Investigation of ion-selective binding equilibrium of phosphate in redox-polymeric films

Nutrients such as phosphorus (P) play an essential role as fertilizers in production of high crop yields. However, most of the P fertilizer is derived from imported phosphate rock, which are extracted from non-renewable deposits. State of the art removal and recovery systems face limitations in selectivity and regeneration, thus, there is a need to develop ion-selective systems for phosphorus recovery. We aim to investigate the behavior of selective redox-polymer interfaces in the presence of Phosphate (PO4x-) anions; in particular, we will address the following points: (i) does solvation of the anion and interface play a role in determining selectivity (e.g., solvent volume fraction entering in the film); (ii) how does polymer structure affect redox-mediated reversibility and solvation (e.g., what is the impact on solvation and ion ingression by adding/removing hydrophilic/hydrophobic moieties to the polymer structure). The flow-cell setup available at ISIS will be essential for screening of electrolytes with different phosphate concentration and pH, allowing to map the redox-polymer response to changes in electrolyte composition within the same experiment.