Simultaneous reductive and adsorptive removal of bromate from water using acid-washed zero-valent aluminum (ZVAI)

摘要

Zero valent aluminum (ZVAI), prepared from washing aluminum powder with acids, is employed for the first time to remove bromate from water. With a short acid-washing time (i.e., 120 s), the inherent layer of Al2O3 of aluminum powder could be removed, allowing ZVAI to react with bromate. The removal of bromate using ZVAI can be primarily attributed to the reduction of bromate to bromide and partially to the adsorption to the surface of ZVAI. Parameters influencing the removal of bromate were examined including temperature, pH, co-existing ions and ultrasonication. Temperature and pH were found to be critical parameters that affect the removal efficiency. ZVA1 could completely remove bromate present in water (i.e., 78.1 mol L-1) at 60 degrees C and pH = 3, while it became ineffective for removing bromate under alkaline conditions. The removal efficiency of ZVAI for bromate remained almost the same when bromate co-existed with other anions (e.g., sulfate, nitrate and phosphate). ZVAI also showed a high selectivity toward the reduction of bromate over nitrate. In addition, ultrasonication was demonstrated as a highly effective facilitator to enhance the removal of bromate using ZVAI. ZVAI was also re-used to remove bromate for multiple times after acid-washing regeneration. These results indicate that ZVAI is a promising material to remove bromate from water and the findings of this study can contribute to developing ZVAI to treat bromate-contaminated water. (C) 2016 Elsevier B.V. All rights reserved.