Banana trunk fibers as an efficient biosorbent for the removal of Cd(II), Cu(II), Fe(II) and Zn(II) from aqueous solutions

Abstract

The biosorption of Cd(II), Cu(II), Fe(II) and Zn(II) from aqueous solutions by an agrowaste, namely banana trunk fibers (BTF), was investigated. The effect of pH, contact time, metal ions concentration, adsorbent dose and change in [M2+]/biomass were studied at ambient temperature (25 °C). The equilibrium process was described well by the Freundlich isotherm model with adsorption capacity, Kf of 8.49, 2.68, 6.58 and 1.74 mg/g for Cd(II), Cu(II), Fe(II) and Zn(II), respectively. Kinetic studies showed good correlation coefficients for a pseudo-second-order kinetic model. The BTF were subjected to different chemical modification methods (mercerization, acetylation, formaldehyde treatment, peroxide treatment, stearic acid treatment and sulphuric acid treatment) and the adsorption capacity (qe) of each modified BTF for the metal ions was obtained. Our findings hitherto reveal that the qe values are practically similar to that of the unmodified BTF confirming that the latter by its nature, that is its chemical composition, is already an efficient biosorbent for the removal of the heavy metal ions.