Extraction Of Palladium(?) From Nitric Acid Medium With 1,2,3-triazole Type Ligands

In this thesis,a new class of 1,2,3-three?1,2,3-Tz?ligands has been synthesized.These ligands are insoluble in water,soluble in conventional organic solvents such as chloroform and imidazolium ionic liquids.These ligands with elecctron donor nitrogen atoms are easy to form stable complexes with palladium?II?with soft acid properties.These ligands were used to extract palladium.The contact time,extractant structure and concentration,acidity and nitrate ions concentration on extraction Pd²⁺ were studied.The ligands Tz1 and Tz2 with higher extraction performance for palladium were chosed to extract palladium in ionic liquid and in chloroform.The results show that the extraction process can quickly reach extraction equilibrium,and the extraction capacity is higher in ionic liquid than in chloroform.Extraction capacity increases in two solvents with an increase of nitric acid concentration.And the extraction mechanism has been studied in detail.Slope analysis and mole ratio method confirmed that 1,2,3–triazole ligands in ILs or in chloroform formed 1:1 complexes with Pd²⁺.According to the data of FTIR and ESI-MS,it is inferred that 1,2,3-three extractant is coordinated with Pd²⁺ by nitrogen atom of three triazole ring and nitrogen atom on pyridine ring.A neutral solvation mechanism and a anion exchange coexisted in ionic liquid but in chloroform only a neutral solvation occurred.We also conducted a competitive extraction research,its results show that 1,2,3-triazole ligands has good selective extraction capability on palladium in the mixed solution of lanthanides,alkali,alkaline earth metal,actinide elements and palladium.After extraction,palladium can be stripped easily from the extraction phase with low concentration of nitric acid or acidic thiourea solution.Finally,we discussed the thermodynamics of 1,2,3-azole nitrogen ligands extraction of palladium in the ionic liquid and calculate the parameters values??H,?S and ? G?of the extraction reaction,the data results show that 1,2,3-triazole nitrogen ligands for palladium extraction process is a spontaneous endothermic extraction process.