Environmental Chemistry Letters最新文献

Traditional industrial methods of the leather industry produce toxic chromium-containing wastewater and solid wastes, calling for alternative procedures. Here, we review greener technologies to produce leather with focus on principles to design materials, high-efficiency chrome tanning, chrome-free processes, e.g., organic tanning, combination tanning, nanomaterial-based tanning, and tanning agent-free technology, as well as high-performance post-tanning using multifunctional polymers, integrated tanning-dyeing systems, and socioeconomical aspects. High-efficiency chrome tanning is done by high-exhaustion chrome tanning or inverse chrome tanning, which reduce the usage of chrome. Organic tanning employs biomass-derived and polymeric tanning agents.

The rapid development of vanadium redox flow batteries has recently boosted research in methods to obtain high-purity vanadium pentoxide, the active material of battery electrolytes. Here, we review techniques for producing high-purity vanadium pentoxide with emphasis on methods published in Chinese that are not well-known by Western academia. We describe purification methods, chlorination, and eco-friendly processes. Purification can be done by precipitation, solvent extraction, and ion exchange. We propose three viable approaches for industrialized applications.

Contamination of groundwater by microplastics is a major health concern because groundwater is a major source of drinking and agricultural water. Here, we review microplastics with focus on contamination sources, characteristics, migration, water quality, ecological and health risks, and preventive and removal strategies. Contamination sources include landfills, waste dump leachates, wastewater treatment plants, industrial waste streams, land use, agriculture, urban and residential activities, and atmospheric transport and runoff. Contamination levels reach up to 6,832 microplastics per liter of groundwater. Membrane technologies, such as microfiltration, ultrafiltration, nanofiltration, and reverse osmosis, achieve 93–99% removal of microplastics.

Climate change is increasing the frequency of extreme weather events such as vegetation fires. Vegetation fires emissions contain numerous organic compounds that impact the Earth system and human health. Here, we review the sources, stability, transport, degradation and geochemical records of levoglucosan, a dehydration monosaccharide produced by the pyrolysis of cellulose and hemicellulose. Levoglucosan has been detected in aerosols, water, snow and ice, and lake or marine sediments. Analysis of levoglucosan in environmental and geological samples enable the identification of temporal rhythms and detailed features of changes in vegetation fire patterns, ranging from individual events to seasonal to annual scales, up to glacial-interglacial cycles.

Water scarcity and wastewater pollution are major health issues, yet traditional wastewater treatment technologies are limited by high operational costs and energy demands, and membrane fouling. Here we review low-cost ceramic membranes for wastewater treatment and bioenergy production, with emphasis on bioreactors, and microbial fuel cells to generate electricity. Ceramic membranes display high filtration performance and resistance to harsh conditions, achieving water flux rates up to 250 L/m² per h, significantly outperforming polymeric membranes. Ceramic membranes are now affordable due to recent advances in as clay-based ceramics, extrusion and electrospinning. Ceramic membranes integrated into microbial fuel cells and anaerobic bioreactors could enhance power generation by 20% and biogas yield by 15–30%. Surface modifications and nanomaterial use have reduced fouling by up to 60%, yet issues of biofouling and high fabrication costs persist.

The aviation sector is a major emitter of fossil fuel-derived carbon dioxide contributing to global warming. For instance, jet fuel consumed by the aviation industry is 1.5–1.7 billion barrels per year, resulting in 705 million metric tons of carbon dioxide emissions. Aircraft manufacturers have set ambitious goals, aiming for carbon-free growth post-2020 and a 50% reduction in greenhouse gas emissions by 2030. This issue can be solved by replacing fossil fuels with biofuels produced from modern biomass, thus meeting the carbon neutral objective. Here, we review the technologies to convert biomass into jet biofuel with focus on reactants, catalysts, and the chemistry of combustion. Reactants include alcohols, oil, esters, fatty acids, gas and sugars. Catalysts include Fischer–Tropsch catalysts, palladium, platinum, ruthenium, nickel, and molybdenum. The utilization of jet biofuels could potentially reduce greenhouse gas emissions by up to 80%. We also discuss economic implications.

Biodegradable plastics have been developed as an alternative to fossil fuel-derived plastics, yet knowledge on pollution by microbioplastics has not been summarized. Here, we review microbioplastics with focus on their formation from biodegradable plastics, their mobility, distribution, impact on soils and aquatic organisms, and their management by recycling, incineration, composting, anaerobic digestion, and landfill disposal. We observe that incorporating carbon–oxygen ester linkages into the molecular backbone of biodegradable plastics, together with plant-derived additives, should enhance the usability of biodegradable plastics by augmenting thermal stability and barrier properties. Separation, recycling, and anaerobic digestion of biodegradable plastic materials should generate methane and biofertilizer.

The wide use of anticoagulant rodenticides for rat control has led to indirect poisoning of non-target birds, mammals, and vertebrates by anticoagulant rodenticides, yet contamination of insects is poorly known. We studied the behavior of two cockroach species feeding on commercial rodenticide bait formulations under laboratory conditions. Rodenticides comprised brodifacoum, difenacoum, and bromadiolone. We measured bait uptake by cockroaches, mortality, and their anticoagulant rodenticide body burden after 21 days of exposure. Results show that rodenticide residue levels in cockroaches ranged between 0.01 and 1.32 ± 0.15 µg/g dry weight. No mortality associated with rodenticide bait consumption was observed over a 21 days exposure period. Cockroaches consumed up to 50% of offered bait when attracted by this formulation, otherwise close to none. Overall, insects such as cockroaches may contribute to the environmental spread of anticoagulant rodenticides.

Per- and polyfluoroalkyl substances (PFAS) have been recently identified as contaminants of concern for human health, yet their influence of birth and child growth is not well understood, notably under gestational diabetes mellitus. Here we measured PFAS concentrations in cord blood serum of 532 mother–child pairs under gestational diabetes mellitus and in 532 pairs without gestational diabetes mellitus, by high-performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry. We analyzed birth outcomes and child growth up to two years of age using generalized linear models, generalized estimation equations, and quantile g-computation models. Results show that PFAS, including perfluorooctanoic acid, perfluorooctanesulfonic acid, perfluorohexanesulfonic acid, perfluorodecanoic acid, and 6:2 chlorinated polyfluorinated ether sulfonate, adversely affected birth outcomes. Both individual and mixed PFAS exposure delayed early child growth. Under gestational diabetes mellitus, prenatal PFAS exposure was highly associated with weight-for-length Z-scores and body mass index-for-age Z-scores.

Landfill leachate is a highly polluted wastewater resulting from the decomposition of organic waste in landfills. It contains high levels of organic matter, nitrogen, phosphorus, heavy metals, and other contaminants of environmental and health concerns, but landfill leachate could also be used to produce nutrient and energy. Here we review physical, chemical, and biological methods to treat landfill leachates. Methods include adsorption, membrane separation, coagulation and flocculation, ion exchange, air stripping, chemical precipitation, electrochemical oxidation, Fenton oxidation, ozonation, photocatalysis, activated sludge process, sequential batch reactor, rotating biological contactors, nitrification and denitrification, upflow anaerobic sludge blanket, phytoremediation, and bioremediation. We discuss the technical, social, economic and environmental benefits of removing contaminants, and of recovering nutrient and energy. Physicochemical methods remove 12–95% of chemical oxygen demand, 1–100% of ammonia nitrogen, 40–96% of metals, and 44–99% of color. Advanced oxidation processes remove 19–98% of the chemical oxygen demand, 12–85% of ammonia nitrogen, and 74–98% of total organic carbon. Biological methods remove 15–93% of the chemical oxygen demand, 43–97% of the biochemical oxygen demand, 14–100% of ammonia nitrogen, and 42–98% of phosphates. Optimized leachate treatment technology can recover 10–80% of nutrients and 0.1–7 kWh/m³ of energy.