Bioinspired construction of magnetic nano stirring rods with radially aligned dual mesopores and intrinsic rapid adsorption of palladium

Quick and precise recovery of palladium (Pd) from electronic waste remains a serious task, owing to the strong acid and complexity of chemical compounds in leachate. Here, bioinspired construction of magnetic nano stirring rod with radially aligned dual mesopores and abundant 8-aminoquinoline (MNSR-DM-AQ) is proposed for selective and rapid extraction of Pd(II) from highly acidic sample solutions. Benefit from the unique dual mesoporous (12.4 nm and 3.6 nm) and the stirring motion under an external magnetic field, MNSR-DM-AQ possesses enhanced adsorption capacity and kinetics, achieving 11.62 mg g^-1 (97.2 % of the maximum adsorption capacity) in 15 min. Distribution coefficient (K_D = 299.0 mL g^-1), separation factor (α above 25.54) and concentration factor (CF = 230.2 mL g^-1) reveal the excellent selectivity of MNSR-DM-AQ towards Pd(II) when comparing with the coexisting ions (Ca(II), Co(II), Cu(II), Fe(II), Mg(II), Ni(II), Pb(II), Zn(II)). The adsorption mechanisms of MNSR-DM-AQ are ion exchange and chelation due to a strong affinity between Pd(II) and N. Meanwhile, 96.82 % of the captured Pd(II) can be easily eluted within 15 min, and the adsorption capacity remains stable after five adsorption-desorption cycles. It is worthwhile to mention that MNSR-DM-AQ exhibits a high adsorption capacity of 8.39 mg g^-1 from leachate of abandoned high-voltage patch capacitor, which is greatly desired in Pd(II) extraction from electronic waste.