Synthesis, Structural Characterization, and Dynamic Swelling of Chitosan-Graft-Polyacrylamide Hydrogels for Heavy Metal Extraction

International Journal of Chemistry | Vol. 4, No. 3, March 2013 | pp. 17–24

DOI: 10.46882/2013/IJC/000054

Article Type: Original Research Paper

Title: Synthesis, Structural Characterization, and Dynamic Swelling of Chitosan-Graft-Polyacrylamide Hydrogels for Heavy Metal Extraction

Names of Authors: J. K. Mensah¹, S. Chatterjee²*

Authors’ Affiliations:
¹Department of Chemistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
²Department of Chemical Engineering, Indian Institute of Technology, Kharagpur, India.

Abstract: Developing high-capacity polymeric adsorbents from biopolymer backbones is essential for green remediation of heavy metals from industrial effluents. This study describes the chemical synthesis and structural optimization of a crosslinked hydrogel prepared via the free-radical graft copolymerization of acrylamide onto a highly purified chitosan backbone. The reaction was initiated using ammonium persulfate (APS) and crosslinked via N,N'-methylenebisacrylamide (MBA). The structural configuration of the chitosan-graft-polyacrylamide (Ch-g-PAM) matrix was verified through FT-IR spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Swelling kinetics were systematically evaluated across varying solution pH (2.0 to 10.0) and ionic strengths. The hydrogel displayed sensitive pH-dependent swelling profiles, achieving a maximum water absorption capacity of 310 g/g at pH 5.5 due to the complete protonation of amine functional groups causing maximum polymer chain expansion. Batch adsorption tests showed that the Ch-g-PAM hydrogel possessed high affinity for copper(II) and lead(II) ions in aqueous solutions. The adsorption data matched the Langmuir isotherm model with maximum monolayer adsorption capacities of 54.5 mg/g for Cu(II) and 82.6 mg/g for Pb(II) at 298 K, presenting an effective bio-sorption framework.

Keywords: Chitosan; Acrylamide; Graft copolymerization; Hydrogel; pH-sensitive swelling; Heavy metal adsorption

Manuscript Timeline: Received: August 05, 2012; Revised: September 18, 2012; Accepted: October 12, 2012; Published: March 02, 2013.

Citation: Mensah, J. K., & Chatterjee, S. (2013). Synthesis, Structural Characterization, and Dynamic Swelling of Chitosan-Graft-Polyacrylamide Hydrogels for Heavy Metal Extraction. International Journal of Chemistry, 4(3), 17–24.

Subscribe to read the full article: https://www.internationalscholarsjournals.org/subscribe-to-read