Biomedical Engineering ETDs

Publication Date

Summer 7-28-2026

Abstract

Contaminants regulated at trace levels, such as uranium, must be quantified at and below regulatory limits, both for regulatory compliance and environmental surveillance. However, trace measurements typically require costly laboratory instruments that limit monitoring capacity. To enable lower-cost, benchtop and field-deployable analyzers for trace contaminants, pre-concentration is needed. Here, we investigate forward osmosis (FO) for trace analyte pre-concentration. We designed and evaluated a 3D-printed batch FO cell using commercial membranes and NaCl draw solution. Performance was first validated under baseline conditions (concentrating calcium in ultrapure water): flux was ~10–11 L m⁻² h⁻¹, Ca²⁺ rejection was ≥99%, and concentration factor (CF) reached ~6× in 20 minutes with 100 ± 10% recovery. We then concentrated uranium in spiked solutions and environmental samples, from initial concentrations of ~11 and ~330 µg L⁻¹ at pH 5.5–10. Flux was stable, but CF depended strongly on pH: at 11 μg L-1 and pH 10, CF reached ~12×, but at pH 5.5, CF was only ~1.3×, likely due to lower rejection and greater adsorption of uranium at lower pH values as supported by speciation modeling. Our results also reveal a trade-off: at lower initial concentrations, CF is higher, improving analytical sensitivity – but solute flux and adsorption are also more significant, reducing uranium recovery and thus lowering analytical sensitivity.

Language

English

Keywords

forward osmosis, pre-concentration, uranium speciation, trace contaminant detection, cellulose triacetate membrane, environmental monitoring

Document Type

Thesis

Level of Degree

Masters

Department Name

Biomedical Engineering

First Committee Member (Chair)

Allyson L. McGaughey

Second Committee Member

Gabriel P. López

Third Committee Member

José M. Cerrato

Project Sponsors

National Science Foundation (Grant No. 2318897); New Mexico Water Resources Research Institute

Download

Available for download on Friday, July 28, 2028

Share

COinS