A comprehensive study on the kinetics of olive mill wastewater (OMWW) polyphenols adsorption on macroporous resins. Part II. The case of Amberlite FPX66 commercial resin

摘要

The commercially available macroporous resin Amberlite FPX66 was evaluated for its capacity to adsorb the polyphenols contained in olive mill wastewater (OMWW). The adsorption was performed in the mode of fixed packed-bed contactor. The effects of OMWW flow rate, temperature, dilution and pH on the resin adsorption capacity were investigated. Polyphenols concentration decreased with time. The pattern of the total polyphenols concentration dependence on time was found to be similar in all cases. The pattern included a very steep section for roughly the first hour of the operation, followed by a second section of decreasing gradient down to a final asymptotic equilibrium limit. Regarding the time required for approaching the equilibrium, this was found to be unaffected by the temperature. On the contrary, the magnitude of the equilibrium concentration was substantially affected by the OMWW temperature presenting an optimum at 40 degrees C. The increase in the OMWW flow rate affected markedly the speed of approaching the equilibrium but not its position. The variation of the total polyphenols concentration with time showed that higher concentrations yielded more rapid kinetics at the initial section, but there was no apparent differentiation of the time required to approach the equilibrium. Acidic pH appeared to be favourable for the adsorption. Finally, a novel modelling approach was developed to simulate the adsorption process kinetics.