Adsorption enhancement of heavy metal ions using chitosan-modified natural zeolite nanocomposite

Abstract

This research is to modify the natural zeolite (NZ) with chitosan (chit) as an adsorbent for Pb(II) ion adsorption. Chit-NZ nanocomposite was synthesized using NZ which has been physically and chemically activated and modified with chitosan in nano size to enhance their adsorption activity. The characterization was conducted by Fourier- transform infrared (FTIR) spectroscopy and transmission electron microscope (TEM). According to FT-IR result, there were hydroxyl and amine groups in Chit-NZ nanocomposite at 3645 and 3290 cm-1, respectively. The formed Chit-NZ nanocomposite from TEM image has particle size approximately 40 nm. Chit-NZ nanocomposite and NZ as a comparison was observed for Pb(II) adsorption using atomic absorption spectrometry (AAS). According to result, the adsorption percentage of Pb(II) on NZ and Chit-NZ nanocomposite were 43.83 and 49.91 %, respectively at pH of 6.0 and initial Pb(II) concentration of 1500 ppm. The Pb(II) adsorption percentage using Chit-NZ nanocomposite was 99.68 % with optimum conditions at pH of 6.0, Pb(II) concentration of 300 ppm, and contact time of 30 min. The kinetic study showed that Pb(II) adsorption followed a pseudo second-order kinetic model with a reaction rate constant, k of 9.74 × 10-3 (g/mmol)-1min-1.