Preparation and characterization of poly (itaconic acid)-grafted crosslinked chitosan nanoadsorbent for high uptake of Hg2+ and Pb2+

A novel nanoadsorbent (PIACS) with average size of 52.6 nm was prepared by controlling grafted polymerization of itaconic acid on chitosan to emulsion stage and then crosslinking with glutaraldehyde. The preparation conditions were optimized and PIACS was characterized by FT-IR, XRD, SEM, TEM and TGA. The adsorption of PIACS for some metal ions was studied. The adsorption results showed that PIACS for adsorption of Hg2+ and Pb2+ had higher uptakes than some reported adsorbents. Various variables for adsorption of Hg2+ and Pb2+ were systematically researched. The adsorption followed the pseudo second-order kinetics and Langmuir isotherm models. The maximum uptakes of Hg2+ and Pb2+ from Langmuir model were 870.1 mg g(-1) and 1320 mg g(-1), respectively. Especially, the uptake of this nanoadsorbent for Pb2+ was 4 times of that of the macro-scale adsorbent with the similar structure reported. As temperature rising, uptake of Pb(2+)decreased while uptake of Hg2+ almost had no change. In addition, the adsorbent could be regenerated with EDTA. Hence, this prepared method of nanomaterial might extend to the similar grafted polymerizing and crosslinking systems of polymers and PIACS would be a promising adsorbent in the removal of Hg2+ and Pb2+ from wastewaters. (C) 2016 Elsevier B.V. All rights reserved.