Phosphate removal from wastewater by model-La(III) zeolite adsorbents
NING Ping , BART Hans-J?rg , LI Bing , LU Xiwu , ZHANG Yong
DOI:
Received July 02, 2007,Revised November 18, 2007, Accepted , Available online
Volume 20,2008,Pages 670-674
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Phosphorus is one of the primary nutrients which leads to eutrophication and accelerates aging process in enclosed water bodies.
Because of the poor phosphorus selectivity of other adsorbents, the novel La(III)-modified zeolite adsorbent (LZA) was prepared by
modifying 90 nm zeolite with lanthanide to selectively remove phosphate in the presence of various omnipresent anions, such as sulfates,
bicarbonates, and chlorides. Through batch and fixed bed operation, the following optimum conditions were obtained: concentration
of lanthanum chloride solution 0.05 mol/L; solid/liquor ratio 1/25; pH 10; calcination temperature 550℃; time 1 h. The value of the
Freundlich model constants Kf and 1/n were found to be 16.76 mg/L and 0.2209, respectively. In addition, when calculated at pH 6.0,
distribution coe cient KD could be as high as 36.6. Furthermore, in the alkaline pH range, solution of 0.8 mol/L NaCl was used to
regenerate the saturated LZA, which could reach the high regeneration e ciency as high as 100%. Because of the good selectivity and
regenerability of LZA, it might serve as a potential way for advanced phosphate removal from the sewage containing other anions.
