Environmental remediation of surface and waste

The over-supply of phosphorus (P) primarily from wastewater discharge and agricultural runoff can lead to eutrophication in many inland and coastal waters, causing substantial detrimental environmental impact, including harmful algal blooms, fish-kills, and the formation of hypoxic “dead zones”. Over 65% of US estuaries and coastal waters now exhibit moderate to severe eutrophication, with significant ecological, industrial, and economic consequences. Removal of P from wastewater and agricultural runoff is key to mitigating eutrophication. Our overarching goal is to close the P cycle by sequestering phosphate (Pi) from polluted wastewater and waterways and recovering it as slow-release fertilizers. The ability to remove phosphate from unwanted locations and to recover it as a valuable resource for agriculture is key to the long-term sustainable use of two critical resources: water and phosphate. With this in mind, we previously designed and developed efficient inorganic receptors with high affinity for inorganic Pi that capture the anion directly in water at neutral pH, at the ppb level, and with very high selectively over competing anions such as chloride, sulfate and bicarbonate. We also developed a set of guiding principles that enable us to control and turn on and off at will the affinity of our receptor for Pi. We are now using these guiding principles to design new materials and polymers to sustainably capture and release phosphate from wastewater upon addition of an external physical or chemical stimulus.