Unveiling the phosphate adsorption sites in a series of Zr-based MOFs by in situ HR-PXRD

The P-compounds, which contaminate fresh waters, lead to severe environmental problems. The study of specifically designed adsorbents for their efficient capture is mandatory. This experiment is meant to get structural understanding of phosphate adsorption in three different Zr-based MOFs, which have been successfully used to remove phosphate from water solutions. UiO-66 [Zr6O4(OH)4(C8H4O4)6], NU-1000 [Zr6(μ3-OH)8(–OH)8(TBAPy)2] and MOF-808 [Zr6O4(OH)4(BTC)2(HCOO)6] show different connectivity: 12-/8-/6- connected ones recpectively. HR-PXRD data at 298 K on different phosphate loaded samples [activated and moisture saturated] will allow us to unveil for the first time the host-guest interactions and to clarify the MOF connectivity and defects role, while rebuilding the adsorption curve. This experiment will allow a deeper understanding on the (PO4)3- capture and recovery process, opening the way to the design and synthesis of improved, new generation adsorbents.