Date of Award

8-2026

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry and Chemical Engineering

First Advisor

M. Toufiq Reza

Second Advisor

Manolis Tomadakis

Third Advisor

Maria Pozo de Fernandez

Fourth Advisor

Spencer Fire

Abstract

The increasing generation of agricultural residues and the growing demand for sustainable chemicals and materials have intensified the interest in valorization of biomass-derived resources within a circular economy setting. Wheat bran, a major by-product of the cereal processing industry, accounting for approximately 14-30% of the wheat grain, represents an abundant and underutilized feedstock rich in phytic acid (PA, IP6), a phosphorus-containing biomolecule with applications in the food preservation, antioxidant, and flame-retardant sectors. However, conventional phytic acid recovery methods rely heavily on acid-assisted extraction processes that generate significant waste streams and environmental burdens. Therefore, the objective of this dissertation was to develop sustainable pathways for the extraction, separation, recovery, and utilization of phytic acid from wheat bran through the integration of hydrothermal processing, computational solvent design, deep eutectic solvent technologies, flame-retardant applications, and sustainability assessment. To achieve these objectives, phytic acid extraction from wheat bran was investigated using hydrothermal treatment at temperatures ranging from 75-150 °C and residence times between 1 and 48 hours. Phytic acid recovery reached approximately 9.6g/kg wheat bran at 125 °C and 6h, while thermodynamic analysis revealed that the extraction process was endothermic (ΔH = 31.81 kJ·mol⁻¹) and entropy-driven (ΔS = 81.94 J·mol⁻¹·K⁻¹). Kinetic modeling demonstrated biphasic extraction and transformation behavior, highlighting the importance of balancing extraction severity and compound stability. Besides, solid samples underwent elaborate characterization using ultimate analysis, thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR) to confirm the retention of a wheat-bran-like composition and functionality, with limited undesirable matrix alteration being observed. To further enhance phytic acid recovery, an integrated computational-experimental framework was developed for the rational design of hydrophobic deep eutectic solvents (HDES). More than 8,000 potential HDES combinations were screened using Virtual models for property Evaluation of chemicals within a Global Architecture (VEGA) toxicity models and COnductor-like Screening Model for Real Solvents (COSMO-RS) thermodynamic simulations, evaluating parameters such as activity coefficients, excess enthalpy, and intermolecular interactions. Experimental validation confirmed the computational predictions, with selected menthol-based HDES achieving phytic acid removal efficiencies exceeding 90% under mild operating conditions. The recovered phytic acid was subsequently utilized as a renewable phosphorus source for the synthesis of DES-based flame-retardant systems. The synthesized solvents exhibited densities ranging from 1260-1400 kg/m3, viscosities between 0.12 and 0.17 Pa·s, and enhanced thermal stability compared to their individual constituents. Cotton fabrics treated with phytic acid-based DES demonstrated self-extinguishing behavior and significant improvements in fire performance. Cone calorimetry revealed a reduction in peak heat release rate from 213.4 ± 1.8 kW/m2 for untreated cotton to as low as 50.3 ± 2.6 kW/m2 for treated fabrics, while char residue increased from 11.8% to 33.5% at 800 °C. Toxicity assessment using VEGA further confirmed minimal human health and environmental risks associated with the developed formulations. Finally, the technoeconomic feasibility and environmental performance of the integrated hydrothermal extraction and HDES recovery process were evaluated for a facility processing 50 tonne/day of wheat bran. Technoeconomic assessment (TEA) for the three investigated cases (Case I - 100 °C, 6h; Case II: 125 °C, 6h; Case III: 150 °C, 1h) demonstrated that all scenarios were economically viable, with the most favorable cases achieving internal rates of return exceeding 23% and breakeven periods of approximately six years. Life cycle assessment (LCA) showed that the proposed HDES-based process consistently outperformed conventional acid-assisted extraction pathways by reducing water consumption, acidification potential, and toxicity-related impacts. Overall, this dissertation demonstrates a comprehensive and sustainable framework for converting wheat bran into high-value phytic acid-based products, advancing agricultural residue valorization, green solvent design, sustainable phosphorus management, and bio-based flame-retardant technologies.

Download

Share

COinS