Adsorption studies and separation of platinum and palladium using amine functionalized styrene-based beads and nanofibers

摘要

The adsorption and separation of platinum and palladium chloride-species (PtCl_6~(2-) and PdCl_4~(2-)) on polystyrene beads and nanofibersfunctionalized with ammonium centres based on ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetriamine (TETA) and tris-(2-aminoethyl)amine (TAEA) are described.The functionalized sorbent materials were characterized by using SEM, XPS, BET and FTIR. The surface area of EDA-fibers and beads were 241.31m~2/g and 107.35 m~2/g respectively. The adsorption and loading capacities of the sorption materials were investigated using both the batch and column studies and at 1 M HC1 concentration. The adsorption studies for both PtCl_6~(2-) and PdCl_4~(2-)on the different sorbent materials fit the Langmuir isotherm with R~2 values □ 0.99. The highest loading capacity of Pt and Pd were 7.4mg/g and 4.3 mg/g respectively for the nanofiber sorbent material based on, ethylenediamine (EDA) while the beads with ethylenediamine (EDA) gave 1.0 mg/g and 0.2 mg/g for Pt and Pd respectively. Metals loaded on the sorbent materials were recovered by using 3% m/v thiourea solution as the eluting agent with quantitative desorption efficiency under selected experimental conditions. Separation of platinum from palladium was achieved by selective stripping of PtCl_6~(2-) with 0.5M of NaC10_4 in 1.0 M HCl while PdCl_4~(2-) was eluted with 0.5 M thiourea in 1.0 M HCl. The separation of platinum from a mixture containing iridium and rhodium under 1 M HCl concentration was successful on beads sorbent with triethylenetriamine (TETA) showing selectivity for platinum.