Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that are detected ubiquitously in the aquatic environment, biota, and humans. Human exposure and adverse health of PFAS through consuming impacted drinking water is getting regulatory attention. Adsorption using granular activated carbon (GAC) and ion exchange resin (IX) has proved to be efficient in removing PFAS from water. There is a need to study the effectiveness of commercially available sorbents in PFAS removal at the pilot-scale with real PFAS contaminated water, which would aid in efficient full-scale plant design. Additionally, there is also a need to have validated bench-scale testing techniques to aid municipalities and researchers in selecting or comparing adsorbents to remove PFAS. Rapid Small-Scale Column Tests (RSSCTs) are bench-scale testing to assess media performance and operational life to remove trace organics but have not been validated for PFAS. Different design considerations exist for RSSCTs, which rely upon either proportional diffusivity (PD) or constant diffusivity (CD) dimensionless scaling relationships.

This thesis aims to validate the use of RSSCTs to simulate PFAS breakthrough in pilot columns. First, a pilot-scale study using two GACs and an IX was conducted for five months at a wellsite in central Arizona. PFAS adsorption capacity was greatest for a commercial IX, and then two GAC sources exhibited similar performance. Second, RSSCTs scaled using PD or CD relationships, simulated the pilot columns, were designed and performed. For IX and the two types of GAC, the CD–RSSCTs simulated the PFAS breakthrough concentration, shape, and order of C8 to C4 compounds observed pilot columns better than the PD-RSSCTs. Finally, PFAS breakthrough and adsorption capacities for PD- and CD-RSSCTs were performed on multiple groundwaters (GWs) from across Arizona to assess the treatability of PFAS chain length and functional head-group moieties. PFAS breakthrough in GAC and IX was dictated by chain length (C4>C6>C8) and functional group (PFCAs>PFSAs) of the compound. Shorter-chain PFAS broke through earlier than the longer chain, and removal trends were related to the hydrophobicity of PFAS. Overall, single-use IX performed superior to any of the evaluated GACs across a range of water chemistries in Arizona GWs.

Light-driven reactions can replace chemical and material consumption of advanced water treatment technologies. A barrier to light-driven water treatment is optical obstructions in aquafers (i.e. granular media) or built infrastructures (i.e. tubing) that limits light propagation from a single source such as the sun, or lamps. Side emitting optical fibers (SEOFs) can increase light distribution by > 1000 X from one-point source, but absorbance of UV light by conventional optical fibers limits their application to visible light only.

This dissertation assessed how SEOFs can enable visible through ultraviolet light-driven processes to purify water. I first used an existing visible light polymer SEOF and phototrophic organisms to increase the dissolved oxygen level of a granular sand reactor to > 15 mg DO/L. The results indicated that SEOFs successfully guide light past optical obstructions for environmental remediation which encouraged the fabrication of UV-C SEOFs for microbial inactivation.

I was the first to obtain consecutive UV-C side emission from optical fibers by placing nanoparticles on the surface of a UV transmitting glass core. The nanoparticles induced side-emission via Mie scattering and interactions with the evanescent wave. The side emission intensity was modulated by tuning the separation distance between the nanoparticle and fiber surface. Coating the fiber with a UV-C transparent polymer offered the optical fiber flexibility and prevented nanoparticle release into solution. One SEOF coupled to a 265 nm LED achieved 3-log inactivation of E. coli. Finally, a method was developed to quantify the zone of inhibition obtained by a low flux output source. By placing a SEOF connected to a UV-C LED over a nutrient-rich LB agar plate, I illustrated that one SEOF inhibited the growth of P. aeruginosa and E. coli within 2.8 cm along the fiber’s length. Ultimately this research informed that side-emitting optical fibers can enable light-driven water purification by guiding and distributing specific wavelengths of light directly to the microbial communities of interest.

Limited access to clean water due to natural or municipal disasters, drought, or contaminated wells is driving demand for point-of-use and humanitarian drinking water technologies. Atmospheric water capture (AWC) can provide water off the centralized grid by capturing water vapor in ambient air and condensing it to a liquid. The overarching goal of this dissertation was to define geographic and thermodynamic design boundary conditions for AWC and develop nanotechnology-enabled AWC technologies to produce clean drinking water.

Widespread application of AWC is currently limited because water production, energy requirement, best technology, and water quality are not parameterized. I developed a geospatial climatic model for classical passive solar desiccant-driven AWC, where water vapor is adsorbed onto a desiccant bed at night, desorbed by solar heat during the day, and condensed. I concluded passive systems can capture 0.25–8 L/m2/day as a function of material properties and climate, and are limited because they only operate one adsorption-desorption-condensation cycle per day. I developed a thermodynamic model for large-scale AWC systems and concluded that the thermodynamic limit for energy to saturate and condense water vapor can vary up to 2-fold as a function of climate and mode of saturation.

Thermodynamic and geospatial models indicate opportunity space to develop AWC technologies for arid regions where solar radiation is abundant. I synthesized photothermal desiccants by optimizing surface loading of carbon black nanoparticles on micron-sized silica gel desiccants (CB-SiO2). Surface temperature of CB-SiO2 increased to 60oC under solar radiation and water vapor desorption rate was 4-fold faster than bare silica. CB-SiO2 could operate >10 AWC cycles per day to produce 2.5 L/m2/day at 40% relative humidity, 3-fold more water than a conventional passive system.

Models and bench-scale experiments were paired with pilot-scale experiments operating electrical desiccant and compressor dehumidifiers outdoors in a semi-arid climate to benchmark temporal water production, water quality and energy efficiency. Water quality varied temporally, e.g, dissolved organic carbon concentration was 3 – 12 mg/L in the summer and <1 mg/L in the winter. Collected water from desiccant systems met all Environmental Protection Agency standards, while compressor systems may require further purification for metals and turbidity.

Iodide (I-) in surface and groundwaters is a potential precursor for the formation of iodinated disinfection by-products (I-DBPs) during drinking water treatment. The aim of this thesis is to provide a perspective on the sources and occurrence of I- in United States (US) source waters based on ~9200 surface water (SW) and groundwater (GW) sampling locations. The median I- concentrations observed was 16 μg/l and 14 μg/l, respectively in SW and GW. However, these samples were rarely collected at water treatment plant (WTP) intakes, where such iodide occurrence data is needed to understand impacts on DBPs. Most samples were collected in association with geochemical studies. We conclude that I- occurrence appears to be influenced by geological features, including halite rock/river basin formations, saline aquifers and organic rich shale/oil formations. Halide ratios (Cl-/I-, Br-/I- and Cl-/Br-) were analyzed to determine the I- origin in source waters. SW and GW had median Cl-/I- ratios of ~3600 μg/μg and median Br-/I- ratios of ~15 μg/μg. For states with I- concentration >50 μg/l (e.g., Montana and North Dakota), a single source (i.e., organic rich formations) can be identified. However, for states like California and Texas that have wide-ranging I- concentration of below detection limit to >250 μg/l, I- occurrence can be attributed to a mixture of marine and organic signatures. The lack of information of organic iodine, inorganic I- and IO3- in source waters limits our ability to predict I-DBPs formed during drinking water treatment, and new occurrence studies are needed to fill these data gaps. This is first of its kind study to understand the I- occurrence through historical data, however we also identify the shortcomings of existing databases used to carry out this study.

Connected health is an emerging field of science and medicine that enables the collection and integration of personal biometrics and environment, contributing to more precise and accurate assessment of the person’s state. It has been proven to help to establish wellbeing as well as prevent, diagnose, and determine the prognosis of chronic diseases. The development of sensing devices for connected health is challenging because devices used in the field of medicine need to meet not only selectivity and sensitivity of detection, but also robustness and performance under hash usage conditions, typically by non-experts in analysis. In this work, the properties and fabrication process of sensors built for sensing devices capable of detection of a biomarker as well as pollutant levels in the environment are discussed. These sensing devices have been developed and perfected with the aim of overcoming the aforementioned challenges and contributing to the evolving connected health field. In the first part of this work, a wireless, solid-state, portable, and continuous ammonia (NH3) gas sensing device is introduced. This device determines the concentration of NH3 contained in a biological sample within five seconds and can wirelessly transmit data to other Bluetooth enabled devices. In this second part of the work, the use of a thermal-based flow meter to assess exhalation rate is evaluated. For this purpose, a mobile device named here mobile indirect calorimeter (MIC) was designed and used to measure resting metabolic rate (RMR) from subjects, which relies on the measure of O2 consumption rate (VO2) and CO2 generation rate (VCO2), and compared to a practical reference method in hospital. In the third part of the work, the sensing selectivity, stability and sensitivity of an aged molecularly imprinted polymer (MIP) selective to the adsorption of hydrocarbons were studied. The optimized material was integrated in tuning fork sensors to detect environmental hydrocarbons, and demonstrated the needed stability for field testing. Finally, the hydrocarbon sensing device was used in conjunction with a MIC to explore potential connections between hydrocarbon exposure level and resting metabolic rate of individuals. Both the hydrocarbon sensing device and the metabolic rate device were under field testing. The correlation between the hydrocarbons and the resting metabolic rate were investigated.

Flame retardants (FRs) are applied to variety of consumer products such as textiles and polymers for fire prevention and fire safety. Substantial research is ongoing to replace traditional FRs with alternative materials that are less toxic, present higher flame retardancy and result in lower overall exposure as there are potential health concerns in case of exposure to popular FRs. Carbonaceous nanomaterials (CNMs) such as carbon nanotubes (CNTs) and graphene oxide (GO) have been studied and applied to polymer composites and electronics extensively due to their remarkable properties. Hence CNMs are considered as potential alternative materials that present high flame retardancy. In this research, different kinds of CNMs coatings on polyester fabric are produced and evaluated for their use as flame retardants. To monitor the mass loading of CNMs coated on the fabric, a two-step analytical method for quantifying CNMs embedded in polymer composites was developed. This method consisted of polymer dissolution process using organic solvents followed by subsequent programmed thermal analysis (PTA). This quantification technique was applicable to CNTs with and without high metal impurities in a broad range of polymers. Various types of CNMs were coated on polyester fabric and the efficacy of coatings as flame retardant was evaluated. The oxygen content of CNMs emerged as a critical parameter impacting flame retardancy with higher oxygen content resulting in less FR efficacy. The most performant nanomaterials, multi-walled carbon nanotubes (MWCNTs) and amine functionalized multi-walled carbon nantoubes (NH2-MWCNT) showed similar FR properties to current flame retardants with low mass loading (0.18 g/m2) and hence are promising alternatives that warrant further investigation. Chemical/physical modification of MWCNTs was conducted to produce well-dispersed MWCNT solutions without involving oxygen for uniform FR coating. The MWCNTs coating was studied to evaluate the durability of the coating and the impact on the efficacy during use phase by conducting mechanical abrasion and washing test. Approximately 50% and 40% of MWCNTs were released from 1 set of mechanical abrasion and washing test respectively. The losses during simulated usage impacted the flame retardancy negatively.

Electrospinning is a means of fabricating micron-scale diameter fiber networks with enmeshed nanomaterials. Polymeric nanocomposites for water treatment require the manipulation of fiber morphology to expose nanomaterial surface area while anchoring the nanomaterials and maintaining fiber integrity; that is the overarching goal of this dissertation. The first investigation studied the effect of metal oxide nanomaterial loadings on electrospinning process parameters such as critical voltage, viscosity, fiber diameter, and nanomaterial distribution. Increases in nanomaterial loading below 5% (w/v) were not found to affect critical voltage or fiber diameter. Nanomaterial dispersion was conserved throughout the process. Arsenic adsorption tests determined that the fibers were non-porous. Next, the morphologies of fibers made with carbonaceous materials and the effect of final fiber assembly on adsorption kinetics of a model organic contaminant (phenanthrene, PNT) was investigated. Superfine powdered activated carbon (SPAC), C60 fullerenes, multi-walled carbon nanotubes, and graphene platelets were added to PS and electrospun. SPAC maintained its internal pore structure and created porous fibers which had 30% greater PNT sorption than PS alone and a sevenfold increase in surface area. Carbon-based nanomaterial-PS fibers were thicker but less capacious than neat polystyrene electrospun fibers. The surface areas of the carbonaceous nanomaterial-polystyrene composites decreased compared to neat PS, and PNT adsorption experiments yielded decreased capacity for two out of three carbonaceous nanomaterials. Finally, the morphology and arsenic adsorption capacity of a porous TiO2-PS porous fiber was investigated. Porous fiber was made using polyvinylpyrrolidone (PVP) as a porogen. PVP, PS, and TiO2 were co-spun and the PVP was subsequently eliminated, leaving behind a porous fiber morphology which increased the surface area of the fiber sevenfold and exposed the nanoscale TiO2 enmeshed inside the PS. TiO2-PS fibers had comparable arsenic adsorption performance to non-embedded TiO2 despite containing less TiO2 mass. The use of a sacrificial polymer as a porogen facilitates the creation of a fiber morphology which provides access points between the target pollutant in an aqueous matrix and the sorptive nanomaterials enmeshed inside the fiber while anchoring the nanomaterials, thus preventing release.

Petroleum contamination is ubiquitous during extraction, transportation, refining, and storage. Contamination damages the soil’s ecosystem function, reduces its aesthetics, and poses a potential threat to human beings. The overall goals of this dissertation are to advance understanding of the mechanisms behind ozonation of petroleum-contaminated soil and to configure an effective integrated bioremediation + ozonation remedial strategy to remove the overall organic carbon. Using a soil column, I conducted batch ozonation experiments for different soils and at different moisture levels. I measured multiple parameters: e.g., total petroleum hydrocarbons (TPH) and dissolved organic carbon (DOC), to build a full understanding of the data that led to the solid conclusions. I first demonstrated the feasibility of using ozone to attack heavy petroleum hydrocarbons in soil settings. I identified the physical and chemical hurdles (e.g., moisture, mass transfer, pH) needed to be overcome to make the integration of chemical oxidation and biodegradation more efficient and defines the mechanisms behind the experimental observations. Next, I completed a total carbon balance, which revealed that multiple components, including soil organic matter (SOM) and non-TPH petroleum, competed for ozone, although TPH was relatively more reactive. Further experiments showed that poor soil mixing and high soil-moisture content hindered mass transfer of ozone to react with the TPH. Finally, I pursued the theme of optimizing the integration of ozonation and biodegradation through a multi-stage strategy. I conducted multi-stages of ozonation and bioremediation for two benchmark soils with distinctly different oils to test if and how much ozonation enhanced biodegradation and vice versa. With pH and moisture optimized for each step, pre-ozonation versus post-ozonation was assessed for TPH removal and mineralization. Multi-cycle treatment was able to achieve the TPH regulatory standard when biodegradation alone could not. Ozonation did not directly enhance the biodegradation rate of TPH; instead, ozone converted TPH into DOC that was biodegraded and mineralized. The major take-home lesson from my studies is that multi-stage ozonation + biodegradation is a useful remediation tool for petroleum contamination in soil.

Nanomaterials (NMs), implemented into a plethora of consumer products, are a potential new class of pollutants with unknown hazards to the environment. Exposure assessment is necessary for hazard assessment, life cycle analysis, and environmental monitoring. Current nanomaterial detection techniques on complex matrices are expensive and time intensive, requiring weeks of sample preparation and detection by specialized equipment, limiting the feasibility of large-scale monitoring of NMs. A need exists to develop a rapid pre-screening technique to detect, within minutes, nanomaterials in complex matrices. The goal of this dissertation is to develop a tiered process to detect and characterize nanomaterials in consumer products and environmental samples. The approach is accomplished through a two tier rapid screening process to screen likely presence/absence of elements present in common nanomaterials at environmentally relevant concentrations followed by a more intensive three tier characterization process, if nanomaterials are likely to occur. The focus is on SiO2 and TiO2 nanomaterials with additional work performed on hydroxyapatite (Ca5(PO4)3(OH)). The five step tiered process is as follows: 1) screen for elements in the sample by laser induced breakdown spectroscopy (LIBS) and X-ray fluorescence (XRF), 2) extract nanomaterials from the sample and screen for extracted elements by LIBS and XRF, 3) confirm presence and elemental composition of nanomaterials by transmission electron microscopy paired with energy dispersive X-ray spectroscopy, 4) quantify the elemental composition of the sample by inductively coupled plasma – mass spectrometry, and 5) identify mineral phase of crystalline material by X-ray diffraction. This dissertation found LIBS to be an accurate method to detect Si and Ti in food matrices (tier one approach) with strong agreement with the product label, detecting Si and Ti in 93% and 89% of the samples labeled as containing each material, respectively. In addition XRF identified Ti, Si, and Ca in 100% of food samples TEM-confirmed to contain Ti, Si, and Ca respectively. As a tier two approach, LIBS on the 0.2 micrometer filter identified nano silicon in 42% of samples confirmed by TEM to contain nano Si and 67% of TEM-confirmed samples to contain Ti. XRF identified Si, Ti, and Ca loaded on to a 0.1 µm filter and Ti in the surfactant rich phase of CPE of water and water with NOM.

Specific inorganic and organic pollutants in water (As(V), Cr(VI), THMs, and hardness) cause health concerns or aesthetic problems. The goal of this dissertation is to demonstrate novel approaches to improve the performance of point of use and municipal activated carbon processes to provide safe and reliable water to the public at distributed centralized locations.

Template Assisted Crystallization system would adjust saturation index (SI) value of TAC treated water to zero when SI value of influent water was in the range at 0.08~0.3. However, the reduction in SI when SI values were higher (e.g. 0.7~1.3) was similar to the reduction at lower SI values which could be due to limitations in kinetics or mass transfer with the template on TAC media.

Pre-chlorination prior to municipal-scale granular activated carbon (GAC) treatment was evaluated to control THM formation in distribution systems. Pre-chlorination decreased UVA, shift the dissolved organic carbon (DOC) molecular weight distribution and pre-formed trihalomethanes (THM). GAC treatment of pre-chlorinated water achieved lower THM formation in distribution systems.

To add functionality in POU systems to remove As(V) and Cr(VI), activated carbon was nano-tized to fabricate nano-enabled carbon block (CB) by (1) impregnating iron or titanium metal oxides chemically or (2) attaching titanium based P25 through electrostatic attraction force. Nanoparticle loadings of 5 to 10 wt % with respect to activated carbon enables reduction of As(V) or Cr(VI) from levels of common occurrence to below regulatory levels across carbon block designs. Minimal impacts on As(V) and Cr(VI) sorption were observed up to a nanoparticle pre-treatment temperature of 200 C, which is the temperature for CB production. Through controlling pH at 4.5 during mixing of nanoparticles with pH IEP=6 and activated carbon with pH IEP=3, electrostatic attachment of nanoparticles to activated carbon could be achieved prior to fabricating carbon block. A mini carbon block test device was designed, fabricated, and validated to mimic performances of full-scale carbon block using less volumes of test water. As(V) removal tests showed Fe impregnated CB achieved the highest As(V) removal while P25 attached CB had the lowest among three nanoparticles loaded CBs.