Adsorptive Removal of Lead Ions in Aqueous Solution by Kapok-Polyacrylonitrile Nanocomposites

In this study, the naturally hydrophobic kapok fibers were modified with polyacrylonitrile (PAN) to reverse its wetting property for adsorption of lead (Pb) ions in aqueous solution. Increasing the initial amount of the acrylonitrile (AN) monomer in solution resulted in thicker PAN coating on the surface of the kapok fibers after in situ polymerization. Consequently, the static water contact angle of the nanocomposite was reduced to zero. The kapok-PAN nanocomposites were then used for adsorption of lead (Pb) II in aqueous solution. Adsorption capacities for Pb(II) increased from 22.05 to 26.81 mg/g with higher AN concentration. Hydrolysis of the kapok-PAN nanocomposite was performed by immersing in a sodium hydroxide (NaOH) solution, which results to significantly enhanced adsorption of about 78.34 mg/g. (C) 2019 Elsevier Ltd. All rights reserved.