Removal of arsenious ion by calcined aluminum oxyhydroxide (boehmite)

Aluminum oxyhydroxide (boehmite, BE) shows adsorption ability of arsenious ion. In this study, we calcined BE in the temperature range 200–1150 °C, and examined the amount of arsenious ion adsorbed and adsorption mechanism. As a result, the adsorption amount of arsenious ion by BE calcined at 400 °C showed the highest value as compared with those by BE calcined at other temperatures. On the other hand, the amounts of arsenious ion adsorbed onto BE showed lower values at 200, 600, and >1000 °C than that by BE before calcination. The amount of surface hydroxyl group of calcined BE showed the highest value at the calcination temperature of 400 °C. As a result of X-ray analysis, BE showed boehmite structure at less than the calcination temperature of 300 °C, while BE was converted to the transitional state of aluminum oxide at more than 400 °C. From the result of the amount of arsenious ion adsorbed and FT-IR, it turned out that calcined BE dissociated water molecule when suspended in the water, hydroxyl group was generated on the surface, and the amount of arsenious ion adsorbed was increased because of the ion exchange of these hydroxyl groups with arsenious ions. It was clarified that an adsorbent with high adsorption ability of arsenious ion was obtained by calcination of BE.

Graphical abstractThe adsorption of arsenious ion onto calcined boehmite was investigated. The structure of boehmite calcined at temperature range 200–1150 °C and the adsorption mechanisms of arsenious ion onto them was discussed.Figure optionsDownload full-size imageDownload as PowerPoint slide