静电纺丝纳米炭纤维的电容去离子化技术用于海水淡化

Electrospun carbon nanofibers for use in the capacitive desalination of water

  • 摘要: 电容去离子技术(CDI)已迅速发展成为极具前景的海水淡化方法之一,该技术主要通过在两个多孔电极之间施加电势,使水中的带电物质向电极表面移动,去除水中的盐分进行海水淡化。当离子可以在电极材料的多孔结构中畅通无阻地通过时,海水淡化的效果最佳。纳米结构的多孔炭材料具有较高的比表面积和表面活性,因此更有利运用CDI进行海水淡化。从这个意义上来说,高比表面积静电纺丝炭纳米纤维(CNFs)是非常理想的炭材料,可以在其表面进行掺杂/接枝活性剂增强表面特性。与传统的用粉状材料制备得到的电极不同,CNF可以无需使用黏合剂自支撑形成电极,从而避免了电极材料微观结构和导电性的改变。因此,中孔和微孔均匀分布的分层孔结构使得CNF电极具有较好的海水淡化性能。此外,CNFs与法拉第材料的复合材料可以通过双电层(EDL)和赝电容机制的协同作用进一步增强离子的存储能力。本文重点综述了在CDI工艺中静电纺丝CNFs电极的主要前驱体材料、结构改性及其在盐离子电吸附中的性能。

     

    Abstract: Capacitive deionization (CDI) has rapidly become a promising approach for water desalination. The technique removes salt from water by applying an electric potential between two porous electrodes to cause adsorption of charged species on the electrode surfaces. The nature of CDI favors the use of nanostructured porous carbon materials with high specific surface areas and appropriate surface functional groups. Electrospun carbon nanofibers (CNFs) are ideal as they have a high specific surface area and surface characteristics for doping/grafting with electroactive agents. Compared with powdered materials, CNF electrodes are free-standing and don’t require binders that increase resistivity. CNFs with an appropriate distribution of mesopores and micropores have better desalination performance. Compositing CNFs with faradaic materials improve ion storage by adding pseudocapacitance to the electric double layer capacitance. The use of electrospun CNFs as electrodes for CDI is summarized with emphasis on the major precursor materials used in their preparation and structure modification, and their relations to the performance in salt electrosorption.

     

/

返回文章
返回