Nanoporous Aromatic Framework with Bulky Binding Groups for Palladium Recovery
Tingting Ma, Zhangnan Li, Rui Zhao, Jian Song, Yuyang Tian, Shuang Ding, Guangshan Zhu
Abstract
Effective extraction of palladium from secondary resources is a promising solution for the sustainable utilization of precious metals. A cyclic molecule containing four N atoms was modified on a nanoporous aromatic framework (PAF) to give PAF-1-N4, which provided a meaningful route to introduce bulky molecules with multiple coordination sites into the PAF materials. Through the interaction of multiple binding sites to Pd(II), PAF-1-N4 showed rapid and deep adsorption of Pd(II) at a low initial concentration. The maximum Pd(II) adsorption capacity of PAF-1-N4 reached 299.4 mg g–1, and PAF-1-N4 reduced the concentration of Pd(II) from 5.35 ppm to 84 ppb within 5 min and finally to 42 ppb within 60 min. After the in situ reduction, the obtained Pd@PAF-1-N4 exhibited good catalytic activity and reusability for the Suzuki–Miyaura coupling reaction in five-cycle catalytic experiments, thus realizing its sustainable utilization of palladium extracted from secondary resources.