电容去离子(CDI)是一种基于电场力驱动的快速去除水中带电离子的新型脱盐技术,在盐水预富集和降低零排能耗方面极具潜力。但目前CDI技术受限于多孔碳电极低电吸附活性及不可控的孔结构分布导致脱盐容量和电荷效率较低,限制其进一步应用。为此,以吡啶在为碳源、碱式碳酸镁为模板剂通过化学气相沉法,构建了高活性表面、结构可控的N掺杂碳纳米笼状结构(N-CNC),探究其脱盐性能。通过精准控制载气与吡啶进入量,制备的N-CNC是由3~5层石墨化碳层层堆叠的空心长方体形貌,且外壁平均壁厚在1~2nm,其中N质量分数高达4.2%。得益于这种优异的孔隙结构分布和丰富的表面化学性质,N-CNC展现出以赝电容贡献为主的电化学行为。组装N-CNC//N-CNC对称模块,采用单通道脱盐模式脱盐测试,结果表明,盐吸附量和电荷效率分别为21.8mg/g和82%,能耗低至0.71Wh/g。进一步使用自组装CDI模块处理煤化工高盐水,在1.2V吸附电压下获得Cl-、SO2-4和NO-3电吸附脱盐容量分别为33.4、20.5和8.9mg/g,其中Cl-/SO2-4选择性比高达5.1。本研究提供了一种简便可控的N掺杂碳纳米笼状结构制备方法,为CDI浓缩工业卤水预富集应用提供理论和技术支撑。

field force. It has great potential in brine pre-concentration and reducing the energy consumption of zero liquid discharge desalination.However, the current CDI technology is limited by the low electro-adsorption active sites and uncontrollable pore structure distribution ofporous carbon electrodes, resulting in low desalination capacity and charge efficiency, which hinders its further application. Therefore,highly active surfaces and structurally controllable N-doped carbon nanocages (N-CNC) were constructed by a chemical vapor deposition method using pyridine as a carbon source and alkaline magnesium carbonate as a templating agent to investigate their desalinationproperties. Through precise control of the carrier gas and pyridine quantities, the resulting N-CNC consists of 3- 5 layers of graphitized carbon arranged in a hollow rectangular morphology. The average thickness of the outer wall ranges from 1 to 2 nm, with an impressive N content reaching up to 4.2%. Benefitting from its exceptional porous structure distribution and rich surface chemistry, N-CNC exhibits electrochemical behavior primarily contributed by its pseudo-capacitive properties. The desalination test results of the assembled N-CNC/ / N-CNC symmetric module using the single-pass desalination mode show that the salt adsorption capacity and charge efficiency are21.8 mg/ g and 82%, respectively, with low energy consumption of 0.71 Wh/ g. Further treatment of coal chemical high-salinity water testshow excellent anion absorption performance. Electric adsorption desalination capacity of Cl,SO ,NO are 33.4,20.5,8.9 mg/ g,of which theselectivity ratio of Cl / SO is as high as 5.1. This study provides a simple and controllable preparation method for N-doped carbon nanocagestructure, which provides certain theoretical and technical support for the industrialization application of CDI concentrated industrial brine.

0 引言

1 试验

   1.1 原料与试剂

   1.2 材料制备

   1.3 材料表征

   1.4 电极制备与器件组装

   1.5 性能测试

2 结果与讨论

   2.1 结构表征

   2.2 电化学性能

3 结论