(193ab) Selective Recovery of PGM from Secondary Sources Using Nanofiber Based on Molecularly Imprinted Polymer

Polymerizable polydentate PGM-selective, sulfur-containing amide ligands were synthesized from dibromoalkanes and mercaptoacetanilide. The resulting dithiadiamides with different number of carbons (i.e. 1-3) in alkane linker were all characterized by high-resolution ¹H and ¹³C NMR spectroscopic methods. These ligands were complexed with Pt(II) salt to prepare the molecularly imprinted ligands and characterized by elemental analysis and spectroscopic methods (MIL).

Molecularly imprinted polymers (MIP) were prepared by copolymerizing the Pt(II)-MIL complex with ethylene glycol dimethacrylate (EGDMA) via radical copolymerization. Three types of MIPs were prepared based on the dithiadiamides with different alkane linkers. After removal of Pt(II) via washing with dilute HCl, these MIPs were evaluated for their Pt(II) adsorption capacity. Dithiaoctanediamide was found to be more effective than its heptane and nonane analogues.

Nanofiber (NF) was prepared by processing the dope solution based on dithiaoctanediamide MIP via electrospinning. Electrospinning conditions were optimized based on pure EGDMA dope solution. The physicochemical properties of the MIP and blank NFs were thoroughly characterized via FTIR, ¹H and ¹³C NMR, XPS, FE-SEM EDS, BET, and UTM. Finally, performance of the materials for Pt(II) and Pd(II) recovery was evaluated via batch adsorption experiments in order to elucidate their respective adsorption isotherms, kinetics, thermodynamics, selectivity, and recyclability. This research was supported the Ministry of Science and ICT (No. 2017R1A2B2002109 and No. 2016R1A2B1009221) and Ministry of Education (No. 2009-0093816).