Abstract
In order to evaluate the possible use of natural fluor-hydroxyapatite (FOHAp) crystals as soil additive for the in situ remediation of heavy-metal contaminated soils, the crystal structure of FOHAp crystals, used in batchexperiments at 22 °C with pH within the range 4.8-9.5 and in presence of Zn 2 + ions, was determined. Crystal structures (space group P6 3 /m) converged to R = 0.026 for untreated FOHAp and to R = 0.028 (Experiment 1) and R = 0.032 (Experiment 2) for Zn 2 + -treated FOHAp crystals. The site occupancy ratios [(Zn-Ca)2/(Zn-Ca)1] obtained from the refinement of electron density is = 1.500 for natural FOHAp, 1.500 (Experiment 1) and 1.520 (Experiment 2) in Zn 2 + -treated crystals. The value deriving from experiment 2 agrees with small changes in Ca2 site occupancy. Ca2O 6 X polyhedron distortions may be related both to a slight preference of Zn for Ca2 and to OH for F substitution during the overall reaction sequence.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
