Preparation and investigation of M-MWCNT nanocomposite by hydrothermal method for Pb(II) ions adsorption

Abstract

In this present work, MWCNTs modified NiFe₂O₄ NPs (M-MWCNT) were successfully fabricated based on a hydrothermal route, and then utilized to Pb(II) sorption from an aqueous solution. The M-MWCNT was characterized and analyzed by SEM, TEM, FTIR, XRD, and VSM techniques. TEM image demonstrated that the size of NiFe₂O₄ nanoparticles in the structure of MWCNT was 20 nm. VSM results indicated that the M-MWCNT with saturation magnetization (Ms) value of  7 emu/g would have a fast magnetic response. According to X-ray data the average crystal sizes of the pure NiFe₂O₄ and M-MWCNT are 21.62 and 7.25 nm, respectively. The sorption kinetics, isotherms, thermodynamic and regeneration performance for lead ((Pb(II)) ions were evaluated. The M-MWCNT can effectively remove Pb(II) from aqueous solution at optimum pH of 5.5. Based on the Langmuir model, the maximum saturated adsorbed amount (q_max) of Pb(II) was up to 85.12 mg/g. The kinetic characteristic was appropriate for pseudo 1^st order model expression, and the isothermal characteristic can be described via Longmuir model. The data obtained from the thermodynamic study show that the Pb(II) sorption using M-MWCNT nanocomposite was a spontaneous, exothermic and physisorption process with a good regeneration performance.