改性活性炭电极制备及电容脱盐性能研究

发布时间：2018-06-18 16:18

  本文选题：改性活性炭电极 + 氯化锌活化　； 参考：《东华大学》2015年硕士论文

【摘要】：电容去离子技术由于具有能耗低、脱盐效率高及无二次污染等特点，是一种具有较好发展前景的海水、苦咸水淡化技术。具有比表面积高、空隙丰富且廉价易得的活性炭是一种常用的电极材料。但传统商业活性炭存在介孔分布较少和亲水性较差等缺点，限制了在电容脱盐过程中离子在电极上的扩散与传输。本论文选择氯化锌活化及聚多巴胺改性等方法对活性炭进行处理，分别制备孔径分布及亲水性改善的改性活性炭电极并组装成电容器，研究其电化学及电容脱盐性能。由于孔径分布及亲水性得到改善，在电容脱盐过程中能提高电极对离子的吸附速率和吸附量。本文主要研究结果如下： 1、以氯化锌为活化剂，将活性炭用氯化锌溶液浸渍处理后，在氮气保护作用下设置一定温度进行活化处理，制备氯化锌活化活性炭。比表面积测试结果表明活化后活性炭的比表面积和介孔孔容均得到提高。傅里叶变换红外-拉曼（FTIR-Raman）光谱分析氯化锌活化前后炭样表面结构成分的变化。以氯化锌活化活性炭制备电极用于电容去离子，其脱盐容量比活化前有明显改善。研究了活化温度对比表面积及电化学性能的影响，发现，随着活化温度升高，比表面积逐渐降低，但电极比电容及对应的电容脱盐量增加。800℃时活化电极的电容脱盐量比未活化炭电极提高了1.3倍，达到10.5mg/g。活化电极的循环稳定性好，制备步骤简单，易于批量生产。 2、通过多巴胺自身聚合机理，在室温条件下只需将活性炭分散在多巴胺碱性溶液中简单搅拌一定时间，，即可得到表面负载聚多巴胺的亲水性活性炭。XPS和FTIR证明了聚多巴胺在活性炭表面的成功负载，接触角测试证明负载聚多巴胺活性炭亲水性的改善。以聚多巴胺改性活性炭制备电极用于电容脱盐，并研究了聚合时间对其电化学性能和脱盐性能的影响。发现，随着聚合时间增加，聚多巴胺负载量增加，但电极的比电容及对应的电容脱盐量先增加，后降低。其中4h聚合时间对应聚多巴胺改性活性炭电极的脱盐量及脱盐速率分别达到12mg/g和0.35mg/(g.min)，比纯活性炭电极有明显提高。聚多巴胺改性活性炭电极制备方法简单，易于批量生产，且电极循环稳定性好，可用于连续脱盐。
[Abstract]:Because of the characteristics of low energy consumption, high desalination efficiency and no secondary pollution, capacitive deionization technology is a kind of seawater desalination technology with good development prospect and brackish water desalination. Activated carbon with high specific surface area, rich void and cheap and easy to obtain is a common electrode material. However, the traditional commercial activated carbon has the disadvantages of less mesoporous distribution and poor hydrophilicity, which limits the diffusion and transport of ions on the electrode during the process of capacitor desalination. In this paper the activated carbon was treated by zinc chloride activation and polydopamine modification. The modified activated carbon electrodes with improved pore size distribution and hydrophilicity were prepared and assembled into capacitors to study their electrochemical and capacitance desalination properties. Due to the improvement of pore size distribution and hydrophilicity, the adsorption rate and amount of ion adsorbed by the electrode can be increased during the desalting process of capacitance. The main results are as follows: 1. Zinc chloride activated carbon was prepared by impregnating activated carbon with zinc chloride solution and setting a certain temperature under nitrogen protection. The results of specific surface area test showed that the specific surface area and mesoporous volume of activated carbon were improved. Fourier transform infrared (FTIR) Raman spectroscopy (FTIR-Raman) was used to analyze the changes of surface structure of carbon samples before and after zinc chloride activation. The electrode prepared from activated carbon activated by zinc chloride was used for capacitive deionization, and its desalination capacity was obviously improved compared with that before activation. The effect of activation temperature on specific surface area and electrochemical performance was studied. It was found that the specific surface area decreased with the increase of activation temperature. However, the capacitance desalination capacity of the activated electrode was 1.3 times higher than that of the unactivated carbon electrode, and reached 10.5 mg / g when the specific capacitance and the corresponding capacitance desalination amount increased by 0.800 鈩

本文编号：2036085