Optimization of phosphate recovery from urine by layered double hydroxides.

Urine contains sufficient phosphorus (P) to consider P recycling form urine as an interesting strategy. In this study, the potential of MgAl or ZnAl layered double hydroxides (LDHs) to be used in such recovery was assessed. LDHs are anion exchangers with a high P selectivity, and P-loaded LDHs have demonstrated fertiliser potential.

Solid-state speciation of interlayer anions in layered double hydroxides.

Layered double hydroxides (LDH) have been proposed for phosphate (PO) recovery and recycling from waste streams due to their high anion exchange capacity, good stability and high affinity towards PO. The high affinity towards PO strongly relates to the electrostatic interaction with PO, and thus the charge of PO. However, the anion speciation of intercalated PO, i.

The isotopic exchangeability of phosphate in Mg-Al layered double hydroxides.

Layered double hydroxides (LDH) of Mg/Al are anion exchangers that are candidate materials for phosphate (PO) recovery and recycling from waste streams. However, PO recycling in agriculture might be limited by incomplete desorption of PO from the minerals. This study was set up to identify the factors explaining irreversible PO sorption ("fixation") on LDHs by comparing the isotopic exchangeability (PO) with the PO desorption from LDH materials and from boehmite as a P fixing reference mineral.