Bioapatite from Aquatic Resources as Remedial Matrix for Water Purification

Hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 (HAP) has gained widespread attention as a green and environmentally friendly adsorbent due to its excellent ability in removing several organic and inorganic pollutants from waste water and natural water bodies. The unique hexagonal crystal structure of HAP along with abundant reactive moieties supports the quenching of pollutants from aqueous media particularly through an adsorption mechanism. Both chemical and physical forces play a major role in the removal of pollutants from water media, including ionic exchange reaction, surface complexation, coprecipitation, electrostatic interaction, and hydrogen bonding. The efficacy of pollutant removal may be enhanced by surface modification and composite formation with synergistic adsorbents. Magnetic HAP is such an option as it also provides a solution for the regeneration and recovery of HAP from treatment system and hence may be reused in subsequent cycles. The first part of this chapter is devoted to natural hydroxyapatite and extraction of biological hydroxyapatite from aquatic sources. The second part of this chapter focuses on its use as remedial material for water purification.