Osman Karatum

AbstractThe economy of southwest Florida relies heavily on beach-related tourism, which results in increasing input of sunscreen to aquatic ecosystems. This sunscreen input represents an environmental risk because sunscreens are known to negatively impact human health and aquatic ecosystems. Our estimate indicates that the water in Lee County, Florida, will receive at least 38.7 million g per year (106,000  g/day) of chemicals from sunscreens used by tourist beachgoers. We considered direct sunscreen chemical contamination, which occurs from the application of sunscreen and subsequent swimming or water activities, as well as indirect contamination, which occurs when people wash their skin in beach showers whose water then enters the drainage system. The results of this study indicate the potential loading rate of sunscreen chemicals, which is valuable in environmental risk assessments and estimating the near-shore concentrations of sunscreen chemicals in southwest Florida.

Population growth drives increasing energy demands, agricultural production, and organic waste generation. The organic waste contributes to greenhouse gas emissions and increasing landfill burdens, highlighting the need for novel closed-loop technologies that integrate water, energy, and food resources. Within the context of the Water–energy–food Nexus (WEF), wastewater can be recycled for food production and food waste can be converted into clean energy, both contributing to environmental impact reduction and resource sustainability. A novel household-scale, closed-loop WEF system was designed, installed and operated to manage organic waste while retrieving water for irrigation, nutrients for plant growth, and biogas for energy generation. The system included a biodigester for energy production, a sand filter system to regulate nutrient levels in the effluent, and a hydroponic setup for growing food crops using the nutrient-rich effluent. These components are operated with a daily batch feeder coupled with automated sensors to monitor effluent flow from the biodigester, sand filter system, and the feeder to the hydroponic system. This novel system was operated continuously for two months using typical household waste composition. Controlled experimental tests were conducted weekly to measure the nutrient content of the effluent at four locations and to analyze the composition of biogas. Gas chromatography was used to analyze biogas composition, while test strips and In-Situ Aqua Troll Multi-Parameter Water Quality Sonde were employed for water quality measurements during the experimental study. Experimental results showed that the system consistently produced biogas with 76.7% (±5.2%) methane, while effluent analysis confirmed its potential as a nutrient source with average concentrations of phosphate (20 mg/L), nitrate (26 mg/L), and nitrite (5 mg/L). These nutrient values indicate suitability for hydroponic crop growth and reduced reliance on synthetic fertilizers. This novel system represents a significant step toward integrating waste management, energy production, and food cultivation at the source, in this case, the household.

Blanket aerogels (i.e., Cabot™ Thermal Wrap® (TW) and Aspen™ Spaceloft® (SL)) with surfaces that have controllable wettability are promising advanced materials for oil recovery applications, where high oil uptake during deployment could be coupled with high oil release to enable reusability of recovered oil. The study presented here details the preparation of CO2-switchable aerogel surfaces through the application of switchable tertiary amidine (i.e., tributylpentanamidine (TBPA)) onto aerogel surfaces using drop casting, dip coating, and physical vapor deposition techniques. TBPA is synthesized via two step processes: (1) synthesis of N, N-dibutylpentanamide, (2) synthesis of N, N-tributylpentanamidine. The deposition of TBPA is confirmed by X-ray photoelectron spectroscopy. Our experiments revealed that surface coating of TBPA onto aerogel blankets was partially successful within limited set of process conditions (e.g., 290 ppm CO2 and 5500 ppm humidity for PVD, 106 ppm CO2 and 700 ppm humidity for drop casting and dip coating), but that the post-aerogel modification strategies yielded poor, heterogeneous reproducibility. Overall, more than 40 samples were tested for their switchability in the presence of CO2 and water vapor, respectively, and the success rate was 6.25 %, 11.7 % and 18 % for PVD, drop casting, and dip coating, respectively. The most likely reasons for unsuccessful coating onto aerogel surfaces are: (1) the heterogeneous fiber structure of the aerogel blankets, (2) poor distribution of the TBPA over the aerogel blanket surface.
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•CO2 switchable aerogel surfaces were prepared via application of tertiary amidine.•First study on surface modifications of blanket composite aerogels•Reversible switching from hydrophobic to hydrophilic was impacted by material structure.•It is a challenge to modify the surface of composite aerogels.

This chapter discusses the emerging and promising field of environmental applications of aerogels. Due to their large pore volume, specific surface area, and diverse range of tailorable solid-phase and surface chemistries, aerogel materials are interesting candidates for addressing many challenging environmental remediation objectives. Herein we review the use of silicate, non-silicate, and allophane-clay-based aerogels in several challenging environmental remediation applications including the removal of air pollutants, water remediation, oil spill reclamation, heavy metal capture, CO2 sequestration, trapping of pesticides, immobilization of nuclear waste, and capture of orbital space debris.

Organic UV filters are emerging contaminants with increasing evidence of their negative impact on environmental health and water quality. One of the most common and environmentally relevant organic UV filters is oxybenzone (OBZ). While much of the initial focus has been on investigating the interaction of OBZ with coral reefs, there have been several recent studies that indicate that organic UV filters are affecting other environmental endpoints, including marine animals, algae, and plants. OBZ has been found to bioaccumulate in marine animals such as fish and mussels and then potentially acting as an endocrine disruptor. In plants, exposure to OBZ has been associated with decreased photosynthesis, inhibited seed germination, and impaired plant growth. In this review, we summarize the current state of knowledge regarding the environmental impacts of OBZ and suggest potential future directions.

Artisanal and small-scale gold mining (ASGM) is a significant contributor of mercury (Hg) contamination and deforestation across the globe. In the Colorado River watershed in Madre de Dios, Peru, mining and deforestation have increased exponentially since the 1980s, resulting in major socioeconomic shifts in the region and two national state of emergency (2016 and 2019) in response to concerns for wide-scale mercury poisoning by these activities. This research employed a watershed-scale soil particle detachment model and environmental field sampling to estimate the role of land cover change and soil erosion on river transport of Hg in a heavily ASGM-impacted watershed. The model estimated that observed decreases in forest cover increased soil mobilization by a factor of two in the Colorado River watershed during the 18 year period and by 4-fold in the Puquiri subwatershed (the area of most concentrated ASGM activity). If deforestation continues to increase at its current exponential rate through 2030, the annual mobilization of soil and Hg may increase by an additional 20–25% relative to 2014 levels. While, the estimated total mass of Hg transported by rivers is substantially less than the estimated tons of Hg used with ASGM in Peru, this research shows that deforestation associated with ASGM is an additional mechanism for mobilizing naturally occurring and anthropogenic Hg from terrestrial landscapes to aquatic environments in the region, potentially leading to bioaccumulation in fish and exposure to communities downstream.

Unconventional natural gas development (UNGD) generates large volumes of wastewater, the detailed composition of which must be known for adequate risk assessment and treatment. In particular, transformation products of geogenic compounds and disclosed additives have not been described. This study investigated six Fayetteville Shale wastewater samples for organic composition using a suite of one- and two-dimensional gas chromatographic techniques to capture a broad distribution of chemical structures. Following the application of strict compound-identification-confidence criteria, we classified compounds according to their putative origin. Samples displayed distinct chemical distributions composed of typical geogenic substances (hydrocarbons and hopane biomarkers), disclosed UNGD additives (e.g., hydrocarbons, phthalates such as diisobutyl phthalate, and radical initiators such as azobis(isobutyronitrile)), and undisclosed compounds (e.g., halogenated hydrocarbons, such as 2-bromohexane or 4bromoheptane). Undisclosed chloromethyl alkanoates (chloromethyl propanoate, pentanoate, and octanoate) were identified as potential delayed acids (i.e., those that release acidic moieties only after hydrolytic cleavage, the rate of which could be potentially controlled), suggesting they were deliberately introduced to react in the subsurface. In contrast, the identification of halogenated methanes and acetones suggested that those compounds were formed as unintended byproducts. Our study highlights the possibility that UNGD operations generate transformation products and underscores the value of disclosing additives injected into the subsurface.

[Display omitted] •The treatment of 7 dilute VOCs vapors in air using non-thermal plasma was investigated.•Very fast degradation rates were obtained.•Benzene and MEK were most difficult to degrade while hexane was the easiest.•Large residual ozone concentrations were observed.•Tar-like deposits was observed when treating ethylbenzene and toluene. Non-thermal plasma (NTP) is an emerging technology for the treatment of volatile organic compounds (VOCs) in polluted point source air streams. Here, a dielectric barrier discharge NTP was used to evaluate the treatment efficiency of several common VOCs at constant experimental conditions (gas residence time of 0.016s in the plasma zone, 95–100ppmv average inlet VOC concentration in air). When treated as single pollutant with a specific input energy (SIE) of 350JL−1, the removal efficiency of the VOC followed the following sequence: methyl ethyl ketone (50%), benzene (58%), toluene (74%), 3-pentanone (76%), methyl tert-butyl ether (80%), ethylbenzene (81%), and n-hexane (90%). The effects of pollutant structure on VOC removal efficiency were investigated. The highest removal efficiencies were observed for compounds with the highest percentage of hydrogen in their molecular structures. During treatment of toluene and ethylbenzene vapors, a dark brown, tar-like deposit formed inside the plasma reactor. The deposit formation rate depended on both treated VOCs as well as on experimental conditions such as VOC concentration, and SIE.

More than 30 years separate the two largest oil spills in North American history (the Ixtoc I and Macondo well blowouts), yet the responses to both disasters were nearly identical in spite of advanced material innovation during the same time period. Novel, mechanically durable sorbents could enable (a) sorbent use in the open ocean, (b) automated deployment to minimize workforce exposure to toxic chemicals, and (c) mechanical recovery of spilled oils. Here, we explore the use of two mechanically durable, low-density (0.1-0.2 g cm(-3)), highly porous (85-99% porosity), hydrophobic (water contact angles >120 degrees), flexible aerogel composite blankets as sorbent materials for automated oil capture and recovery: Cabot Thermal Wrap (TW) and Aspen Aerogels Spaceloft (SL). Uptake of crude oils (Iraq and Sweet Bryan Mound oils) was 8.0 +/- 0.1 and 6.5 +/- 0.3 g g(-1) for SL and 14.0 +/- 0.1 and 12.2 +/- 0.1 g g(-1) for TW, respectively, nearly twice as high as similar polyurethane- and polypropylene-based devices. Compound-specific uptake experiments and discrimination against water uptake suggested an adsorption-influenced sorption mechanism. Consistent with that mechanism, chemical extraction oil recoveries were 95 +/- 2 (SL) and 90 +/- 2% (TW), but this is an undesirable extraction route in decentralized oil cleanup efforts. In contrast, mechanical extraction routes are favorable, and a modest compression force (38 N) yielded 44.7 +/- 0.5% initially to 42.0 +/- 0.4% over 10 reuse cycles for SL and initially 55.0 +/- 0.1% for TW, degrading to 30.0 +/- 0.2% by the end of 10 cycles. The mechanical integrity of SL deteriorated substantially (800 +/- 200 to 80 +/- 30 kPa), whereas TW was more robust (380 +/- 80 to 700 +/- 100 kPa) over 10 uptake-and-compression extraction cycles.