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Abstract
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In this study, a new effective Pb2+ ions absorbent is obtained by surface modification of magnetic (Fe3O4) nanoparticles with polythiophene (PTh). The morphology and structure of Fe3O4/PTh nano-adsorbents are determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Formation of Fe3O4/PTh nanocomposite is confirmed by Fourier transform infrared spectroscopy (FTIR) analysis. Then the effective factors on process adsorption were investigated including pH of the solution, the initial concentration of Pb2+ ions in the solution, adsorbent dosage, temperature and the contact time. According to the findings, the maximum adsorption capacity is achieved at pH 6, temperature 60 C and 10 g/L adsorbent dosage. The Sips and pseudo-second-order equation have been shown maximum acceptable correlation coefficient (R2) among the adsorption and kinetic equations. Sips isotherm capacity in terms of monolayer adsorption is obtained 47.577 mg/g. From DFT calculations, it is found that Pb2+ ion adsorbs with the significant adsorption energy, but has negligible effects on the electronic structure of Fe3O4/PTh nanocomposite. The values of enthalpy (ΔH) and Gibbs free energy (ΔG) are positive and negative, respectively, confirming the endothermic and spontaneous nature of adsorption. Also, desorption studies represent acceptable results in 5 cycles.
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