The potential for removing anionic pollutants such as F-, HAsO42- and NO3- from water by mixed oxides issued from the moderate thermal treatment of quintinite (Mg4Al2 LDH) has been studied. This compound shows good trapping properties for F- and HAsO42-, and a low potential for NO3-, due to the competition with OH-. The competition between these three anions and CO32- has been envisaged and shows that CO32- is able to easily replace F- and NO3-, making the mixed oxides issued from MgAl LDH an inappropriate trap for F- and NO3-. However, only small amounts of arsenic are released after the CO32- introduction in water. Moreover, arsenates are able to replace carbonates even at lower concentrations. This means that HAsO42- anions present a stronger affinity than CO32- for the LDH structure. This makes mixed oxides issued from MgAl LDH very promising materials for the removal of arsenic in polluted waters.