磁性载钴有序介孔碳的制备及其去除水体罗丹明B的研究

发布时间：2018-04-29 21:25

本文选题：磁性载钴有序介孔碳 + 罗丹明B　；参考：《湖南大学》2015年硕士论文

【摘要】：本课题针对目前日益严重的水环境污染现象,利用介孔碳的大比表面积和特定孔径等特性以及磁性纳米粒子在固液分离方面的优势,制备出负载钴纳米粒子的磁性有序介孔碳复合材料,用于高效去除水体染料罗丹明B,从而改善水环境。本研究主要围绕磁性载钴有序介孔碳的制备及其在染料废水中的应用而展开的,并深入研究了吸附剂去除罗丹明B的吸附机理,同时探讨了它在工业废水处理方面实际应用的潜在价值。本文利用后浸渍法制备出磁性载钴有序介孔碳(Co/OMC)。具体地,采用传统水热合成法制备出有序介孔硅SBA-15,后以其为模板,蔗糖为碳源,在强酸条件下途经热聚合、高温炭化形成有序介孔碳(OMC),再以OMC为基体,硝酸钴为金属源,利用浸渍、热聚合手段将Co纳米粒子负载在OMC上,从而形成磁性载钴有序介孔碳(Co/OMC)。其SEM和TEM电镜图证实有序介孔碳呈棒状结构,介孔碳条纹排列整齐、均一有序,同时表面均匀分布着黑色Co纳米粒子。在负载钴纳米粒子以后,Co/OMC的孔径尺寸集中在4.3nm左右,其比表面积降至955.3m2/g,且介孔碳表面石墨化程度加剧,饱和磁强值为2.9emu/g。在探讨吸附参数影响Co/OMC对罗丹明B去除实验中发现,负载Co纳米粒子后的OMC具有更大的吸附容量,在初始罗丹明B浓度为200mg/L时,吸附剂的平衡吸附量为468mg/g,且其吸附速率比较快,对初始浓度为100mg/L的罗丹明B,在前25min左右,吸附效率能达到96%。此外,Co/OMC的吸附容量随着溶液p H值、吸附剂量和初始罗丹明B浓度的增加而增加。动力学研究证实准二阶动力学模型能够很好的拟合Co/OMC对罗丹明B的吸附,表明该吸附是一个化学速率控制过程,且还发现该吸附过程具有两段式内扩散吸附趋势,说明罗丹明B的去除是一个受孔径和比表面积影响的吸附。热力学研究证实该吸附过程是一个自发、吸热的形式,且在反应过程中,固液混乱度增加。吸附等温线研究发现Langmuir吸附模型能很好的拟合罗丹明B的去除过程,这表明在其去除过程中,在Co/OMC表面形成了单分子层结构,Co/OMC表面的各个吸附位点的位能大小相等。同时,吸附剂的再生实验发现Co/OMC具有很好的稳定性,在7次吸脱附循环后,其对罗丹明B的吸附率仍在83%以上。这证实Co/OMC的再生性能很好,其在实际处理含罗丹明B废水中具有很大应用优势。
[Abstract]:In view of the increasingly serious pollution phenomenon of water environment, this paper makes use of the characteristics of large specific surface area and specific pore size of mesoporous carbon and the advantages of magnetic nanoparticles in solid-liquid separation. A magnetic ordered mesoporous carbon composite loaded with cobalt nanoparticles was prepared for the removal of Rhodamine B in water and the improvement of water environment. This study focused on the preparation of ordered mesoporous carbon containing magnetic cobalt and its application in dye wastewater. The adsorption mechanism of adsorbent for Rhodamine B removal was studied. At the same time, the potential value of its practical application in industrial wastewater treatment is discussed. In this paper, Co / O / O MCs with magnetic cobalt bearing ordered mesoporous carbon were prepared by post-impregnation method. In particular, the ordered mesoporous silicon SBA-15 was prepared by traditional hydrothermal synthesis method. Then the ordered mesoporous silicon SBA-15 was synthesized by thermal polymerization under strong acid condition and carbonized at high temperature. Then, the ordered mesoporous silicon SBA-15 was prepared with OMC as the matrix and cobalt nitrate as the metal source. The Co nanoparticles were loaded on OMC by impregnation and thermal polymerization, and the ordered mesoporous CO / O MCS with magnetic cobalt was formed. The SEM and TEM electron microscopy showed that the ordered mesoporous carbon was rod-like, the mesoporous carbon stripes were arranged neatly and uniformly, and the black Co nanoparticles were uniformly distributed on the surface. After loading cobalt nanoparticles, the pore size of Co / O MC is concentrated around 4.3nm, its specific surface area is reduced to 955.3 m2 / g, and the graphitization degree of mesoporous carbon surface is increased, and the saturation magnetic intensity is 2.9 emu / g. In the study of the effect of adsorption parameters on the removal of Rhodamine B by Co/OMC, it was found that the adsorption capacity of OMC loaded with Co nanoparticles was larger. When the initial concentration of Rhodamine B was 200mg/L, the equilibrium adsorption capacity of adsorbent was 468 mg / g, and the adsorption rate was relatively fast. For Rhodamine B with initial concentration of 100mg/L, the adsorption efficiency of Rhodamine B can reach 96% at the pre- level. In addition, the adsorption capacity of Co- / OMC increases with the increase of pH value of solution, the amount of adsorbent and the initial concentration of Rhodamine B. The kinetic studies show that the quasi-second-order kinetic model can fit the adsorption of Rhodamine B by Co/OMC, which indicates that the adsorption is a chemical rate-controlled process, and it is also found that the adsorption process has a two-stage internal diffusion adsorption trend. It shows that the removal of Rhodamine B is an adsorption affected by pore size and specific surface area. Thermodynamic studies show that the adsorption process is a spontaneous, endothermic form, and in the reaction process, the degree of solid-liquid confusion increases. The adsorption isotherm results show that the adsorption model of Langmuir can fit the removal process of Rhodamine B well, which indicates that the potential energy of each adsorption site on Co/OMC surface is equal. At the same time, the regeneration experiment of adsorbent showed that Co/OMC had good stability. After 7 cycles of adsorption and desorption, the adsorption rate of Rhodamine B was still over 83%. It is proved that Co/OMC has good regeneration performance, and it has a great advantage in practical treatment of Rhodamine B wastewater.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.11;X703

【相似文献】