Boron recovery from seawater with a new low-cost adsorbent material

• A new composite containing chitosan and iron(III) hydroxide has been manufactured.
• SEM-EDX analysis revealed a homogenous distribution of Fe(OH)3 in whole material.
• An adsorption column system was used for boron recovery from seawater.
• Adsorption–desorption cycles were performed and desorption uptake remained >40%.
• Elution was efficiently eluted with water at pH 12.

A new adsorbent [chiFer(III)] for boron recovery from seawater was prepared using chitosan and iron(III) hydroxide. Experiments were carried out in a column system. Seawater samples were collected from the Mediterranean Sea off the coast of Vilanova i la Geltru, Spain (coordinates: 41.18; 1.75). Several adsorption–desorption cycles were performed to evaluate the efficiency of the adsorbent, and a desorption step was carried out using MilliQ-water of pH 12 (0.01 M NaOH solution). The molar ratio between the mass of adsorbed boron in the five consecutive cycles and the mass of iron(III) hydroxide present in the adsorbent beads was 10.7 mmolB·(molFe(OH)3)-1(molFe(OH)3)-1. The experimental results were evaluated using the Thomas, Yoon and Nelson, and Bohart–Adams models, which fitted the experimental data adequately. The adsorbent was characterized by SEM-EDX analyses and BET surface; porosity studies confirmed that the chiFer(III) composite is a mesoporous material.

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