“…Porous materials such as activated carbon, zeolite, metal–organic frameworks (MOFs), covalent organic frameworks (COFs), and porous organic polymers (POPs) have already been explored to recover Pd(II). − However, a portion of them suffer from poor stability and low adsorption capacity and selectivity, which hindered their development. Therefore, the development of new Pd(II) adsorbents is urgent.…”