Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
583766 | Journal of Hazardous Materials | 2008 | 8 Pages |
Abstract
In situ immobilization of heavy metals in polluted soils using phosphates leads to formation of products which are highly insoluble and thermodynamically stable over a broad pH and Eh range. In this research effectivity of Cd ions immobilization (initial [Cdaq]-4.800 mM) from aqueous solutions by different phosphorus compounds (K2HPO4, NH4H2PO4 and “Polifoska 15” fertilizer) was compared at pH in the range 4.00-9.00 and for reaction times 2-1440 h. The highest reduction of cadmium concentration (>99%), owing due to the formation of cadmium phosphates, was observed for all used phosphorus sources within pH range of 6.75-9.00. Uptake of cadmium for pH â¤Â 5.00 did not exceed 80% and was lowest in the reaction with “Polifoska 15” fertilizer (28.25%). Identification of phases formed in the reactions using XRD, FTIR and SEM-EDS-EBSD was carried out. It was noticed that crystallinity of formed solid decreased with pH increase. Formation of Cd5H2(PO4)4·4H2O was observed in acidic conditions (pH â¤Â 5.00), at pH â¼Â 7.00 mixture of following cadmium phosphates Cd(H2PO4)2, Cd3(PO4)2 and Cd5H2(PO4)4·4H2O was formed. Amorphic cadmium phosphates were noticed in alkaline conditions (pH > 8.50).
Keywords
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Chemical Health and Safety
Authors
Jakub Matusik, Tomasz Bajda, Maciej Manecki,