La2O3 modified porous boron nitride for enhanced adsorption and removal of fluoride pollutants from an aqueous solution

Abstract Fluorine contamination has caused great harm to humans and the environment. In this study, novel lanthanum modified porous boron nitride (porous BN) composites (BN−La−X) were successfully prepared and applied to remove fluoride from water. The results indicated that lanthanum was present on the surface of BN in the form of amorphous La 2 O 3 . BN−La‐4 has excellent adsorption performance, and its removal of fluoride is much more effective than that of porous BN with good cyclic regeneration ability. In addition, the fluoride adsorption by BN−La‐4 could reach adsorption equilibrium within 2 h and the adsorption kinetics was conformed to the pseudo‐second‐order model. The maximum adsorption capacity of BN−La‐4 was calculated from the Langmuir model to be 80.04 mg g −1 , which was better than most related adsorbents. Furthermore, the presence of anions and pH values affected the removal of fluoride. The adsorption mechanisms were consisted of electrostatic attraction, ion exchange between hydroxyl and fluorine ions, and the formation of coordination complexes between lanthanide ions and fluoride ions. In summary, La 2 O 3 modified porous boron nitride composite is a promising adsorbent for the removal of fluoride contamination in aquatic environment.