Polypyrrole-polyethyleneimine (PPy-PEI) nanocomposite: an effective adsorbent for nickel ion adsorption from aqueous solution

Abstract

In order to use nitrogen atoms in polymers as the active adsorption sites for heavy metal ions, an effort has been made to couple polyethyleneimine, a water soluble polymer with polypyrrole, a conjugated polymer for nickel ion adsorption from aqueous solution due to a large number of nitrogen atoms available in the prepared water insoluble polypyrrole-polyethyleneimine (PPy-PEI) polymer nanocomposite. The BET surface area and average particle size of the prepared PPy-PEI nanocomposites were found to be 17 m2/g and ∼ 18–34 nm, respectively. TGA and DSC were used to study the thermal behavior of the composites. The nickel ion adsorption efficiency shown by pristine polypyrrole was found to be 42%, while a much higher adsorption efficiency of 99.8% was observed using polypyrrole-polyethyleneimine (PPy-PEI) nanocomposite in a batch equilibrium system. The optimum adsorption dosage was found to be 0.08 g at a pH of 4.5 and a contact time of 60 mins at room temperature. The ATR-FTIR, XRD and EDX provide the evidence of nickel ion adsorption by PPy-PEI nanocomposites. The adsorption data was well-fitted to Freundlich isotherm model and followed the pseudo-first order kinetic model. The adsorbent can be reused with more than 82% at the 3rd cycle.