鱼鳞基磁性多孔炭材料的制备及其对六价铬吸附性能研究

发布时间：2018-04-11 11:23

本文选题：多孔炭 + 鱼鳞　；参考：《北京化工大学》2015年硕士论文

【摘要】：含铬废水毒性大,因此它的净化成为目前研究的热点。多孔炭材料由于具有大比表面积、多孔隙率和含有官能团而成为含铬废水的优良净化剂。磁性炭材料可实现磁性分离,能有效地简化吸附后的分离过程,因此本文对鱼鳞基磁性多孔炭材料的制备及其对含六价铬水溶液的净化作用进行了研究。首先,采用鱼鳞多孔炭作为还原剂和载体成功地制备了鱼鳞基磁性多孔炭,用X射线衍射证明了所制备的鱼鳞基磁性多孔炭由零价铁和无定型炭组成,其中零价铁为体心立方结构晶体。用SEM、TEM和氮气吸脱附实验表征了所制备材料的形貌和结构,并考察了材料载铁量对其结构的影响。含铁量为0.5 mmol时,其最大饱和磁化强度可高达16.49 emu/g。其次,研究了鱼鳞基磁性多孔炭材料对水溶液中六价铬的净化作用。探讨了体系pH值、铬的初始浓度和吸附时间对鱼鳞基磁性多孔炭吸附六价铬性能的影响,揭示了其影响规律。在此基础上,研究了其等温吸附和动力学模型。结果表明,在较低pH值范围,有利于鱼鳞基磁性多孔炭对六价铬的吸附,且应用Langmuir和Freundlich等温吸附模型均能较好地描述鱼鳞多孔炭和鱼鳞基磁性多孔炭对六价铬的吸附行为。根据Langmuir等温吸附模型,鱼鳞基磁性多孔炭的最大吸附量可高达357.12mg/g,高于鱼鳞多孔炭344.83 mg/g,且其吸附行为符合准二级动力学模型,这一结果未见文献报道。最后,对吸附剂的循环使用能力进行了初探。研究表明,经过三次吸附一脱附循环后,鱼鳞基磁性多孔炭仍能保持初次吸附能力的88.5%,显著高于鱼鳞多孔炭的66.1%。并借助XPS对鱼鳞基磁性多孔炭吸附六价铬机理进行了分析。这证明所制备的鱼鳞基磁性多孔炭不仅具有高的吸附量且具有较大的饱和磁化强度,有利于吸附后吸附剂的回收,是一种极具潜力的新型水中六价铬的吸附剂。
[Abstract]:Chromium-containing wastewater is highly toxic, so its purification has become a hot research topic.Porous carbon is an excellent purifying agent for wastewater containing chromium due to its large specific surface area, high porosity and functional groups.Magnetic separation of magnetic carbon materials can effectively simplify the separation process after adsorption. Therefore, the preparation of magnetic porous carbon materials based on fish scales and the purification of aqueous solution containing hexavalent chromium have been studied in this paper.Firstly, the magnetic porous carbon based on fish scale was successfully prepared by using fish scale porous carbon as reducing agent and carrier. The results of X-ray diffraction showed that the magnetic porous carbon based on fish scale was composed of zero valent iron and amorphous carbon.Among them, the zero-valent iron is a body-centered cubic crystal.The morphology and structure of the prepared materials were characterized by SEM TEM and nitrogen adsorption and desorption experiments.When the iron content is 0.5 mmol, the maximum saturation magnetization can reach 16.49 emu / g.Secondly, the purification of hexavalent chromium in aqueous solution by magnetic porous carbon based on fish scale was studied.The effects of pH value, initial concentration of chromium and adsorption time on the adsorption of hexavalent chromium by magnetic porous carbon based on fish scale were discussed.On this basis, the isothermal adsorption and kinetic models were studied.The results show that the adsorption of hexavalent chromium on fish scale based magnetic porous carbon is favorable in the range of lower pH, and the adsorption behavior of hexavalent chromium on fish scale porous carbon and fish scale magnetic porous carbon can be well described by using Langmuir and Freundlich isothermal adsorption models.According to the Langmuir isothermal adsorption model, the maximum adsorption capacity of fish scale based magnetic porous carbon can be as high as 357.12 mg / g, which is higher than that of fish scale porous carbon at 344.83 mg / g, and its adsorption behavior accords with the quasi-second-order kinetic model. This result has not been reported in literature.Finally, the recycling ability of adsorbent was studied.The results show that after three adsorption and desorption cycles, the primary adsorption capacity of fish scale based magnetic porous carbon is 88.5%, which is significantly higher than that of fish scale porous carbon (66.1%).The mechanism of adsorption of hexavalent chromium by magnetic porous carbon based on fish scale was analyzed by XPS.It is proved that the prepared magnetic porous carbon not only has high adsorption capacity and high saturation magnetization, but also is beneficial to the recovery of adsorbent after adsorption. It is a potential new adsorbent for hexavalent chromium in water.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.11;X703

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