Phosphate removal from wastewater by model-La(III) zeolite adsorbents
Phosphate removal from wastewater by model-La（Ⅲ） zeolite adsorbents

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 zedim 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 obtalned: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 he 16.76 mg/L and 0.2209,respectively.In addition,when calculated at pH 6.0,distilhution coefficient 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 efficiency as high as 100%.Because of the good selectivity and regenerability of LZA,it might serve as a potenti way for advanced phosphate removal from the sewage containing other anions.