磁性空心双层微球的制备及性能研究

发布时间：2018-03-16 02:26

本文选题：空心双层微球　切入点：吸附　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：空心微球具有大比表面积、低密度、形貌可控等优点,在污水处理、纳米反应器、催化、药物缓释、超级电容器、光电等领域有很好的应用前景。而空心多层微球与空心单层微球相比具有更大的比表面积、更好的结构稳定性和优异的功能,在相关应用上具有更多的优势。目前空心多层微球的制备主要采用多次化学沉积、层层自组装等方法,过程复杂耗时,且难以回收再利用。因此,如何用简单有效的方法合成易回收的空心多层微球成为了人们的研究热点。本论文采用一步气溶胶法合成了两壳层组分不同的磁性空心双层微球,并研究了该微球的相关性能。论文首先用一步气溶胶法及溶解-再生长机理合成了磁性空心C/SiO2双层微球,该微球内层为C壳,外层为SiO2壳,且两层间有约50nm的空隙,磁性物质均匀分布在壳层中。该微球拥有较大的比表面积和孔体积(分别为226.3m2/g和0.51cm3/g),利于对分子的吸附,研究了其对亚甲基蓝(MB)和金属离子Pb2+、Ag+的吸附性能。结果表明,该微球对MB的最大饱和吸附量可达到171.2mg/g高于SiO2单层微球的最大饱和吸附量(150.0mg/g)。在重复使用5次后,对MB的去除率仍能达到95%以上。磁性微球对MB的吸附符合Langmuir模型。磁性双层微球对Pb2+、Ag+的最大饱和吸附量可分别达到216.5 mg/g和283.1 mg/g高于SiO2单层微球的最大饱和吸附量(189.8mg/g和213.4mg/g),重复使用5次后,双层微球对Pb2+、Ag+的最大饱和吸附量仍能达到180 mg/g和245 mg/g。另外,在吸附过程中可通过外加磁场对磁性微球进行有效回收。将磁性空心C/SiO2双层微球作为载体制备了磁性空心C/SiO2-Au微球和C/Au/C微球并考察了它们对对硝基苯酚(4-NP)的催化性能。实验结果表明磁性空心C/SiO2-Au微球对4-NP具有很好的催化性能,C/Au/C微球与C/SiO2-Au微球相比具有更好的稳定性,且催化性能良好。两种微球均可通过外加磁场进行回收。最后以该磁性空心C/SiO2双层微球作为模板制备了空心C/C双层微球,该微球具有较大的比表面积(482.0m2/g)和孔体积(0.92cm3/g)是一种较理想的超级电容器电极材料。测试结果表明,其在电流密度为0.1A/g时电极的比电容达到251F/g。在电流密度为1A/g时,经过5000次的循环实验电极的比电容减少了5.4%,说明空心C/C双层微球电极具有优异的电极循环稳定性能。
[Abstract]:Hollow microspheres have many advantages, such as large specific surface area, low density, controllable morphology, etc., in sewage treatment, nanoreactor, catalysis, drug release, supercapacitor, etc. The hollow multilayer microspheres have more specific surface area, better structural stability and better function than hollow monolayer microspheres. There are more advantages in related applications. At present, the hollow multilayer microspheres are prepared by chemical deposition and self-assembly, the process is complicated and time-consuming, and it is difficult to recover and reuse. How to synthesize hollow multilayer microspheres which are easy to be recovered by simple and effective method has become a hot topic. In this paper, the magnetic hollow bilayer microspheres with different components of two shell layers were synthesized by one-step aerosol method. The properties of the microspheres were also studied. Firstly, the magnetic hollow C / Sio _ 2 bilayer microspheres were synthesized by one-step aerosol method and solution-regrowth mechanism. The microspheres were C-shell in inner layer and SiO2 shell in outer layer, with a gap of about 50 nm between the two layers. The magnetic material is uniformly distributed in the shell. The microsphere has a large specific surface area and pore volume (226.3 m2 / g and 0.51cm ~ (-3) / g / g respectively, which is favorable for the adsorption of molecules. The adsorption properties of the microspheres for methylene blue MBs) and metal ion Pb2 (Ag) have been studied. The maximum saturated adsorption capacity of the microspheres to MB was 171.2 mg / g higher than that of SiO2 monolayer microspheres. The removal rate of MB can still reach more than 95%. The adsorption of MB on magnetic microspheres accords with Langmuir model. The maximum saturated adsorption capacity of magnetic bilayer microspheres for Pb2 + Ag can reach 216.5 mg/g and 283.1 mg/g respectively, which is higher than that of SiO2 monolayer microspheres. It's 189.8 mg / g and 213.4mg / g, and it's been reused for five times. The maximum saturated adsorption capacity of the double layer microspheres for Pb2 Ag can still reach 180 mg/g and 245 mg / g. Magnetic hollow C / Sio _ 2-Au microspheres and C / au / C microspheres were prepared by magnetic hollow C / Sio _ 2 bilayer microspheres and their catalytic properties for p-nitrophenol 4-NPs were investigated. The experimental results show that the magnetic hollow C / SiO2-Au microspheres have good catalytic performance for 4-NP. The C / au / C microspheres have better stability than C / SiO2-Au microspheres. The two kinds of microspheres can be recovered by external magnetic field. Finally, hollow C / C bilayer microspheres were prepared by using the hollow C / SiO2 bilayer microspheres as template. The microspheres with a large specific surface area of 482.0 m2 / g) and pore volume of 0.92cm3 / g) are ideal electrode materials for supercapacitors. The test results show that the specific capacitance of the electrode reaches 251F / g when the current density is 0.1Ag. When the current density is 1 / g, the specific capacitance of the electrode is 251F / g. The specific capacitance of the electrode is reduced by 5.4 after 5000 cycles, which indicates that the hollow C / C double layer microsphere electrode has excellent cycling stability.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O613.72;TB383.1

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