Structural evolution of chitosan-palygorskite composites and removal of aqueous lead by composite beads

• Published in: Applied Surface Science
• Main Author: Rusmin R.; Sarkar B.; Liu Y.; McClure S.; Naidu R.
• Format: Article
• Language: English
• Published: Elsevier B.V. 2015
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84941956832&doi=10.1016%2fj.apsusc.2015.06.124&partnerID=40&md5=db5dce050cec6b905cf0c3f3a162f190

This paper investigates the structural evolution of chitosan-palygorskite (CP) composites in relation to variable mass ratios of their individual components. The composite beads' performance in lead (Pb) adsorption from aqueous solution was also examined. The composite beads were prepared through direct dispersion of chitosan and palygorskite at 1:1, 1:2 and 2:1 mass ratios (CP1, CP2 and C2P, respectively). Analyses by Fourier transform Infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the dependence of the composites' structural characteristics on their composition mass ratio. The chitosan-palygorskite composite beads exhibited a better Pb adsorption performance than the pristine materials (201.5, 154.5, 147.1, 27.7 and 9.3 mg g -1 for CP1, C2P, CP2, chitosan and palygorskite, respectively). Adsorption of Pb by CP1 and CP2 followed Freundlich isothermal model, while C2P fitted to Langmuir model. Kinetic studies showed that adsorption by all the composites fitted to the pseudo-second order model with pore diffusion also acting as a major rate governing step. The surface properties and specific interaction between chitosan and palygorskite in the composites were the most critical factors that influenced their capabilities in removing toxic metals from water. © 2015 Elsevier B.V. All rights reserved.