A highly efficient supramolecular adsorbent for precious metal: adsorption behavior of Pd-II by melamine cyanurate

作者：Nagai D^*; Kimoto T

来源：RSC Advances, 2016, 6(105): 103304-103310.

DOI：10.1039/c6ra22425c

Melamine cyanurate (M-CA) was found to be a highly recoverable and selective supramolecular adsorbent for recovery of Pd-II ion. Adsorption of Pd-II by M-CA was fast in the first 30 min, with 93% adsorption efficiency, and equilibrium was reached within 1 h. Langmuir and Freundlich isotherm models were employed to correlate the experimental data. The adsorption of Pd-II by M-CA is well supported by a Langmuir isotherm model, with a high maximum adsorption capacity of 0.874 gPd g(M-CA)(-1). M-CA was also capable of selective adsorption of Pd-II from a solution containing other metals. Pd adsorbed on M-CA was separated quantitatively by reductive treatment, and the M-CA could be recycled at least 3 times. We propose an in-plane adsorption mechanism for M-CA, which is a pi-pi stacked layered complex, based on the results of X-ray spectroscopy and computational calculations. This study demonstrates that M-CA is promising as a selective and highly efficient adsorbent for recovery of precious metals.

• 出版日期2016