Evaluation of pomegranate peel carbon potential as a adsorbent of pigment and bi and trivalent metals in liquid media

Pomegranate peel is an important source of bioactive compounds which have high potential of alternative source of activated carbon for bleaching and the removal of heavy metal from liquid media. The present study was undertaken to evaluate the feasibility of pomegranate peel carbon for the removal of heavy metal from oil and aqueous solution and then to investigate its activity in the bleaching of sesame oil. Response surface methodology and Box-Behnken design were applied to study and optimize the adsorption condition to remove metal ions on prepared pomegranate peel adsorbent. For this purpose, the effects of three independent variable pH(X1), contact time (X2) and adsorbent dose (X3) on metal ions concentration (dependent variable) were studied using a three-level three-factor Box–Behnken design. In addition, different types of adsorbents (pomegranate peel carbon and activated earth) were tested for adsorption of pigment, peroxides and heavy metals of sesame oil. Results showed that optimum condition required for maximum adsorption were found to pH= 5.3, equilibrium time 200 min and adsorbent concentration 2.5 g/L. Under the optimal conditions the removal of heavy metals i.e. Fe, Cr, Pb, as and Hg from aqueous solution by activated carbon developed from pomegranate peel are more than 80%. Results of sesame oil bleaching with pomegranate peel carbon showed good bleaching efficiency and oxidative stability. Furthermore, pomegranate peel carbon comparing with bleaching earth showed better ability to decrease heavy metal content of oil.