The Future Poison: Selectively Removing Arsenate in Our Water Systems Using a Responsive Probe to Enable Environmental Phosphate Recycle Systems

Oral Presentation
2:35-2:55 p.m. CDT on April 14, 2021

Arsenic is a toxic heavy metal seen in movies like Arsenic and Old Lace, and universally recognized as a poison. While the Environmental Protection Agency regulates the concentration of a water soluble form, arsenate, in surface waters (<10 micrograms/liter for the U.S.), high levels of this anion are seen regularly in locations, such as Bangladesh. If this anion is ingested at 200 micrograms/liter, it can cause arsenicosis with symptoms ranging from headaches and diarrhea to cancer or death. With rising prices of fertilizer to feed our crops, an electronically similar anion, phosphate, is simultaneously being lost to waterways and requiring immense expenses to obtain the phosphorous rock source. This calls for a new system of recycling this resource from waterways to avoid production of toxic algae and unnecessary expenses. However, in recycling there is no guarantee that poison will not be administered to our crops as well. Our research investigates the selectivity of synthesized probes to bind arsenate over phosphate through lanthanide-based luminescent responses using hard/soft acid/base theory and “on/off” binding recognition. This ligand is structured with a portion capable of absorbing light energy and assisting in the production of fluorescent enhancement upon arsenate binding. This would be paired with a metal lanthanide to form a tunable metal complex. Lanthanides are hard metals that are good at binding hard anions, such as arsenate, and are optimal for this system as they have long luminescent lifetimes and simple electronic tunability. The metal ligand complex formed then will be tested for selectivity by measuring the fluorescence response in the presence of common biological and environmental anions. While ideally all arsenate would be removed from bodies of water, the goal is to maintain a safe concentration of arsenate. This will ensure that in recycle, arsenate will not bind as well and create a poison, so we can have clean water before phosphate recycle concentrates this similar resource and utilizes it on our food.

Natalie Smaron, Skylar Washington, Amelia Vopat, Sarah Harris, Chemistry and Biochemistry

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