Hydrolyzed olive cake as novel adsorbent for copper removal from fertilizer industry wastewater

Olive cake, a solid waste resulting of olive-oil industry, was recycled as an adsorbent material for the decontamination of real fertilizer industry wastewater. Particularly, adsorption behaviour of the system working with columns in series and the effect of flow rate on the removal of copper were studied. The material exhibited a good adsorption capacity. The best results were obtained by working with three columns, reaching an adsorption capacity at exhaustion time of 7.32 mg g(-1). At lower flow rate, higher removal of copper was obtained. Different models were analyzed to fit breakthrough curves and determine characteristic parameters of the system. Among all mathematical models studied, Dose-Response model fitted better the experimental data. The effect of addition of packed-bed columns with commercial resins (Amberlite XAD-4 and Dowex MAC-3) was also evaluated. Amberlite XAD-4 showed better results than Dowex MAC-3 but not as good as hydrolyzed olive cake. For example, at an operating time of 120 min, copper concentration in the effluent was 3.4 mg/L and 5.5 mg/L when Amberlite XAD-4 and Dowex MAC-3 were used, respectively. For regeneration and reuse of adsorbent, hydrochloric acid was investigated as eluting agent. Four adsorption-desorption cycles were performed with 0.5 M HCl. The desorption curves showed a high desorption rate. Also, the desorption yield changed from 86% to 67.1% when adsorption-desorption cycles were conducted. Overall, results suggested that the studied adsorbent will be useful for future scale-up for the removal of copper (II) of fertilizer wastewater. (c) 2020 Elsevier Ltd. All rights reserved.