Theses and Dissertations

ORCID

0000-0002-3842-0217

Advisor

Mlsna, Todd

Committee Member

Pittman Jr., Charles

Committee Member

Wipf, David

Committee Member

Stokes, Sean

Date of Degree

8-12-2026

Original embargo terms

Immediate Worldwide Access

Document Type

Dissertation - Open Access

Major

Chemistry

Degree Name

Doctor of Philosophy (Ph.D.)

College

College of Arts and Sciences

Department

Department of Chemistry

Abstract

Hydrosphere decontamination and sustainable agriculture are economic, health, and environmental concerns. Conventional non-destructive and destructive water treatment methods, and fertilizer formulations, can be expensive or ineffective. Biochar-nutrient composites have gained global acceptance as adsorbents or soil additives due to biochar’s modifiable surfaces, enabling enhanced performance and environmental benefits. This dissertation studied sustainable methods for removal of aqueous arsenic(V) by adsorption and destruction of per- and polyfluoroalkyl substances (PFASs) in liquid ammonia by defluorination and fertilizing phosphorus-deficient soil. Chapter II focuses on the surface morphological and physicochemical changes in alkali-exposed microparticulate magnetite-deposited rice husk (RH) biochar (Fe3O4@RHBC) relative to its pristine biochar (RHBC) to improve aqueous As(V) adsorption. Detailed adsorbent characterizations were employed using SEM, TEM, XPS, XRD, surface area, pore size, and pore volume measurements, and elemental analyses. Furthermore, RH/RHBC silica-to-silicate transformation, which might occur during exposure to strong bases during biochar modification, was investigated using FT-IR and XPS. Chapter III advances early proof-of-concept development of a dual-mode controlled-release fertilizer that combines the benefits of Ca3(PO4)2-amended Douglas fir biochar (PBC) with a modified calcium alginate hydrogels (CA@PBC) to extend nutrient release and enhance crop production. Batch and fixed-bed column nutrient-leaching experiments were employed to assess the release performance of these fertilizers. Greenhouse pot trials were conducted with a corn crop, comparing plant growth in soil amended with CA@PBC, PBC, BC, and the triple superphosphate (TSP) reference fertilizer, versus unamended soil. Batch and fixed-bed column nutrient-leaching studies also demonstrated the potential of CA@PBC as a controlled-release phosphate fertilizer. Chapter IV extends the solvated-electron reductions in liquid ammonia to defluorinate various model PFASs. In this study, PFOA, PFOS, NFBA, and GenX were individually dissolved in liquid NH3, followed by adding metallic Na or Ca to totally mineralize all PFASs’ fluorines. These defluorinations sought to demonstrate defluorination as a function of PFAS conversion, in terms of Na and Ca consumed per mol of fluoride mineralized. Future research aims to remove PFAS from water using commercial PFAS adsorbents like granular activated carbon (GAC) and defluorinate all the adsorbed PFAS by stirring wet GAC in liquid NH3, in the presence of Na and Ca.

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