Timothy S. Goebel^1,2, Kevin J. McInnes¹, Scott A. Senseman³, Robert J. Lascano¹, Alex M. Cullen⁴, Timothy J. Fuhrer⁵, Sarah Pickle⁶, Netochi O. Adeolokun⁶, Todd A. Davis⁴

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¹ USDA Wind, Erosion and Water Conservation Unit, Lubbock, TX, USA.
² Department of Soil and Crop Sciences, Texas A & M University, College Station, TX, USA.
³ Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.
⁴ Department of Chemistry, United States Air Force Academy, USAF Academy, Colorado Springs, CO, USA.
⁵ Department of Chemistry, Radford University, Radford, VA, USA.
⁶ Department of Chemistry, Idaho State University, Pocatello, ID, USA.
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Abstract: Inorganic phosphate is a common nutrient that is applied as a fertilizer to both agricultural fields as well as urban settings such as private yards, public parks and other urban landscaping. While phosphate typically binds tightly to soil, movement of phosphate off of application sites can occur through soil erosion. The soil and its bound phosphate can then end up in surface waters such as rivers and lakes. Phosphate found in surface water bodies exists both as bound to the suspended clay as well as that free in solution. Elevated phosphate concentration in surface waters can lead to algal blooms and eutrophication. While the phosphate bound to clay in suspension in surface water bodies can be removed by commercially available polymer flocculants, the phosphate that is free in solution is more challenging as it is usually found in low concentrations and other anionic salts are generally present in higher concentrations. To remove phosphate from contaminated water systems, where other anions exist at higher concentrations, it is favorable to have a method of removal that is selective for phosphate. As a proof of principle, thiourea derivatized polymer flocculants were examined for the selective removal of phosphate in the presence of competing anions. The polymer flocculants exhibited selectivity for phosphate through hydrogen bonding and were effective at removing up to 43% of phosphate from simulated wastewater. Computational studies and ¹H NMR were used to investigate the selectivity of the thiourea monomer for phosphate over competing anions such as chloride and sulfate.

Keywords: Molecular Recognition, Thiourea, Polymers, Flocculants, Phosphate

Cite this paper: Goebel, T. , McInnes, K. , Senseman, S. , Lascano, R. , Cullen, A. , Fuhrer, T. , Pickle, S. , Adeolokun, N. , Davis, T. (2020) Addition of Thiourea Host Monomer to Polymer Flocculants to Improve Selectivity of Phosphate Sorption. Journal of Agricultural Chemistry and Environment, 9, 147-158. doi: 10.4236/jacen.2020.93013.

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