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Selective Transport of Phosphorous Through Anion Exchange Membranes

Selective Transport of Phosphorous Through Anion Exchange Membranes

David Jassby
Dept. of Civil and Environmental Engineering, University of California, Los Angeles, USA

The selective extraction of phosphorous from wastewater remains a challenge. Phosphorous, in the form of phosphate, is a valuable commodity chemical that is widely used in many industrial applications, but is particularly valuable as a fertilizer. Wastewater (municipal and certain industrial streams) is rich in phosphate, but this phosphate is largely lost in the treated effluent (i.e., discharged into the environment) or trapped in biosolids. While struvite precipitation is a viable option, it often requires the addition of magnesium and a pH adjustment. Therefore, the ability to extract phosphate from wastewater in its pure form without additional chemical modifications is an attractive target. In this presentation, we present our preliminary findings regarding the development of a phosphate-specific membrane. The membrane is based on the formation of a composite organic-inorganic framework, where the inorganic component form specific and reversible complexes with phosphate, while the organic fraction functions as an anion exchange membrane that prevents the passage of competing anions. Using this material, we demonstrate excellent selectivity towards phosphate, and propose a novel platform towards the selective extraction of other valuable compounds.