Highly-polar layered double hydroxides are efficient adsorbents of low-concentrated trihalomethanes present in water

Replacement of (Al(OH) ₆ ) ^3- blocks by (AlF ₆ ) ^3- was explored as a strategy to modify the dipolarity of layered double hydroxides materials (LDHs). The presence of fluorine augments the dipolarity/polarizability of LDHs. LDHs were tested as adsorbents of the trihalomethanes CHCl ₃ and CHBr ₃ that are present (low concentrated) in water. Fluorinated LDHs were significantly more efficient compared to that without fluorine. Thermal treated fluorinated LDHs are able to remove 95% and 90% of CHCl ₃ and CHBr ₃ , respectively, present in low concentrated aqueous solutions. The effect of concentration of triahalomethanes, time of contact and structure of adsorbent were explored. Linear isotherms were obtained when un-fluorinated adsorbents were used but the isotherm turns to match that of Freundlich-type when adsorbent contains fluorine.