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201388 https://hdl.handle.net/2286/R.2.N.201388 http://rightsstatements.org/vocab/InC/1.0/ http://creativecommons.org/licenses/by-nc-sa/4.0 2025-05 23 pages Park, Hannah Muhich, Christopher D'arcy, Richard Barrett, The Honors College Chemical Engineering Program Selective separation of environmentally relevant oxyanions is critical for water treatment and resource recovery. In this study, density functional theory (DFT) was used to evaluate the adsorption behavior of vanadate (H₂VO₄⁻), chromate (HCrO₄⁻), silicate (H₄SiO₄), and perchlorate (ClO₄⁻) on porphyrin derivatives. Modifications included functionalization, metalation, and a combination of both. The hypothesis posited that combining functionalization and metalation would enhance selectivity for toxic oxyanions (vanadate and chromate) over structurally similar, benign species. Binding energies revealed that functionalization alone did not improve selectivity, with silicate showing the strongest binding with an average of –0.780 eV due to extensive hydrogen bonding. Metalation significantly increased binding strength. V porphyrins in the 3+ state exhibited the following lowest binding energy values: –2.873 eV, –2.621 eV for chromate and vanadate, respectively. Selectivity, defined as a minimum of 0.1 eV difference in binding energy between target and competing adsorbates, was achieved in metallated systems, particularly for V 3+ porphyrins with chromate with a binding energy of 0.370 eV over silicate. The combination of functionalization and metalation offered minimal additional improvement over metallation. These results highlight metalation, especially with high-valent vanadium and iron, as the dominant factor in enhancing selective oxyanion adsorption, whereas functionalization contributes little additional benefit. The findings support the rational design of metalloporphyrins for targeted contaminant removal applications. Porphyrin Adsorption DFT Industrial stormwater runoff Examining modified porphyrins’ for the selective adsorption of toxic heavy metal oxyanions from water using DFT