Materials and synthesis (NH 4 ) 2 HPO 4 (DAP) (ChemSolute, 99%) and MgCl 2 •6H 2 O (ChemSolute, 99%) were used to synthesise struvite. The experiments were carried out in equimolar concentrations of 0.1 M for MgCl 2 and DAP resulting in a metal-to-phosphate ratio of 1. These aqueous solutions were prepared by dissolving the calculated amount of salt in deionised water (> 18 MΩ•cm).