Spray Coating of Adsorbent with Polymer Latex on Sand Particles for Fluoride Removal in Drinking Water

Abstract

An iron−aluminum−cerium trimetal hydroxide (Fe—Al—Ce) adsorbent with an acrylic−styrene copolymer latex binder, which can cross-link and cure at room temperature, was coated on sand particles by spray coating. The adhesion of the coated layer increased with the latex/Fe—Al—Ce ratio. A suitable latex/Fe—Al—Ce ratio and thickness of coated adsorbent were determined to be 0.8 and 70 μm, respectively, giving good stability and adsorption capacity. The corresponding adsorption capacity of fluoride ions on the coated sand reached 3.46 mg/g at pH 7.0 and an initial fluoride concentration of 50 mg/L. Sand coated with Fe−Al−Ce is a potential adsorbent for use in a packed bed for fluoride removal from drinking water.