Reaction of calcium phosphate with textile dyes for purification of wastewaters

W. Lemlikchi (1) , P. Sharrock (2) , M. O. O Mecherri (1) , M. Fiallo (3) , Ange Nzihou (2)

1 LCAGC - Laboratoire de Chimie appliquée & génie chimique [Tizi-Ouzou]
2 RAPSODEE - Centre de recherche d'Albi en génie des procédés des solides divisés, de l'énergie et de l'environnement
3 UT3 - Université Toulouse III - Paul Sabatier

When unsintered hydroxyapatite (HA) is dissolved in acidic solution (pH less than 3), the calcium salt dissolves readily and may be re-precipitated at neutral pH values by neutralization with base. Maturation of this precipitate eventually leads to the neo-formation of calcium phosphates similar to HA. HA is a stable solid under neutral or basic conditions and has interesting adsorption properties. Particularly, textile dyes can be adsorbed on HA particles. Thermal treatment below 800 degrees C degrades adsorbed organic matter and generates mineral HA. Such HA can be recovered and reused by re-dissolution in acidic water. We have experimented with such recycled HA the co-precipitation of textile dyes and found that HA can be reused several times. For most textile dyes, a very high level of color removal was observed (above 98%), with a small loss of HA during the recycling process (12%). This makes the treatment of textile dye polluted waters by HA co-precipitation feasible and sustainable.

Mots clés: Dye removal; Hydroxyapatite; Adsorbent regeneration; Elimination rate

Domaines: Sciences de l'ingénieur [physics]

W. Lemlikchi, P. Sharrock, M. O. O Mecherri, M. Fiallo, Ange Nzihou. Reaction of calcium phosphate with textile dyes for purification of wastewaters. Desalination and Water Treatment, 2014, 52 (7-9), p.1669-1673. ⟨10.1080/19443994.2013.807008⟩. ⟨hal-01625028⟩