Phosphates in Soils Treated with Sewage Water: IV. Bonding of Phosphate from Sewage Water in Sand Columns Containing Aluminum Hydroxide1
- W. H. Van Riemsdijk,
- J. Beek and
- F. A. M. De Haan2
The reaction of phosphate (P) with Al(OH)3 can be distinguished by adsorption and a process designated here as long-term reaction. The long-term reaction may remove several times the amount of P removed initially. No long-term reaction of P (0.5 mmol/liter) and Xray amourphous Al(OH)3 was detected at pH 8. To columns of quartz sand mixed with Al(OH)3 domestic sewage water (pH ≅ 8) was added during 10 mo once every 2 weeks. The phosphate retention in these columns was much higher than could be expected from the pure Al(OH)3 system experiments, indicating the occurrence of a long-term reaction. Column segments were analyzed for organic-, (Al + Fe)-, and Ca-P. Negligible Ca-P was formed. Electron microscopy and Xray analysis showed quartz particles, Al-containing particles with no detectable P, and particles containing Al, P, and Ca. Formation of the Al-P-Ca particles contributes to the capacity of soils to store or retain P.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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