Adsorption of fluoride ions from water using modified attapulgite with magnesium and aluminum salts was conducted by batch experiments. The effects of temperatures and mass ratios of attapulgite, magnesium and aluminum salts were investigated. Linear and non-linear methods were applied for fitting the adsorption data with Langmuir, Freundlich, and Redlich-Peterson isotherms. Modified attapulgite with a mass ratio attapulgite:MgCl2 center dot 6H(2)O:AlCl3 center dot 2H(2)O = 2:1:2 had higher fluoride adsorption capacity. In addition, the fluoride adsorption using the modified attapulgite included an anion exchange process. (C) 2008 Elsevier B.V. All rights reserved.