Selective Extraction of Cu (II) Using Novel C=O–NOH-Contained Compound-Dodecyl Phenyl Ethyl Hydroxamic Acid and Its Extraction Mechanism

Herein, a novel C=O–NOH-contained compound was synthesized and used in the extraction and recovery of copper from sulfate solution. Dodecyl phenyl ethyl hydroxamic acid (DPEHA) exhibited high selectivity to Cu(II) over the competing ions, and the separation factors (β) obtained were βCu/Zn = 227.370, βCu/Co = 199.094, βCu/Ni = 188.889, respectively. The separation effect was stronger than that of 2-hydroxy-5-nonyl acetophenone oxime. Meanwhile, extraction capacity of 0.10 g Cu(II) per gram DPEHA was reached, and the extracted Cu(II) can be stripped effectively. The investigation of extraction mechanism revealed that O atoms in C=O and O-H groups of DPEHA operate as active sites, which could powerfully chelate with Cu(II) by forming stable five-membered rings. The high copper extraction efficiency and selectivity associated with a simple synthesis of DPEHA make it to serve as the potential selective Cu(II) extractant, which also provide a novel insight for the research and development of economical Cu(II) extractants.