Environmental Chemistry Letters最新文献

Polystyrene microplastics, especially those smaller than 10 μm, reduce male fertility in murine models, but whether they affect male reproduction in humans is poorly understood. Here, we studied polystyrene microplastics smaller than 10 μm in human semen samples and evaluated their toxicity to human sperm. We also tested the use of magnetic iron oxide nanoparticles to remove nanoplastics and decrease their toxicity in human sperm. Results show that human semen is contaminated by approximately 3.57 ± 0.32 μg/mL polystyrene microplastics smaller than 10 μm. Polystyrene nanoplastics of 25–100 nm penetrate and damage human sperm at semen-relevant concentrations of 5 and 50 μg of nanoplastic per mL, while 0.5–10 μm polystyrene microplastics bind to the sperm. We also found that 25-nm polystyrene nanoplastics exhibited a synergistic toxicity with bisphenol A on human sperm. Nonetheless, we observed that environmental microplastics released from disposable paper cups do not pose a significant hazard to human sperm under our conditions. Furthermore, magnetic iron oxide nanoparticles can aggregate and coprecipitate with 25-nm polystyrene nanoplastics to eliminate their adverse effects on human sperm.

Some pharmaceutical and personal care products, including endocrine disruptors, are polluting ecosystems, thus requiring advanced materials and methods for detection and remediation. Here we review carbon nanotubes for detection and remediation of pharmaceutical and personal care products, with focus on green synthesis of hybrid carbon nanotubes, removal of pollutants, and deep learning networks to predicts adsorption. Pollutants include bisphenol, phthalates, tetracycline, and ciprofloxacin. We found that magnetic carbon nanotubes are easily recovered from water with a relatively low production cost. Functionalized carbon dots/carbon nanotube hybrids can detect ciprofloxacin contamination at 0.001 mg/L. Some studies report the adsorption of 95% or the photocatalytic degradation of 100% of pollutants using magnetic carbon nanotubes.

The use of fossil fuels has been essential to the development of society, but has also contributed partly to global warming. For example, carbon dioxide emissions from fossil fuels and industries have increased by 60% since 1990, calling for the recycling of modern biomass in the context of a carbon neutral economy. Here we review the hydrothermal conversion of biomass into biofuels, chemicals and biomaterials with emphasis on subcritical water properties, hydrolysis of biomass, steam explosion, fractionation, carbonization, liquefaction, gasification, and fractionation of bio-oil. We observe that hydrothermal conversion of biomass in the presence of water at subcritical conditions produces value-added compounds with high process efficiency. Subcritical water allows rapid reaction rates, low mass transfer resistance, and gas-like diffusivity.

1.6 Million metric tons of spent carbon electrodes modify carbon-rich solid wastes from aluminum electrolysis are produced annually, threatening ecosystems by cyanide and fluoride pollution. Here, we review carbon-rich solid wastes with focus on sources and hazards, detoxification, separation, recovery, recycling and disposal. Treatment techniques include roasting, calcination, vacuum distillation, flotation, water leaching, acid leaching, alkali leaching, complexation leaching, and alkali fusion. Waste can be disposed of alone or in combination with other waste such as cooper slag, sludge, red mud, and coal gangue. Recovery of fluorides and applications of recycled carbon are presented. Fluoride and carbon materials are separated based on differences in hydrophobicity, volatility, flammability, acidity, and alkalinity. The fluorides prepared from the solution are mainly aluminum hydroxyfluoride hydrate and cryolite.

The access to clean and drinkable water is becoming one of the major health issues because most natural waters are now polluted in the context of rapid industrialization and urbanization. Moreover, most pollutants such as antibiotics escape conventional wastewater treatments and are thus discharged in ecosystems, requiring advanced techniques for wastewater treatment. Here we review the use of artificial intelligence and machine learning to optimize pharmaceutical wastewater treatment systems, with focus on water quality, disinfection, renewable energy, biological treatment, blockchain technology, machine learning algorithms, big data, cyber-physical systems, and automated smart grid power distribution networks. Artificial intelligence allows for monitoring contaminants, facilitating data analysis, diagnosing water quality, easing autonomous decision-making, and predicting process parameters. We discuss advances in technical reliability, energy resources and wastewater management, cyber-resilience, security functionalities, and robust multidimensional performance of automated platform and distributed consortium, and stabilization of abnormal fluctuations in water quality parameters.

The accelerating climate warming requires fast methods to reduce atmospheric carbon dioxide levels. Here, we converted carbon dioxide into titanium carbide using four magnetrons which were sequentially operated to emit microwave on titanium swarf. Carbon dioxide molecules dissociated in the plasma to react with ionized titanium atoms to form a stable titanium carbide product, using a microwave frequency is 2.3 gigahertz and 800 watts electrical power for each magnetron. Results show a reduction of carbon dioxide concentration from 2000 to 385 ppm within 30 s. Titanium carbide could be further functionalized as a three-dimensional printed gas sensor.

Hydrogen is viewed as the future carbon–neutral fuel, yet hydrogen storage is a key issue for developing the hydrogen economy because current storage techniques are expensive and potentially unsafe due to pressures reaching up to 700 bar. As a consequence, research has recently designed advanced hydrogen sorbents, such as metal–organic frameworks, covalent organic frameworks, porous carbon-based adsorbents, zeolite, and advanced composites, for safer hydrogen storage. Here, we review hydrogen storage with a focus on hydrogen sources and production, advanced sorbents, and machine learning. Carbon-based sorbents include graphene, fullerene, carbon nanotubes and activated carbon. We observed that storage capacities reach up to 10 wt.% for metal–organic frameworks, 6 wt.% for covalent organic frameworks, and 3–5 wt.% for porous carbon-based adsorbents. High-entropy alloys and advanced composites exhibit improved stability and hydrogen uptake. Machine learning has allowed predicting efficient storage materials.

Bioplastics such as polylactic acid are actually promoted as eco-friendly alternatives to fossil fuel-derived plastics, yet bioplastic toxicity remains poorly known. Here we studied the acute and multigenerational effects of polylactic acid microplastics on the copepod Eurytemora affinis, a bioindicator species of zooplankton. Results on acute toxicity revealed that lethal concentration values are higher for adult males, of 134.6 mg microplastic/L, than for adult females, of 106.9 mg/L. In multigeneration exposure, 400 µg/L polylactic acid microplastics induced higher mortality, production of smaller-sized eggs, elongation of the naupliar phase, and offspring with lower fitness. This led to reduction in female body size, including prosome length, width, and volume. Noteworthy, we also observed a recovery in copepod survival and reproductive parameters in the fifth filial generation.

Leather production for human protection has been an essential industrial activity since the start of civilization, yet classical leavering methods induce pollution of ecosystems by dyes, chromium-containing wastewater, and solid waste. Here, we review sustainable leather production using polysaccharides and modified polysaccharides, which are cheap, easy to obtain, and non-toxic. Polysaccharides include starch, chitosan, cellulose, and cyclodextrins. We discuss application for leather tanning, prevention of leather mildew, leather finishing and dyeing, and wastewater treatment. The leather properties meet the requirements of garment leathers, with tear strength higher than 18 N per mm and tensile strength higher than 6.5 MPa.

While the toxicity of pollutants has been rather well explored in simple laboratory conditions, there is little knowledge on their real toxicity in natural environments and living organisms because pollutants are often interacting and trapped into organic matter. Because of these interactions, their real concentrations can also be underestimated. Here we studied the nature, intensity, and strength of the interactions between bisphenol A and nano-sized natural organic matter. The bioavailability and toxicity of the complexed bisphenol A were tested with human colon adenocarcinoma cell lines. Results show that that interaction of bisphenol A with organic matter reduces bisphenol A cytotoxicity. Moreover, the bisphenol A-organic matter interaction is weak in the first hour then very stable after 24 h. Once formed, the bisphenol A-organic matter complex escapes detection and, as a consequence, the levels of pollutants in organic-rich media is most probably underestimated. The mechanism of interaction involves hydrophobic and π-stacking forces inside the core of nano-sized organic matter.