聚合氯化铝中Al13形态的分离纯化方法及特性

采用柱层析法、沉淀置换法和乙醇-丙酮混合溶剂法对聚合氯化铝(PAC)中的Al₁₃形态进行了分离提纯, 采用Al-Ferron逐时络合比色法, ²⁷Al NMR, TEM, SEM, 电位测定法, 粒度测定法等多种现代分析仪器和方法对不同分离提纯方法得到的Al₁₃形态进行了分析表征和比较, 并初步比较研究了Al₁₃形态的水处理效果. 实验结果表明, 不同分离纯化方法得到的 Al₁₃形态具有不同的结构形貌、粒度分布、电性和水处理效果. 乙醇-丙酮混合溶剂法得到的Al₁₃形态具有良好的纯度和水处理效果. 该研究初步证实了Al₁₃是PAC中的最佳絮凝形态.     

高浓度高Al13含量聚合氯化铝溶液的制备

通过快速加碱在82 ℃下合成0.2 mol·L^-1、Al_b为60%～70%的低浓度高Al_b聚合氯化铝(L-PAC)，在热侧温度为50～95 ℃，冷侧温度约9～12 ℃的条件下进行膜蒸馏浓缩，制备出总铝浓度在2 mol·L^-1以上，Al_b含量大于90%，Al₁₃含量约为70%的高浓度高Al_b含量的聚合氯化铝溶液。对膜蒸馏浓缩过程中热侧温度、PAC的碱化度和初始pH值等因素对最终聚合氯化铝溶液产品中聚铝形态分布、总铝浓度的影响进行了初步研究，发现在热侧温度低于70 ℃、碱化度为2.47、初始pH值为5.0 ± 0.2的条件下，可以得到高浓度、高Al_b含量的聚合氯化铝溶液，纳米Al₁₃形态在较高的浓度下可以存在；低温贮存条件下，高浓度PAC中Al_b相当稳定。     

KF-Al2O3催化下吡喃并[2,3-d]嘧啶衍生物的一步合成

以芳醛、丙二腈和4,6-二羟基嘧啶为原料, 以乙醇为溶剂, 在80 ℃以KF/Al₂O₃为催化剂合成了一系列的吡喃并[2,3-d]嘧啶衍生物, 产物的结构通过IR, ¹H NMR和元素分析表征, 并进一步通过X射线衍射分析确证.     

KF/Al2O3催化下芳醛和4-羟基喹啉-2-酮的反应研究

以芳醛和4-羟基喹啉-2-酮为原料, 在KF/Al₂O₃催化下以乙醇为溶剂, 在80 ℃合成了一系列新的双(4-羟基-2-氧代喹啉-3-基)-芳基甲烷衍生物, 反应条件温和, 产率较高, 并通过IR, ¹H NMR和元素分析确证产物的结构.     

KF/Al2O3催化下2-氨基-4-芳基-4H-吡喃并[3,2-c]香豆素衍生物的一步合成

以芳醛、4-羟基香豆素和丙二腈或氰乙酸酯为原料, 在KF/Al₂O₃催化下以乙醇为溶剂, 在80 ℃合成了一系列2-氨基-4-芳基-4H-吡喃并[3,2-c]香豆素衍生物, 并通过IR, ¹H NMR和元素分析确证产物的结构.     

钙对铝水解聚合反应及聚合铝物化特性的影响

The polyaluminum chloride containing Ca was prepared by adding Ca before and after the aluminium polymerization, respectively. The effects of Ca on the hydrolysis and polymerization of aluminum, the characteristic of aluminum species, the ζ potential and viscosity of PAC were also studied. The experimental results show that the introduction of Ca retards the formation of Al precipitates during the hydrolysis and polymerization of aluminum and increases the contents of Al_m and Al₁₃ in PAC. Aluminum species can complex with Ca to form heteronuclear hydroxo complexes, which decreases the chemical shifts of Al_m and Al₁₃ in NMR. The ζ potential and the viscosity of PAC increase with the rise of Ca/Al molar ratio. Comparing with adding Ca after the aluminium polymerization, there are much more Al-Ca heteronuclear hydroxo complexes formed by adding Ca before the polymerization, which leads to a more obvious influence of Ca/Al molar ratio on the ζ potential and the viscosity of PAC.     

Sr3Al2O6∶Eu2+红色发光纳米晶的新型形貌与发光性能的研究

A red luminescent Sr₃Al₂O₆∶Eu²⁺ nanocrystallites with new morphology were synthesized by sol-gel route assisted by microwave irradiation. The phosphor powders were characterized by X-ray diffraction (XRD)， scanning electron microscopy (SEM) and fluorescence spectroscopy. The results reveal that the calcination temperature of the Sr₃Al₂O₆∶Eu²⁺ phosphor crystallites greatly affects its morphology. With temperature increasing， the phosphor crystallites morphology showed primarily from nanorod-like， mixture of nanorod and flower-like to homogeneous flower-like morphology. The effects of new morphology on luminescent properties of phosphors were investigated. Uniformly dispersed flower-like Sr₃Al₂O₆∶Eu²⁺ phosphor powders showed the strongest luminescent intensity and the longest afterglow time.     

以α型氢氧化物前驱体制备LiNi0.8Co0.15Al0.05O2及其电化学性能

本文采用球形Al/Co部分取代α型Ni(OH)₂为前驱体成功制备了锂离子电池正极材料LiNi_0.8Co_0.15Al_0.05O₂。首先采用氢氧化钠与碳酸钠为沉淀剂合成出Al/Co部分取代α型Ni(OH)₂,然后将之与LiOH·H₂O混合,最后在氧气气氛中不同温度下热处理8 h,即可得到球形LiNi_0.8Co_0.15Al_0.05O₂材料。X射线衍射结果表明,LiNi_0.8Co_0.15Al_0.05O₂材料为α-NaFeO₂相。扫描电镜结果表明,材料颗粒形貌为球形。热重分析结果表明合成LiNi_0.8Co_0.15Al_0.05O₂的主反应温度在700～750 ℃之间。振实密度测试结果表明, 750 ℃下制备的LiNi_0.8Co_0.15Al_0.05O₂材料可达2.2 g·cm^-3。恒流充放电结果表明,该材料在0.5 mA·cm^-2电流密度下,在3.0～4.3 V间的首次充电容量可达210.3 mAh·g^-1,首次放电容量为179.7 mAh·g^-1,充放电效率为85.4%。与采用以β-Ni_0.85Co_0.15(OH)₂为前驱体合成的LiNi_0.85Co_0.15O₂和Al掺杂的LiNi_0.8Co_0.15Al_0.05O₂相比,尽管其首次放电容量与放电效率都有所降低,但循环性能有所提高,50周期后容量仍为初始容量的89.5％。研究表明,以球形Al/Co部分取代α型Ni(OH)₂作为前驱体为球形氧化镍钴铝锂材料的制备提供了一条新的途径。     

AlmN2和AlmN2＋ (m＝1～8)团簇结构与稳定性的量子化学研究

用密度泛函理论(DFT)的B3LYP方法, 在6-311G*水平上对Al_mN₂和Al_mN₂^＋ (m＝1～8)团簇的几何构型、电子结构、振动频率和分子轨道进行了理论研究. 结果表明, Al_mN₂类团簇的基态结构有两种基本构型, 一种是以N—N键为核心周围与Al原子相配位形成的, 一种是由两个Al_nN (n≤m/2)分子碎片通过共用Al原子或Al—Al键相互结合形成的. 对Al_nN分子碎片相互结合形成结构的绝热电离能讨论得到, m为偶数的团簇比m为奇数的稳定.     

KF/Al2O3催化下吡啶并[2,3-d]嘧啶衍生物的三组分一步合成

以芳醛、丙二腈和2,6-二羟基-4-氨基嘧啶为原料, 在KF/Al₂O₃催化下以乙醇为溶剂, 在80 ℃三组分一步合成了一系列吡啶并[2,3-d]嘧啶衍生物, 有趣的是在空气氧化作用下进一步发生了芳构化作用. 和其它合成方法相比, 该方法具有反应条件温和、容易操作和产率较高等优点, 并通过IR, ¹H NMR和元素分析确证产物的结构.     

Al13形态的分离纯化与表征

采用乙醇－丙酮沉淀法提取了聚合氰化铝（PAC）中的Al13形态并采用Al-Ferron逐时络合比色法、27Al NMR，SEM，TEM和XRD等方法对所获得的水溶性Al13形态进行了分析表征．结果表明，通过向聚合氯化铝溶液中不断加入乙醇和丙酮，聚合氯化铝中各形态组分便会按照在混合溶剂中溶解度由小到大的顺序，依次从溶液中析出．截取中间组分得到Al13 形态．Al-Ferron逐时络合比色法和27Al NMR的鉴定结果表明，采用该方法分离提纯得到的样品中Al13 的含量达95％以上．SEM和TEM的鉴定结果表明，固体Al13聚集体主要为棱柱、单斜长方体和四面体等多面晶粒，小的聚集体粒径约 200mm，大的可达 2μm．溶液中的Al13 形态聚集成束并以枝状排列．XRD结果表明，Al13的特征衍射峰出现在2θ为5°～25°的范围内．     

Characterzation and separation of Al13 species using gel-filtration chromatography

A polyaluminum chloride (PAC) sample was prepared using a slow alkaline titration method. The Bio-Gel P-100 gel column chromatographic technique was used to separate and characterize the various forms of aluminum present in the prepared PAC solution. The effluents from a gel column were monitored using online chemical method: Al-Ferron timed complexation spectrophotometry and by 27Al nuclear magnetic resonance (NMR) spectroscopy. Effects of different experimental conditions such as eluent flow rate, ionic strength and pH on separation of Al13 were investigated. Experimental results indicated that molecule size exclusion was not the only parameter affecting the column chromatographic separation efficiency of Al13 but molecule charge as well. Reducing the eluent flow rate, increasing the ionic strength and suitable pH resulted in increase in the separation efficiency. Experimental results clearly indicated that by varying the experimental conditions, it is possible to produce pure Al13 species using a gel column chromatographic technique.     

Characterization and separation of Al_(13) species using gel-filtration chromatography

Polyaluminum chloride (PAC) coagulant has been developed and widely used in water and wastewater treatment industry since the 1980s[1]. PAC is normally made by partial hydrolysis of acid aluminum chloride solution using slow alkaline titration method. However, this method would result in many different Al species. Among these Al species, it seems that tridecamer (Al13O4(OH) 724 , often denoted by Al13) is the most effective and stable polymeric Al species for water and wastewater treatme…     

Preparation and characterization of polyaluminum chloride containing high content of Al13 and active chlorine

This paper introduces a new electrochemical method for preparation of polyaluminum chloride (PACl) which contains high content of Al₁₃ and active chlorine and presents integrated properties of flocculation with oxidation. E-PACl (PACl prepared by electrolysis process) samples were successfully prepared in an electrochemical reactor, which used Ti/RuO₂–TiO₂ anodes and Ti cathodes. Anode potential was the key electrochemical parameter that needed to be controlled at 1.5 V to ensure the maximal current efficiency of main reactions in electrolysis process. Analyses by ferron colorimetric method and ²⁷Al NMR spectroscopy indicated that Al₁₃ was the predominant species in the final product when total Al concentration (Al_T) was in the range of 0.1–1.5 mol/L. The amount of active chlorine was in inverse proportion to Al_T. Contents of the most active component, Al₁₃ and active chlorine could respectively reach 90.9% and 5650 mg/L with Al_T = 0.51 mol/L and basicity (B, OH/Al molar ratios) = 2.23 in the liquid product of PACl (E-PACl2). In E-PACl2, the sulfate precipitate of Al₁₃ was the unique material detected by X-ray diffraction patterns and clusters of small spheres that might be the aggregates of Al₁₃ were observed on the surface of its air-dried sample by atomic force microscopy. Results of dynamic light scattering showed that the particle size distributions of E-PACl were related with the Al species distributions and ageing time. The active chlorine in E-PACl2 performed well on disinfection of raw water.     

Investigation of dynamic processing on aluminum floc aggregation:Cyclic shearing recovery and effect of sulfate ion

The floc formation and re-aggregation potential and the effects of sulfate on coagulation by AlCl3, polyaluminum chloride (PAC), and Al13 species using a photometric dispersion analyzer (PDA) are in- vestigated. It is found that the recovery level from shearing is the highest for the Al13 species. This is likely a result of increased collision efficiency due to more effective charge neutralization. The ex- perimental results show that sulfate has a significant effect on coagulation and promoting aggregation of hydrolyzed species for the Al13 species. It results in significant improvement of the coagulation effi- ciency through an electrostatic patch effect. The results further indicate that zeta potential of the parti- cle suspension is not the only indicator for the coagulant efficiency when precipitate formation sig- nificantly improves coagulation.     

基于Endo-M N175Q糖链转移反应与丙酮富集糖肽的LC-MS分析糖蛋白N-糖链

基于化学酶标记和丙酮富集糖肽方法,建立了一种可靠、有效、简单的糖蛋白N-糖链分析方法。以唾液酸糖肽(SGP)为模型糖肽,比较了样品中丙酮加入量对SGP的富集效果,最终选择加入样品体积5倍量的丙酮。用丙酮富集经胰蛋白处理的核糖核酸酶B(RNase B)酶解液中的糖肽,以富集分离得到的糖肽(糖基供体)和PDPZ-Boc-Asn-GlcNAc(糖基受体)作为酶反应底物,进行Endo-M N175Q的转糖基反应,得到PDPZBoc-Asn-GlcNAc-N-糖链标记物。采用YMC C18色谱柱为分析柱,10 mmol/L甲酸铵-乙腈为流动相梯度洗脱,经液相色谱-串联质谱(LC-MS)检测得到5种高甘露糖型糖链。结果表明,丙酮可有效地富集大量肽和少量糖肽混合溶液中的糖肽,Endo-M N175Q可将天然糖肽的糖链转移到PDPZ-Boc-Asn-GlcNAc受体上。将该方法应用于胎球蛋白N-糖链分析,检测到5种复杂型N-糖链。该研究为各种糖蛋白N-糖链检测提供了新的分析方法。     

沉淀法高效制备聚多巴胺纳米粒子

为得到分散性和稳定性较好的聚多巴胺纳米粒子,利用“沉淀-再分散法”高效制备了聚多巴胺纳米粒子水分散液。 首先利用溶液氧化法制备了分散在水/乙醇中的聚多巴胺纳米粒子,然后向分散液中加入丙酮使聚多巴胺纳米粒子絮凝。 收集沉降物,用丙酮冲洗并干燥后,加水重新分散得到纯化的聚多巴胺纳米粒子水分散液。 丙酮沉淀法得到的聚多巴胺纳米粒子形貌规整,分散性好,粒径分布在250 nm左右,在水中具有良好的储存稳定性和光热性能,与传统的超速离心提纯法相比,产率可提高57.4%。 此方法为其之后在药物载体及光热治疗等方面的应用研究提供了便利。     

Losses of chlorophylls and carotenoids in aqueous acetone and methanol extracts prepared for RPHPLC analysis of pigments

Summary RPHPLC methods for analysis of photosynthetic pigments (chlorophylls and carotenoids) usually require addition of water to methanol or acetone extracts to prevent distortion of early-eluting peaks corresponding to the more polar compounds. In this work we have investigated the short-(<2 min) and long-term (up to 48 h) effect of adding water to acetone and methanol extracts from two marine phytoplankton species,Emiliania hyxleyi andDunaliella tertiolecta. Solvent extracts were prepared and separated into fractions that were subsequently diluted with water to 90%, 80%, 70%, 60%, 50%, and 40% for methanol, and the same range extended to 30% and 20% for acetone. Changes in pigment concentration with time were followed spectrophotometrically and chromatographically. Losses of pigments as a result of precipitation were clearly observed immediately after dilution of acetone extracts to 60% or less and methanol extracts to 80% or less. For chlorophyll a the most substantial losses were recorded for 50% acetone (up to 27% decrease) and for 70% methanol (31% decrease). This effect increased considerably with time. Only for 90% and 80% acetone were the initial concentrations of all the pigments unchanged after 24h, and even up to 48 h. In contrast, more than 60% and 57% of the initial amounts of chlorophyll a were lost after 24 h in 50% acetone and 70% methanol extracts, respectively. These losses increased to 83% and 60% after 48 h. There was a clear correlation between the polarity of a pigment and the polarity of the solvent at which maximum precipitation occurred. Losses of pigment from pure acetone and methanol extracts with time were also observed, although we attribute these to pigment degradation rather than precipitation. Some of the losses occurring with time can be avoided by use of autosamplers in which the sample can be mixed with water immediately before injection.     

Characterization and separation of Al13 species using gel-filtration chromatography

A polyaluminum chloride (PAC) sample was prepared using a slow alkaline titration method. The Bio-Gel P-100 gel column chromatographic technique was used to separate and characterize the various forms of aluminum present in the prepared PAC solution. The effluents from a gel column were monitored using online chemical method: Al-Ferron timed complexation spectrophotometry and by ²⁷Al nuclear magnetic resonance (NMR) spectroscopy. Effects of different experimental conditions such as eluent flow rate, ionic strength and pH on separation of Al₁₃ were investigated. Experimental results indicated that molecule size exclusion was not the only parameter affecting the column chromatographic separation efficiency of Al₁₃ but molecule charge as well. Reducing the eluent flow rate, increasing the ionic strength and suitable pH resulted in increase in the separation efficiency. Experimental results clearly indicated that by varying the experimental conditions, it is possible to produce pure Al₁₃ species using a gel column chromatographic technique.     

Characterization and separation of Al13 species using gel-filtration chromatography

A polyaluminum chloride (PAC) sample was prepared using a slow alkaline titration method. The Bio-Gel P-100 gel column chromatographic technique was used to separate and characterize the various forms of aluminum present in the prepared PAC solution. The effluents from a gel column were monitored using online chemical method: Al-Ferron timed complexation spectrophotometry and by ²⁷Al nuclear magnetic resonance (NMR) spectroscopy. Effects of different experimental conditions such as eluent flow rate, ionic strength and pH on separation of Al₁₃ were investigated. Experimental results indicated that molecule size exclusion was not the only parameter affecting the column chromatographic separation efficiency of Al₁₃ but molecule charge as well. Reducing the eluent flow rate, increasing the ionic strength and suitable pH resulted in increase in the separation efficiency. Experimental results clearly indicated that by varying the experimental conditions, it is possible to produce pure Al₁₃ species using a gel column chromatographic technique.