纳米碳球的制备及其吸附性能的研究

发布时间：2018-03-28 12:27

本文选题：纳米碳球　切入点：介孔　出处：《河北科技大学》2017年硕士论文

【摘要】：因水体污染和温室效应问题的存在,迫切需要开发新的吸附材料于以应对。球形纳米碳材料具有较大的比表面积和孔体积、均一的孔道结构、可控的形貌及可调的表面化学性质等特点,可应用于催化、超级电容器、吸附分离及能量储存等诸多现代科学领域。本论文从球形纳米碳材料的制备方法入手,制备出不同性质球形纳米碳材料,并研究其在吸附方面的应用性能。论文的主要研究内容如下:1)以苯酚和甲醛为碳源,嵌段共聚物F127为模板剂,制备直径约为110 nm的介孔纳米高分子球,再通过改性掺铁和碳化过程,制备出不同掺铁量的磁性介孔纳米碳球。通过水溶液中六价铬离子吸附性能测试证明,所制备的磁性介孔纳米碳球结合了Fe_3O_4纳米颗粒和介孔碳纳米球的特点,显示出较高的协同吸附六价铬离子的性能。并且随着掺铁量的增加,吸附量随之增加。同时,在外磁场作用下,磁性介孔纳米碳球可以很好的实现磁性分离。实验中结合吸附动力学和吸附等温线研究,全面分析了其作为工业吸附剂的可能性。2)提出“自催化”方法制备空心纳米碳球的新思路。本实验选用间苯二酚和甲醛为碳源,改性的纳米二氧化硅球为模板和催化剂,在不加氨水和阳离子催化剂十六烷基苯甲基溴化铵的条件下,自催化制备出空心纳米碳球。嫁接在纳米二氧化硅球表面的氨基,不仅提供了轻微的碱性环境,催化间苯二酚-甲醛树脂的聚合,并且提供正电荷包覆在纳米二氧化硅球表面,吸附表面带负核电荷的酚醛树脂沉积包覆在纳米二氧化硅球表面,形成纳米二氧化硅球@酚醛树脂的核壳结构。最后经碳化、去除二氧化硅,得到的纳米空心碳球完全复制了二氧化硅球的形貌,粒径均一,比表面积为777 m2 g-1。实验结果表明,经KOH活化后得到的纳米空心碳球具有良好的CO_2吸附性能。另外,自催化的方法也成功扩展到用其他碳源(如:间氨基苯酚)制备出粒径均一的空心纳米碳球。3)采用改进的St?ber制备的二氧化硅球为硬模板,HMF作为碳前驱体,在水热条件下直接快速的制备空心纳米碳球。该材料具有大的空心结构、薄壳渗透性和高的比表面积,表现出优异的吸附CO_2的性能。重复的CO_2吸附-解吸实验揭示了空心纳米碳球具有良好的重复利用性,这为进一步利用生物质衍生物制备空心纳米碳球提供了新思路。
[Abstract]:Because of water pollution and Greenhouse Effect problem, it is urgent to develop new adsorption materials to deal with the problem. Spherical nano-carbon materials have larger specific surface area, larger pore volume and uniform pore structure. Controllable morphology and adjustable surface chemical properties can be used in many modern scientific fields, such as catalysis, supercapacitor, adsorption separation and energy storage. Spherical nano-carbon materials with different properties were prepared and their application properties in adsorption were studied. The main contents of this paper are as follows: (1) Phenol and formaldehyde were used as carbon source and block copolymer F127 was used as template. Mesoporous nanopolymer spheres with a diameter of about 110 nm were prepared, and magnetic mesoporous carbon spheres with different iron content were prepared by modified iron doping and carbonation process. The adsorption properties of hexavalent chromium ions in aqueous solution were tested. The magnetic mesoporous carbon nanospheres combine the characteristics of Fe_3O_4 nanoparticles and mesoporous carbon nanospheres, and show high synergistic adsorption of hexavalent chromium ions. Magnetic separation can be achieved by magnetic mesoporous carbon nanocrystals under external magnetic field. The adsorption kinetics and adsorption isotherm were studied in the experiment. The possibility of using it as an industrial adsorbent. 2) A new idea of "autocatalytic" method for the preparation of hollow carbon nanospheres was put forward. Resorcinol and formaldehyde were used as carbon sources, and modified nano-silica spheres were used as templates and catalysts. Hollow nano-carbon spheres were prepared by autolysis without ammonia and cationic catalyst decaalkylbenzene methyl ammonium bromide. The amino groups grafted on the surface of nano-silica spheres not only provided a slight alkaline environment, It catalyzes the polymerization of resorcinol-formaldehyde resin, and provides positive charge coating on the surface of nano-silica sphere. The adsorbed surface of phenolic resin with negative nuclear charge is deposited on the surface of nano-silica sphere. The core-shell structure of nano-silica spheres @ phenolic resin was formed. Finally, after carbonization and removal of silica, the morphology of silica spheres was completely reproduced, the particle size was uniform, and the specific surface area was 777 m2 g-1.The experimental results showed that, In addition, the autocatalytic method has been successfully extended to other carbon sources (such as m-aminophenol) to prepare homogenous hollow carbon nanospheres. 3. The silica sphere prepared by ber is a hard template and a carbon precursor. The hollow carbon nanospheres are prepared directly and quickly under hydrothermal conditions. The material has large hollow structure, thin shell permeability and high specific surface area. Repeated CO_2 adsorption-desorption experiments revealed that hollow carbon nanospheres have good reusability, which provides a new idea for the further preparation of hollow carbon nanospheres from biomass derivatives.
【学位授予单位】：河北科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ424;TB383.1

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