Trimellitic acid functionalized magnetite nanoparticles for the efficient removal of Pb(II) and Cr(VI) from wastewater streams

Abstract

Silica-coated Fe3O4 nanoparticles were prepared and functionalized with trimellitic anhydride generating novel amide and two acid moieties on the surface of the nanoparticles. These nanoparticles were found to be ferrimagnetic with average particle size 50–60 nm as characterized by XRD, SEM, EDS, VSM and FTIR analyses. The functionalized nanoparticles were exploited as adsorbent for the removal of Pb(II) cations and Cr(VI) anions from their aqueous solutions and uptake of metal ions was monitored by atomic absorption spectroscopy (AAS). These nanoparticles were found to be more effective for the removal of Pb(II) cations due to the negatively charged surface groups relative to Cr(VI) anions. The adsorption data fitted well with Langmuir as well as Freundlich adsorption isotherms, showing a complex nature of adsorption phenomena, comprising electrostatic as well as chemical attraction between surface groups and metal ions. The metal bearing nanoparticles were easily separated from the solution by simply applying external magnetic field.