Selective removal of antimony(III) from aqueous solution using antimony(III)-imprinted organic–inorganic hybrid sorbents by combination of surface imprinting technique with sol–gel process

• We develop a Sb(III)-imprinted sorbent for selective removal of Sb(III) ion.
• The imprinted sorbent had high selectivity and adsorption capacity for Sb(III) ion.
• Experimental data follow the Langmuir and pseudo-second-order kinetic models.
• Adsorption of Sb(III) on the imprinted sorbent is spontaneous and exothermic process.

A Sb(III)-imprinted iodole-functionalized organic–inorganic hybrid sorbent was synthesized by combination of surface imprinting technique with sol–gel process for the selective removal of Sb(III) from aqueous media. The material was characterized by Fourier-transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis and nitrogen adsorption–desorption isotherms. Compared to the non-imprinted sorbent, the imprinted hybrid sorbent had higher selectivity and adsorption capacity for Sb(III) ion. The static adsorption capacity of the imprinted and non-imprinted sorbents for Sb(III) was 32.4 and 11.1 mg g−1, respectively. The relative selectivity coefficients of the imprinted hybrid sorbent for Sb(III)/Cr(III) Sb(III)/Fe(III) and Sb(III)/As(III) were 13.2, 10.4 and 11.8, respectively. The imprinted hybrid sorbent possessed fast kinetics for the removal of Sb(III) from aqueous solution with a saturation time of 30 min, had a stable binding capacity in the range of pH 4–6, and could be used repeatedly. Both the pseudo-second-order kinetic model and the Langmuir model fit the experimental data well. It could be concluded from the thermodynamic parameters that the adsorption of Sb(III) on the imprinted hybrid sorbents was an exothermic and spontaneous process.