The zeolite modified by chitosan as an adsorbent for environmental applications

Fly ash (FA) and zeolite Na-A obtained on it were modified by chitosan (CS) and investigated for heavy metal ions removal from aqueous solutions. FA–CS and Na-A–CS were characterized by the X-ray fluorescence method, X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), nitrogen adsorption/desorption measurements, Fourier transform infrared spectroscopy (FTIR) and atomic absorption spectroscopy (AAS) methods. Cation exchange capacity and pHzpc of used sorbents were also determined. The kinetic and sorption characteristics were made as regard Cu(II), Fe(III), Mn(II) and Zn(II) ions removal from one- and multi-ion solutions. It was found that the phase contact time (1–1440 min), pH (3–5), the amount of fly ash and zeolite (2.5–25 g/dm3), the initial concentration of metal ions (20–240 mg/dm3) and zeolite modification (glutaraldehyde and epichlorohydrin) affect the sorption process. The best adsorptions were obtained at 250 mg/L concentration, pH solution of about 5.0 and 120 min contact time for Cu(II), Fe(III), Mn(II) and Zn(II) ions. The results suggested that the sequence for sorption efficiency decreases in the order in the one- and multi-ion systems: Cu(II) > Fe(III) > Zn(II) > Mn(II).