生物炭基多孔炭材料的制备及其电吸附脱盐性能研究

发布时间：2018-05-01 11:25

  本文选题：多孔炭 + 亚甲基蓝　； 参考：《安徽理工大学》2015年硕士论文

【摘要】：随着水污染现象的日益严重,水资源短缺是我国面临的重大问题之一,而海水淡化、工业含盐废水脱盐回用是解决此问题的重要途径。电吸附脱盐技术因其能耗低、对环境污染小等优点成为一种重要的脱盐方法。影响电吸附脱盐效果的关键在于电极材料的比表面积和孔隙结构。因此,如何制备高比表面积和丰富孔隙结构的炭材料成为国内外研究的重点。 本研究以花生壳生物质炭为先驱体,采用KOH活化法改性制备多孔炭。考察了KOH与生物质炭的浸渍质量比、活化时间和活化温度等操作条件对制得多孔炭材料的比表面积和孔隙结构的影响,探讨了多孔炭吸附模型化合物亚甲基蓝的吸附行为,获得了吸附容量、动力学和热力学等基本参数。将制备的多孔炭材料做成吸附电极,深入研究了其电化学性能及脱盐率。在此基础上,将多孔炭材料进一步进行三聚氰胺掺杂改性,初步考察了其电化学特征。主要结论如下： (1)控制浸渍比为1.5：1、活化温度为800℃且活化时间为90min时,制备的多孔炭材料对水溶液中亚甲基蓝具有最高的吸附容量。比表面积及孔径表征结果显示,最佳制备条件下制得的多孔炭材料具有丰富的孔隙结构和较高的比表面积,比表面积达到597.93m2·g-1,显著高于未活化的花生壳炭的比表面积(12.28m2·g-1)。亚甲基蓝吸附中,溶液pH、初始亚甲基蓝浓度、温度等对多孔炭吸附亚甲基蓝效果有明显影响。pH值为6时,多孔炭对亚甲基蓝的吸附效果最好；活化后的多孔炭材料对亚甲基蓝的吸附效果远强于未活化的花生壳炭,吸附容量144.55mg·g-1；当亚甲基蓝的初始浓度由100mg·L-1增加到400mg·L-1时,吸附平衡时间由100min增加到500min,而去除率则由99.25%降低到54.35%。 (2)多孔炭吸附电极循环伏安测试表明,最佳制备条件下制得的多孔炭材料电吸附脱盐效果最好；扫速越高,多孔炭电极的比电容越小,电极的离子吸附容量越低；盐浓度越高,多孔炭电极的比电容越大,电极的离子吸附容量越大。离子半径越小,电荷越大,电吸附性能越好。交流阻抗测试表明,活化多孔炭电极的内阻比未活化的花生壳炭电极的内阻小,具有更好的导电性能。恒流充放电测试发现,活化多孔炭电极亦具有较好的稳定性和循环再生性,内压降小于未活化的花生壳炭。当NaCl溶液的浓度为20ppm时,未活化的花生壳炭电极的脱盐效率只达到25%左右,而经过KOH活化后的多孔炭电极脱盐效率可达到98%左右；随着NaCl溶液的浓度的增加,出水的电导率逐渐增大,脱盐效率逐渐降低。 (3)以三聚氰胺为原料,制备氮掺杂的多孔炭电极。XPS表征看出,三聚氰胺掺杂改性后提高了材料中氮含量,且主要为质子化吡啶氮和吡啶氮氧化物；氮掺杂多孔炭电极的比电容为53.8F·G-1,高于改性前的比电容41.6F·g-1；脱盐测试发现,氮掺杂改性后电吸附脱盐性能亦有所改善。
[Abstract]:With the increasing water pollution, the shortage of water resources is one of the major problems in China, and desalination and reuse of industrial salt-containing wastewater is an important way to solve this problem. Electrosorption desalting technology has become an important desalting method because of its low energy consumption and low environmental pollution. The specific surface area and pore structure of electrode materials are the key factors affecting the desalination effect of electrosorption. Therefore, how to prepare carbon materials with high specific surface area and rich pore structure has become the focus of research at home and abroad. In this study, porous carbon was prepared by KOH activation with peanut shell biomass carbon as precursor. The effects of the impregnation mass ratio of KOH and biomass carbon, activation time and activation temperature on the specific surface area and pore structure of porous carbon materials were investigated. The adsorption behavior of porous carbon adsorption model compound methylene blue was discussed. The basic parameters of adsorption capacity, kinetics and thermodynamics were obtained. The electrochemical properties and desalinization rate of porous carbon materials were studied. On this basis, the porous carbon materials were further modified by melamine, and their electrochemical characteristics were preliminarily investigated. The main conclusions are as follows: When the impregnation ratio is 1.5: 1, the activation temperature is 800 鈩，

本文编号：1829154