Environmental Chemistry Letters最新文献

Low-quality cotton fibers are a low-value waste material within the cotton industry. Upcycling and transforming into high-value materials are highly desired. This study investigates upcycling fibers into hydrogel biosorbents and assesses their efficacy in dye adsorption. An effective gelation approach was employed via simply dropping droplets of suspension mixture of sodium alginate and fibers into acidic bath. Resulting composite hydrogel beads were utilized for dye removal. Composite beads successfully immobilized less than 70 wt% of fibers and achieved a significant improvement in thermal stability. Composite beads with 50 wt% fibers and alginate showed no decrease in methylene blue adsorption capacity. This outcome was unexpected considering the lower dye adsorption capacity of fibers than alginate, particularly notable since it indicated that reduced quantities of the more costly sodium alginate were sufficient to achieve comparable dye adsorption capacity. Mechanistic study unveiled that both the loose crosslinking structure and the electrostatic forces were responsible for the unexpected high adsorption capacity of 50% fiber-alginate. This study reports a promising, innovative and effective upcycle strategy for the first time that can transform fibers into high-value biosorbents without compromising dye adsorption capability.

Traditional building materials have some drawbacks in the construction industry, particularly in terms of greenhouse gas emissions and energy consumption. Biomaterials derived from renewable sources are a promising alternative, significantly reducing the greenhouse effect and enhancing energy efficiency. However, traditional materials still dominate the construction sector, and there is a lack of understanding among some policymakers and developers regarding biomaterials. Here, we review building biomaterials and their policies and life cycle assessment through case studies. Bio-based materials have the potential to reduce over 320,000 tons of carbon dioxide emissions by 2050. They also exhibit advantages like decreasing water absorption by 40%, reducing energy consumption by 8.7%, enhancing acoustic absorption by 6.7%, and improving mechanical properties. We summarize recent advancements in mycelial materials, bioconcrete, natural fibers, and fiber-reinforced composites. We also explore the contributions of nanotechnology and microalgae technology in enhancing biomaterials' thermal insulation and eco-friendliness.

Migration of microplastics in porous media is an important, yet overlooked phenomenon because most microplastic research has focused mainly on microplastic behavior in aquatic environments. Here we review experimental advances of microplastic migration in porous media, with emphasis on factors influencing microplastic migration. We observed that microplastic migration is influenced by environmental factors and microplastic properties. The effect of microplastic surface charge and functional groups, and of soil organisms on microplastic migration is unclear. Research at the macro-scale, higher than 1 m, predominantly starts with field sampling, and then carries out measurements or mathematical modeling to explore migration patterns. At the meso-scale, below 1 cm, studies often employ filled sand columns as proxies for porous media to generate breakthrough curves and retention profiles. At the micro-scale, below 1 mm, visualization of microplastic migration in pores is done by lab-on-a-chip devices to build transparent micromodels. Current research predominantly relies on industrially produced regular spherical microplastics, with limited focus on macro- and micro-scale studies.

Excessive carbon dioxide (CO₂) emission has caused problems associated with environmental pollution and climate deterioration. As a consequence, the selective conversion of CO₂ into liquid fuels by artificial photosynthesis has gained increasing attention. However, the rational design of photocathode to achieve selective CO₂ photoelectroreduction is challenging. Here, we sensitized cuprous oxide (p-nCu₂O) loaded on hydroxyl iron oxide (FeOOH) with cobalt-doped cadmium sulfide (Co:CdS) quantum dots to prepare a novel photocathode FeOOH/p-nCu₂O/Co:CdS by sequential electrodeposition and chemical bath deposition. The composite photocathode exhibited a larger photovoltage, which is 1.9 times higher than the pristine counterpart, and was efficient for CO₂ reduction to produce formic acid with high selectivity of up to 82.9% (Faradaic efficiency). Theoretical calculations revealed that the photocathode out-layer Co:CdS quantum dots had increased binding energy toward the key intermediate *OOCH through additional hybridization orbitals to exclusively favor the formation of formic acid. An impurity energy level was revealed to form by doping Co to the CdS-containing composite, which could reduce the photocathode band gap with improved absorption toward visible light, thus remarkably increasing the photoelectrochemical properties. This is the first work undertaking the energy band structure optimization of the photocathode enabled by elemental doping to improve its photoelectrocatalytic performance.

Nanomaterials have been rapidly developed during the last decades, yet many nanoparticles synthesized by classical methods are toxic and their synthesis procedure is not sustainable. Here we review the green synthesis of nanoparticles from biomass and waste with a focus on synthetic mechanisms and applications in energy production and storage, medicine, environmental remediation, and agriculture and food. Biomass use for synthesis include microorganisms, fungi, plants, and agro-industrial bio-waste. Compared to conventional synthesis, green synthesis allows a 30% reduction in energy consumption, cost savings of up to 40%, and a 50% increase in production output. Biomedical applications comprise antibacterials, anticancers, antioxidants, and drug delivery mechanisms. Carbon quantum dots and photovoltaics are discussed in the energy section. Agricultural and food applications focus on nanofertilization, pest control, and food quality. Environmental remediation includes water and soil purification.

Polycyclic aromatic hydrocarbons (PAHs) are present in the environment due to both natural sources and human activities. They are abundant and resistant to decomposition. Humic substances, depicted as a significant component of soil organic matter, can influence the effectiveness of PAHs bioremediation in contaminated environments. We review bioremediation studies on soil contamination with PAHs in the presence of humic substances in reports published from 2000 to 2023. Around 36% of the studies indicated that the presence of humic substances enhances the bioavailability and biodegradation rate of PAHs in soils and sediments. This enhancement is attributed to the surfactant properties of humic substances, particularly humic acids, which display a micellar microstructure. In contrast, approximately 19% of the studies suggested that humic substances could diminish the bioavailability and biodegradation rate of PAHs due to the sequestration of PAHs within humic substances. Moreover, the impact of humic substances on the bioavailability of PAHs seems to be concentration-dependent. Humic acidx can function as a carrier for PAHs, aiding in their transfer to bacterial cells. In contrast, humin, a substantial component of soil organic matter, has the ability to adsorb more PAHs, potentially resulting in their long-term aging.

Microplastics have multidimensional traits, as compared to other emerging contaminants, presenting a concern to terrestrial, aquatic life and humans through inhalation or ingestion. Hazardous chemicals adsorbed on microplastics could potentially be transferred to the environment or consumed by living organisms. We review the transformation of plastic waste in the environment, the origin and transportation of microplastics, the regulatory measures for plastic and microplastic pollution, and the fate of microplastics in wastewater treatment plants. Plastic debris is building up in the environment despite legislative attempts by many countries. Accumulated plastic waste from a range of sources breaks down into smaller fragments and microplastics through chemical, physiochemical and biodegradation mechanisms. This review also discusses personal protective equipment in relation to COVID-19 as a source of microplastics. Millions of microplastics are discharged into the environment through effluents and biosolids. Daily microplastic emissions to the environment from effluent range about 0.46 million to 140 billion. Previous studies had only explored the existence of microplastics in wastewater treatment plants, with limited visualization of how microplastics interact with the various treatment technologies used in wastewater treatment plants.

Rainfall and land-use interactions drive temporal shifts in suspended sediment sources, yet the magnitude of such changes remains poorly understood due to the lack of land-use specific source tracers. We investigated α,ω-dicarboxylic fatty acid root-specific biomarkers, as diagnostic tracers for apportioning sources of time-integrated suspended sediment samples collected from a grassland dominated agricultural catchment in the southwest of England during the wet winter period. Applying fatty acids-specific stable carbon isotope analysis and a Bayesian isotope mixing model, we show that stream banks contributed most of the sediment in the early winter, i.e. October–December, while winter cereal-dominated arable land contributed more than half of the sediment during the late winter, i.e. January–March. The dominant sediment source shifted in conjunction with a period of prolonged consecutive rainfall days in the later period suggesting that intervention required to mitigate soil erosion and sediment delivery should adapt to changing rainfall patterns. Our novel findings demonstrate that isotopic signatures of α,ω-dicarboxylic fatty acids are promising tracers for understanding the resistance of agricultural soils to water erosion and quantifying the interactive effects of extreme rainfall and land use on catchment sediment source dynamics.

Human exposure to environmental arsenic induces cardiovascular diseases such as arrhythmias, hypertension, and arteriosclerosis. Here, we review the toxicological and cardiovascular impacts of arsenic in in vitro cardiac and vascular models. The mechanism of arsenic-induced cardiovascular impairments includes oxidative stress, epigenetic modifications, chromatin instability, subcellular damage, and premature aging. The different types of cardiac and vascular cells exhibit distinct responses to arsenic exposure. Arsenic causes arrhythmias, which involve alteration of cardiomyocyte potassium channels and, in turn, repolarization issues. This is mainly due to redox signals that cause epigenetic modifications of potassium channels. On the other hand, vascular lesions, such as damage to blood vessels, occur mainly due to an imbalance in redox levels. This imbalance leads to premature senescence of cells and stop the cell cycle. Furthermore, intracellular accumulation of calcium and ferrous ions plays a major role in arsenic-induced vascular cell apoptosis and cardiomyocyte ferroptosis, respectively.

Algae play a vital role in aquatic ecosystems, contributing to oxygen production and serving as a foundational component of the food chain. Environment stress and contamination can lead to harmful algal blooms, depleting oxygen levels and creating dead zones in water bodies. When exposed to contaminants such as industrial chemicals, pharmaceuticals, pesticides, heavy metals, and synthetic nano/microparticles, algae can exhibit adverse responses, disrupting the balance of aquatic ecosystems. Furthermore, environmental issues related to ecotoxicology responses of algae include the disruption of biodiversity and the loss of crucial habitats, which can lead to health issues. We reviewed the response of algae exposed to contaminants in the aquatic environments, including ecotoxicology and environmental stresses. The major points are: (1) The accumulation of polycyclic aromatic hydrocarbons in food chains and ecosystems and their uptake is widely revealed as a major concern for environmental health and human beings. (2) Bisphenol A can negatively impact algae by inhibiting biochemical and physiological processes, in which half maximal effective concentration varies from 1.0 mg L^-1 to 100 mg L^-1. (3) Though the level of per- and polyfluoroalkyl substances in the environment is generally low, ranging from ng L^-1 to mg L^-1, the combined contaminant exposure leads to significantly more significant toxic effects than individual compounds. (4) An exposure level of 1000ng L is unsafe for the ecosystems, and per- and polyfluoroalkyl substances could lead to algal growth inhibition, e.g., damage to the photosynthetic, inhibition of deoxyribonucleic acid replication, and reactive oxygen species metabolism. (5) The ecotoxicity of chemicals to algae is influenced by chemical, biological, and physical factors, creating complex effects at the biological community level. (6) This research indicated the importance of the ecotoxicology response of algae to contaminants, emphasizing the necessity for monitoring and strategic interventions to protect the sustainability of aquatic ecosystems.