究

由于吡啶乙酸及其衍生物具有多种的键合模式和广泛的生物学特性,近十年来由其与金属离子所形成的配合物研究已引起了人们的极大关注[1]。目前的研究多集中于过渡金属和稀土金属离子体系[2￣5],而对于主族金属离子所形成的配合物报道较少。镁钙离子在调节细胞壁的功能、控制半透     

Effect of amino and polysiloxane groups on the chemical adsorption of polymers containing thiophosphate at the oil/metal interface under extreme pressure

Copolymers that separately contained thiophosphate–polysiloxane, thiophosphate–amino, and thiophosphate–polysiloxane–amino groups were synthesized and characterized. The performances of these synthesized copolymers on metal surfaces under a high load and rotary velocity were examined by the measurement of the oil temperature, frictional coefficient, and electrical contact resistance between two metal surfaces. The configuration of the adsorption layer was studied with energy‐dispersive spectrometry (EDS) and scanning electron microscopy (SEM). Copolymers that contained amino–thiophosphate groups reduced the frictional coefficient between two metal surfaces and markedly limit the increase in the oil temperature. Notably, a higher content of polysiloxane groups in the copolymer corresponded to an increased operating time to establish the adsorption layer on the metal surface. However, a higher content of amino groups reduced the time required for the layer to form. The adsorption layers that formed on the metal surfaces were investigated by EDS as phosphides produced by a chemical reaction of the thiophosphate‐containing copolymer with the metal surface. These adsorption layers on the metal surface were directly observed with SEM. The layer that formed on the metal surface of copolymers containing less polysiloxane and more amino groups was the thickest layer for all the synthesized copolymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1795–1803, 2002     

重金属离子敏感型聚合物胶体晶体的研究

以含有双硫键的二丙烯酰胱胺与双丙烯酰胺作为交联剂, 与单体丙烯酰胺紫外光引发聚合, 嵌入聚苯乙烯胶体晶体, 制备了聚丙烯酰胺胶体晶体水凝胶. 将水凝胶中双硫键打断形成巯基, 利用巯基可与重金属离子偶合的作用, 水凝胶体积收缩而改变胶体晶体中胶粒之间的距离, 根据胶体晶体带隙位移, 可分析水中重金属离子的浓度. 紫外可见光反射图谱表明, 胶体晶体带隙最大可蓝移约80 nm. 带隙移动与时间的关系曲线表明, 胶体晶体水凝胶对重金属离子有较好的灵敏度. 该体系可用于分析铅、锌等重金属离子.     

Coordination chemistry of N-tetraalkylated cyclam ligands—A status report

N-alkylation of macrocyclic amines has a significant impact on their properties as ligands for metal ions. This article examines the development of the coordination chemistry of N-alkylated cyclam ligands from its inception in 1973 with the first report of tetramethylcyclam. Emphasis is on: (1) the stereochemistry of metal complexation, including the effects of inclusion of functional groups in one or two of the N-alkyl groups; (2) the effect of N-alkylation on the metal–donor interaction; (3) the ability of tertiary amine ligands to stabilize complexes of metal ions in unusual oxidation states.     

Selective electrochemical recognition of ions in solution and at self-assembled monolayers

Quinone-functionalized calix[4]arenes having carboxylic acid groups or thiol groups were prepared and their spontaneous adsorption on silver and gold surfaces, respectively, was studied. Since the cavity-like structure of calixarenes was immobilized on the noble metal electrodes, they exhibited a selective affinity towards specific hard metal ions in aqueous media. Voltammetric and spectroscopic studies showed the well-ordered deposition of organic receptors and entrapment of metal ions. It also was found that the repeated capture and removal of metal ions reversibly with chelating agents such as ethylenediaminetetraacetic acid (EDTA) was possible. This is the first example, to our knowledge, of voltammetric detection of hard metal ions in aqueous media using a chemically modified electrode with redox-active macrocyclic receptors.     

Axial Bonding Capabilities of Square Planar d(8)-ML(4) Complexes. Theoretical Study and Structural Correlations

A qualitative molecular orbital study and a structural analysis of the bonding capabilities of the metal atoms in square planar ML(4) complexes of d(8) ions are presented. In addition to analyzing the donor-acceptor properties of the metal atom in such complexes, the following aspects are also studied: (a) the effect of axial groups (bases or acids) on the donor-acceptor properties of the metal atom; (b) the effect of the axial groups on the deviation of the ML(4) ensemble from planarity; (c) the effect of an axial group on the bond between the metal atom and another group in trans; and (d) the implications on chemical reactivity.     

STUDY ON THE INTERACTION BETWEEN POLYVINYLPYRROLIDONE AND PLATINUM METALS DURING THE FORMATION OF THE COLLOIDAL METAL NANOPARTICLES

Several PVP-stabilized colloidal platinum metals nanoparticles have been synthesized and characterized by FTIR and TEM.Comparing with the pure PVP,carbonyl groups of PVP in the mixture of PVP and the metal precursors or in the PVP-stabilized metal nanoparticles have obvious peak shifts in FTIR spectra.The peak shifts reveal the interaction between PVP and the metal species.The interaction between PVP and metal precursors has effect on the formation of the colloidal metal nanoparticles.Strength of the int...     

Interactions between metal chlorides and poly(vinyl pyrrolidone) in concentrated solutionsand solid‐state films

The rheological behavior of poly(vinyl pyrrolidone) (PVP)/N,N‐dimethylformamide (DMF) solutions containing metal chlorides (LiCl, CaCl₂, and CoCl₂) were investigated, and the results showed that the nature of the metal ions and their concentration had an obvious effect on the steady‐state rheological behavior of PVP–DMF solutions with different molecular weights. The apparent viscosity of the PVP–DMF solutions increased with an increasing metal‐ion concentration, and the viscosity increment was dependent on the metal‐ion variety_. For a CaCl₂‐containing PVP–DMF solution, for example, the critical shear rate at the onset of shear thinning became smaller with increasing CaCl₂ concentration. It was believed that multiple interactions among metal ions, carbonyl groups of PVP, and amide groups in DMF determined the solution properties of these complex fluids; therefore, ¹³C NMR spectroscopy was used to detect the interactions in systems of PVP–CaCl₂–DMF and PVP–LiCl–DMF solutions. NMR data showed that there were obvious interactions between the metal ions and the carbonyl groups of the PVP segments in the DMF solutions. Furthermore, IR spectra of the PVP/metal chloride composites demonstrated that the interaction between the metal ions and carbonyl groups in the PVP unit occurred and that the PVP chain underwent conformational variations with the metal‐ion concentration. DSC results indicated that the glass transition temperatures of the PVP/metal chloride composites increased with the addition of metal ions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1589–1598, 2007     

Metal ion complexation in acetonitrile by cone,di-ionised calix[4]arene-1,2-crown ethers with two pendant dansyl fluorophores

Four cone calix[4]arene-1,2-crown ethers each with two ionisable side arms containing dansyl groups are synthesised. The crown ether ring on the lower rim is varied from crown-4 to crown-5 with hydrogen or tert-butyl groups on the para position of the upper rim. Di(tetramethylammonium) salts of the di-ionised ligands are utilised for spectrofluorimetric titration experiments in MeCN. The influence of alkali metal, alkaline earth metal and selected transition and heavy metal (Co²⁺, Fe²⁺, Hg²⁺, Mn²⁺, Pb²⁺, Zn²⁺ and Fe³⁺) cations on the spectroscopic properties of the two dansyl groups linked to the lower rim of the conformationally locked, di-ionised calix[4]arene-1,2-crown ether frameworks is investigated by emission spectrophotometry. All of the metal cations induce red shifts in the emission spectra of the di-ionised ligands. The metal cations produce enhancement or quenching of the fluorescence emissions. Changes in the fluorescence emission as a function of the metal cation identity, the lower rim crown ether ring size and the absence or presence of upper rim tert-butyl groups are investigated.     

Scintigraphic Measurement of Liquid Holdup in Foam Fractionation Columns

Alumina-supported copper and copper-manganese oxide catalysts as well as the parent formates were characterized by means of FTIR spectroscopy in situ and nitrogen physisorption. The IR spectroscopic results are discussed on the basis of the deposition scheme proposed recently by Kapteijn et al. (J. Catal. 150, 94 (1994). The infrared bands in the high-frequency region (OH stretches) indicate that the aqueous copper species formed in the solutions are deposited on the basic and neutral surface OH groups, while as our previous studies show the aqueous manganese species are deposited on the basic and acidic OH groups. However, the aqueous manganese species are deposited on the basic and neutral OH groups in the presence of copper ions (pH 4.6-4.7). The deposition of the aqueous metal species on the protonated basic OH groups occurs as a result of the "ion-pairing" process. The driving forces resulting in the deposition of the aqueous metal species on the neutral OH groups are considered to be hydrogen bonds. The deposition of the formate ions is also discussed. The higher uptake of copper as compared to manganese is discussed in terms of the metal ion properties (electronic configuration, the ability to form hydrogen bonds of different strength, metal species-support interaction). The nitrogen physisorption shows that the initial mesoporous character of gamma-Al(2)O(3) structure does not change during impregnation. The r(FHH) values which characterized the adsorbent-adsorbate interaction forces are calculated. The comparative analysis of the pore size distribution curves of the oxide-supported samples and their parent formates proves to be a useful tool to elucidate the metal species-support interaction strength. Copyright 2000 Academic Press.