Environmental science. Advances最新文献

Bimetallic nanoparticles provide promising active sites for many reactions, and such materials can be synthesized with different spatial distributions, such as disordered alloys, core–shell structures, and Janus-type heterogeneous structures. Catalytic activity, selectivity, and stability of bimetallic nanoparticles can be modified by the geometric, electronic, multifunctional and mixing effects, as compared with single metals. Accurate control of bimetallic compositions and their distributions is crucial to obtain high-performance catalysts. The present review summarizes the recent advances in preparation methods and catalytic applications of supported bimetallic nanomaterials. In addition, representative case studies are also provided to investigate how bimetallic nanoparticles can be used as desired catalysts and how specific functional catalysts are designed for targeted reactions. The structure–performance relationships of supported bimetallic catalysts for a number of reactions are discussed to achieve a fundamental understanding. Synthetic strategies and perspectives for precise control of bimetallic active components and element distributions with distinctive nanostructures are proposed for potential industrial applications.

Cadmium contamination of ground water and soil has drastically increased in some areas through the last few decades and remediation strategies are currently being investigated. The coupled dissolution–precipitation of calcium carbonate in cadmium-containing solutions leads to the precipitation of a (Ca,Cd)CO₃ phase of lower solubility, this process trapping cadmium from a solution into a solid phase. The present study analyses the reactions of two types of calcium carbonates (calcite as Carrara marble and aragonite) in cadmium solutions and compares the different reaction pathways and their respective efficiency. X-ray tomography scans of different Carrara marble and aragonite samples reacted in cadmium solutions for 16 to 64 days at 200 °C were acquired and analysed. The reaction in Carrara marble proceeds through a dissolution–precipitation reaction from the surface of the sample. The fluid moves through the porosity developed in the newly precipitated phase and along grain boundaries. Tomograms show that the porosity at the post-reaction time of imaging is mainly disconnected and that the reaction extent decreases with an increase in cadmium concentration of the solution. For aragonite, the main reaction pathway is opened by reaction-induced fracturing, which leads to a faster reaction than for the Carrara marble as the reaction pathways open faster towards the centre of the sample through successive hierarchical fracturing. The reaction rate for aragonite increases with time and cadmium concentration of the solution. Thus, the sequestration of cadmium from solution is potentially more efficient using aragonite due to the reaction-induced fracturing process taking place.

The prevalence of type 2 diabetes is escalating worldwide and it has been suggested that exposure to endocrine disrupting chemicals, such as phthalates, contributes to the alarming increase. Di(2-ethylhexyl)phthalate (DEHP) is used as a plasticizer in a variety of everyday products; thus humans are constantly exposed to it. Animal studies have associated DEHP with adverse health effects such as reproduction and developmental toxicity, carcinogenicity and metabolic disruption. Concerns over the potential for similar adverse effects in humans are mounting. Recent reviews have reported the link between exposure to a broad set of phthalates and diabetes as well as diabetes-related metabolic conditions. This review evaluates the available information in the literature regarding the association between DEHP exposure and type 2 diabetes and related metabolic conditions, specifically insulin resistance and obesity.

Household air pollution exposure can lead to various diseases, including stroke, ischaemic heart disease, chronic obstructive pulmonary disease (COPD), and lung cancer. In this study, an indoor air purification technique was developed employing a visible light-activated photocatalyst consisting of a WO₃/Pt-coated ceramic foam filter (CFF). Under visible light irradiation, the coated porous filter was able to decompose toluene, a prevalent indoor air contaminant. The interconnected three-dimensional structure of the CFF with open pores facilitated toluene adsorption and simultaneous decomposition by the photocatalyst. XRD analysis revealed that WO₃/Pt had tungsten oxide in a monoclinic crystal structure with immiscible platinum metal clusters. The specific surface area and pore diameter were analyzed using the BET method, while the energy band gap was determined using DRS. XRF spectroscopy was used to find the percentage composition of the material, and structural and morphological studies of the samples were conducted using TEM and FESEM analyses. Photodegradation studies were performed for toluene removal, demonstrating a significant drop in toluene concentration in a short period (99.1% degradation in 150 min). A comparative investigation of the visible light photoactivity of WO₃/Pt and TiO₂ (P25) in water was conducted utilizing dye degradation tests, and WO₃/Pt dominated with its excellent degradation efficiency.

Microplastics have raised global alarm because of their pervasiveness, potential human toxicity, and ecotoxicity. This paper reviews studies conducted on mammals and mammalian cell lines to illustrate the toxic effects of MPs and the MP levels causing or not causing an observable negative response. Most current studies in this area have been conducted on polystyrene with few studies dedicated to polyethylene and polypropylene. In vivo studies commonly use mice or rats as the experimental subjects and ingestion as the exposure mode, while in vitro studies use different types of cell lines, with intestinal cell models being the most common. The toxic effects of microplastics are size- and biomarker-dependent, with polystyrene microplastics at 1.49 × 10⁶ to 4.55 × 10⁷ particles per mouse not leading to observable negative effects but 0.01 mg day⁻¹ to 0.15 mg day⁻¹ per mouse yielding negative responses. For cell lines, polystyrene microplastics at 10 μg mL⁻¹–20000 particles mL⁻¹ did not induce negative effects but a level of 0.01 μg mL⁻¹–5000 particles mL⁻¹ caused negative effects, depending on the types of cells used. Polyethylene microplastics at 0.125 mg day⁻¹ generally could cause mice to respond negatively, whereas polypropylene microplastics at 5000 particles mL⁻¹ were observed to cause a negative response in THP-1 macrophages. The different units for the toxic doses used make comparison of the doses challenging. It is, therefore, recommended that a common unit is used in reporting the toxic levels of microplastics, particularly mg kg⁻¹–bw day⁻¹ for in vivo studies and μg mL⁻¹ or mg L⁻¹ for in vivo studies. Standardized biomarkers and bioindicators could also be used to facilitate comparison.

Ballast water released from ships into coastal environments has been identified as a mechanism that introduces contaminants of concern into coastal ecosystems. This study investigates the treatment processes employed at a ballast water treatment facility in Valdez, Alaska, that remove hydrocarbons from unsegregated ballast water. Specifically, the aim is to quantify and characterize hydrocarbons of emerging concern, known as dissolved hydrocarbon oxidation products (HOPs) and heavy metals (HMs), throughout the treatment process. Specialized analytical techniques were employed, such as non-volatile dissolved organic carbon analysis, fluorescence spectroscopy, Fourier transform-ion cyclotron resonance-mass spectrometry, and inductively coupled plasma triple quadrupole mass spectrometry. Results demonstrate that the treatment removes benzene, toluene, ethylbenzene, and xylene (BTEX) compounds, while HOPs remain. Optical and molecular analyses provide insights into the composition and transformation of HOPs, showing a shift towards more oxygenated and complex compounds during the treatment process. Quantitative analysis of 18 HMs revealed a decrease in the concentration of most dissolved HMs throughout the treatment process, with none exceeding regulatory limits. The findings highlight the need for comprehensive monitoring and regulation of ballast water treatment processes, considering the presence of HOPs and HMs. The results provide valuable insights for environmental monitoring and risk assessment in ballast water treatment, emphasizing the significance of understanding and mitigating the impacts of petroleum derived contaminants on aquatic ecosystems.

Carbon dots (CDs) have received a lot of interest in recent years because of their unique features and wide range of uses, especially in environmental research. Several reviews have already addressed different aspects of CDs, including production, optical characteristics, and applications in bioimaging and drug administration. However, there is a significant void in the research regarding CDs' full environmental potential, particularly in addressing environmental deterioration through monitoring and rehabilitation. This article separates itself by concentrating on the significance of co-formed molecules in modifying CD properties, as well as the importance of purifying methods for optimal environmental performance. Previous assessments have typically neglected how co-formed compounds during synthesis can have a significant impact on CD surface chemistry, solubility, and photoluminescence properties. This perspective delves into how tailoring the synthesis and purification of CDs can optimize them for environmental applications. The article then looks into the promising future of CDs for environmental monitoring and remediation. Their distinguishing characteristics make them appropriate for sensing applications such as fluorescence-based detection, colorimetric sensing, and electrochemical sensing. Furthermore, CDs have the potential to accelerate the breakdown of organic pollutants, hence increasing the effectiveness of environmental restoration efforts. Their vast surface area and variable surface chemistry enable the effective sorptive removal of organic and inorganic contaminants from water. Integrating CDs with membrane filtration systems improves pollutant removal efficiency. Then, we investigated the mechanisms behind the antibacterial properties of CDs. By extensively studying these issues, this paper intends to demonstrate the revolutionary potential of CDs in building a more ecologically friendly and sustainable future.

Monitoring the movement of plastic into marine food webs is central to understanding and mitigating the plastic pollution crisis. Bioindicators have been a component of the environmental monitoring toolkit for decades, but how, where, and which bioindicators are used in long-term monitoring programs has not yet been assessed. Moreover, these programs have yet to be synthesized and evaluated globally. Doing so is imperative if we are to learn from these pioneering programs and expand on their efforts. We reviewed global monitoring programs using bioindicators that focus on plastic pollution and found 11 worldwide that met our definition of long-term monitoring. Limited data availability and few programs in the Global South hinder progress on tracking global trends. Most commonly, long-term programs either tracked macroplastics with opportunistic sampling of large vertebrates or monitored microplastics with targeted sampling of invertebrates. These long-term bioindicators could be incorporated as essential ocean variables in the global ocean observing system, and thus provide critical insights into the trajectory and effects of plastic pollution on marine ecosystems. However, to enhance the effectiveness and inclusivity of these monitoring efforts, there is a pressing need for the implementation of harmonized and standardized methods, increased collaboration between regions, and greater support for data sharing and open science practices. By addressing these challenges and expanding the geographic scope of monitoring programs, we can better inform evidence-based policies and interventions aimed at mitigating plastic pollution on a global scale.

The removal of phosphates and nitrates from wastewater treatment plant (WWTP) effluents is important for preventing pollution of receiving waters. In this study, we chemically modified alkaline lignin (aLN) with quaternary ammonium groups to obtain biodegradable cationic lignin (cLN). We characterized the cLN and tested its efficacy for removing phosphates and nitrates in a lab setting and on field-collected WWTP samples. Adsorption isotherm and kinetic studies were performed in aqueous media, and the effects of several variables (contact time, pH, initial concentration, and adsorbent dose) were investigated. The Langmuir isotherm described phosphate and nitrate adsorption well, with R² values of 0.97 and 0.84, and maximum adsorption capacities of 0.59 mg g⁻¹ and 2 mg g⁻¹ respectively. For phosphate, the data fit the Freundlich isotherm model with an R² of 0.95, suggesting that both homogenous and heterogeneous adsorbent surfaces were involved in phosphate adsorption. Adsorption kinetics revealed that both phosphate and nitrate sorption onto cLN was better described by the pseudo-second-order model, with a correlation coefficient of 1. Furthermore, a 2-dimension Doehlert matrix was used to model the effect of initial concentration and adsorbent dose on the phosphate and nitrate removal. The results showed that cLN 1516 mol% was most effective for low phosphate and nitrate concentrations. With an obtained optimum adsorbent dose of 10 mg mL⁻¹, we achieved a successful reduction of nutrient loads of WWTP effluent from 0.42 mg L⁻¹ to 0.18 mg L⁻¹ (adsorption capacity of 0.6 mg g⁻¹) and from 4.1 mg L⁻¹ to 2.3 mg L⁻¹ (adsorption capacity of 4.5 mg g⁻¹), corresponding to the removal of 57.7% and 43.9% for phosphates and nitrates respectively.

Microplastics (MPs) are a class of non-degradable pollutants of global concern. MPs ubiquitously exist in the natural environment and can get inevitably transferred to the human body. Although the impacts of MPs on the ecosystem are not clearly defined yet, their toxicity to human health is becoming a concern. The complexity of MPs caused by the presence of heavy metals and organic pollution further makes it a great challenge to analyze MPs rapidly and accurately. Demanding pretreatment and insufficient data acquisition seriously hinder the precise understanding of the risk of MPs to the ecosystem and human health. Herein, this review covers recent advances in the separation of MPs, identification, and quantification methods while discussing their mechanisms and efficacy. Furthermore, this review details the use of Fourier transform infrared spectroscopy, Raman spectroscopy, and mass spectrometry for the qualitative and quantitative analysis of MPs, offering a comprehensive overview of the up-to-date strategies that overcome current technological limitations. Finally, challenges and prospective outlooks for the rapid and accurate analysis of MPs are presented.