Journal of Hazardous Materials, Vol.376, 188-199, 2019
Development of Two novel silica based symmetric triazine-ring opening N-donor ligands functional adsorbents for highly efficient separation of palladium from HNO3 solution
The synthesis and characterization of two novel symmetric triazine-ring opening ligands CA-MP (pyridine derivative)/CA-BOPhen (1,10-phenanthroline derivative) functionalized SiO2-P (P = Polymer) adsorbents for separation of Pd(II) from HNO3 solutions are presented. SEM, N-2 adsorption/desorption isotherms, TGA and EDS spectroscopy characterization results showed that CA-MP and CA-BOPhen were successfully introduced into the pores of SiO2-P carrier via physical intermolecular interactions. CA-MP@SiO2-P and CA-BOPhen@SiO2-P show high efficiency, high selectivity, extremely fast adsorption rates towards Pd(II) over 19 typical fission or corrosion products in HNO3 solution. The distribution coefficient K-d values of CA-MP@SiO2-P and CA-BOPhen@SiO2-P are up to 206.5 and 205.7 cm(3)/g, respectively, within 10-15 min of contact time in 0.4 M HNO3. The adsorption capacities of them to Pd(II) were determined to be 0.36 mmol/g and 0.23 mmol/g, respectively. The fast adsorption rates and high selectivity of two adsorbents towards Pd(II) were related to the formation of the highly preorganized complex [Pd(NO3)(L)](+) (L = CA-MP or CA-BOPhen). These results demonstrate that CA-MP@SiO2-P and CA-BOPhen@SiO2-P possess great potential for highly efficient removal of Pd(II) from highly active liquid waste (HLW).