The recovery of palladium from waste streams is of importance for metal recycling and environmental remediation.Herein,we present a“single-ion trap”strategy for efficiently recovering Pd(II)from superacidic solution...The recovery of palladium from waste streams is of importance for metal recycling and environmental remediation.Herein,we present a“single-ion trap”strategy for efficiently recovering Pd(II)from superacidic solutions and laboratory wastes.This was realized by rational design and synthesis of an antiparallel stacked covalent organic framework(ACOF)with hydrazine-carbonyl sites and pyridine sites for cooperative Pd(II)capture.The single-ion traps provided Lewis base sites with a high Pd(II)binding affinity,enabling the trapping of Pd(II)ions under a wide range of conditions.The developed ACOF-1 adsorbent demonstrated fast kinetics,excellent selectivity,and a high adsorption capacity of 412.9±14.2 mg/g for Pd(II)in a 3M HNO_(3) solution.When applied in a packed column,ACOF-1 dynamically captured Pd(II)from3M HNO_(3) solutions or laboratorywastes containing trace amounts of palladium and many other metals,realizing extraction efficiencies of 232.9 and 320.9 mg/g,respectively.Detailed experimental and theoretical studies revealed that the single-ion traps offered exceptionally strong binding of Pd(II)under both acidic and high ionic strength conditions,enabling selective adsorptive behavior not accessible using traditional adsorbents.Importantly,the general design strategy reported here could be used to create porous adsorbents for the capture of other precious metals.展开更多
基金supported by the National Natural Science Foundation of China(NSFC,grant nos.U2167218,22322603,and 22276054)the Beijing Outstanding Young Scientist Program,the Robert A.Welch Foundation(grant no.B-0027)the New Zealand James Cook Research Fellowship.
文摘The recovery of palladium from waste streams is of importance for metal recycling and environmental remediation.Herein,we present a“single-ion trap”strategy for efficiently recovering Pd(II)from superacidic solutions and laboratory wastes.This was realized by rational design and synthesis of an antiparallel stacked covalent organic framework(ACOF)with hydrazine-carbonyl sites and pyridine sites for cooperative Pd(II)capture.The single-ion traps provided Lewis base sites with a high Pd(II)binding affinity,enabling the trapping of Pd(II)ions under a wide range of conditions.The developed ACOF-1 adsorbent demonstrated fast kinetics,excellent selectivity,and a high adsorption capacity of 412.9±14.2 mg/g for Pd(II)in a 3M HNO_(3) solution.When applied in a packed column,ACOF-1 dynamically captured Pd(II)from3M HNO_(3) solutions or laboratorywastes containing trace amounts of palladium and many other metals,realizing extraction efficiencies of 232.9 and 320.9 mg/g,respectively.Detailed experimental and theoretical studies revealed that the single-ion traps offered exceptionally strong binding of Pd(II)under both acidic and high ionic strength conditions,enabling selective adsorptive behavior not accessible using traditional adsorbents.Importantly,the general design strategy reported here could be used to create porous adsorbents for the capture of other precious metals.
