Efficient sorption of Pb(ii) from an aqueous solution using a poly(aniline-co-3-aminobenzoic acid)-based magnetic core–shell nanocomposite

Abstract

A novel poly(aniline-co-3-aminobenzoic acid)-based magnetic core–shell (PA3ABA@Fe₃O₄) nanocomposite was successfully synthesized via an in situ copolymerization approach of aniline and 3-aminobenzoic acid in the presence of Fe₃O₄ magnetic nanoparticles. The products were characterized using Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (¹H-NMR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The transmission electron microscopy (TEM) image of the PA3ABA@Fe₃O₄ nanocomposite showed a core–shell structure. Magnetic measurements displayed that the PA3ABA@Fe₃O₄ nanocomposite was super-paramagnetic with a saturation magnetization (M_s) of 37.8 emu g⁻¹. Then, uptake of Pb(II) from an aqueous solution by the products was investigated as a function of pH, adsorption dosage, contact time, and initial concentration of Pb(II) through batch studies. The PA3ABA@Fe₃O₄ nanocomposite exhibited a higher adsorption percentage (89%) than that found for PA3ABA (80%) during the uptake of Pb(II). The PA3ABA@Fe₃O₄ nanocomposite adsorbent could be easily separated from an aqueous solution using a magnet and regenerated easily by acid treatment. The experimental data were analyzed using isotherm and kinetic models. The results showed that the interactions between Pb(II) and the PA3ABA@Fe₃O₄ nanocomposite were in agreement with the Freundlich isotherm and pseudo-first-order kinetic model, and the maximum adsorption capacity (Q_m) of Pb(II) was found to be 138.31 (mg g⁻¹). Therefore, the PA3ABA@Fe₃O₄ nanocomposite could be considered as a promising adsorbent for Pb(II) removal from water.