Polyamidoxime-based membranes for the rapid screening of uranium isotopes in water

Abenazer W Darge; Timothy A DeVol; Scott M Husson

doi:10.1016/j.aca.2022.339997

Polyamidoxime-based membranes for the rapid screening of uranium isotopes in water

Anal Chim Acta. 2022 Aug 8:1220:339997. doi: 10.1016/j.aca.2022.339997. Epub 2022 Jun 7.

Authors

Abenazer W Darge¹, Timothy A DeVol², Scott M Husson³

Affiliations

¹ Department of Chemical and Biomolecular Engineering, Clemson University, 127 Earle Hall, Clemson, SC, 29634, USA; Center for Nuclear Environmental Engineering Sciences and Radioactive Waste Management Center (NEESRWM), Clemson University, Clemson, SC, 29634, USA.
² Department of Environmental Engineering and Earth Sciences, Clemson University, 342 Computer Court, Anderson, SC, 29625, USA; Center for Nuclear Environmental Engineering Sciences and Radioactive Waste Management Center (NEESRWM), Clemson University, Clemson, SC, 29634, USA.
³ Department of Chemical and Biomolecular Engineering, Clemson University, 127 Earle Hall, Clemson, SC, 29634, USA; Center for Nuclear Environmental Engineering Sciences and Radioactive Waste Management Center (NEESRWM), Clemson University, Clemson, SC, 29634, USA. Electronic address: shusson@clemson.edu.

PMID: 35868695
DOI: 10.1016/j.aca.2022.339997

Abstract

Traditional radiochemistry approaches for the detection of trace-level alpha-emitting radioisotopes in water require lengthy offsite sample preparations and do not lend themselves to rapid quantification. Therefore, a novel platform is needed that combines onsite purification, concentration, and isotopic screening with a fieldable detection system. This contribution describes the synthesis and characterization of polyamidoxime membranes for isolation and concentration of uranium from aqueous matrices, including high-salinity seawater. The aim was to develop a field portable screening method for the rapid quantification of isotopic distribution by alpha spectroscopy. Membranes with varying degree of modification were prepared by chemical conversion of nitrile groups to amidoxime groups on the surface of polyacrylonitrile ultrafiltration (UFPAN) membranes. Attenuated total reflectance Fourier-transform infrared spectroscopy was used to analyze changes in surface chemistry. Flow through filtration experiments conducted using deionized (DI) water and simulated seawater solutions indicated that the modified membrane was effective in capturing more than 95% of the uranium in the solution prior to breakthrough even in the presence of salt ions. Batch uptake experiments were conducted and compared with the flow through experimental data to elucidate likely binding mechanisms. Alpha spectra of uranium loaded membranes were analyzed, and the effects of solution matrix and degree of modification on peak energy resolution were studied. Peak energy resolutions of 24 ± 2 keV and 32 ± 6 keV full width at half maximum (FWHM) were obtained by loading uranium from DI and seawater solutions onto modified membranes. Full width at 10% maximum of the same spectra were calculated to be 63 ± 9 keV and 160 ± 34 keV to quantify differences seen in peak tailing. Calculations performed based on the results show that it would take less than 3 h of analysis time to screen a sample provided enough volumes of solution are available. This work offers a facile method to prepare polyamidoxime-based membranes for uranium separation and concentration at circumneutral pH values, enabling the rapid, onsite screening of unknown samples.

Keywords: Alpha spectrometry; Functionalized membrane; Isotopic analysis; Nuclear forensics; Polyacrylonitrile.

MeSH terms

Adsorption
Hydrogen-Ion Concentration
Seawater / chemistry
Uranium* / analysis
Water / chemistry

Substances

Water
Uranium