负载ZnO复合纳米纤维膜的制备及其光催化性能研究

发布时间：2018-07-11 12:12

  本文选题：静电纺丝 + 聚丙烯腈　； 参考：《浙江理工大学》2017年硕士论文

【摘要】：本文以聚丙烯腈(PAN)与氯化锌(ZnCl_2)作为前驱物,采用静电纺丝工艺和溶液浸渍法相结合的方法,制备出了复合纳米纤维膜R-11/1、R-7/1、R-5/1、和S-5/1。以亚甲基蓝为污染物模型,评价其光催化降解性能,研究了纺丝液配比与不同的溶液浸渍方法对复合纳米纤维膜结构以及光催化性能的影响。将复合纳米纤维膜进行预氧化、碳化处理,提高其光催化降解性能。(1)以DMF作为溶剂,用聚丙烯腈配得纺丝液,得到了最优的静电纺丝工艺参数:纺丝液浓度12wt%、电压18kV、纺丝速率为0.7mL/h。采用静电纺丝和溶液浸渍法制备出了复合纳米纤维膜R-11/1、R-7/1、R-5/1、和S-5/1,其中R表示采用多次冷热交替浸渍法,S表示采用单次冷热静置浸渍法。利用扫描电镜(SEM)、傅里叶红外光谱(FT-IR)、X-射线衍射(XRD)、X-射线能量色散光谱(XPS)和热重分析(TG)对复合纳米纤维膜的表面形貌和微结构进行了表征,研究了不同的纺丝液配比和溶液浸渍法对复合纳米纤维膜性能的影响。结果表明:当PAN(g)/ZnCl_2(g)=7/1时,通过多次冷热浸渍法处理的复合纳米纤维膜ZnO含量较高,结晶性能较好。通过比较样品R-5/1与S-5/1可知,多次冷热浸渍法要比单次冷热静置法更有利于ZnO粒子负载在纳米纤维上。(2)以亚甲蓝溶液为污染物模型,研究了纺丝液配比和不同的溶液浸渍方法对复合纳米纤维膜光催化性能的影响。研究表明当PAN(g)/ZnCl_2(g)=7/1时,降解性能最优;多次冷热交替浸渍法比单次冷热静置浸渍法更容易使ZnO粒子负载在纳米纤维上。对样品R-7/1与S-5/1进行3次循环使用的光催化降解试验,证明了复合纳米纤维膜可以回收进行多次重复利用,具有很好的光催化性能稳定性。其次研究了影响光催化性能的因素,结果表明,MB溶液初始浓度越小,催化剂用量越多,染料溶液呈碱性时复合纳米纤维膜催化效率越高。(3)研究了预氧化时间和温度、碳化温度对PAN/ZnO复合纳米纤维膜形貌的影响,确定了最优的碳化工艺:预氧化时间60 min、预氧化温度200℃、碳化温度1000℃。按照最优碳化工艺对复合纳米纤维膜PAN/ZnO进行处理,发现样品R-11/1与R-7/1纤维直径减小,但表面ZnO粒子脱落严重;而样品R-5/1与S-5/1纤维直径没有比较明显的变化,且表面负载的ZnO粒子脱落较少。经过碳化工艺处理后的复合纳米纤维膜光催化性能均得到一定程度的改善。
[Abstract]:In this paper, using polyacrylonitrile (pan) and zinc chloride (ZnCl2) as precursors, the composite nanofiber membranes R-11 / 1 / 7 / 1 / 1 R-5 / 1 and S-5 / 1 were prepared by using electrospinning process and solution impregnation method. The photocatalytic degradation of methylene blue was evaluated using methylene blue as a pollutant model. The effects of spinning solution ratio and different solution impregnation methods on the structure and photocatalytic properties of composite nanofibers were studied. The composite nanofiber membrane was preoxidized and carbonized to improve its photocatalytic degradation. (1) the spinning solution was prepared with polyacrylonitrile (pan) and DMF as solvent. The optimum parameters of electrostatic spinning were obtained: spinning solution concentration 12 wts, voltage 18kV, spinning rate 0.7mL / h. Composite nanofiber membranes R-11 / 1 / 7 / 7 R-5 / 1 and S-5 / 1 were prepared by electrospinning and solution impregnation. The surface morphology and microstructure of composite nanofibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) X-ray diffraction (XRD), X-ray energy dispersive spectroscopy (XPS) and thermogravimetric analysis (TG). The effects of different ratio of spinning solution and solution impregnation on the properties of composite nanofibers were studied. The results show that when pan / ZnCl _ 2 (g) / 7 / 1, the content of ZnO is higher and the crystallinity is better. By comparing R-5 / 1 with S-5 / 1, we can see that the multiple cold and hot impregnation method is more favorable than the single cold and hot static method to the ZnO particle loading on the nanofibers. (2) the methylene blue solution is used as the pollutant model. The effects of spinning solution ratio and different solution impregnation methods on the photocatalytic properties of composite nanofibers were studied. The results show that when pan / ZnCl _ 2 (g) / 7 / 1, the degradation performance is the best, and the alternative cold and hot impregnation is easier than the single cold and thermal static impregnation to make the particles loaded on the nanofibers. The photocatalytic degradation tests of R-7 / 1 and S-5 / 1 were carried out for three times. It was proved that the composite nanofiber membrane could be recycled for many times and had good photocatalytic stability. Secondly, the factors influencing the photocatalytic performance were studied. The results showed that the lower the initial concentration of MB solution, the more the amount of catalyst was, the higher the catalytic efficiency of composite nanofiber membrane was when the dye solution was alkaline. (3) the pre-oxidation time and temperature were studied. The effect of carbonization temperature on the morphology of pan / ZnO composite nanofiber film was studied. The optimum carbonization process was determined as follows: preoxidation time 60 min, preoxidation temperature 200 鈩，

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