1,720,963 research outputs found
Remediation of Pb, Zn, Cu and Cd-contaminated mine soils using synthetic and natural phosphates
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Heavy metals immobilization by phosphates in polluted soils from an industrial site. 8th European Meeting on Environmental Chemistry
No full textRemoval of heavy metals from aqueous solutions by sorption on hydroxyapatite.
No full textHydroxypatite, heavy metals, EXAF
Studio spettroscopico infrarosso per la caratterizzazione di malte ed intonaci di siti archeologici
No full textRom
Removal of Cu from aqueous solutions by synthetic hydroxyapatite: EXAFS examination
No full textThe sorption of aqueous Cu on synthetic hydroxyapatite has been investigated by means of the results of a combined structural simulation and extended X-ray absorption fine structure (EXAFS) analysis. The removal of Cu was studied in batch experiments at 25±2 ◦C. The sorption of Cu follows Langmuir behaviour and was attributed to a two-step mechanism involving surface complexation and ion exchange with Ca resulting in the formation of a copper-containing hydroxyapatite. EXAFS results suggest that the heavy metal is present in the Cu2+ form. The structural
experimental and theoretical analysis shows that Cu is bond to about four O atoms at a distance of about 1.95 A° . In all the studied cases the immobilization site of Cu is the same. The fixation of Cu occurs in the surface sites of hydroxyapatite whereas the sorption in the Ca sites in the inner part of the structure is unlikely
Synthetic phosphates as binding agent of Pb, Zn, Cu and Cd in the environment
No full textThe sorption of Pb, Zn, Cu and Cd from aqueous multiple-species solutions by synthetic hydroxyapatite (HAP) was investigated. HAP was reacted with solutions containing different heavy metals concentrations (10, 100 and 500 mg/L) for four times (2, 4, 24 and 48h). The results showed that HAP was very effective in removal heavy metals from aqueous solutions. Approximately 95-99% of the Pb applied was removed from solutions, with the best sorption capacity of 497 mg of Pb/g of HAP, while 92-99% of Zn, 93-99% of Cu and 88-99% of Cd added were attenuated, with best removal capacity of 498, 485 and 477 mg/g, respectively. Sorption mechanisms other than dissolution/precipitation of crystalline phases could be involved in attenuating heavy metals concentrations such as ion exchange, coprecipitation, surface complexation and formation of amorphous phases. The study results confirm HAP provides a cost effective method for the decontamination of solutions polluted by heavy metals
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