ACS Environmental Au最新文献

The increased presence of toxic chemicals in aquatic matrices and their associated health effects raise the need for more effective treatment technologies. The application of Fe(VI), an advanced oxidation treatment agent with disinfecting and coagulating capabilities, is limited by Fe(VI) aqueous instability. Our previous study proposed an Fe(VI)-coated sand media to overcome this constraint and demonstrated that Fe(VI)-coated sand was an effective medium for the treatment of phenolic compounds. In this study, we assessed the potential of the media for treatment of acetaminophen (ACM), benzotriazole (BZT), sulfamethoxazole (SMX), copper (Cu), lead (Pb), and zinc (Zn)─common contaminants found in wastewater effluents─in ultrapure and synthetic wastewater effluent. Fe(VI)-coated sand reactivity was influenced by the solution pH and aqueous chemistry. For example, the removal of Pb improved by 39% in the presence of trace organics, indicating that trace metal removal was enhanced by Fe(III) phases formed during Fe(VI) reactions with trace organics. While oxidation of trace organic compounds increased as pH decreased, trace metal sorption was more favorable at higher pH (i.e., pH 8 and 9). The oxidation efficiency of trace organics by the media was the highest for ACM and SMX while BZT degradation was limited due to formation of Cu–BZT complexes. Batch tests in synthetic wastewater effluent revealed that the presence of divalent cations (i.e., Ca²⁺ and Mg²⁺) can catalyze Fe(VI) self-decay and promote Fe(III) production and subsequent trace metal removal; however, oxidation of trace organics was hindered in this matrix. This study highlights the potential for Fe(VI)-coated sand application for the treatment of complex matrices more representative of natural and engineered aquatic systems.

Point-of-use (POU) water disinfection technologies can be adopted to provide access to safe drinking water by treating water at the household level; however, navigating various POU disinfection technologies can be difficult. While numerous conventional POU devices exist, emerging technologies using novel materials or advanced processes have been under development and claim to be of lower cost with higher treatment capacity. However, it is unclear if these claims are substantiated and how novel technologies compare to conventional ones in terms of cost and environmental impacts when providing the same service (i.e., achieving a necessary level of disinfection for safe drinking water). This research assessed the sustainability of four different POU technologies (chlorination using sodium hypochlorite, a silver-nanoparticle-enabled ceramic water filter, ultraviolet mercury lamps, and ultraviolet light-emitting diodes). Leveraging open-source Python packages (QSDsan and EXPOsan), the cost and environmental impacts of these POU technologies were assessed using techno-economic analysis and life cycle assessment as per capita cost (USD·cap^–1·yr^–1) and global warming potential (kg CO₂ eq·cap^–1·yr^–1). Impacts of water quality parameters (e.g., turbidity, hardness) were quantified for both surface water and groundwater, and uncertainty and sensitivity analyses were used to identify which assumptions influence outcomes. All technologies were further evaluated across ranges of adoption times, and contextual analysis was performed to evaluate the implications of technology deployment across the world. Results of this study can potentially provide valuable insights for decision-makers, nonprofit organizations, and future researchers in developing sustainable approaches for ensuring access to safe drinking water through POU technologies.

Column chromatography is a technique widely used for the purification of active pharmaceutical ingredients (APIs). One of the common solvent systems used by this technique is blends of dichloromethane (DCM) and methanol (MeOH), thereby exposing workers to health and safety risks and making the pharmaceutical sector one of the major contributors to chlorinated solvent waste. In this work, API separation and purification using several alternative safer solvent blends in column chromatography were evaluated and compared to DCM/MeOH. Ibuprofen and acetaminophen were used as model APIs, and caffeine was used as a model additive. Overall, some of the safer solvent blends tested provided better performance, with higher API recovery and purity compared to DCM/MeOH, in addition to potential health, safety, and environmental benefits. Specifically, blends of heptane/ethyl acetate and heptane/methyl acetate showed the most promise. Our work demonstrates the potential of these safer solvent blends as possible replacements for DCM/MeOH in API purification, thereby addressing a critical safety concern in the pharmaceutical industry.

While mercury occurs naturally in the environment, human activity has significantly disturbed its biogeochemical cycle. Inorganic mercury entering aquatic systems can be transformed into methylmercury, a strong neurotoxicant that builds up in organisms and affects ecosystem and public health. In the Arctic, top predators such as beluga whales, an ecologically and culturally significant species for many Inuit communities, can contain high concentrations of methylmercury. Historical mercury concentrations in beluga in the western Canadian Arctic’s Beaufort Sea cannot be explained by mercury emission trends alone; in addition, they could potentially be driven by climate change impacts, such as rising temperatures and sea ice melt. These changes can affect mercury bioaccumulation through different pathways, including ecological and mercury transport processes. In this study, we explore key drivers of mercury bioaccumulation in the Beaufort Sea beluga population using Ecopath with Ecosim, an ecosystem modeling approach, and scenarios of environmental change informed by Western Science and Inuvialuit Knowledge. Comparing the effect of historical sea ice cover, sea surface temperature, and freshwater discharge time series, modeling suggests that the timing of historical increases and decreases in beluga methylmercury concentrations can be better explained by the resulting changes to ecosystem productivity rather than by those to mercury inputs and that all three environmental drivers could partially explain the decrease in mercury concentrations in beluga after the mid-1990s. This work highlights the value of multiple knowledge systems and exploratory modeling methods in understanding environmental change and contaminant cycling. Future work building on this research could inform climate change adaptation efforts and inform management decisions in the region.

Oxygenation of aromatic and aliphatic hydrocarbons by Rieske oxygenases is the initial step of various biodegradation pathways for environmental organic contaminants. Microorganisms carrying Rieske oxygenases are able to quickly adapt their substrate spectra to alternative carbon and energy sources that are structurally related to the original target substrate, yet the molecular events responsible for this rapid adaptation are not well understood. Here, we evaluated the hypothesis that reactive oxygen species (ROS) generated by unproductive activation of O₂, the so-called O₂ uncoupling, in the presence of the alternative substrate exert a selective pressure on the bacterium for increasing the oxygenation efficiency of Rieske oxygenases. To that end, we studied wild-type 2-nitrotoluene dioxygenase from Acidovorax sp. strain JS42 and five enzyme variants that have evolved from adaptive laboratory evolution experiments with 3- and 4-nitrotoluene as alternative growth substrates. The enzyme variants showed a substantially increased oxygenation efficiency toward the new target substrates concomitant with a reduction of ROS production, while mechanisms and kinetics of enzymatic O₂ activation remained unchanged. Structural analyses and docking studies suggest that amino acid substitutions in enzyme variants occurred at residues lining both substrate and O₂ transport tunnels, enabling tighter binding of the target substrates in the active site. Increased oxygenation efficiencies measured in vitro for the various enzyme (variant)-substrate combinations correlated linearly with in vivo changes in growth rates for evolved Acidovorax strains expressing the variants. Our data suggest that the selective pressure from oxidative stress toward more efficient oxygenation by Rieske oxygenases was most notable when O₂ uncoupling exceeded 60%.

Per- and polyfluoroalkyl substances (PFAS) constitute a notorious category of anthropogenic contaminants, detected across various environmental domains. Among these PFAS, perfluoroalkyl acids (PFAAs) stand out as a focal point in discussions due to their historical industrial utilization and environmental prominence. Their extensive industrial adoption is a direct consequence of their remarkable stability and outstanding amphiphilic properties. However, these very traits that have made PFAAs industrially desirable also render them environmentally catastrophic, leading to adverse consequences for ecosystems. The amphiphilic nature of PFAAs has made them highly unique in the landscape of anthropogenic contaminants and, thereby, difficult to study. We believe that well-established principles from surface science can connect the amphiphilic nature of PFAAs to their accumulation and transport in the environment. Specifically, we discuss the role of interfacial science in describing the stability, interfacial uptake (air–liquid and solid–liquid), and wetting capability of PFAAs. Surface science principles can provide new insights into the environmental fate of PFAAs, as well as provide context on their deleterious effects on both the environment and human health.

The urgent need to address the current climate crisis has led to concerted efforts to develop low-cost and sustainable methods to remove carbon dioxide from the atmosphere. Carbon capture and storage (CCS) and negative emissions technologies (NET’s) offer the most promising paths forward to offsetting global emissions. In this study, we explore the potential of kraft lignin, a readily available biomaterial, as a low-cost alternative for the development of a CO₂ sorbent. The approach leverages the known ability of amines to reacting with carbon dioxide and forming a stable compound. Commercially available kraft lignin was modified with diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA) using a one-pot synthesis approach via the Mannich reaction. The sorbent was evaluated for porosity, accessible amine density, and nitrogen content. The CO₂ capture experiments revealed that the resulting sorbent can capture 0.80 (±0.03) mmol of CO₂ per gram of sorbent.