Competitive adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) from aqueous media using biochar from oil palm (Elaeis guineensis) fibers: a kinetic and equilibrium study

ABSTRACT The aim of this study was to investigate the competitive adsorption of a quaternary system of Pb(II), Cu(II), Fe(II) and Zn(II) from aqueous media using biochar from oil palm (Elaeis guineensis) fibers. The focus of the study was the kinetic and equilibrium investigations. Hybrid biochar produced from the biomass with LDPE was also considered. The adsorbents were characterised by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and Branueur-Emmet-Teller (BET) analysis. The BET specific surface area of the biomass and hybrid biochar was 352.5 and 392.5 m2/g and the pore volume was 0.2166 and 0.2201 m3/g respectively. FTIR revealed the presence of functional groups that play important roles in the electrophilic interactions of the biochar with heavy metal species. The Elovich isotherm was the best fit for the experimental data. The pseudo-second order kinetic model was also observed to be the best fit kinetic model for experimental data. From the experiments the capacity of Pb(II), Cu(II), Fe(II) and Zn(II) removed at equilibrium was 16.67, 16.59, 16.65 and 16.54 mg/g respectively for biomass biochar and 16.66 mg/g, 16.57 mg/g, 16.65 mg/g and 16.54 mg/g respectively for hybrid biochar. GRAPHICAL ABSTRACT