Identifying the iron phase and the binding mechanism responsible for phosphate binding in materials applied to reduce the phosphate loading

This proposal is related to the H2020-MSCA-ITN project P-TRAP (www.h2020-p-trap.eu). P-TRAP aims at intercepting the flux of phosphorus (P) from agricultural areas and aquatic sediments into surface waters and, by this, at improving surface water quality status. The scientific concept, unifying the individual PhD research projects in P-TRAP, is based on the naturally close coupling of the biogeochemical cycles of iron (Fe) and P in soils and sediments. In this ESRF experiment, we will focus on 2 PhD projects connected to two work packages within P-TRAP: 1) Using Fe-containing by-products from water treatment to develop filter systems to remove water at the outlet of tile drains; 2) Adding Fe-containing by-products from treating drinking water to lakes in order to reduce the internal P loading of lakes. Using the SXM we aim to unravel the connection between the formation, transformations and dissolution of solid Fe phases and its consequences for the mobility and bioavailability of P.