Fluoride removal from water using high-activity aluminum hydroxide prepared by the ultrasonic method

Different Al(OH)(3) powders were used as adsorbents for fluoride removal from water. The results showed that the defluoridation performance of ultrasonically prepared Al(OH)(3) (UAH) is much better than that of commercially available Al(OH)(3) and is comparable to that of activated alumina, because the ultrasonic waves effectively break the agglomerates in the suspension so that the UAH particles are fine and have a beneficial phase constituent. Furthermore, the residual aluminum concentration in aqueous solution after defluoridation by Al(OH)(3) was found to be one order of magnitude lower than that obtained with activated alumina which is below the World Health Organization (WHO) guideline for aluminum (0.2 mg L-1) in drinking water. The defluoridation dynamics and mechanism for UAH are discussed in detail.