Breakthrough Analysis for Water Defluoridation Using Surface-Tailored Zeolite in a Fixed Bed Column

Abstract

Treatment of drinking water containing fluoride ion requires a robust and an effective technique. This can be achieved by the use of an appropriate sorption material in a fixed-bed filter. Consequently, fluoride adsorption behavior, expressed as breakthrough curve (BTC), has been investigated both in a continuous and intermittent mode of operation, using charged-reversed zeolite particles in a fixed bed filter. The fluoride concentration ranged from 5 to 20 mg/L, typical of what is found in natural systems such as groundwater. In all the fluoride removal experiments, the BTC curves were consistent with the ideal s-shape. A large volume of water was processed for low initial concentration of fluoride, for slow flow velocity, and for bed containing large amount of the sorption media. Equally important, no aluminum was eluted from the zeolite structure, making the sorption media safe for water treatment. A two-parameter logistic model was used to simulate the BTCs. Separately, the fingerprint of intraparticle diffusion was confirmed through operation of the fixed-bed in an intermittent mode.

Fluoride removal performance of phosphoric acid treated lime: Breakthrough analysis and point-of-use system performance

“…In this mode of operation, the solid-phase fluoride concentration gradient has a chance to relax completely (approaching equilibrium) during the off-periods. This leads to a high concentration gradient between the liquid and the surface of the solid, thus resulting in improved fluoride removal when the unit is used again (Onyango et al, 2009). …”

Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters

“…Dental fluorosis and other health problems caused by elevated fluoride in drinking water have been known for years now [14,17,18,45,56]. Efficient F´removal by chemical methods alone (e.g., precipitation) is not possible because the typical F´concentration in natural waters is generally too low (typically less than 30 mg¨L´1) to result in super-saturation and subsequent precipitation ( [24] and refs.…”

Water defluoridation by bauxite-gypsum magnesite (B-G-Mc) based filters calcined at 350 500C

“…Fluoride has been identified as a cause of dental and skeletal fluorosis world over (Maliyekkal et al, 2010;Rango et al, 2010;Peter, 2009;Onyango et al, 2009). The World Health Organisation (WHO) set a guideline value of 1.5 mg/L as an acceptable upper limit (WHO, 2006).…”