Selective Separation of Palladium from Organic Solutions Containing Nickel or Platinum using Polythioamide as a Sorbent

The feasibility of the selective recovery of Pd from organic liquid waste using polythioamide (PTA) as a sorbent has been investigated. PTA effectively sorbed Pd(II) in some organic solutions under not only acidic conditions but also basic conditions. PTA was also able to sorb Pd from organic solutions containing PdCl2(PhCN)2 and Pd2(dba)3. The results for the molecular structure of a model compound ([Pd(C11H15NS)4]Cl2) suggest that the presence of a S donor plays an important role in the sorption of Pd(II) by PTA. The sorbed Pd was quantitatively eluted using 1,3-bis(diphenylphosphino)propane in MeOH, and the recovered PTA can be reused at least five times. The selective separation of Pd(II) was achieved even from organic solutions containing a 100 times larger amount of Ni(II) or Pt(IV) under acidic conditions or basic conditions, respectively.