Adsorption behavior of As(III) onto chitosan resin with As(III) as template ions

摘要

A novel, biobased chitosan resin was successfully synthesized, characterized, and applied for the selective removal of As(III) from aqueous solutions. Batch adsorption experiments were performed to evaluate its adsorption conditions, selectivity, and reusability. The results showed that the maximum adsorption capacity was 2.16 mg/g, observed at pH 6 and 40°C. Equilibrium adsorption was achieved within 8 h. The kinetic data, obtained at optimal pH 6, could be fitted with a pseudosecond order equation. Adsorption process could be well described by Langmuir adsorption isotherm model and the maximum adsorption capacity calculated from Langmuir equation was 4.45 mg/g. The selectivity coefficient of As(III) ions and other metal cation onto As-ICR indicated an overall preference for As(III) ions, which was much higher than nonimprinted chitosan resins. Finally, the adsorption mechanisms were studied by Fourier transform infrared spectra, X-ray diffraction, and differential scanning calorimetry analysis. The result reveals that the adsorption of As-ICR for As(III) is a chelation process. These results earlier confirmed that As-ICR is a very promising sorbent for selective adsorption of As(III) ions from aqueous solutions.