Use of Eucalyptus camaldulensis as Biosorbent for Lead Removal from Aqueous Solution

The removal of lead ions from aqueous solution by the biosorbent Eucalyptus camaldulensis leaf powder (ECLP) was investigated. The ECLP with and without nitric acid conditioning was characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy and Fourier transformation infrared spectroscopy (FTIR). The FTIR spectra for the sorbents tested in this work revealed lead complexation to functional groups. The effects of biosorbent dosage, contact time, salinity, pH, and temperature on the removal efficiency of lead ion by ECLP were evaluated. The optimal parameters were determined to be 2 g/L of biosorbent dosage, pH 7.0, salinity 500 ppm and equilibrium time of 40 min in case of conditioned ECLP (ECPL-N). The adsorption isotherms of lead ions on ECPL-N was best described by the Freundlich isotherm with Freundlich constants of A(f)= 23.8 and n = 1.84 at 25 degrees C. The kinetics of lead ions adsorption on ECPL-N was found to follow pseudo-second-order reaction kinetics with rate constant of 0.02 g/mg.min at 25 degrees C. It is found that at optimal conditions, ECLP-N was able to reduce lead concentration below 0.1 ppm. The fixed bed column adsorption of lead using ECLP-N was best described by the Yan model. These findings strongly suggest that ECPL-N can be implemented as an efficient alternative to other adsorbents for lead removal.