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

Abstract

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.