Study of Pb(II) removal ZIF@NiTiO3 nanocomposite from aqueous solutions

Abstract

Zeolitic imidazolate frameworks (ZIFs) are a subclass of metal-organic frameworks (MOFs). In this work, the nickel titanate (NiTiO3) nanoparticles and ZIF based nickel titanate (ZIF@NiTiO3) were prepared by sol-gel method and were characterized by powder X-Ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), Scanning Electron Microscopy (SEM) and BET(Brunauer-Emmett-Teller) methods. The NiTiO3 had rhombohedral crystal structure and crystallite size of 40−50 nm. FTIR confirmed of composite and metal-oxide NiO and TiO bands. BET analysis showed ZIF@NiTiO3 nanocomposite had higher surface area (345 m2 g−1) than NiTiO3 (31 m2 g−1). The adsorption studies of Pb(II) by NiTiO3 and ZIF@NiTiO3 nanocomposite were carried out by batch method. The effects of varying parameters like contact time; pH and mass of sorbent on Pb(II) were investigated. The ZIF@NiTiO3 was found to follow by pseudo second order kinetic model better than the pseudo-first order (k2 = 1.3 × 10 -2), since the adsorption isotherm experimental data was fitted better by Langmuir model than Freundlich and Temkin models. The maximum adsorption capacity of Pb(II) for NiTiO3 and ZIF@NiTiO3 was observed 72 and 155 mg g−1, respectively at pH 5. ZIF@NiTiO3 acts as sufficient reusable sorbent for Pb(II).