Abstract
In this study, a synthetic layered double hydroxide modified with chloride ions (LDH-Cl) was employed for the removal of phosphorus from wastewaters. A series of phosphate adsorption experiments demonstrated that the adsorption capacity of LDH-Cl was described well by the three-parameter isotherm model (Langmuir-Freundlich combination model). LDH-Cl was found to have ∼50 mg P/g of ion exchange capacity for phosphate, which was sufficient for phosphate recovery from wastewaters. Phosphate adsorption by LDH-Cl also followed pseudo-second-order reaction kinetics. Effective replacement of Cl- with PO43- during sorption was confirmed by X-ray diffraction and Fourier transform infrared analyses. Adsorption capacity varied with pH and reached a maximum value at pH 3. Anions commonly present in most wastewaters, such as nitrate, sulfate, and chloride, had a minimal effect on phosphate adsorption by LDH-Cl. On the contrary, the amount of phosphate ions removed by LDH-Cl decreased with increasing bicarbonate ion concentration. LDH-Cl also exhibited a sufficient chemical stability against adsorption/desorption repetitions and ∼80% of desorption rate was achieved at 5 M NaCl concentration. LDH-Cl exhibited a high phosphate removal capacity and a low sensitivity to the environmental conditions of wastewaters, supporting use as an effective means for the removal of phosphate.
Original language | English |
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Pages (from-to) | 805-810 |
Number of pages | 6 |
Journal | Environmental Engineering Science |
Volume | 27 |
Issue number | 9 |
DOIs | |
Publication status | Published - 2010 Sept 1 |
Keywords
- Adsorption
- layered double hydroxide
- phosphate
- secondary effluent
- selectivity
ASJC Scopus subject areas
- Environmental Chemistry
- Waste Management and Disposal
- Pollution