ACS Environmental Au最新文献

Actinides are elements that are often feared because of their radioactive nature and potentially devastating consequences to humans and the environment if not managed properly. As such, their chemical interactions with the biosphere and geochemical environment, i.e., their “biogeochemistry,” must be studied and understood in detail. In this Review, a summary of the past discoveries and recent advances in the field of actinide biogeochemistry is provided with a particular emphasis on actinides other than thorium and uranium (i.e., actinium, neptunium, plutonium, americium, curium, berkelium, and californium) as they originate from anthropogenic activities and can be mobile in the environment. The nuclear properties of actinide isotopes found in the environment and used in research are reviewed with historical context. Then, the coordination chemistry properties of actinide ions are contrasted with those of common metal ions naturally present in the environment. The typical chelators that can impact the biogeochemistry of actinides are then reviewed. Then, the role of metalloproteins in the biogeochemistry of actinides is put into perspective since recent advances in the field may have ramifications in radiochemistry and for the long-term management of nuclear waste. Metalloproteins are ubiquitous ligands in nature but, as discussed in this Review, they have largely been overlooked for actinide chemistry, especially when compared to traditional environmental chelators. Without discounting the importance of abundant and natural actinide ions (i.e., Th⁴⁺ and UO₂²⁺), the main focus of this review is on trivalent actinides because of their prevalence in the fields of nuclear fuel cycles, radioactive waste management, heavy element research, and, more recently, nuclear medicine. Additionally, trivalent actinides share chemical similarities with the rare earth elements, and recent breakthroughs in the field of lanthanide-binding chelators may spill into the field of actinide biogeochemistry, as discussed hereafter.

Microbial electrosynthesis of H₂O₂ offers an economical and eco-friendly alternative to the costly and environmentally detrimental anthraquinone process. Three-dimensional (3D) electrodes fabricated through additive manufacturing demonstrate significant advantages over carbon electrodes with two-dimensional (2D) surfaces in microbial electrosynthesis of H₂O₂. Nevertheless, the presence of oxygen-containing free acidic groups on the prototype electrode surface imparts hydrophilic properties to the electrode, which affects the efficiency of the two-electron oxygen reduction reaction for H₂O₂ generation. In this study, we elucidated that the efficiency of microbial H₂O₂ synthesis is markedly enhanced by utilizing oxygen-free 3D electrodes produced via additive manufacturing techniques followed by surface modifications to eradicate oxygen-containing functional groups. These oxygen-free 3D electrodes exhibit superior hydrophobicity compared to traditional carbon electrodes with 2D surfaces and their 3D printed analogues. The oxygen-free 3D electrode is capable of generating up to 130.2 mg L^–1 of H₂O₂ within a 6-h time frame, which is 2.4 to 13.6 times more effective than conventional electrodes (such as graphite plates) and pristine 3D printed electrodes. Additionally, the reusability of the oxygen-free 3D electrode underscores its practical viability for large-scale applications. Furthermore, this investigation explored the role of the oxygen-free 3D electrode in the bioelectro-Fenton process, affirming its efficacy as a tertiary treatment technology for the elimination of micropollutants. This dual functionality accentuates the versatility of the oxygen-free 3D electrode in facilitating both the synthesis of valuable chemicals and advancing environmental remediation. This research introduces an innovative electrode design that fosters efficient and sustainable H₂O₂ synthesis while concurrently enabling subsequent environmental restoration.

Mineral scale formation reduces the heat transfer efficiency and clogs pipes and valves, increasing power consumption. To address the environmental concerns of conventional scale inhibitors, this paper explores biodegradable and eco-friendly alternatives. It examines the effects of organic additives on calcium (Ca) and magnesium (Mg) scaling in water vaporization. Batch experiments were conducted with potable water and various organic molecules (saponin, caffeine, tannic acid, dextran, citrus pectin, Ficoll 400, and Triton X-100). Saponin showed the highest calcium scale inhibition efficiency (60.9%) followed by caffeine (49.6%) and tannic acid (39.6%), while Ficoll 400, pectin, and Triton X-100 were less effective. For the magnesium scale, caffeine was the most effective (97.4%) followed by saponin (88.6%) and tannic acid (67.1%). Inhibition efficiencies for magnesium-containing scales were generally higher than those for calcium scales. Regarding the inhibition mechanisms, saponin, caffeine, dextran, and tannic acid adsorbed onto mineral crystal growth sites according to the Langmuir model, while pectin, Triton X-100, and Ficoll 400 formed complexes with Ca²⁺ and Mg²⁺ in solution. Needle-like aragonite was the predominant form of calcium carbonate (CaCO₃) with the most additives, except tannic acid, which produced rhombohedral calcite, and caffeine, which promoted flower-like vaterite CaCO₃ crystallites. Saponin, caffeine, tannic acid, and dextran are effective, biodegradable, and environmentally friendly inhibitors for mineral scaling.

The global challenge of water scarcity has fueled significant interest in membrane desalination, particularly reverse osmosis (RO), for producing fresh water from various unconventional sources. However, mineral scaling remains a critical issue that compromises the membrane efficiency and lifespan. This study explores the use of naturally occurring proteins to develop scaling-resistant RO membranes through an eco-friendly modification method. We systematically evaluate three protein modification techniques, namely, polydopamine (PDA)-assisted coating, protein conditioning, and protein drying, for fabricating membranes resistant to gypsum scaling. Protein conditioning is found to be the most effective approach, resulting in protein-decorated membranes with an exceptional resistance to gypsum scaling. We also demonstrate that a hydrated protein layer is essential for optimal scaling resistance. To further understand the mechanism underlying the scaling resistance of protein-decorated membranes, five proteins (i.e., bovine serum albumin, casein, lactalbumin, lysozyme, and protamine) with distinct physicochemical properties are used to explore the key factors governing membrane scaling resistance. The results of dynamic RO experiments indicate that the molecular weight of proteins plays a crucial role, with higher molecular weights leading to higher membrane scaling resistance through steric effects. However, static experiments of bulk crystallization highlight the importance of electrostatic interactions, where proteins with more negative charge delay gypsum crystallization more effectively. These findings suggest the difference between gypsum scaling in the RO and gypsum crystallization in bulk solutions. Overall, this research offers a novel approach to developing resilient and sustainable RO membranes for the desalination of feedwater with high scaling potential while elucidating mechanistic insights on the mitigating effects of protein on gypsum scaling.

Current strategies to assess water quality are ineffective at prioritizing the most toxic chemicals within a treated water sample. Although it is well known that oxidation byproducts (OBPs) from water treatment processes (e.g., chlorination and ozonation) are linked to adverse health outcomes such as skin diseases, reproductive toxicity, and various cancers, we are still unable to account for a large fraction of the toxicity drivers. Previous approaches utilize in vitro or in vivo assays to assess OBPs on an individual basis, which is too time- and resource-intensive considering the countless number of transformation byproducts of unknown toxicities that exist in treated waters. In vitro assays have also been developed to analyze the toxicity of OBPs in environmental mixtures, but these approaches do not provide identification information about the responsible toxicants. Furthermore, an additional challenge for OBP detection arises during the extraction and detection stages of analysis, as certain OBPs are typically lost using traditional extraction methods or are not detectable via liquid-chromatography–high-resolution mass spectrometry (LC-HRMS) without derivatization. To address these issues, we have developed the analytical assay Solid-Phase Reactivity-directed Extraction (SPREx), which aims to provide an all-in-one evaluation for (i) in chemico toxicity screening, (ii) extraction, (iii) detection, and (iv) identification via LC-HRMS. The performance of SPREx was evaluated by testing different nucleophile probes for the capture and detection of 24 different carbonyl compounds, which serve as model electrophiles and are known OBPs that provide unique extraction and detection challenges. SPREx provided distinct advantages for extraction recoveries and was an effective screening tool for carbonyl detection and quantification in complex water matrices such as drinking water and wastewater.

Phosphorus is a nonrenewable resource, yet an essential nutrient in crop fertilizers that helps meet growing agricultural and food demands. As a limiting nutrient for primary producers, an excess amount of phosphorus entering water sources through agricultural runoff can lead to eutrophication events downstream. Therefore, to address global issues associated with the depletion of phosphate rock reserves and minimize the eutrophication of water bodies, numerous studies have investigated the removal and recovery of phosphates in usable forms using various chemical, physical, and biological methods. This review provides a comprehensive and critical evaluation of the literature, focusing on the widely employed adsorption and chemical precipitation for phosphate recovery from various wastewaters. Several experimental performance parameters including temperature, pH, coexisting ions (e.g., NO₃^–, HCO₃^–, Cl^–, SO₄^2–), surface area, porosity, and calcination are highlighted for their importance in optimizing adsorption capacity and struvite crystallization/precipitation. Furthermore, the morphological and structural characterization of various selected adsorbents and precipitated struvite crystals is discussed.

Constructed wetlands are artificial ecosystems designed to replicate natural wetland processes. Microbial communities play a pivotal role in cycling essential elements, particularly sulfur, which is crucial for trace metal fixation and remobilization in these ecosystems. By their response to their environment, microbial communities act as biological indicators of the wetland performance. To address knowledge gaps pertinent to the changes in trace metal bioavailability in relation to microbial activities in the H-02 constructed wetland, we performed this study to investigate temporal and spatial variations in microbial communities by using molecular biology tools. Quantitative polymerase chain reaction and next generation sequencing techniques were employed to analyze archaeal and bacterial groups associated with sulfur and methane cycling. Alpha diversity indices were used to assess species richness, evenness, and dominance. Results indicated high gene abundance of Desulfuromonas (5.37 × 10⁶ g.cell^–1), methane oxidizing bacteria (6.92 × 10⁶ g.cell^–1), and methanogenic microorganisms (3.02 × 10⁵ g.cell^–1) during cool months. Warm months were marked by sulfate reducing bacteria dominance (3.31 × 10⁶ g.cell^–1), potentially due to competitive interactions and environmental conditions, higher temperatures, and lower redox potential. Spatial variability among microbial groups was insignificant, but trends in gene abundance indicated complex factors influencing these groups. Next generation sequencing data demonstrated Firmicutes as the most abundant phylum with over 50% regardless of the season or sampling location. Cool months exhibited higher alpha diversity than warm months. Overall, this study showed that seasonal changes significantly impacted the microbial communities in the H-02 constructed wetland that are associated with the sulfur cycle and eventually trace metal biogeochemistry, revealing two distinct mechanisms of the sulfur cycle between the two main seasons, whereas spatial variability effects were not conclusive.