Bench-scale and packed bed sorption of methylene blue using treated olive pomace and charcoal.

A combination of olive pomace after solvent extraction and charcoal produced from the solid waste of olive oil press industry was used as an adsorbent for the removal of methylene blue (MB) dye from aqueous solutions. Batch tests showed that up to 80% of dye was removed when the dye concentration was 10 mg/ml and the sorbent concentration was 45 mg/ml. An increase in the olive pomace concentration resulted in greater dye removal from aqueous solution, and an increase in MB dye concentration at constant adsorbent concentration increased the dye loading per unit weigh of adsorbent. In the kinetic of the adsorbent process, the adsorption data followed the second-order kinetic model better than first order kinetic model. Charcoal showed higher sorption capacity (uptake) than that of olive pomace. In the fixed bed adsorption experiment, the breakthrough curves showed constant pattern behavior, typical of favorable isotherms. The breakthrough time increased with increasing bed height, decreasing flow rate and decreasing influent concentration and methylene blue dye uptake. The uptake of MB dye was significantly increased when a mixture of olive pomace and charcoal was packed in the column in a multi-layer fashion. Different models were used to describe the behavior of this packed-sorption process.