Simultaneous removal of ammonium and phosphate by zeolite synthesized from coal fly ash as influenced by acid treatment.
Zeolite synthesized from fly ash (ZFA) without modification is not efficient for the purification of NH4+ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 (> or = 0.9 mol/L) resulted in a limited maximum phosphate immobilization capacity (PIC). It was concluded that through a previous mild acid treatment (e.g. 0.01 mol/L of H2SO4), ZFA can be used in the simultaneous removal of NH4+ and P at low concentrations in simulating real effluent.
Zhang
Bao-Hua
BH
School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. scidust@sjtu.edu.cn
Wu
De-Yi
DY
Wang
Chong
C
He
Sheng-Bing
SB
Zhang
Zhen-Jia
ZJ
Kong
Hai-Nan
HN
D002244:Carbon; D003031:Coal; D060729:Coal Ash; D006863:Hydrogen-Ion Concentration; D052638:Particulate Matter; D010710:Phosphates / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013464:Sulfuric Acids / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D017641:Zeolites / Q000737:chemistry*
D003031:Coal; D060729:Coal Ash; D052638:Particulate Matter; D010710:Phosphates; D000644:Quaternary Ammonium Compounds; D013464:Sulfuric Acids; D014874:Water Pollutants, Chemical; D017641:Zeolites; D002244:Carbon; C033158:sulfuric acid