Preparation of high specific surface area hydroxyapatite for environmental applications

Abstract

We report the preparation of hydroxyapatite in powdered form by aqueous reaction of calcium nitrate or hydroxide with phosphate ion at room temperature. With a slow maturation step of 48 h avoiding heat, the resulting products show large specific surface areas above 150 m 2 /g. The specific surface areas also depend on stirring speed with a maximum observed with gentle mixing. Ageing causes a decrease in specific surface area which tends to stabilize near 100 m 2 /g following a 1 year period. The hydroxyapatite may be spray dried and conserve interesting physical properties for environmental applications.

Application of hydroxyapatite and cement kiln dust mixture in adsorption of lead ions from aqueous solution

“…The ion sorption capacity of HAp increases with decrease in crystallinity and increase in specific surface area. Poorly crystalline HAp was suggested for use in the wastewater treatment because the sorption capacity of the nano-crystalline HAp significantly exceeds than that for the crystalline type [11][12][13][14].…”

Preparation of Magnetic Hydroxyapatite and Their Use as Recyclable Adsorbent for Phenol in Wastewater

“…The magnetic materials SSA was 307. , and Cd 2þ can exchange with Ca 2þ in the HAP [18,19,34], so the magnetic sorbents has the ability for purifying the heavy metal ions in the wastewater. Using the external magnetic, the sorbents can be recycled easily, which did not produce the second pollution.…”

“…A hydroxyapatite (HAP) is chemically similar to the mineral component of bones and hard tissues in mammals, and is one of few materials that are classed as bioactive for application in biomaterial. The specific surface area (SSA) can reach up to 150 m 2 /g by changing the synthesis strategy [18], which has been used to adsorb heavy metal ions, phosphate, and oxovanadium(IV) [19][20][21][22] in wastewater. Similar to TiO 2 powder, the HAP would form a suspension in solution and is not easy for recovery and reuse.…”

Vaporisation et/ou stabilisation de métaux lourds au cours du traitement thermique de déchet : cas des déchets ménagers solides et des boues de dragage

“…D'autres configurations ont également été étudiées dans notre équipe. Il s'agit de la capture des ML contenus en phase liquide (Bailliez, 2003), ou en phase gazeuse (Verwilghen, 2006) (Ma et al, 1995 ;Laperche et al, 1996 ;Crannell et al, 2000 ;McGowen et al, 2001 ;Mavropoulos et al, 2004). Les deux approches sont complémentaires en ce qui concerne l'aspect revalorisation des résidus de combustion.…”