o-Sulfonamidophenol Ligands and Derivatives for f-Element Sensing, Complexation, and Extraction from Alkaline High-Level Waste

Authors

Oluwaseun William Adedoyin, Florida International UniversityFollow

Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Chemistry

First Advisor's Name

Dr. Konstantinos Kavallieratos

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Dr. Christopher Dares

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Dr. Stanislaw Wnuk

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Dr. Raphael Raptis

Fourth Advisor's Committee Title

Committee member

Fifth Advisor's Name

Dr, Joerg Reinhold

Fifth Advisor's Committee Title

Committee member

Keywords

Sulfonamide, sulfonamidophenols, lanthanides, actinides, alkaline, high-level waste, legacy waste, Savannah river site, dodecane, ligand, solvent extraction, optical sensing, fluorescence sensing

Date of Defense

2-9-2022

Abstract

The accumulated (>100 Mgal) alkaline high-level waste (HLW), which is a legacy of nuclear weapons manufacturing during the cold war era, is an issue of environmental concern that has presented reprocessing challenges, due to its complex physicochemical properties and the presence of ¹³⁷Cs, ⁹⁰Sr, and long-lived actinides.

This study is focused on o-sulfonamidophenol derivatives bearing electron-rich O- and N- donor sites (when deprotonated in alkaline conditions) for effective complexation, sensing, and extraction of f-elements from highly alkaline solutions. Using Ln(III) as experimental surrogates for An(III), a family of o-sulfonamidophenol ligands (L1H₂ – L4H₂) bearing tert-butyl and/or isopropyl groups gave high extraction for Sm(III), with recoveries as high as 96.1 (±4.4)% and 93.3 (±5.2)% at pH 13.0 and 14.0, respectively, after just one extraction/stripping contact using CH₂Cl₂ as a diluent (Chapter 2). Using a diluent similar to those used in the waste reprocessing industry (n‑dodecane:octanol (80:20, v/v)), extraction as high as 82.6 (±9.3)% and 53.9 (±4.0)% was achieved at pH 12.5 and 14.0 respectively as well as a binding constant range of ß₂ = 3.98 (±0.01) × 10¹⁰ – 1.26 (±0.04) × 10¹² M^-2. DFT studies further suggested the likely formation of close ion pairs of type {Na[Sm(III)L₂(H₂O)_x]}_org as the extracted species. This work was expanded to even more lipophilic analogs (Chapter 3) that showed extraction even in n-dodecane with recoveries as high as 50.7 (±1.2)%. Sensing for Ln(III) in alkaline conditions was explored using dansyl (Chapter 4) and p‑nitro (Chapter 5) derivatives of our o-sulfonamidophenol framework. The dansyl derivative (Chapter 4) demonstrated fluorescent sensing along with Sm(III) recovered after extraction in CH₂Cl₂, as high as 92.2 (±13.5)% at pH 13.0. The p‑nitro derivative demonstrated µM optical sensing for Lu(III) (in CH₃CN) in the presence of competing metals which are predominant in HLW - with color change from yellow to colorless observed only in the presence of Lu(III). Lu(III) complexation was further confirmed with the isolation and X-ray characterization of two unique complexes, a monomeric (Et₃NH)₃[Lu(LH)₆] and a trimeric (Et₃NH)₅[Lu₃(µ₃-OH)₂(LH)₆(L)₃]. These results, overall, point to the potential application of easily synthesized and affordable o‑sulfonamidophenol ligands for large-scale actinide extraction and sensing from alkaline HLW.

Identifier

FIDC010520

Recommended Citation

Adedoyin, Oluwaseun William, "o-Sulfonamidophenol Ligands and Derivatives for f-Element Sensing, Complexation, and Extraction from Alkaline High-Level Waste" (2022). FIU Electronic Theses and Dissertations. 4998.
https://digitalcommons.fiu.edu/etd/4998