Polyethylenimine-crosslinked chitin biosorbent for efficient recovery of Pd(II) from acidic solution: Characterization and adsorption mechanism

Abstract

This study reports a polyethylenimine-chitin composite biosorbent (PCCB) capable of high-efficiency recovery of Pd(II) from acidic solutions. To confirm that PCCB was successfully prepared, it was characterized by elemental analysis, FE-SEM, BET analysis, FT-IR, C-13 solid-state NMR, and XPS. The PCCB exhibited a high adsorption capacity of 758.4 mg/g for Pd(II), and its adsorption equilibrium reached very quickly (within 10 min) in the initial Pd(II) solution of 50 to 200 mg/L. In addition, Pd(II) adsorption by PCCB maintained high adsorption capacities in the temperature range of 298 to 328 K and was not affected by interfering ions. Besides, mechanism studies revealed that the binding between PCCB and Pd(II) was mainly achieved by electrostatic interaction and reduction reaction. Even after 5 times of reuse, the adsorption and desorption efficiencies remained above 99%. Therefore, PCCB can be considered as a candidate adsorbent with a high potential for Pd(II) recovery from acid solutions.