Pore size adjustment of sodium alginate-based composite aerogel spheres by zirconia for efficient selective removal of Cu(II)

[Display omitted] •Slit-shaped pores can be formed via the stacking effect of GO nanosheets.•Compared with GS, the denseness and ordered properties of the slit-shaped pores are improved by adding ZrO2.•Slit-shaped pores exhibit greater affinity for planar hydrated copper ions. In order to eliminate the great threat posed by Cu(II) in water to human health and ecosystem safety, graphene oxide-zirconium oxide/sodium alginate (GZS) aerogel spheres are prepared for adsorbing Cu(II) using the sol-gel method and freeze-drying technique in this paper. The adsorbent is preferentially selective for Cu(II) even in the presence of competing cations. This is due to the slit-shaped structure of the aerogel spheres which has strong affinity for planar Cu(II), deriving from the GO nanosheets stacking effect as well as crosslinking with SA,. The adsorption kinetics and isothermal experiments show that the adsorption process of GZS is multi-molecular layer adsorption with a maximum adsorption capacity of 132.57 mg/g, exhibiting a better capacity than previous similar adsorption materials. FT-IR and XPS mechanistic analysis indicate that the good adsorption performance of GZS on Cu(II) might be related to the synergistic effect of strong electrostatic force, ion exchange and complexation. The adsorption order of GO, ZrO2 and SA on Cu(II) is also investigated by density functional theory (DFT). In conclusion, GZS has the potential to selectively remove Cu(II) from water bodies.