As(III) removal from aqueous solution using α-Fe2O3 impregnated chitosan beads with As(III) as imprinted ions

A novel, bio-based α-Fe2O3 impregnated chitosan beads (As-IFICB) was successfully synthesized using As(III) as imprinted ions for adsorption and removal of As(III) ions from aqueous solutions. Batch adsorption experiments were performed to evaluate the adsorption conditions, selectivity and reusability. The results showed that the maximum adsorption capacity was 6.18 mg/g, observed at pH 5 and temperature 30 °C. Equilibrium adsorption was achieved within 6 h. The kinetic data, obtained at the optimum pH 5, could be fitted with a pseudo-second order equation. Adsorption process could be well described by Langmuir adsorption isotherms and the maximum adsorption capacity calculated from Langmuir equation was 9.355 mg/g. The selectivity coefficient of As(III) ions and other metal cations onto As-IFICB indicated an overall preference for As(III) ions, which was much higher than non-imprinted chitosan beads. The adsorption of As-IFICB for As(III) was analyzed and explained using SEM, EDAX, XRD and BET–N2 adsorption measurement. The results above indicated that As-IFICB is a very promising sorbent for selective removal of As(III) ions from aqueous solutions.