Abstract：
Biochar materials have shown great potential for broad catalytic application. However, using these materials in the capacitive deionization technology (CDI) system for heavy metal removal still faces a significant challenge due to their low specific capacity and removal capability. Here, a comprehensive regulation on the interfacial/bulk electrochemistry of biochar by Zn doping is reported, which suggests a high renewable capacity (20 mg g-1) and outstanding selective capacitive removal ability (SCR) of Pb2+ from leachate. The SCR efficiency of Pb2+ is as high as 99% compared to K+ (8%), Na+ (13%), and Cd2+ (37%). This work proves that the doped Zn on the biochar can combine with OH- generated by water splitting to form M─OH bonds, which is beneficial for improving the specific capacity. Significantly, the relationship between double-layer capacitance and pseudo-capacitance can also be optimized by regulating the content of Zn, leading to different removal abilities of heavy metals. Therefore, this work offers insights into charge-storage kinetics, which provide valuable guidelines for designing and optimizing the biochar electrode for broader environmental applications.
摘要：
生物炭材料已显示出广阔的催化应用潜力。然而,在电容去离子技术（CDI）系统中使用这些材料去除重金属仍然面临着巨大的挑战，因为它们的比容量和去除能力低。这里,报道了锌掺杂对生物炭界面/本体电化学的综合调控，这表明从渗滤液中Pb2的高可再生容量（20mgg-1）和出色的选择性电容去除能力（SCR）。与K+(8%)相比，Pb2+的SCR效率高达99%，Na+(13%),和Cd2+(37%)。这项工作证明了生物炭上掺杂的Zn可以与水分解产生的OH-结合形成M─OH键，有利于提高比容量。重要的是,也可以通过调节Zn的含量来优化双层电容和伪电容之间的关系，导致重金属的去除能力不同。因此,这项工作提供了对电荷存储动力学的见解，这为为更广泛的环境应用设计和优化生物炭电极提供了有价值的指南。
