The ability of lateritic soils to remove fluoride from water was studied to clarify some basic issues a) is there arncorrelation between the mineral composition of the soils and their ability to remove fluoride? b) which processesrnaccount for the fluoride removal? c) is the fluoride removal ability increased by a thermal treatment of the soils?rnand d) which kind of fluoride containing species remain in the soil treated water? The results obtained indicaternthat fluoride removal and gibbsite content of the soils are correlated. From this it can be concluded that gibbsiternis the active component in lateritic soils in the fluoride removal. Speciation analysis reveals that at low freernfluoride concentrations the dissolution of gibbsite facilitated by the adsorption of fluoride onto gibbsiternaccompanied by the formation of aluminum fluoro complexes can explain the mechanism of fluoride removal.rnThe question to which extent the exchange of hydroxide ion with fluoride ion in gibbsite takes place in therndefluoridation process cannot be answered with certainty. The electrochemical investigations of aluminumrnelectrodes by cyclic voltammetry, impedance spectroscopy and potentiometry have shown that passivation of thernaluminum electrodes is a drawback of the defluoridation of low fluoride solutions by electrochemically generatedrnAl(OH)3 but it might be possible at higher fluoride concentrations.rnKey words: Fluoride removal, lateritic soils, speciation analysis, complexed fluoride,rnAlzheimerâ€™s disease, electrochemical behaviors, passivation, votammogram,rnimpedance spectroscopy, removal capacity and adsorption isotherm.