超重力法制备纳米材料的研究现状

纳米材料的合成与制备技术已成为全球的研究热点。介绍了一种独创性的纳米材料合成方法即超重力法。论述了超重力法的理论依据,并介绍了目前根据该法合成碳酸钙、氢氧化铝、硫化锌、氧化锌、硫酸钡、钛酸钙等纳米粉体材料的制备方法和工艺流程。     

爆炸合成纳米粉体及其团聚控制研究进展

作为一种新兴的纳米材料制备方法，爆炸法具有操作简单、高效、经济、节能和环保等特点。但是，合成过程的复杂性和纳米材料特殊的性能，导致爆炸合成的纳米粉体极易团聚，这不仅破坏纳米粉体的超细性和均匀性，还影响其发挥自身的优越性能。目前，爆炸合成纳米粉体及其团聚控制研究已经成为爆炸加工领域的研究热点之一。本文首先概述了国内外爆炸合成纳米粉体的发展现状；然后从爆炸合成纳米粉体团聚的主要影响因素（如纳米粉体的理化特性、制备工艺、提纯工艺和分散工艺）和粉体团聚机理等方面综述了研究成果；最后指出了今后的研究热点和亟待解决的关键问题。     

低热固相反应合成纳米粉体的研究现状

低热固相反应法是近年发现的一种合成纳米材料的方法。本文介绍了低热固相反应法纳米粉体的研究现状,并且对低热固相反应法合成纳米粉体的热力学条件、反应物的选择、反应过程的控制以及表面活性剂、反应物配比对合成产物的影响作了详述。     

纳米碳酸锶制备的研究现状

碳酸锶纳米粉体是一种重要的工业固体材料,本文在简单回顾了近年来纳米材料的研究现状的基础上,总结了纳米碳酸锶的原料来源,介绍了液相反应法、超重力反应沉淀法、微波反应法、微乳液法、低温固相反应法等制备方法,探讨了各种方法的优缺点,并对纳米碳酸锶的原料来源及制备方法进行了展望.     

ATO纳米粉体制备方法与研究现状

锑掺杂二氧化锡(antimony doped tin oxide,ATO)纳米材料是一种新颖的透明导电复合纳米材料,可用于节能玻璃、导电抗静电材料、疏水材料、催化剂和光伏材料等领域。本文综述了ATO纳米粉体的主要制备方法,并对各种方法进行了比较和评价,探讨了ATO纳米粉体的研究现状和有待改进的地方。     

水热反应法制备纳米粉体的研究进展

介绍了水热氧化、沉淀、结晶、合成和分解等制备纳米粉体的相关技术特点和研究现状,并介绍了水热技术的改进和与其他方法的组合与创新,如微波水热合成、反应电极埋弧法、水热机械化学反应等新技术.指出今后要加强对水热反应机理的研究,在此基础上才能实现对水热产物微观结构的控制;加强对水热温度、pH值和表面活性剂等水热工艺条件的系统、定量研究;加强对水热装置的研究以提高水热反应性能和降低纳米粉体的制备成本.     

SiC和Si_3N_4纳米陶瓷粉体制备技术

纳米材料科学是近年来兴起的新的科学领域，纳米粉体的制备则是纳米材料研究的主要方面。本文比较详细地介绍了制备碳化物、氮化物纳米陶瓷粉体的四种主要工艺：热化学气相反应法、激光诱导化学气相沉积法、等离子气相合成法和溶胶凝胶法。对于目前碳化物、氮化物纳米陶瓷粉体的制备工艺和目前水平作了一个总体概括     

一步水热法制备核壳型纳米粉体研究

简述了纳米微粒表面修饰的重要性以及修饰方法，并指出制备核壳型纳米材料是一种重要的表面修饰方法。液相法制备核壳纳米粉体具有反应温度低、设备简单、能耗低的优点。而一步水热法在液相法中具有其它方法无法比拟的优越性。因此，重点讨论了一步水热法制备核壳纳米粉体的工艺流程和机理，并对一步水热法制备核壳型纳米材料进行了展望。     

激光隐身涂料的应用研究进展

概述了激光隐身涂料的应用与研究现状,重点介绍了纳米材料应用于激光隐身涂料中的隐身原理以及制备方法、特点和应用现状.材料纳米化后,具有极好的吸波特性,具有频带宽、兼容性好、质量小和厚度薄等特点,而且纳米粉体对电磁波的透射率及吸收率比微米粉体要大得多.使用纳米材料可以制备出与可见光、红外、雷达波兼容性良好的激光隐身涂料.多频段兼容的隐身涂料也将是隐身涂料的发展趋势,而纳米隐身涂料是一个重要的发展方向.     

SiC和Si3N4纳米陶瓷粉体备技术

纳米材料科学是近年来兴起的新的科学领域，纳米粉体的制备则是纳米材料研究的主要方面。本文比较详细地介绍了制备碳化物、氮化物纳米陶瓷粉体的四种主要工艺：热化学气相反应法、激光诱导化学气相沉积法、等离子气相合成法和溶胶－凝胶法。对于目前碳化物、氮化物纳米陶瓷粉体的制备工艺和目前水平作了一个总体概括。     

Structure controlling and process scale-up in the fabrication of nanomaterials

Nanotechnology is already having a significant commercial impact, and will very certainly have a much greater impact in the future. The research on process engineering and scale-up will be very important for the commercial production and application of nanomaterials, because the properties and structure of nanomaterials are not only determined by the nucleation and growth process, but also strongly affected by the engineering properties, such as the mixing, the heat and mass transfer, and also the distribution of temperature, concentration, etc. This paper will present some research work in our laboratory on the fabrication of nanomaterials. Based on the chemical engineering principle and methods, many kinds of novel nanomaterials can be synthesized and their structure can be easily controlled through adjusting the parameters of the fluid mixing, and the distribution of temperature, residence time and concentration, etc. By using the micro-mixing, heat and mass transfer and reaction control methods, the host-guest nanocomposites have been assembled and assumed as the novel electroanalytical sensing nanobiocomposite materials. Based on the principles of chemical engineering, the manufacturing technologies for magnetic powders, calcium carbonate, and titanium dioxide have been developed for commercial-scale production, and the largest production scale has reached 15 kt/year.     

Structure controlling and process scale-up in the fabrication of nanomaterials

Nanotechnology is already having a significant commercial impact, and will very certainly have a much greater impact in the future. The research on process engineering and scale-up will be very important for the commercial production and application of nanomaterials, because the properties and structure of nanomaterials are not only determined by the nucleation and growth process, but also strongly affected by the engineering properties, such as the mixing, the heat and mass transfer, and also the distribution of temperature, concentration, etc. This paper will present some research work in our laboratory on the fabrication of nanomaterials. Based on the chemical engineering principle and methods, many kinds of novel nanomaterials can be synthesized and their structure can be easily controlled through adjusting the parameters of the fluid mixing, and the distribution of temperature, residence time and concentration, etc. By using the micro-mixing, heat and mass transfer and reaction control methods, the host-guest nanocomposites have been assembled and assumed as the novel electroanalytical sensing nanobiocomposite materials. Based on the principles of chemical engineering, the manufacturing technologies for magnetic powders, calcium carbonate, and titanium dioxide have been developed for commercial-scale production, and the largest production scale has reached 15 kt/year.     

Alkaline scale formation in boiling sea water brines

A laboratory method for the study of alkaline scale is described. Evaporator conditions are easily simulated in experiments of relatively short duration (5 hours). Reproducible results have been achieved by chemical analysis for total scale which consisted of mixtures of calcium carbonate and magnesium hydroxide. Experiments with natural sea water show the amount and composition of alkaline scale to be a function of temperature, brine concentration, bicarbonate ion concentration, and flow conditions through the evaporator. The transition between calcium carbonate and magnesium hydroxide was shown to be influenced by factors other than temperature. A new mechanism for alkaline scale formation is proposed in this paper. The first step involves a unimolecular breakdown of bicarbonate ion to form hydroxide ion. This concept is in disagreement with the generally accepted mechanism described in the literature.     

A Visible Light Photocatalyst of Carbonate‐Like Species Doped TiO2

Carbon‐doped TiO₂ nanomaterials have been successfully synthesized via an effective two‐step procedure involving hydrothermal method and followed by a low‐temperature calcination treatment process, through which a controllable amount of carbonate‐like species could be incorporated into TiO₂. First‐principles calculations suggest the TiO₂ doped with carbon in form of carbonate‐like species can effectively extend the adsorption of the material from ultraviolet region to visible light. And it is experimentally found that carbon‐doped TiO₂ nanomaterials exhibit much higher photocatalytic activity than reference P25 and TiO_2?xN_x catalysts toward the liquid‐phase degradation of organic pollutants under visible light (420 nm < λ < 800 nm) irradiation. The presence of synergic effect between carbonate‐like doping and anatase TiO₂ is believed to play an essential role in affecting the photocatalytic reactivity, and the response to the visible light is ascribed to the narrowed band gap energy controlled by carbon doping. Moreover, the roles of active species in the photocatalytic process are compared using different types of active species scavengers. Meanwhile, the degradation mechanism of the photocatalysis is proposed. It is hoped that our work could provide valuable information on the design of carbonate‐like doped semiconductor with more excellent properties and set the foundation for the further industrial application.     

聚羧酸类阻垢剂对碳酸钙的沉淀及溶解过程的影响研究

利用VB语言自编的计算机程序对不同形态CaCO3在各种条件下的溶解度 进行了计算,并对过饱和体系进行了分析,在此基础上研究了PAA1、PAA2、PMA－AA,PPMA四种聚羧酸类阻垢剂对CaCO3的再溶解和沉淀过程的影响,从阻垢剂对CaCO3沉淀形态影响的角度,解释了阻垢剂对CaCO3过饱和溶液亚稳态的影响和阻垢剂的阻垢作用。     

分级结构纳米材料研究进展

将纳米级材料通过模板法或自组装方法进行组装可以获得有序复杂的分级结构微纳米材料,它能展现出优于单一纳米材料的特殊性能,因此是科学界研究的热点。文章主要针对几种常见的复杂结构纳米材料的制备及形成机理进行了简要的探讨。     

正磷酸盐的阻垢协同作用研究

采用静态阻垢法、SEM、XRD分析技术研究了PO4^3-与三元共聚物AA/AMPS/HPA对CaCO3垢的作用.结果表明：单独的PO4^3-对CaCO3无任何阻垢作用;8～20mg/LAA/AMPS/HPA＋1～6mg/LPO4^3-在阻CaCO3垢时表现出显著的协同效应,当PO4^3-质量浓度超过6 mg/L时,两者阻CaCO3的阻垢率下降,协同效应也不明显.PO4^3-与AA/AMPS/HPA三元共聚物使CaCO3的形貌发生变化,对方解石的形成有明显的抑制作用.     

Inline monitoring the effect of chemical inhibitor on the calcium carbonate precipitation and agglomeration

The formation of mineral scale particularly calcium carbonate is a problem for industries ranging from oil and gas to desalination plants. Various techniques have been studied to prevent the formation of scale. The use of chemical inhibitors to prevent calcium carbonate agglomeration is widely studied. The present study attempts to show that the inline monitoring technique is a useful tool for laboratory experimental investigation of agglomeration phenomenon. This method is successful in providing the induction time of starting agglomeration. It was shown that the presence of inhibitor delays the agglomeration and affects the deposition of calcium carbonate.In addition the method is found useful in determining the minimum inhibitor concentration and also to screen various types of inhibitors for the selection. The influence of an inhibitor is studied on scaling solution of various calcium ion concentrations. Finally, the result of inline technique was validated by comparing with the conventional one called offline technique. The SEM images reveal that the mechanism of inhibition might be the surface adsorption or distortion of inhibitor molecules on the growing calcium carbonate crystals.     

烟柴杆提取物的阻垢和缓蚀性能

研究了烟柴杆提取物提取方式对阻垢性能的影响,以水作溶剂所得烟柴杆提取物对碳酸钙、硫酸钙和磷酸钙均有较好的阻垢效果。通过红外、XRD、SEM对烟柴杆提取物阻垢机理进行研究,认为所得提取物对沉积物质具有阻垢性能是其螯合作用和晶格畸变作用的协同表现。采用旋转挂片法和极化曲线对提取物缓蚀机理进行分析,烟柴杆提取物作为碳钢缓蚀剂,属于阳极型的缓蚀剂。由于烟柴杆提取物具有优良的生物降解性,所以是一种对环境友好型的水处理剂。     

Controlled synthesis of carbon nanocoils and carbon nanotubes on common paper substrates

The commercially available copy papers and pure papers have been adopted to synthesize carbon nanomaterials. It is found that carbon nanocoils (CNCs) are efficiently synthesized on the copy paper substrates using Fe₂(SO₄)₃/SnCl₂ catalyst by a thermal chemical vapor deposition method, while only carbon nanotubes (CNTs) are obtained on the pure paper substrate using the same process. It is evidenced that the particles of calcium carbonate existing in copy paper aggregate catalyst and adsorb more sulfur elements which promote the growth of CNCs. In addition, CNCs can successfully grow out from the pure paper by adding calcium carbonate.