化学富集X射线荧光光谱法测定微量元素的方法研究

本文介绍了我们研究的化学X射线荧光光谱分析法中化学富集方面的工作。这些方法提供了大量试样中富集痕量元素的简单手段。我们对目前国内外在X射线荧光光谱分析中常用的化学富集法如:有机沉淀、还原沉淀、离子交换、活性炭吸附、萃取色谱及离子交换树脂填充纸等分离富集技术进行了系统的研究。     

离子交换树脂在制备发光原料中的应用

本文描述了利用离子交换树脂提纯硫酸锌的方法。用亚硝基红盐作络合剂,它与硫酸锌中的重金属离子生成络合阴离子,通过阴离子树脂的交换作用而被除去。文中讨论了某些树脂的性能、络合剂的用量、交换条件和树脂再生方法,并给出对产品质量进行检验的结果。离子交换树脂也可以用来提纯锌、镁、钙、锶、钡、钠等的氯化物和某些硫酸盐。     

FTIR分峰拟合法定量分析精制煤沥青热转化过程的结构变化

精制煤沥青(QI＜0.2%)是制备煤系针状焦的原料，其热转化性质决定着所生产的煤系针状焦的质量。利用FTIR光谱及分峰拟合的方法考察了精制煤沥青在不同热转化温度下的结构变化。主要研究了芳香性指数(Iar)、支链化指数(CH₃/CH₂)、各基础官能团(C==O， C-O，芳环C==C)含量、芳环取代种类的变化情况。结果表明：精制煤沥青的Iar指数随着热转化温度的提高，逐渐变大，并且CH₃/CH₂指数逐渐增大，说明精制煤沥青热转化过程中支链的断裂形成活性位点是诱导芳香环增大的原因之一；随着热转化温度的升高，C==O含量由最初的26.25%降低为15.62%，芳环C==C含量由43.39%增加为51.28%，而C-O含量变化很少，说明C==O是诱导大分子芳环缩合反应的重要因素；精制煤沥青中芳环1H和3H含量随着温度升高逐渐减小，而4H含量逐渐升高，说明芳环取代逐渐减小，芳香性逐渐增加，与Iar分析结果相吻合。     

一种含硫光学树脂的合成与表征

采用低温脱水剂法合成了一种含硫、苯环及双键的化合物甲基丙烯酸苯硫酚酯( TPMA) ,并利用 FTIR、1H- NMR、HPLC等技术进行了结构表征。将其作为一种单体与苯乙烯进行共聚 ,制备得到含硫透明光学树脂。对树脂的性能测试结果表明 ,共聚树脂具有较高的可见光透光率 ,而且随着 TPMA含量的增加 ,树脂的折光指数和密度线性增大 ,冲击强度提高     

烧结烟气脱硫脱硝用活性炭混合钢渣复合材料的光谱学分析

钢渣是冶金工业中产生的主要固体废弃物,其产量约为每年粗钢产量的15%~20%。由于技术的局限,导致我国钢渣利用率较低,仅为年钢渣产量的10%,同时加之管理制度的不健全,导致钢渣大量露天堆放,对土地资源、地下水源,以及空气质量形成严重影响。固体废弃物再利用是资源可持续发展的重要途径之一,钢渣的主要化学成分为CaO, SiO2, Al2O3, MgO, Fe2O3, MnO, f-CaO等。面对上述问题,利用冶金固体废弃物与活性炭开发一种价格低廉且性能优越的活性炭混合钢渣复合材料,既是冶金固体废弃物的高附加值利用与资源可持续发展的重要途径之一,也是大幅降低改性活性炭生产成本与提高经济效益的重要途径之一。该研究创新性以活性炭与钢渣为研究对象,利用钢渣中含有的金属氧化物对活性炭进行改性处理制备用于烧结烟气脱硫脱硝的活性炭混合钢渣复合材料,通过搭建实验反应装置对活性炭混合钢渣复合材料的脱硫脱硝性能进行测试。利用X射线荧光光谱仪(XRF)对钢渣的化学成分进行测试与分析,比表面积及孔径测定仪(BET)对活性炭混合钢渣复合材料的孔结构进行测试与分析,傅里叶变换红外光谱仪(FTIR)对钢渣的结构组成进行测试与分析,扫描电子显微镜(SEM)对活性炭混合钢渣复合材料的微观结构进行测试与分析,以揭示活性炭与钢渣制备活性炭混合钢渣复合材料的机理,以及活性炭混合钢渣复合材料对烧结烟气脱硫脱硝的机理。结果表明:当钢渣为电炉热泼渣、钢渣与活性炭质量比为2∶4、钢渣与活性炭细度为400目时,活性炭混合钢渣复合材料具有良好的脱硫脱硝性能与合理的经济性,即脱硫效率为100%、脱硝效率为58%。活性炭混合钢渣复合材料具有的多孔结构对SO2和NO进行有作用,钢渣中Fe2O3与MnO2促使活性炭官能团进行催化还原反应提高脱硫脱硝性能,其中吸附作用是主导与前提,催化还原反应是辅助与协同。以期为高附加值的钢渣利用提供新途径,实现钢铁企业以废治废、以废增效的目的。     

模板法制备α-MoO3纳米棒和纳米矩形片及光谱表征

以(NH4)6Mo7O24.4H2O为钼源,十六烷基三甲基溴化铵(CTAB)为模板剂,通过强酸性离子交换树脂(R-H)进行静态交换制备出前驱物,前驱物在600℃经不同时间焙烧,制备了α-MoO3纳米棒和纳米矩形小片。用FTIR,XRD,TEM和SEM等测试手段对样品的相态、结构和形貌进行了光谱表征,结果表明:前驱物经过600℃焙烧4和8h后,分别得到长度约1～1.6μm,直径约0.10～0.20μm,长径比为8的α-MoO3纳米棒和长度约0.14～0.18μm,宽度约60～80nm,厚度约28～32nm的纳米矩形小片。该法制备工艺简单,不用人为地调节pH、省去过多洗涤等过程,树脂可再生重复使用,副产品氯化铵可回收利用,无环境污染。     

二次离子交换法改进自聚焦透镜折射率分布

对二次离子交换制作自聚焦透镜的理论和工艺进行了研究.利用KNO3和NaNO3混合盐进行二次离子交换.对二次离子交换前后的自聚焦透镜的折射率分布和畸变进行了测试,结果表明,经过二次离子交换后,折射率分布明显改善,更接近理想折射率分布曲线,相对畸变由二次交换前的13.1%减小到7.7%.     

环维黄杨星D^13C和^1H化学位移的全归属

环维黄杨星D为自黄杨木中提取精制的有效生物碱,临床上已长期用于心血管疾病的治疗.本文用制备高效液相色谱提取、分离并纯化环维黄杨星D,用1D,2D NMR技术 (COSY,DEPT,HMQC 和 HMBC)对其结构进行研究,并且首次对环维黄杨星D的1H NMR 和 13C NMR 信号进行了全归属,同时通过NMR数据确证了环维黄杨星D的结构.     

电炉渣超微粉改性生物质废弃物制备生态活性炭的光谱学分析

利用木材、竹子、等其他生物资源制备具有发达多孔结构与丰富比表面积的活性炭,存在生产成本较高、不利于生态环境的可持续发展、使用寿命短和失效后容易造成室内环境二次污染的问题。冶金固体废弃物与生物质废弃物是工业生产与农业生产主要的副产品,因利用难度大、附加值低且成本高,导致大量堆放和填埋,不仅造成生态环境的污染,而且极大的浪费潜在资源。面对上述问题,利用冶金固体废弃物与生物质废弃物开发一种价格低廉且性能优越的生态活性炭,既是冶金固体废弃物与生物质废弃物的高附加值利用与资源可持续发展的重要途径之一,也是大幅降低改性活性炭生产成本与提高经济效益的重要途径之一。以核桃壳与电炉渣为研究对象,利用电炉渣中含有的金属氧化物对生物质废弃物进行改性处理制备用于甲醛降解的生态活性炭,依据《室内装饰装修材料人造板及其制品中甲醛释放限量》(GB18580-2017)对生态活性炭性能进行测试。利用X-射线光电子能谱(XPS)对元素含量进行测试与分析,X-射线荧光光谱仪(XRF)对化学成分进行测试与分析,傅里叶变换红外光谱仪(FTIR)对结构组成进行测试与分析,X-射线衍射仪(XRD)对矿物组成进行测试与分析,扫描电子显微镜(SEM)对微观结构进行测试与分析,激光粒度仪(LPSA)对粒度分布进行测试与分析和比表面积及孔径测定仪(BET)对孔结构进行测试与分析,以揭示核桃壳与电炉渣制备生态活性炭的机理,以及生态活性炭对甲醛的降解机理。结果表明:核桃壳超微粉与电炉渣超微粉进行复合制备具有良好降解甲醛性能的生态活性炭,不仅实现了冶金固体废弃物与生物质废弃物的高附加值的利用,而且提出了"以废治危"的新室内空气甲醛治理理念。电炉渣超微粉较好的被包裹于生态活性炭层状结构中,提高生态活性炭的粉化率,形成粒径较小的颗粒,有利于提高生态活性炭与甲醛的降解作用面积。电炉渣超微粉中含有Fe元素、Mn元素与Ti元素,Fe元素具有磁性促使大量甲醛在生物质活性炭孔结构表面形成富集,Mn元素与Ti元素对已经富集的甲醛进行催化降解,实现吸附降解与催化降解的协同作用。     

离子交换树脂均匀沉淀法制备Nd2O3纳米粒子的研究

以Nd(NO)3·6H2O和(NH4):C2O4·2H2O为原料,分别采用阴离子交换树脂均匀沉淀法和阳离子交换树脂均匀沉淀法制备Nd2O3前驱体,经700℃焙烧后制得Nd2O3纳米晶体a和b.分别用热分析、X射线粉末衍射、透射电子显微镜、高分辨电子显微镜、选用电子衍射和BET等对前驱体和样品进行表征,并对均匀沉淀形成机理进行了探讨.结果表明,制备的Nd2O3纳米晶体属六方晶系,样品分散性较好,平均粒径约为26～32 nm;Nd2O3纳米晶体清晰、有序的电子衍射点阵,表明晶体的结晶度较好;样品a和样品b的比表面积分别是42.57和29.43 m2·g-1.离子交换树脂均匀沉淀法具有操作简单易行,对设备要求不高,成本低,同时避免使用有机溶剂和表面活性剂,污染小,后处理容易,离子交换树脂可再生重复使用等优点.     

Ion-exchange resin decomposition in supercritical water

Abstract

Using supercritical water oxidation, the cation exchange resin was decomposed fast and completely to water, carbon dioxide and sulfuric acid. While the resin decomposition yield increased with the reaction time and the amount of hydrogen peroxide added as oxidizing agent, it was constant in the resin concentration from 0.14 to 1.9 dry resin weight percent to water. More than 99% of the cation exchange resin was decomposed with hydrogen peroxide added in the amount of 7 times the stoichiometric value at 673 K and 30MPa for 30 minutes of the reaction time. The cation exchange resin is decomposed through two main reaction pathways. One has a rate controlling intermediate such as acetic acid whose decomposition rate was very slow, and the other does not have stable intermediates. The decomposition of the acetic acid is a significant factor for the complete decomposition of the resin, although it does not dominate the whole resin decomposition. A simple kinetic model that estimates the resin decomposition yield was developed.     

Synthesis and Characterization of a Fluorinated Phenolic Resin/phenolic Resin Blend

Fluorine atoms were introduced into the molecular chain of a phenolic resin (PR) by a two-step acid synthesis process to improve its thermal and hydrophobic properties. The successful synthesis of a fluorinated phenolic resin/phenolic resin blend (F-PR/PR) was proven by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance 19F (¹⁹F-NMR). The thermal properties of F-PR/PR were analyzed by differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA) and the results indicate that the F-PR/PR had good thermal stability. The hydrophobic properties of PR were effectively modified as demonstrated by the water drop contact angles. The flexural and tribological properties of F-PR/PR were also investigated. The fluorine atom, by virtue of its electronegativity, size and bond strength with carbon, can be used to create composites from F-PR/PR with remarkable properties. For comparison, two other resin blends were also synthesized.     

Adsorption of Zn(II) and Cd(II) ions onto magnesium and activated carbon composite in aqueous solution

Magnesium and coconuts shell activated carbon composite was prepared to selectively remove heavy metals ions in aqueous solution. Zinc(II) and cadmium(II) ions were used to clarify the adsorption capacity of the composite in comparison with no magnesium containing activated carbon. Influence of the initial heavy metal concentration, time course and solution temperature on the adsorption amounts were examined for the two adsorbents, and surface chemistry of the adsorbents was also characterized using Boehm titration. The magnesium composite adsorbed greater amount of Zn(II) and Cd(II) ions than the no magnesium counterpart. The adsorption amount of Cd(II) was not influenced with rise in solution temperature for the composite, whereas decrease in adsorption was observed for the counterpart. The loaded magnesium was estimated to be combined with carbon surface via oxygen bridge. Cadmium(II) was adsorbed onto the composite surface by ion exchange process with releasing equivalent amount of Mg(II) from the carbon surface, while Zn(II) would adsorb onto the composite by not only the ion exchange, but also the electrostatic interaction with the Cπ electrons on the graphite surface from the experimental results.     

氯化聚丙烯与醇酸树脂共混物的红外光谱测定

利用FTIR红外光谱法对氯化聚丙烯与短油度醇酸树脂共混物的相容性进行了研究 ,并用涂膜光泽度进行对比。结果表明 ,在氯化聚丙烯与醇酸树脂共混物的谱图中 ,羟基谱带发生了明显的位移。且当短油醇酸树脂的固含量x小于 0 5时 ,两种树脂基本上是相容的 ;x大于 0 5时 ,共混物是不相容的。     

Interphase characterization in epoxy resin/carbon fibre composites

In this paper, interphase properties of carbon fibre/epoxy resin single-fibre model and unidirectional (UD) composites are reported. To study the contribution of the carbon fibre surface chemistry and morphology and of the resin itself to the overall properties of the composites, untreated, oxidized and sized fibres are used with bi- and tetrafunctional, diglycidylether of Bisphenol A, DGEBA and tetraglycidyl 4,4'-diaminodiphenylmethane, TGDDM-based resins, cured with amine and anhydride hardeners. Adsorption measurements and single fibre contact angle experiments, as well as the pull-out test were applied to characterize the surface of carbon fibre and the interfacial shear strength with different matrices. It was shown that the presence of the size on the surface can drastically affect the wettability as well as the starting rate of the cure reaction of epoxide in the vicinity of the fibre surface, as revealed by FTIR microscopy. Different elastic-plastic behavior of model composites before debonding is found for untreated, oxidized and sized fibres, due to the various interphase structures formed. Both micro-and macromechanical properties of the composites are found to be significantly affected by the matrix properties. The role of the surface treatment of fibers becomes especially important in high performance resin systems.     

Modification of bamboo-based activated carbon using microwave radiation and its effects on the adsorption of methylene blue

Modification of bamboo-based activated carbon was carried out in a microwave oven under N₂ atmosphere. The virgin and modified activated carbons were characterized by means of low temperature N₂ adsorption, acid-base titration, point of zero charge (pH_pzc) measurement, FTIR and XPS spectra. A gradual decrease in the surface acidic groups was observed during the modification, while the surface basicity was enhanced to some extent, which gave rise to an increase in the pH_pzc value. The species of the functional groups and relative content of various elements and groups were given further analysis using FTIR and XPS spectra. An increase in the micropores was found at the start, and the micropores were then extended into larger ones, resulting in an increase in the pore volume and average pore size. Adsorption studies showed enhanced adsorption of methylene blue on the modified activated carbons, caused mainly by the enlargement of the micropores. Adsorption isotherm fittings revealed that Langmuir and Freundlich models were applicable for the virgin and modified activated carbons, respectively. Kinetic studies exhibited faster adsorption rate of methylene blue on the modified activated carbons, and the pseudo-second-order model fitted well for all of the activated carbons.     

在监测固相反应过程中显微红外和漫反射红外光谱方法的比较

文中利用傅里叶红外显微镜和漫反射红外光谱监测聚苯乙烯磺酰氯树脂与乙醇胺在不同温度下的反应程度,对两种方法进行了比较。结果证明漫反射红外光谱是简单有效的方法,而显微红外光谱是研究单个树脂小球之间差异的有效手段。     

Study of Pollutant gas Adsorption on Activated Charcoal Using FTIR Spectroscopy

In this study, the efficiency of an air cleaning system, using activated charcoal cartridges, which must operate in a confined atmosphere with particularly high air flow rate, is tested.

A device which generates dynamic polluted atmospheres is described. A continuous quantitative analysis is made by means of the Fourier Transform Infrared Spectroscopy (FTIR). The pollutants studied are: carbon monoxyde (1500 ppm), sulfur dioxyde (100 ppm), nitrogen dioxyde (50 ppm) and hydrogen chloride (500 ppm). Gas adsorption kinetics on activated carbon are given and discussed by using breakthrough curves.     

新型腰果酚基不饱和树脂的结构及其紫外光固化行为的红外光谱研究

以天然产物腰果酚为原料,利用其酚羟基与环氧基的反应活性,通过开环醚化反应制备了两种腰果酚基不饱和树脂单体。通过傅里叶红外光谱研究了合成过程中主要活性基团的变化,结合核磁共振氢谱及凝胶渗透色谱分析进一步确定了合成树脂单体的分子结构,并利用红外光谱法对树脂单体的紫外光固化行为进行了研究,且对其光固化物进行了热重分析。研究表明：分子结构分析确认了目标产物的成功合成,树脂单体的分子结构以及不饱和双键含量对树脂的固化速度和固化物的热稳定性有着重要影响,两种单体在30 s内均已基本达到最高固化水平,光固化物的主分解初始温度均可达到350 ℃以上。