Highly efficient and selective recovery of Cu(II) from wastewater via ion flotation with amidoxime functionalized graphene oxide as nano collector

Abstract

In this work, amidoxime functionalized graphene oxide ([email protected]) was prepared with 1,3-diamino-1,2,3-trioximido-propane as chelation group and used as nano collector for enhancing and selectively recovering Cu(II) from wastewater via ion flotation. [email protected] was characterized by scanning electron microscope/energy dispersive X-ray detector (SEM/EDX), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). Effects of pH, contact time, [email protected] and hexadecyl trimethyl ammonium bromide (HTAB) concentration, and aeration rate on Cu(II) recovery and the turbidity of the residual solution were examined systematically. The experimental results showed that as compared with GO, the adsorption capacity and selectivity of [email protected] for Cu(II) was greatly improved. Almost 99.26% of Cu(II) could be recovered with selectivity coefficient of 54.161, 73.430, 50.365 and 21.630 for Cu(II)/M(II) (M = Co, Ni, Zn and Cd, respectively). Moreover, the relative Cu(II) recovery maintained over 90.45% after five flotation- desorption cycles, indicating [email protected] could be reused as nano collector in ion flotation. In addition, density functional theory (DFT) calculation suggested that [email protected] had a stronger affinity to Cu(II) originated from both O and N from oximido contributed to the stable configuration of [email protected]@Cu(II) complexes, endowing it possessed a higher selectivity coefficient for Cu(II).