Application of polyrhodanine modified multi-walled carbon nanotubes for high efficiency removal of Pb(II) from aqueous solution

In the present work, multiwall carbon nanotubes (MWCNTs)/polyrhodanine nanocomposite was fabricated through one-step chemical oxidation polymerization. The synthesized nanocomposite was characterized by using Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). In addition, the adsorption performance of MWCNTs/polyrhodanine toward Pb(II) ions removal from aqueous solution was explored. Factors influencing the uptake of Pb(II) ions including solution pH, initial concentration of Pb(II) ions, contact time and temperature were investigated systematically in batch experiments. The adsorption isotherm of Pb(II) onto MWCNTs/polyrhodanine fitted well to both Langmuir and Freundlich isotherm models and from the Langmuir isotherm, the maximum monolayer adsorption capacity was found to be 8118 mg/g. The rate of Pb(II) adsorption encountered a rise with increasing solution temperature and followed the pseudo second-order kinetics, suggesting that the adsorption mechanism might be a chemisorption process. Various thermodynamic parameters, such as Delta G degrees, Delta H degrees and Delta S degrees were calculated and the obtained values demonstrated that adsorption was spontaneous and endothermic in nature. (C) 2016 Elsevier B.V. All rights reserved.