Effects of pore-structure and Surface Acidities of Activated Carbon Electrodes on The Double-layer Adsorption

活性炭电极孔隙结构和表面酸度对双层吸附的影响

基本信息

批准号：
13650897
负责人：
ODA Hirokazu
金额：
$ 2.05万
依托单位：
Kansai University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650897/
关键词：
Electric double layer Removal ions Activated carbon electrodes Pore-structure Surface functional groups Capacitor Cyclic operation of electrode 孔隙構造比表面積

项目摘要

It was possible to efficiently remove electrolytes from dilute solution using the flow-through capacitor (FTC), and a greater then 85% removal efficiency was achieved when porous activated carbon electrodes were used. It was confirmed that the amount of removal is generally dependent on the surface area and micropore volume of the activated carbon. Also, surface functional groups had the effect of improving ion removal, but there is a limit to the amount of groups mainly due to the interference of the transport of ions. The mechanisms for removal of the ions is proposed to include 1) adsorption by electrostatic force, 2) electrochemical ion exchange reactions when voltage is applied, and 3) normal ion exchange reactions by contact between the electrolyte and the activated carbon (especially for copper), and 1) electrolysis on the surface of the electrode (for example, for copper and zinc ions). The metal formed by electrolysis affected the pore structure of the activated carbon electrodes during prolonged ion removal. Alkali metals could be recovered and concentrated the easiest, but heavy metals were the most difficult. The latter ions were removed mainly by electrolysis at the interface of the electrode and the metals were being produced on the electrode surface. Therefore it was impossible to concentrate and recover the metal ions by this method.Cations have been demonstrated to be removed and desorbed in the following descending order of ease: alkaline metal > alkaline earth metal > transition metal. A high recovery rate has been obtained in the cycle characteristics of sulfuric acid and nitrates. In both one- and electric double layer are not easily desorbed.In order to increase volume of wastewater treatment, the FTC was large scaled. The optimum running conditions were determined for high efficiency better than small ones.

使用流通式电容器 (FTC) 可以有效地从稀溶液中去除电解质，并且当使用多孔活性炭电极时，去除效率可达到 85% 以上。已证实去除量通常取决于活性炭的表面积和微孔体积。此外，表面官能团具有改善离子去除的效果，但主要由于离子传输的干扰，基团的数量受到限制。去除离子的机制被认为包括 1) 通过静电力吸附，2) 施加电压时发生电化学离子交换反应，以及 3) 通过电解质和活性炭（尤其是铜）之间接触发生的正常离子交换反应，以及1）电极表面的电解（例如，对于铜离子和锌离子）。在长时间的离子去除过程中，电解形成的金属会影响活性炭电极的孔隙结构。碱金属最容易回收和浓缩，但重金属最难回收和浓缩。后者的离子主要通过电极界面处的电解被去除，并且在电极表面上产生金属。因此，通过该方法不可能浓缩和回收金属离子。已证明阳离子被去除和解吸的难易程度按以下顺序递减：碱金属>碱土金属>过渡金属。在硫酸和硝酸盐的循环特性中获得了较高的回收率。无论是单电层还是双电层都不易解吸。为了增加废水处理量，FTC进行了大规模的改造。确定了最佳运行条件，以获得高效率优于小效率。