Synthesis of amine imprinted manganese ferrite and its application in the removal of free fatty acid from waste vegetable oil

Abstract

The presence of free fatty acid (FFA) in waste vegetable oil (WVO) is undesired and must be removed. The present study synthesized amine imprinted manganese ferrite (MnFe2O4-DEA) via coprecipitation method and used it for the removal of FFA in WVO. Fourier transformed Infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results confirmed the formation of MnFe2O4-DEA and further analysis by Brunauer-Emmett-Teller (BET) surface area showed the nanoparticles possessed a surface area of 20.64 m² g−1. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) revealed elemental composition and surface morphology. MnFe2O4-DEA showed promising results of FFA separation, recording 99.57% removal rate. The process obeyed langmuir isotherm and can be described by pseudo-second-order kinetic model. The values of Gibb's free energy change (∆Go) decreased with increase in temperature, the entropy change (∆So) was positive while enthalpy change (∆Ho) value suggested an endothermic sorption process. The mechanism for the removal of FFA by MnFe2O4-DEA may have occurred by simple chemical bonding, which could be described as donor-acceptor interaction by quantum chemical analysis.