title: Phosphate removal from digested sludge supernatant using modified fly ash.
abstract: The removal of phosphate in digested sludge supernatant by modified coal fly ash was investigated in this study. Modification of the fly ash by the addition of sulfuric acid could significantly enhance its immobilization ability. The experimental results also showed that adsorption of phosphate by the modified fly ash was rapid with the removal percentage of phosphate reaching an equilibrium of 98.62% in less than 5 minutes. The optimum pH for phosphate removal was 9 and the removal percentage increased with increasing adsorbent dosage. The effect of temperature on phosphate removal efficiency was not significant from 20 to 40 degrees C. X-ray diffraction and scanning electron microscope analyses showed that phosphate formed an amorphous precipitate with water-soluble calcium, aluminum, and iron ions in the modified fly ash.
authors.affiliation: Department of Civil Engineering and Construction Engineering, Zhengzhou Institute of Aeronautical Industry Management, Zhengzhou 450015, China. xuke72@126.com
authors.forename: Ke
authors.initials: K
authors.lastname: Xu
authors.forename: Tong
authors.initials: T
authors.lastname: Deng
authors.forename: Juntan
authors.initials: J
authors.lastname: Liu
authors.forename: Weigong
authors.initials: W
authors.lastname: Peng
mesh_terms: D000327:Adsorption; D060729:Coal Ash / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008854:Microscopy, Electron; D010710:Phosphates / Q000302:isolation & purification*; D012722:Sewage / Q000032:analysis*; D013464:Sulfuric Acids / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D060729:Coal Ash; D010710:Phosphates; D012722:Sewage; D013464:Sulfuric Acids; C033158:sulfuric acid