Development of Iron Oxide Coated Sand (IOCS) Adsorbent for Defluoridation Technology

Abstract

Although safe and reliable water supply is badly needed, the installation of advanced defluoridation plants in regions with low economic resources such as Ethiopia is, at present, very scarce mainly due to operational consideration and settlement characteristics of the people. In such cases the development and popularizing of low cost fluoride removal technologies, which does not demand much money and skilled manpower, is important. Therefore, this study focuses on the removal of fluoride from groundwater by using Iron oxide coated sand (IOCS), which could be used as an alternative defluoridation adsorbent. The influence of design parameters such as contact time, adsorbent dose, solution pH, and initial fluoride concentration was investigated. Basic process characteristics were determined under batch conditions. Fluoride adsorption onto IOCS was strongly pH dependent. The maximum adsorption capacity for IOCS was found to be 136 mg kg-1. This result was obtained at optimized conditions of solution pH (4.0), contact time (8.0 h), dose (15.0 g L-1) and initial fluoride concentration (5.0 mg L-1). The uptake of fluoride slightly increased with increasing equilibrium concentration of fluoride ion in solutions. By increasing the initial concentration of fluoride from 3.0 to 10.0 mg L-1 , the adsorption capacity, increased from 90.73 mg kg-1 to 252.17 mg kg-1. IOCS was found to be promising adsorbent for defluoridation technology.