{Reference Type}: Journal Article
{Title}: Selective Capacitive Removal of Pb2+ from Wastewater over Biochar Electrodes by Zinc Regulation.
{Author}: Wu Y;Feng H;Tang J;Yang Z;Lan C;Guo Y;Tang L;
{Journal}: Small
{Volume}: 20
{Issue}: 28
{Year}: 2024 Jul 13
{Factor}: 15.153
{DOI}: 10.1002/smll.202311401
{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.