Environmental Chemistry Letters最新文献

Fiber-reinforced polymer composites, reaching a production of approximately 2.56 million tons in 2023 in Europe, display unique properties, yet they are disposed of at their end of service by conventional methods such as landfill and incineration. Here, we review the recycling of fiber-reinforced polymer wastes in the construction industry, with emphasis on fiber-reinforced polymer composites, recycling methods, and applications of carbon and glass fiber polymer composites in civil engineering. Recycling methods include mechanical, thermal, and chemical techniques. Applications comprise the use in fine fillers, coarse and fine aggregates, macro-fibers, alkali-activated materials, geopolymers, asphalt composites, and cement composites. We discuss workability, mechanical properties including compressive, flexural and tensile properties, durability, and surface modification. Future applications include three-dimensional concrete printing, self-sensing cement composites, self-heating and energy harvesting cement composites, and electromagnetic shielding. We propose a waste management hierarchy, considering the source of composites and their intended applications, to improve circularity.

Microbial electric syntrophy, involving direct electron transfer between electron-donating strains and electron-accepting strains, could reduce more than 50% of methane emissions and remove 90% of nitrate pollution in some wastewaters. Microbial electric syntrophy is also a key natural process allowing the survival of bacteria in harsh environmental conditions. Here we review natural and artificial cases of interspecies electron transfer in microbial syntrophy, with emphasis on methane production, electroactive bacteria, methanogens, anaerobic methane-oxidizing consortia, Geobacter species, phototrophic bacteria, co-cultures, anaerobic digestion, environmental remediation and microbial electrosynthesis. Environmental remediation includes nitrogen removal, reductive dechlorination and pollutant degradation. Microbial electrosynthesis can be used for carbon dioxide reduction. Conductive proteins and materials, and light-assisted electron transfer contribute to the direct interspecies electron transfer.

The circular economy requires advanced methods to recycle waste matter such as ammonia, which can be further used as a fuel and a precursor of numerous value-added chemicals. Here, we review methods for the recovery of ammonia from wastewater with emphasis on biological and physicochemical techniques, and their applications. Biological techniques involve nitrification, denitrification, and anammox processes and the use of membrane bioreactors. Physicochemical techniques comprise adsorption, membrane filtration, ion exchange, chemical precipitation, ammonia stripping, electrochemical oxidation, photocatalytic oxidation, bioelectrochemical systems, and membrane hybrid systems. We found that nitrification and anammox processes in membrane bioreactors stand out for their cost-effectiveness, reduced sludge production, and energy efficiency. The use of struvite precipitation is an efficient, environmentally friendly, and recyclable method for ammonia removal. Membrane hybrid systems are promising for ammonia recovery, nutrient concentration, and wastewater treatment, with applications in fertilizer production and water purification. Overall, nitrogen removal ranges from 28 to 100%, and nitrogen recovery ranges from 9 to 100%.

Total plastic production is expected to reach 33 billion tons by 2050, and microplastic emissions from effluents to the environment range from 0.46 million to 140 billion tons. Microplastic distribution and toxicological effects are actually poorly known. Here we review microplastic pollution with emphasis on their environmental distribution, their aging, their analysis in the environment and living organisms, their toxicity alone or combined with other contaminants, and their mitigation techniques. We present microplastic distribution in soil, water, and the atmosphere. Microplastic aging is controlled by physical, chemical, and biological factors. Model organisms of microplastic exposure include zebrafish, earthworms, Caenorhabditis elegans, and Arabidopsis thaliana. Microplastic exposure to humans could induce gastrointestinal, pulmonary, reproductive, and cardiovascular toxicity, and neurotoxicity. We discuss the combined toxicity of microplastics with organic pollutants, heavy metals, endocrine disruptors, and antibiotics. Fourier transform infrared spectroscopy and Raman spectroscopy are currently the most commonly used techniques for microplastic analysis.

The industrial laundry sector is a major user of water and chemicals such as surfactants, and one of the largest producers of wastewater. Although treated wastewaters comply with regulations, they still contain contaminants. Here we review laundry wastewater with focus on industrial laundry activities and their challenges, chemical composition of wastewater, and treatment techniques. We discuss advantages and drawbacks of treatment techniques that can be used as secondary treatment in already existing plants, or as tertiary treatment, i.e., complementary to an existing treatment. We observe that laundry is an expanding industrial sector with increasing water requirements, an abundant use of chemical substances, and increasingly stringent discharge regulations. There is a lack of chemical and biological knowledge on aqueous discharges. Moreover, the chemical composition, temporal variability, treatment information, and environmental and ecotoxicological data are poorly reported. The composition of wastewaters and additives, and their temporal variability are also poorly known. Similarly, detailed information on treatments is rare, and environmental and ecotoxicological data are poorly reported. Finding a tertiary water treatment process that is efficient, viable, and environmentally friendly is challenging since wastewater volumes are very high and contaminants are present at trace level in complex organo-mineral mixtures.

In the context of climate change and the circular economy, most municipal wastewater treatment plants are not efficient because they generate huge amount of organic sludge, which in turn requires costly post-treatment by biological processes such as anaerobic digestion. An emerging solution is to add biochar to improve anaerobic digestion efficiency by enhancing microbial activity, aiding in the breakdown of complex organic compounds, producing more biogas, and promoting overall reactor stability. Here, we review the effects of adding biochar in anaerobic digestion, with emphasis on digester performance, process stability, biochar properties, and mechanisms. We discuss methane production, lag phase, electrical conductivity, volatile fatty acids, ammonia nitrogen, pH, and oxidation–reduction potential. We also review the process inhibition by biochar addition, with focus on phenols, heavy metals and microbial composition. Biochar properties are controlled by feedstock type, pyrolysis temperature, specific surface area, electrical conductivity, carbon and mineral content, electron exchange capacity, aromaticity, and particle size. We found that 6–16 g/L biochar supplementation consistently yielded higher cumulative specific methane compared to control without biochar, across diverse conditions and substrate types. Biochar’s role is explained by four mechanisms: enhancing functional microbes, facilitating direct interspecies electron transfer, improving the degradation of refractory compounds, and increasing reactor stability.

The contamination of ecosystems by pharmaceuticals and personal care products represents a significant threat to public health, necessitating innovative approaches to clean wastewater before release into aquatic environments. Here, we review the emerging strategies and methods for the remediation of gemfibrozil and carbamazepine, emphasizing toxicological impacts, advanced oxidation processes, membrane-based removal techniques, and the underlying mechanisms driving these removal processes. We found that engineered composites with strong electron transfer capabilities can enhance the removal efficiency as they boost the generation of highly oxidative radicals. For instance, a nano zero-valent ion incorporated carbon–nitrogen composite removes 100% of gemfibrozil within 60 min. Similarly, a ruthenium perovskite-based heterogeneous catalyst achieved 100% elimination of carbamazepine in 7.5 min.

Levels of biological thiols, or “biothiols,” in mitochondria can be used to assess environmental and biological oxidative stress, which can cause health issues such as malignant tumors and neurological diseases. Here, we review fluorescent probes for detecting biothiols, targeting mitochondria, and emitting red and near-infrared light, with focus on nitrogen cation and oxonium ion units as mitochondrial biomarkers. Red-emitting and near-infrared fluorescent probes for detecting biothiols are classified according to the way they target mitochondria. We present the structure, fluorescence behavior, and biological imaging of the probes.

Exposure of wildlife to anticoagulant rodenticides from sewer baiting and bait application is poorly understood. We analyzed residues of eight anticoagulant rodenticides in liver samples of 96 great cormorants, 29 common mergansers, various fish species, and coypu, in different German regions. Results show that hepatic residues of anticoagulant rodenticides were found in almost half of the investigated cormorants and mergansers due to the uptake of contaminated fish from effluent-receiving surface waters. By contrast, exposure of coypu to rodenticides via aquatic emissions was not observed. The maximum total hepatic anticoagulant rodenticide concentration measured in waterfowl specimens was 35 ng per g based on liver wet weight. Second-generation anticoagulant rodenticide active ingredients brodifacoum, difenacoum, and bromadiolone were detected almost exclusively, reflecting their estimated market share in Germany and their continuing release into the aquatic compartment. Overall, our findings reveal that second-generation anticoagulant rodenticides accumulating in wild fish are transferred to piscivorous predators via the aquatic food chain.

The recent discovery of nanoplastics in most ecosystems is a major, yet poorly known health issue. Here, we review nanoplastics with focus on their presence in the environment, their methods of detection, and their impact on the nitrogen cycle. Nanoplastics are widely distributed in ecosystems; however, their real concentrations are not known due to the limitation of actual detection methods. Detection methods include techniques based on mass spectrometry, optical instruments, and total organic carbon. Total organic carbon-based methods involve first membrane filtration and oxidation as pretreatment, then the measurement of total organic carbon as the total concentration of nanoplastics. Total organic carbon-based methods are easy and cost-effective, compared with other methods. Nanoplastics negatively impact ecosystems and nitrogen removal. Nanoplastics can adsorb on microbial cell membranes then disrupt the membrane integrity. Nanoplastics can also induce oxidative stress. Nitrogen cycling is substantially inhibited by nanoplastics during laboratory tests.