溶胶-凝胶法的技术进展与应用现状

溶胶－凝胶法是一种在较低温度下即可得到希望的化合物的新方法。简述了溶胶－凝胶法的基本原理,总结了溶胶－凝胶技术发展现状,着重介绍了溶胶－凝胶技术在制备块状、纤维、涂层和薄膜、超细粉末及复合材料方面的应用现状。     

TiO2/蛭石复合材料的制备及光催化性能研究

以天然层状蛭石为载体,钛酸四丁酯为钛源,采用溶胶-凝胶法制备了TiO2/蛭石复合光催化材料,利用XRD、SEM、TG-DTA、FTIR和BET等分析技术对催化剂进行了表征,通过对甲基橙溶液的降解实验检测了其光催化活性。探讨了催化剂用量、甲基橙初始浓度、pH值、煅烧温度等对光催化效率的影响规律。结果表明:采用溶胶-凝胶法制备的TiO2/蛭石经过200℃焙烧后,具有较好的光催化效率,利用300 W的高压汞灯紫外光辐照90 min,甲基橙溶液的脱色率达99%,COD去除率达81%。     

活性炭颗粒负载TiO2的光催化性能研究

文章研究了溶胶-凝胶法制备活性炭颗粒负载TiO2的光催化作用.以20W紫外灯作光源,酸性大红染料为目标物,探讨光催化剂的最佳制备条件.实验结果表明,当钛酸四丁脂与无水乙醇按1:8比例制备Ti02溶胶,活性炭颗粒浸涂凝胶一次,在450℃煅烧2h,酸性大红染料的降解率可达78%.当溶胶掺杂Fe(3 )时,可增强光催化效果,实验表明120min对酸性大红染料废水的光催化降解率由78%提高到97%.     

Sol—gel法制取Al2O3系陶瓷涂层的研究

本文研究了用溶胶－凝胶（Ｓｏｌ－ｇｅｌ）法制备Ａｌ２Ｏ３系陶瓷涂层的工艺过程和反应原理，阐述了溶胶制备，涂层工艺及其影响因素等问题，结果表明，涂层的性质与溶胶的性质、溶胶与基层的润湿性认及涂覆工艺有关。Ａｌ（ＯＨ）３溶胶的粘度应控制在２４￣４６ｃｐ，烧结加热速率不易高于１℃／ｍｉｎ；选用添加剂和多次涂覆技术等可以增加涂层厚度。     

纳米TiO2光催化降解亚甲基蓝

在以钛酸丁酯为钛源,采用溶胶-凝胶法合成制备纳米TiO2催化剂样品的基础上,将其用于在紫外光照射和无光照射条件下进行亚甲基蓝降解的实验研究,并与P-25纳米TiO2进行光催化降解对比研究。对在不同条件下合成制备样品的光催化降解率的差异,通过X射线粉晶衍射、扫描电镜等从物相组成、微观结构等因素上进行了分析和探讨。结果表明,采用溶胶-凝胶法在450℃焙烧2 h所得到的纳米TiO2具有很好的光催化降解亚甲基蓝的能力,当催化剂样品质量浓度为2.5 g/L,亚甲基蓝初始浓度为5.0 mg/L时,室温下光催化反应3 h,其降解率达98%以上,其光催化降解率比P-25纳米TiO2高;光催化降解率与催化剂样品的制备条件、物相组成、颗粒尺寸等因素有关。     

铁氧体磁性材料应用的进展及合成方法

综述了近年来铁氧体磁性材料应用及合成领域的一些最新研究进展.详细介绍了M-型和W-型铁氧体磁性材料的应用;介绍了最新的几种合成方法,包括水热法、醇盐水解法、微乳液法、共沉淀法和溶胶凝胶法.     

高温高压合成翡翠的溶胶-凝胶法粉料制备的工艺方法探索

采用溶胶-凝胶法合成具有翡翠成分的玻璃料,再对其进行高温高压处理,实现玻璃体向晶质硬玉的转化,从而得到合成翡翠。从金属醇盐浓度、pH值、去离子水的添加量、水浴温度四个方面探讨了最佳凝胶条件。常规宝石学特征测试、偏光显微镜下岩矿薄片分析、X射线粉末衍射和傅里叶变换红外光谱表明,合成翡翠与天然翡翠的常规宝石学性质相近,其结晶矿物为硬玉,样品的结晶转化程度较好,具有硬玉的标准红外特征吸收峰。     

坡缕石/氧化铝复合材料对磷的吸附动力学和热力学

以坡缕石粘土为原料,通过溶胶-凝胶法制备坡缕石/氧化铝复合材料,通过静态吸附实验研究了复合材料吸附水中磷的动力学特征、吸附平衡和热力学参数,探讨了吸附机理。结果表明,复合材料对磷有较好的吸附作用,吸附过程能较好地符合准二级动力学方程,吸附速率常数随初始浓度的增大而减小,随温度的升高有所增大;吸附平衡能较好地符合Langmuir方程和D-R方程,吸附过程吸热,ΔG为-25~-21 kJ/mol,是物理吸附和化学吸附并存的过程。     

硅烷偶联剂改性TiO2/膨胀石墨复合材料的制备及其光催化性能研究

以硅烷偶联剂黏结剂,利用溶胶-凝胶法将TiO2（P25）负载在膨胀石墨上,利用XRD、EDS以及SEM等分析技术对TiO2/膨胀石墨复合材料进行表征;以橙黄Ⅱ为目标降解物,考察了TiO2/膨胀石墨复合材料光催化性能以及重复使用性能。结果表明：随着TiO2含量的增加,TiO2/膨胀石墨复合材料的光催化效率随之增加,对橙黄Ⅱ的光催化降解符合一级反应动力学方程,TiO2负载量为15%时,反应速率常数为0.387 h-1,高于P25的反应速率常数。TiO2/膨胀石墨复合物使用4次仍保持较高的光催化活性。     

堇青石合成的研究进展

堇青石是一种具有较低热膨胀系数、良好抗热震性的矿物材料。天然的堇青石矿物原料很少,因此常常采用人工合成的方法来合成堇青石材料。本文根据近年来合成堇青石的最新研究,论述了堇青石合成方法的研究进展,具体包括高纯氧化物高温固相反应合成法、天然矿物高温固相反应合成法、利用工业废料合成法、利用农业废料合成法、溶胶-凝胶法和低温燃烧合成法。目前工业化生产堇青石大多采用天然矿物高温固相反应法,此法虽有众多优点,但同时也存在许多的不足之处。因此,如何能将其他方法用于工业化生产,将成为合成堇青石今后研究中的一个发展方向。     

细粒沉积物(岩)中重矿物提取方法的改进

随着近百年的重矿物研究,从沉积物中提取重矿物的实验方法已经形成了固定模式,然而这些传统方法都是对砂岩粗颗粒矿物研究经验的积累,并不适用于泥质含量高的细粒沉积物.根据溶胶稳定(DLVO)理论,悬浮于溶液中的微细颗粒会因分子间作用力的相互吸引絮凝成团,从而影响细粒沉积物中重矿物提取的效果.实验研究证明,影响重矿物提取的主要因素是微细矿物颗粒间的絮凝作用,而并非有机重液的黏度.如何克服微粒间的絮凝作用是提取泥岩和粉砂岩中重矿物的关键.实验对比分析表明,添加分散剂的超声波振动和自然沉降法可以在克服絮凝作用的前提下有效去除泥质成分,同时对粉砂级矿物进行精确的粒径分选;离心分离同样也可以克服微粒间的絮凝作用,在重液分离过程中使重矿物顺利从轻矿物中分离.以上3种方法的联合使用可以弥补传统的重矿物提取方法的不足,并显著提高泥岩、粉砂岩中重矿物的提取率.     

First results of U–Pb dating of detrital zircons from the Ordovician clastic sequences of the Sol-Iletsk Block,East European Platform

The first LA–ICP–MS U–Pb isotopic ages of detrital zircons from the Ordovician sandstones of the Sol–Iletsk Block (well 2–Ordovician), located at junction of the East European Platform with the Pre-Caspian Basin and the Pre-Uralian foredeep, are presented. Two detrital zircons with well-defined ages of 561 ± 4 and 570 ± 5 Ma were found in sample K15–501. They confirm the Ordovician age of the sandstones, which earlier had been defined on the basis of seismic–stratigraphic and lithological correlations. The age distribution of the detrital zircons indicates the significant role of Late Precambrian rocks as provenance sources. However, those rocks still remain unknown in the Early Precambrian basement of the Volga–Ural part of the EEP.     

加速溶剂提取/GC-MS同时测定动物组织中有机氯农药和多氯联苯

动物组织样品油脂含量大、干扰杂质多,对其中低含量有机氯农药及多氯联苯的分析会造成较大程度的影响。针对动物组织样品基质复杂的特点,本文以二氯甲烷-丙酮（体积比为1：1）的溶剂体系,采用加速溶剂萃取技术对样品进行提取,在提取过程中尽量减少脂肪的共提出,然后采用凝胶渗透色谱技术去除样品中的大部分油脂,再结合弗罗里硅土为填料的固相萃取方法对样品进一步净化,能够达到充分去除油脂和小分子杂质的目的。采用气相色谱-质谱分析17种有机氯农药及7种指示性多氯联苯,各化合物的回收率在81.6%~113.4%之间,检出限在1.02~3.59 ng/g之间,技术指标优于部分国家标准。本方法改进了动物样品的净化效果,建立了凝胶渗透色谱结合固相萃取技术的净化方法,达到了样品快速自动提取、溶剂用量少、基质净化彻底的目的,降低了方法检出限,能够满足快速、准确检测动物组织中低含量持久性有机污染物的要求。     

The Late Proterozoic ophiolite of Sol Hamed,NE Sudan

The Sol Hamed complex, a sequence from ultramafics, through gabbros, thin sheeted dykes, to pillow lavas, is an ophiolite. It was obducted, tilted nearly to vertical, eroded and covered unconformably by the Nafirdeib Series. This is a volcaniclastic series, dated at 712 ± 58 Ma, the lower part of which includes conglomerates with ophiolitic clasts, olistostromes, one with large oolitic limestone slabs, felsitic and dacitic tuffs, turbidites and black shales, with andesites above. Some of the structures in the ophiolite are attributed to sub-oceanic deformation. Deformation after the deposition of the Nafirdeib Series produced folds and cleavage trending about NE-SW and, more locally, a cleavage trending NW in a shear zone where the ophiolite was thrust northeastwards over the Nafirdeib Series. The ophiolite and the Nafirdeib Series were intruded by the batholithic granite dated elsewhere at ca. 669 Ma. The ophiolite is thought to occur on a suture with the Nafirdeib Series representing part of an island arc sequence.     

沉积物样品中干扰物的去除及多种持久性有机污染物气相色谱分析

建立了沉积物样品中17种有机氯农药和8种多氯联苯持久性有机污染物的气相色谱分析方法。针对沉积物样品基质复杂、含有大量硫干扰的特点,重点研究了前处理技术。采用加速溶剂提取(ASE)技术提取样品中的有机污染物,比较了加入铜粉后ASE在线除硫和超声波提取除硫的效果。结果表明,加入铜粉ASE提取不能完全去除硫的干扰,需进一步采用超声波提取10 min除硫才能大大减少杂质对目标化合物的干扰。沉积物样品中的色素类及小分子干扰物质采用凝胶渗透色谱结合固相萃取技术进行净化,满足了气相色谱-电子捕获检测器分析的要求。25种化合物的平均添加回收率为68%～131%,方法精密度(RSD,n=6)小于22.3%,检出限为0.10～0.51μg/kg。建立的样品前处理技术净化彻底,适合用于不同地区、不同类型的沉积物样品气相色谱分析。     

Acidic compounds in biodegraded petroleum

Twelve oil samples have been characterised by titration, FT-IR and chromatographic analysis to determine the differences between the organic acid composition of biodegraded and non-biodegraded oils. The biodegraded oils have higher total acid and total base contents, both by titration and extraction. The molecular weight ranges of the extracted acids are lowest in the biodegraded oils, and the equivalent weight calculations indicate a dominance of multi-functional molecules. Gel permeation chromatography gives a molecular weight range with most of the molecules between 300 and 500 g/mol. FT-IR shows that the extracted acids from biodegraded oils are more carboxylic and aliphatic while the non-degraded oils are more phenolic. Molecular analysis of the derivatised extracts give UCM envelopes for biodegraded oils, and no molecular identification. The results indicate that the acidic constituents in biodegraded oils are a product of the biodegradation, as the composition is very different from the non-biodegraded oils.     

Geochronology of igneous rocks at and near to the Nezhdaninka gold deposit, Yakutia, Russia: U-Pb, Rb-Sr, and Sm-Nd isotopic data

The intrusive rocks associated with the large Nezhdaninka gold deposit (Au > 470 t) hosted in the Permian carbonaceous terrigenous sequence have been dated on zircon and rock-forming minerals with precision U-Pb (ID-TIMS) and Rb-Sr methods. The lamprophyre of the dike complex that occurs in the ore field and spatially is related to gold mineralization has concordant U-Pb zircon age (121 ± 1 Ma) and the same isochron Rb-Sr age (121.0 ± 2.8 Ma). The concordant U-Pb zircon age of granodiorite that dominates in the Kurum pluton is 94 ± 1 Ma, whereas the Rb-Sr isochron age of various intrusive rocks from this pluton is 1–4 Ma younger. This difference is caused by long-term cooling of the Kurum pluton and later closure of Rb-Sr isotopic system of biotite (300–350°C) and other rock-forming minerals as compared with U-Pb isotopic system of zircon (～ 900°C). The Rb-Sr age of quartz diorite from the Gel’dy group of stocks (92.6 ± 0.8 Ma) coincides within uncertainty limits with the age of the Kurum pluton. Thus, the rocks pertaining to two epochs of magmatic activity, which developed in the South Verkhoyansk Foldbelt and divided by a time span of 25–28 Ma, are documented in the Nezhdaninka ore field. Taking into account that the age of gold mineralization is no less than 120 Ma, the data obtained allow us to specify the previously proposed formation model of the Nezhdaninka deposit. These data give grounds to rule out the Late Cretaceous Kurum pluton and the Gel’dy group of stocks from constituents of the ore-magmatic system, and to suggest that an Early Cretaceous deep-seated magma source existed beneath the deposit. Along with host terrigenous rocks, this magma source participated in the supply of matter to the hydrothermal system. The Nd, Sr, and Pb isotopic systematics of igneous rocks and ore mineralization in the Nezhdaninka ore field show that the Early and Late Cretaceous magma sources were formed in the Precambrian crust dated at ～1.8 Ga.     

Biodegradation of starch blended polyvinyl chloride films by isolated Phanerochaete chrysosporium PV1

The accumulation of plastics in the environment is raising great concerns with respect to long-term environmental, economic and waste management problems. The aim of the present research was to investigate the biodegradability of starch blended polyvinyl chloride films in soil burial and controlled laboratory experiments using selective fungal isolates. Clear surface aberrations as color change and minor disintegration in polyvinyl chloride films were observed after 90 days and later confirmed through scanning electron microscopy. The fungal strains showing prominent growth and adherence on plastic films were isolated. One of the strains showing maximum activity was selected and identified as Phanerochaete chrysosporium PV1 by rDNA sequencing. Fourier transform infrared spectroscopy and nuclear magnetic resonance analyses indicated considerable structural changes and transformation in films in terms of appearance of new peaks at 3,077 cm^?1 (corresponding to alkenes) and decrease in intensity of peaks at 2,911 cm^?1 (C–H stretching). It was supported with a significant decrease in the molecular weight of polymer film from 80,275 to 78,866 Da (treated) through Gel permeation chromatography in shake flask experiment. Moreover, the biodegradation of starch blended polyvinyl chloride films was confirmed through release of higher CO₂ (7.85 g/l) compared to control (2.32 g/l) in respirometric method. So fungal strain P. chrysosporium PV1 has great potential for use in bioremediation of plastic waste.     

枫江溪矿区煤层硅质煤核成因及其环境的探讨

近年来,笔者在湖南邵阳枫江溪矿区上二叠统龙潭组上段煤层中发现了大量硅质煤核。它是煤层对比的良好标志,探索成煤环境的重要依据,在煤田地质勘探和煤田开发工作中具有重要意义。