In the present study, chicken feathers (CFs), obtained from animal waste, were used as bio-adsorbent for the removal of hazardous Cr(VI) ions from aqueous solutions. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), x-ray diffraction (XRD), adsorption of N2 at −196 °C, thermogravimetric analysis (TGA), and point of zero charge (pHpzc) determination were used to characterize the adsorbent. The N2 adsorption results revealed high surface area and microporous structure for the adsorbent. The experimental results in batch adsorption show that optimum conditions are: pH 2.5, equilibrium contact time 180 minutes, concentration of CFs 11 g L−1, and initial Cr(VI) concentration 25 mg L−1. The experimental data on Cr(VI) adsorption were fitted using the Langmuir and Freundlich equations at different temperatures. The Langmuir adsorption model showed the best fit. The maximum monolayer capacity (q max) of CFs was found to be 333.33 mg/g. The kinetic results of Cr(VI) ion were fitted to four kinetic models: pseudo-first-order, pseudo-second-order, intra-particle diffusion, and Elovich. The pseudo-second-order chemisorption model had a higher coefficient. The thermodynamics data showed that the adsorption process of Cr(VI) on CFs was endothermic and spontaneous. The desorption efficiency and reusability of CFs were determined for three adsorption–desorption cycles, which proved to be very effective for the removal of Cr(VI) ions from aqueous solutions.
- adsorption isotherm
- chicken feathers