title: Kinetic research on the sorption of aqueous lead by synthetic carbonate hydroxyapatite.
abstract: The sorption of aqueous lead on carbonate-hydroxyapatite (CHAp) is a complicated non-homogeneous solid/water reaction, which from the kinetic point of view has two stages. In the first stage, the reaction rate is so fast and the kinetic pathway so intricate that further research is required. In the second stage, the reaction rate slows down and the reaction process follows that of a first-order kinetic equation. Experimental results show that the relationship between the reaction rate constant k(1) and temperature T agrees with the Arrhenius equation, and that the activation energy of sorption (E(a)) is 11.93 kJ/mol and the frequency factor (A) is 2.51/s. The reaction rate constant k(1) increases with the Pb(2+) initial concentration and decreasing pH, but with increasing CHAp dosage. X-ray diffraction (XRD), scanning electron microscopy with energy dispersion spectrum (SEM-EDS) and toxicity characteristic leaching procedure (TCLP) tests indicate that the main sorption mechanism is dissolution-precipitation, in conjunction with surface sorption.
authors.affiliation: School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: HuanYan
authors.initials: H
authors.lastname: Xu
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: MingSheng
authors.initials: M
authors.lastname: Peng
mesh_terms: D000327:Adsorption; D002254:Carbonates / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007854:Lead / Q000737:chemistry*; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D002254:Carbonates; D014874:Water Pollutants, Chemical; D007854:Lead; D017886:Durapatite