Recovering Metals from Aqueous Solutions by Biosorption onto Hydrolyzed Olive Cake Fernández González, Rafael Martín Lara, María Ángeles Blázquez García, Gabriel Pérez Muñoz, Antonio Calero De Hoces, Francisca Mónica Biosorption Heavy metals Hydrothermal treatment Olive cake Wastewater treatment Olive cake obtained as a by-product from the olive oil industry has been evaluated as biosorbent of heavy metals from aqueous solutions in batch and continuous systems (fixed-bed columns). First, a complete study of effect of hydrothermal treatment with water on biosorption capacity of resulting solid was performed. Results showed that the values of biosorption capacity increased when the particle size of material decreased and the temperature of treatment increased. Then, hydrolyzed olive cake was treated by common chemicals (hot water, nitric acid, and sodium hydroxide) and the impact of chemical treatment was analyzed. The results were well reproduced by Langmuir and Freundlich isotherm models, getting maximum experimental biosorption capacities that changed between 42.34 mg/g obtained for the solid material modified by NaOH and 14.27 mg/g obtained for the solid material modified by nitric acid. Finally, laboratory tests in fixed-bed columns were performed with four different heavy metals and at three different inlet concentrations. The biosorption capacity increased from 2.83 mg/g (Cr), 4.51 mg/g (Cu), 12.30 mg/g (Pb), and 4.10 mg/g (Zn) to 3.08 mg/g (Cr), 5.17 mg/g (Cu), 13.21 mg/g (Pb), and 5.51 mg/g (Zn) when the concentration of metal ions increased, from 50 mg/L to 200 mg/L, respectively. Also, the experimental data obtained was successfully correlated with the Thomas, Yoon–Nelson, and dose–response models. 2020-01-31T12:47:58Z 2020-01-31T12:47:58Z 2019-11-28 info:eu-repo/semantics/article Fernández-González, R., Martín-Lara, M. Á., Blázquez, G., Pérez, A., & Calero, M. (2019). Recovering Metals from Aqueous Solutions by Biosorption onto Hydrolyzed Olive Cake. Water, 11(12), 2519. http://hdl.handle.net/10481/59346 10.3390/w11122519 eng http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Atribución 3.0 España MDPI