锌铝水滑石的控制合成及吸附性能研究

采用简单的水热法和均匀共沉淀法合成了不同形貌的锌铝水滑石（Zn Al-LDHs）,通过XRD、SEM、N2吸附等对合成的试样进行了表征;研究了甲基橙在Zn Al-LDHs上的吸附性能,考察了酸碱度和温度等对其吸附性能的影响。结果表明：采用水热法,添加乙二醇可合成出海胆状Zn Al-LDHs,添加乙醇可合成出花状Zn Al-LDHs;采用均匀共沉淀法可合成出片状Zn Al-LDHs。其中海胆状Zn Al-LDHs的比表面积最高,达147.3 m2/g,对甲基橙具有优异的吸附性能。在25℃,初始p H=3的条件下,0.2 g/L海胆状Zn Al-LDHs对100 mg/L甲基橙的吸附容量和去除率分别达368 mg/g和73.65%,其吸附动力学和吸附等温线分别符合准二级速率方程和Langmuir方程。     

有机改性水滑石对染料废水的吸附处理研究

采用十六烷基三甲基溴化铵改性制得有机改性水滑石,并用XRD和红外光谱进行表征。考察了有机改性水滑石对染料废水的吸附能力及相关影响因素。结果表明,水滑石改性后对染料吸附能力提高,染料去除率随改性水滑石投加量的增加而提高,随染料初始浓度的增大而降低,温度太高不利于染料的吸附,p H对染料废水的处理效果影响不大。改性水滑石对染料的吸附可用Langmuir等温吸附方程拟合,二级吸附模型能很好地描述改性水滑石对染料的吸附行为。表征结果表明十六烷基三甲基溴化铵进入到水滑石层间,但水滑石结构并没有发生大的变化。     

锌铝水滑石微米球的合成及吸附性能研究

采用多步法合成锌铝复合氧化物（LDO）与锌铝水滑石（LDHs）,通过XRD、SEM、TEM、N2吸附等对合成的试样进行了表征;研究了甲基橙（MO）在LDO及LDHs上的吸附性能,考察了pH值和温度对吸附性能的影响,并结合红外光谱和XRD对吸附机理进行探讨.结果表明：所制备的LDO和LDHs呈空心球状,直径为3～5 μm,分散性较好,LDO比表面积高达210.2 m2/g;LDO对甲基橙具有优异的吸附性能,在25℃,初始pH=3的条件下,0.2 g/L LDO对100 mg/L甲基橙的吸附容量和去除率分别达497 mg/g和99.4％,其吸附等温线和吸附动力学分别符合Langmuir方程和准二级速率方程.     

Synthesis and binding properties of polymeric calix[4]arene nitriles

Two new polymers containing pendant calix[4]arene units with nitrile functionalities at their lower rim have been synthesized via radical initiated reactions involving a vinylic monomer 6 {5,11,17,23-tetra-tert-butyl-25,26,27-tris(cyanomethoxy)-28-(2-acryloyloxy) ethoxycalix[4]arene} and with styrene. A five atom spacer group was incorporated between the bulky calixarene core and the acrylate moiety in order to minimize steric interactions which proved to impede the polymerization. The complexation studies were made by using liquid–liquid extraction procedures. It has been deduced from the observations that both polymers show a good selectivity towards Hg²⁺ like their precursor 5,11,17,23-tetra-tert-butyl-25,26,27-tricyanomethoxy-28-(2-hydroxy)ethoxycalix[4]arene 5, which supports their utility as adsorbents or potential candidate materials for fabricating membranes and sensors, which can separate or detect Hg²⁺ metal ions in a high selectivity.     

New sulfur adsorbents derived from layered double hydroxides: I: Synthesis and COS adsorption

Mixed oxides, prepared via the thermal decomposition of layered double hydroxides (LDHs), were screened gravimetrically for their ability to adsorb carbonyl sulfide (COS). Based on promising results obtained for Ni/Mg/Al, Ni/Mg/Fe and Co/Mg/Al mixed oxides, a study was undertaken to optimize the composition of these materials for COS adsorption. To investigate the effect of the M(II):M(III) ratio, LDHs of the type [M_zMg_yAl_x(OH)₂](CO₃)_x/2·0.5H₂O (where M = Ni or Co, and x + y + z = 1) were prepared at values of x corresponding to 0.33 and 0.20. Simultaneously, the elemental ratio of transition metal to magnesium (z/y) was varied. Mixed oxides obtained from the resulting LDHs were tested in fixed bed mode with a feed of 100 ppm COS in N₂ to determine breakthrough capacity. In general Ni/Mg/Al mixed oxides showed the best performance, a composition with Ni/Mg/Al = 0.32/0.48/0.20 showing the best adsorption capacity. Treatment of the spent adsorbent under an atmosphere of 5% H₂ in N₂ at 450 °C was found to provide an effective means of restoring the adsorption capacity over two cycles of adsorption and regeneration, although after three such cycles, adsorption capacity decreased.     

Mg(Zn)-Al(Fe)层状双氢氧化物磷酸根吸附性能研究

采用共沉淀法合成Mg-Al-LDH、Mg-Fe-LDH和Zn-Al-LDH三类不同的层状双金属氢氧化物,系统研究其磷酸根吸附行为和影响因素。结果表明,Mg-Al-LDH对于磷酸根的饱和吸附量可达99.17 mg/g,吸附过程符合Langmuir模型和准二级动力学模型,弱酸性环境和金属阳离子的存在有利于磷酸根的吸附,而阴离子的加入则会抑制磷酸根的吸附。磷酸根在Mg-Al-LDH表面的吸附是静电吸引、化学吸附和阴离子插层共同作用的结果。     

ZnAlLa类水滑石对污泥脱水液中磷酸根的吸附

通过共沉淀法合成了ZnAlLa三元类水滑石,并考察了其结构特征和对磷酸根的吸附性能。结果表明,在保持类水滑石层状结构的条件下,La的适量掺杂可增强吸附剂对磷酸根的吸附。当Zn∶Al∶La摩尔比为2.00∶0.90∶0.10时,ZnAlLa类水滑石在24h内对污泥脱水液中磷酸根的吸附量为35.15mgP.g-1,比无La时的吸附量提高了41.9%。300℃焙烧处理后,ZnAlLa样品转化为亚稳态的复合金属氧化物,同时比表面积明显增加,其磷酸根吸附量约为焙烧前的1.48倍。ZnAlLa对磷酸根的吸附在pH变化及竞争离子存在时表现出较强的稳定性。该吸附剂对污泥脱水液中磷酸根的吸附符合假二级吸附动力学;吸附等温线表现为Langmuir型。     

几种新型杯[4]芳烃衍生物的合成

以对叔丁基苯酚为起始原料,通过缩合、一步取代反应合成了对叔丁基杯[4]芳烃的衍生物,两步取代反应合成了对叔丁基杯[4]芳烃的衍生物。用FT-IR,^1HNMR,FAB-MS对产物的结构进行了表征。     

镍铝层状双金属氢氧化物的亲油改性及其吸油性能

Ni^(2+)与Al^(3+)物质的量比为3∶1,尿素为沉淀剂,通过水热合成技术制备镍铝层状双金属氢氧化物层状材料(Ni^(2+)-Al^(3+)-CO_3^(2-)-LDHs)。以Ni^(2+)-Al^(3+)-CO_3^(2-)-LDHs为前驱体,分别与Na Cl和十二烷基磺酸钠[CH_3(CH_2)_(11)SO_3Na]进行离子交换反应得到Ni^(2+)-Al^(3+)-CH_3(CH_2)_(11)SO_3^--LDHs新型吸附剂材料。将CH_3(CH_2)_(11)SO_3^-亲油客体负载到Ni^(2+)-Al^(3+)-LDHs层状材料层间,实现镍铝层状双金属氢氧化物的亲油改性。利用Ni^(2+)-Al^(3+)-CH_3(CH_2)_(11)SO_3^--LDHs复合材料对含油污水进行处理,结果表明,镍铝层状双金属氢氧化物亲油改性后增强了LDHs的亲油吸附性能。     

Synthesis and characterization of calix[4]arene-based copolyethers and polyurethanes. Ionophoric properties and extraction abilities towards metal cations of polymeric calix[4]arene urethanes

Copolyethers and polyurethanes containing lower and upper rim calix[4]arene units in the fixed cone conformation were prepared in good yield by polycondensation reactions of distal calix[4]arene diols with bisphenol-A/dibromomethane and 2,4-tolylendiisocyanate (TDI), respectively. In a similar way were prepared calix[4]arene-crown-5 and -crown-6 polyurethanes in the fixed 1,3-alternate conformation by condensation of TDI with lower rim calixcrown-5 and calixcrown-6 diols. However, the poor solubility in common organic solvents of the copolyether derivatives (M_w=11,100-11,600 g/mol) hampered further studies on their ionophoric properties. Aiming to obtain model compounds for the investigation of both extraction abilities and ionophoric properties of the polyurethane materials, several bis-urethanes were also synthesized by reaction of the calix[4]arene diols with p-tolylisocyanate (TI). The extraction ability measurements of monomeric and polymeric calix[4]arene urethanes (M_w=12,300-83,500 g/mol) towards alkali metal cations (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺) and Ag⁺showed a remarkable efficiency and selectivity of calixcrown-6 polyurethane toward Rb⁺, Cs⁺and Ag⁺.     

Electrochemistry and ion-sensing properties of calix[4]arene derivatives

The cyclic voltammetric properties of several substituted calix[4]arenes were examined in acetonitrile and dichloromethane. The compounds that contained one phenolic group in the macrocyclic cavity were able to be electrochemically oxidised at positive potentials. In acetonitrile, cyclic voltammetry experiments indicated that the phenolic compounds were oxidised in a two-electron (one-proton) process over all measured scan rates (up to 50 V s⁻¹), while in dichloromethane, the oxidation process occurred by one-electron at scan rates ≥5 V s⁻¹, to most likely form the radical cations. In both solvents, longer timescale (minutes to hours) controlled potential coulometry experiments indicated that the oxidation process occurred by two-electrons per molecule, to form reactive diamagnetic cations that could not be reduced back to the starting materials under electrolysis conditions. The ion-sensing properties of the compounds were investigated in polymer membrane ion-selective electrodes and it was found that they responded reversibly in a Nernstian fashion to Groups 1 and 2 metals and had the highest selectivity to the cesium cation.     

层状复合氢氧化物的结构调控及其吸附重金属离子的研究进展

层状复合氢氧化物（LDHs）是具有特殊层状结构的阴离子黏土,具有化学组成可调、比表面积大及结构记忆效应独特等性质,在废水处理方面备受关注。调控LDHs自身结构,是进一步扩大其应用范围、提高其吸附性能的有效途径。该文介绍了LDHs特殊的层状结构和其自身性质;总结了LDHs最常用的制备方法,即共沉淀法、离子交换法、尿素水解法、煅烧复原法和溶胶-凝胶法等,分别介绍了各种制备方法的原理和特点;综述了LDHs的结构调控对其吸附重金属离子性能的影响,并总结了LDHs对重金属离子的吸附机理;最后,指出了目前LDHs在处理含有重金属离子废水研究中面临的挑战,并对该材料未来的研究方向和发展趋势进行了展望。     

Effect of template constraints on adsorption properties of synthetic carbons prepared within the gallery of layered double hydroxides

Mg-Al layered double hydroxides have been synthesized and 1,5-naphthalene disulfonate dianions have been intercalated; the organic molecules were carbonized within the layered framework. For comparison, a reference carbon was prepared from the sodium salt of the 1,5-naphthalene disulfonic acid precursor using conventional carbonization under the same thermal and post-treatment conditions. The surface properties of the carbonized product extracted from the carbon-mixed oxide nanocomposite have been studied by adsorption techniques and the results compared to the adsorption characteristics of the reference carbon. The Sorption of nitrogen at 77 K and carbon dioxide at 298 K demonstrate that, although the two carbons have almost the same specific surface area and total pore volumes, there is a significant difference in their micropore structure. Micropore size distributions calculated from adsorption isotherms of methane and sulfur hexafluoride at near ambient temperatures reveal a more heterogeneous micropore structure for the template derived carbon compared to the reference. The factors controlling micropore structure development during two-dimensional carbonization are discussed based on DTA, results of sorption of carbon dioxide and FTIR spectroscopic measurements.     

水滑石类材料的制备及在水污染治理中的应用

本文简要介绍了目前国内外水滑石类材料的各种制备方法,包括共沉淀法、焙烧还原法、离子交换法等。同时总结了其作为催化剂和离子交换剂在修复阴离子污染水体,印染废水脱色、重金属的去除等方面的应用。     

MoO2-4插层Mg/Al/Ti-LDHs的结构及其催化性能研究

用共沉淀法制备层板含钛的镁铝钛三元层状双金属氢氧化物(LDHs),将其作为前驱体,利用离子交换法制备MoO2-4阴离子插层结构的MoO2/4-LDHs型超分子材料,通过X射线衍射(XRD)、红外光谱(FT-IR)和热重及差热分析(TG-DTA)等对插层化合物及其焙烧产物的结构进行了分析,结果表明,通过共沉淀和离子交换法成功得到晶体结构较为理想的层板含Ti4 的三元LDHs以及具有超分子结构的MoO42-4一插层LDH化合物.研究发现,MoO2-4-LDHs在500 ℃焙烧,产物在丙烯环氧化反应中具有较高的催化活性,这与形成一定结合形式和组成的多元复合金属氧化物有关.     

新型杯[4]芳烃醚的合成及其酯交换反应研究

以正丁醛杯[4]芳烃母体化合物1与溴乙酸乙酯反应,得到杯[4]芳烃醚2,再与9-蒽甲醇进行酯交换反应,得到目标化合物3。对化合物2和目标化合物3的结构进行了熔点、红外光谱、核磁共振谱的表征。     

Self-assembled hierarchical porous layered double hydroxides by solvothermal method and their application for capacitors

In this paper, for the first time, Ni/Al layered double hydroxides (LDHs) with high specific surface area and high porosity were developed via a facile and environmentally friendly solvothermal approach. The obtained Ni/Al LDHs have a diameter of 1-10 μm, which are self-assembled by 15 nm-sized primary particles and 200 nm size secondary particles. The BET surface area of the sample is determined to about 300 m² g⁻¹, which is about three times than that prepared by conventional hydrothermal route. The average pore size is 3.97 nm. Notedly, the specific capacitance of this hierarchical porous Ni/Al LDHs reaches 477 F g⁻¹ at a current density of 2.5 A g⁻¹, which is nearly double that of Ni/Al LDHs synthesized by conventional hydrothermal procedure. The capacitance loss is less than 5% after 400 charge-discharge cycles, suggesting the high potential as electrode materials in electrochemical capacitors. The formation mechanism of self-assembled hierarchical porous Ni/Al LDHs through solvothermal method was also proposed.     

Soft-chemical treatment of transition-metal-containing layered double hydroxides and their application in porous materials

Layered double hydroxides (LDH) containing Co or Ni as the divalent cation and Al or Fe as the trivalent cation were prepared by hydrothermal treatment. The LDH phase containing Al can be prepared at a pH of ca. 7, whereas the LDH phase containing Fe can be prepared at pH 10. The chemical composition of the LDH was estimated by the calculation of the weighted mean electronegativity of the cations present in the aqueous metal solution. The decarbonated LDHs are intercalated by sodium dodecyl sulfate and can be exfoliated in 1-butanol solution by ultrasonication. The resulting LDH aggregates with a card-house structure that can then be deposited from these exfoliated colloidal solutions by sodium carbonate. For Ni/Al and Ni/Fe LDHs, in particular, the specific surface area and pore volume drastically increased owing to the card-house texture formed by exfoliation and redeposition.     

Synthesis,extraction, and adsorption properties of calix[4]arene‐poly(ethylene‐glycol) crosslinked polymer

Novel calix[4]arene‐poly(ethylene glycol) crosslinked polymer (CCP) has been synthesized by the polycondensation reaction between a p‐tert‐butylcalix[4]arene derivative and dihydroxyl capped poly(ethylene glycol) (DHPEG, M_n = 1000) catalyzed by neodymium tosylate. The hydrogel, consisted of 66.9% water and 33.1% CCP, can selectively extract aromatic organic molecules from aqueous solution according to the diameter of the guest molecules, which infers that the diameter of the calix[4]arene cavity is about 5.4 Å and the conformation of calix[4]arene units altered from cone conformation to 1,3‐alternate conformation during the polycondensation reaction. Furthermore, CCP can also adsorb naphthalene from gas phase, showing much higher capacity than active carbon does, which may have some potential applications in the field of separation and environment protection. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

水滑石纳米材料特性及其在电化学生物传感器方面的应用

阐述了水滑石纳米材料结构和性能之间的关系及近年来水滑石纳米材料在电化学生物传感器方面应用的最新进展。重点介绍了水滑石纳米材料在吸附生物酶制备电化学传感器、水滑石纳米片固定生物酶制备电化学传感器、水滑石纳米片固定其它活性组分制备电化学传感器、水滑石自构筑电化学传感器等方面的应用。着重对水滑石纳米材料制备电化学传感器的机理和制备方法进行了系统概述。提出了水滑石纳米材料构筑电化学生物传感器应用研究的发展趋势：对水滑石纳米材料进行多层、多组分、微型化和阵列化等多样化设计,指出高选择性和高灵敏度检测是未来新型电化学生物传感器应用研究的主要发展方向。