Studies on synthesis, characterisation and effect of calcination on Mg-Al hydrotalcite for the removal of anionic species

Abstract

The use of Mg-Al Hydrotalcite for removing anionic contaminants such as Bromide, Sulphate, Nitrate, Fluoride and Chloride from aqueous solutions has been studied. The current study analyses the effect of calcination on the anionic removal efficiency of hydrotalcite. The hydrotalcite samples have been calcined batch-wise in a muffle furnace at different temperatures and are added to various anionic solutions in a conical flask and kept for stirring in a shaking incubator for three hours. The filtrate obtained is then analysed using Ion chromatography. The results obtained show a steady increase of anionic removal with an increase in calcination temperature. All anions under study show maximum removal towards calcinated samples than non-calcinated samples.For both calcinated and non- calcinated samples, it is found that the percentage removal of anions decreases with the increase of its ionic radii in the manner F^->Cl^->Br^->NO₃^->SO₄^2-which clearly states that calcination does not affect this behaviour and ionic radius is an influencing factor even without calcination.