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Using CaFe layered double hydroxide transformation to optimise phosphate removal from waste waters
Abstract Single phase CaFe layered double hydroxide (LDH) minerals containing Cl− species in the interlayer was synthesized by coprecipitation with a CaII: FeIII ratio of 2: 1. In both phosphate (PO4) free water and at low aqueous PO4 concentration, the LDH was fully transformed into a mixture of a “ferrihydrite-like” material, calcite and soluble calcium species. Mössbauer spectroscopy and transmission electron microscopy showed that phosphate was removed by the “ferrihydrite like” phase that contained a significant quantity of Ca. At high phosphate concentration the Ca species released from the LDH precipitated to form hydroxyapatite leading to a maximal removal capacity of ~ 130 mg P-PO4 g−1. The CaFe LDH was deposited onto a pozzolana volcanic rock in order to perform a column experiment under hydrodynamic conditions for 70 days. A high removal capacity was observed, a q B of ~ 4 mg P-PO4 g−1 was measured at the breakthrough of the column, however the pH in the outflow was measured to be higher than 11. Such an increase was due to the very high solubility of the CaFe LDH.
Graphical abstract Display Omitted
Highlights CaFe LDH is transformed in an heterogenous ferrihydrite-like phase in P-free water. PO4 is removed by adsorption on the ferrihydrite-like phase at low P concentration. CaFe LDH coatings removed high quantity of P under hydrodynamic conditions.
Using CaFe layered double hydroxide transformation to optimise phosphate removal from waste waters
Abstract Single phase CaFe layered double hydroxide (LDH) minerals containing Cl− species in the interlayer was synthesized by coprecipitation with a CaII: FeIII ratio of 2: 1. In both phosphate (PO4) free water and at low aqueous PO4 concentration, the LDH was fully transformed into a mixture of a “ferrihydrite-like” material, calcite and soluble calcium species. Mössbauer spectroscopy and transmission electron microscopy showed that phosphate was removed by the “ferrihydrite like” phase that contained a significant quantity of Ca. At high phosphate concentration the Ca species released from the LDH precipitated to form hydroxyapatite leading to a maximal removal capacity of ~ 130 mg P-PO4 g−1. The CaFe LDH was deposited onto a pozzolana volcanic rock in order to perform a column experiment under hydrodynamic conditions for 70 days. A high removal capacity was observed, a q B of ~ 4 mg P-PO4 g−1 was measured at the breakthrough of the column, however the pH in the outflow was measured to be higher than 11. Such an increase was due to the very high solubility of the CaFe LDH.
Graphical abstract Display Omitted
Highlights CaFe LDH is transformed in an heterogenous ferrihydrite-like phase in P-free water. PO4 is removed by adsorption on the ferrihydrite-like phase at low P concentration. CaFe LDH coatings removed high quantity of P under hydrodynamic conditions.
Using CaFe layered double hydroxide transformation to optimise phosphate removal from waste waters
Al Jaberi, Muayad (author) / Mallet, Martine (author) / Greenwell, H. Chris (author) / Abdelmoula, Mustapha (author) / Ruby, Christian (author)
Applied Clay Science ; 182
2019-08-25
Article (Journal)
Electronic Resource
English
LDH , Iron , Water treatment , Adsorption , Precipitation , Hydroxyapatite
| American Chemical Society | 2024