Removing cadmium from aqueous solutions by the Canola residuals

Background and

Recently, using agricultural wastes as a biosorbent in removal of heavy metals has been concentrated. The aim of this study was evaluation of Canola residuals on removal of cadmium from aqueous solutions.

This experimental study was performed in laboratory scale in a batch system. The effect of parameters such as contact time (5, 10, 15, 30, 45, 60, and 120 minutes), pH (2, 4, 6, and 7), initiative concentration of cadmium (15, 30, and 60 mg/l) and adsorbent doses (0.2, 0.6,1 g/100 ml) was evaluated. The sampled solutions of cadmium with known concentrations in 100 ml were prepared in Erlen Mayer of 150 ml. The samples were analyzed by atomic absorption spectrometry PG-999 instrument in wavelength of 228 nm. The results were compared using the Langmuir and Freundlich isotherms and kinetic models.

Maximum removal of cadmium was 95% happened in primary five minutes. Optimum pH was 6. Adsorption ability of cadmium increased with increasing initiative concentration of cadmium and adsorbent dose. The adsorption isotherm obeyed Freundlich model and the adsorption kinetic followed pseudo-second-order reaction.

Based on the results, Canola residues could be used as a low-cost and efficient biosorbent for treatment of wastewater with cadmium.