Valorization of Rich-Carbonates Wastes on the Synthesis of Hydroxyapatite
Interest in apatitic calcium phosphates as an adsorbent stems from their efficiency in the treatment of heavy metals from contaminated soils, incinerator fly ashes and polluted wastewaters. Hydroxyapatite (HA), Ca10(PO4)6(OH)2 was prepared by reacting a phosphate solution with calcium carbonate industrial waste. The process consists in mixing the reagents under a fixed set of parameters (pH, Ca/P, temperature, liquid/solid) to make the HA adsorbent as a suspension of small particles. A reference hydroxyapatite was prepared following the same procedure with a pure carbonate grade (95％ wt), in order to compare the outcome with the waste-made HA. The characterization of the synthetized products was carried out by means of SEM, X-ray diffraction (XRD) Infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The reaction rate was followed for 120 hours using the techniques mentioned above to measure the conversion rate of the starting calcium carbonates into HA sorbent. The kinetics of the reaction show two steps. The first one is a fast reaction that lasts 10 minutes and leads to the conversion of 60％ (wt) of CaCO3. This step is followed by a slower transformation which leads to an overall conversion of 85％ (wt) of the calcium into HA following a few hours at room temperature. The convenient synthesis of HA using CaCO3 waste seems to be a promising valorisation for environmental applications.
Hydroxyapatite Adsorbent Calcium-carbonate waste Valorization Heavy metals
M. CHKIR A. NZIHOU P. SHARROCK
Ecole des Mines dAlbi-Carmaux, Albi, France IUT Paul Sabatier, Toulouse, France
国际会议
北京
英文
935-941
2010-05-17（万方平台首次上网日期，不代表论文的发表时间）