title: Lead (Pb2+) and copper (Cu2+) remediation from water using superparamagnetic maghemite (γ-Fe2O3) nanoparticles synthesized by Flame Spray Pyrolysis (FSP).
abstract: Superparamagnetic maghemite (γ-Fe2O3) nanoparticles of controllable morphology were successfully synthesized using a flame spray pyrolysis (FSP) technique. Their physico-chemical properties, size, morphology, and surface chemistries were determined using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), selected area electron diffraction patterns (SAED), SEM-EDX, scanning electron microscopy (SEM), and pHZPC(6.3). Elemental contents before and after adsorption were identified using energy dispersive X-ray fluorescence (ED-XRF), energy dispersive X-ray analysis (EDX) and elemental mapping. Surface area (SBET79.35m2/g) and size distribution analyses were conducted using a surface area analyzer and dynamic light scattering (DLS), respectively. The magnetic moment (44.5 at 300K and 50.16 at 2K) was determined using a physical properties measurement system (PPMS). The first adsorption study using γ-Fe2O3nanoparticles synthesized by FSP to successfully remediate Pb2+and Cu2+from water is reported. Batch adsorption studies were carried out. An optimum pH of 5.0 was studied for Pb2+and Cu2+removal. Pb2+and Cu2+removal mechanisms by these maghemite nanoparticles were presented. The adsorption of Pb2+and Cu2+was highly pH-dependent. The metal ion uptake was mainly governed by electrostatic attractions. Sorption kinetic data followed the pseudo-second-order model. The Freundlich, Langmuir, Redlich-Peterson, Radke and Sips adsorption isotherm models were applied to interpret equilibrium data. The Freundlich and Langmuir isotherm equations best fit the respective equilibrium data for Pb2+and Cu2+. The maximum Langmuir adsorption capacities of these maghemite nanoparticles were 68.9mg/g at 45°C for Pb2+and 34.0mg/g at 25 °C for Cu2+. Thus, these maghemite nanoparticles made by FSP were readily prepared, characterized and showed promise for remediating heavy metal ions from aqueous solutions.
authors.affiliation: School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
authors.forename: Shalini
authors.initials: S
authors.lastname: Rajput
authors.affiliation: Central Building Research Institute, Roorkee, India.
authors.forename: Lok P
authors.initials: LP
authors.lastname: Singh
authors.affiliation: Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA.
authors.forename: Charles U
authors.initials: CU
authors.lastname: Pittman
authors.affiliation: School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India. Electronic address: dm_1967@hotmail.com.
authors.forename: Dinesh
authors.initials: D
authors.lastname: Mohan
keywords: Adsorption; Batch study; Copper; Flame spray pyrolysis; Lead; Maghemite nanoparticles