Methods for Optimizing Activated Materials for Removing Fluoride from Drinking Water Sources

This paper presents the results from amending eucalyptus wood char with the following metal salts: aluminum sulfate, aluminum chloride, iron (II) chloride, and iron (III) nitrate. The results show that amending wood char with metal salts, which precipitate from the solution as metal oxides and amend the char surfaces, increases the ability of the wood char to remove fluoride from drinking water. Wood char alone has a Qe1.5 value of 0.04mg/g, whereas the Qe1.5 values of the metal-amended wood chars range from 0.14 to 2.06mg/g. Iron oxide amendments resulted in greater improvements in fluoride removal capacity than aluminum oxide amendments, with Qe1.5 values of 2.06 and 0.76mg/g for the iron oxide-amended chars and 0.57 and 0.14mg/g for the aluminum oxide-amended chars. Pretreating wood char with the oxidizing agents potassium permanganate and hydrogen peroxide increased the metal loading and fluoride removal capacities in select instances. When wood char was pretreated with potassium permanganate and amended with aluminum sulfate, the Qe1.5 value increased from 0.14 to 0.40mg/g and the metal loading increased from 0.05 to 0.27%. (C) 2015 American Society of Civil Engineers.