simultaneously to the obtained precipitate solution for 30 min with
mechanical stirring. The resulting puce suspension was heated at
90 ◦C for 2 h and then the mixture was cooled to room temperature
and aged for 12–24 h without stirring. The obtained precipitate was
separated by a magnet, washed repeatedly with deionized water
till neutrality, dried in the drying oven at 90 ◦C, and grinded with
mortar. The final products were the prepared MNHAP adsorbents.