Selective adsorption of lead on grafted and crosslinked chitosan nanoparticles prepared by using Pb(2+) as template.

Poly(acrylic acid) grafted and glutaraldehyde-crosslinked chitosan nano adsorbent (PAACS) was synthesized by using Pb(2+) as a template ion. The structure and morphology of PAACS were characterized by FT-IR, XRD, SEM and elemental analyses. The adsorption of PAACS for different heavy metal ions was compared and the effects of various variables for adsorption of Pb(2+) were systematically studied. The results indicated that the PAACS was the aggregates of nanoparticles with the diameter of about 50-200 nm and had selectivity for Pb(2+) adsorption. The adsorption for Pb(2+) showed a maximum adsorption capacity of 734.3 mg g(-1) at pH 5.0 and 303 K, which was higher than in a study previously reported on ion-imprinted adsorbents. The adsorption followed the pseudo-second-order kinetics and Langmuir isotherm models. The adsorption was spontaneous and changed from chemical process into physical process when the temperature exceeded 303 K. The adsorbent could be recycled with EDTA. Therefore, PAACS would be useful as a selective and high uptake nano adsorbent in the removal of Pb(2+) from effluents.