(112a) Phosphate Recovery By a Surface-Immobilized Cerium Affinity Peptide

Phosphorus is an essential nutrient for all living organisms, generally in the form of phosphate ions; the availability and accessibility are important to human society. Cerium oxide/hydroxide adsorbents have emerged as promising phosphate removal materials due to the excellent performance and stability. In our study, an engineered cerium affinity peptide immobilized on a metal surface was utilized to synthesize a novel, nanoscale, and bio-enabled phosphate adsorbent. The goal of this work was to characterize the binding of phosphate, and the affinity over potential competing ions to this novel material, demonstrating the potential utility of the engineered peptide in bio-templating applications. Phosphate binding and competing ion binding with time were investigated via a quartz crystal microbalance with dissipation (QCM-D). Kinetic modeling of the QCM-D data revealed that the bio-enabled material facilitated strong phosphate adsorption behavior in a wide pH range of 3–7. Changing the media from simple phosphate solutions to more complex synthetic wastewater solutions did not negatively impact the observed binding constants. The main phosphate adsorption mechanism likely followed a ligand exchange process, with enhanced adsorption performance achieved by increasing the number of surficial hydroxide groups. This strong binding behavior observed with phosphate was not observed when the material was exposed to common competing ions. Overall, our study presents a sequence-defined peptide as a promising tool for the engineering of advanced phosphate capture materials.