Illite/iron nanoparticles (I-nZVI) with different iron contents were synthesized using a liquid-phase reduction method to remove Pb(II) from aqueous solution. The adsorbents were characterized by Lorentz transmission electron microscopy (L-TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and the BET-N2 technique. The composite adsorbents and illite removed Pb(II) from aqueous solution to explore the effect of different reaction conditions, including contact time, concentration, pH, and temperature. The results of batch experiments demonstrated that the removal efficiency mainly depends on the amount of nanoscale zerovalent iron. Under different conditions, the order of the removal efficiency was 30% I-nZVI > 20% I-nZVI > 10% I-nZVI > illite. Reactions between Fe(0) and Pb(II) took place on the surface of the absorbents, and the removal of Pb(II) was based on adsorption and reductive reactions. The adsorption of lead ions by I-nZVI and pure illite conformed to the pseudo-second-order reaction kinetic model, and intraparticle diffusion may not play a remarkable role in removing Pb(II). The adsorption of Pb(II) by 30% I-nZVI, 20% I-nZVI, 10% I-nZVI, and illite was more in line with the Langmuir adsorption model. Thermodynamic studies indicated that the Pb(II) removal process is endothermic in nature, which is in agreement with the experimental results. The high removal efficiency helps to achieve the goal of remediation.
Keywords: Adsorption; Illite; Pb(II); Removal efficiency; Zerovalent iron.