In this work, we successfully fabricated boron nitride foams by assembling boron nitride into a 3D porous structure using freeze drying. Boron nitride was modified by Hummers method and NaOH, which results in the functionalization with OH groups. Such chemical functionalization enabled the attachment of the surfactant molecules, leading to a 3D foam structure. We found that the type of the surfactant molecules and method of freezing (in liquid nitrogen or in a deep freezer) have significant impact on the structure of the foams and consequently their absorbent properties. Fast freezing technique (with liquid nitrogen) created more stable and porous structures compared to the slow freezing technique (in a deep freezer). The best foam structures were obtained for the samples coded as h-BN-B-H-SA and h-BN-N-DA. The highest absorption capacity was found as 2014.3% for h-BN-B-H-SA. Absorption capacity results show that foams can absorb approximately 2–20 times their own weight. The method we use here is easy to apply, environmentally friendly, and can be readily scaled up for industrial use.

Cyclodextrin nanosponges (CD-NS) are cross-linked cyclodextrin polymers characterized by a nanostructured three-dimensional network. CD-NSs in the last years found many different applications in the pharmaceutical field for the controlled release of drugs and for the absorption of undesired substances from physiological media, food, and wastewater. Most of CD-NS syntheses involve the solubilization of the chosen CD in closed batch, using a suitable organic polar aprotic liquid, which may affect potential environmental or biomedical applications. Since the research is now moving towards more sustainable approaches, new and greener syntheses of CD-NS are now being developed. Here, it is reported a new eco-friendly and efficient synthesis of nanosponges through mechanochemistry. Mechanochemistry involves the application of mechanical forces to drive and control chemical reactions by transferring energy to chemical bonds. The mechanochemical approach involves the use of a twin-screw extruder (TSE) as a chemical reactor: TSE are capable of fine temperature control and, furthermore, TS Extrusion is a continuous process and not a batch process. Among the many available CD-NS syntheses, we tested our solvent-free approach on a β-CD/citric acid (CA) system. Moreover, using TSE, the same polymer was obtained in a considerably shorter time. The so obtained NSs were used for the adsorption and removal of probe molecules, in comparison with NSs prepared by cross-linking β-CD with CA in batch.

Annually, the Cerrado ecosystem alternates between dry periods and long rainy seasons. During the dry season, severe forest fires occur, consuming a considerable part of the native vegetation, which impacts directly on the microbiome of the soil. Evaluate the adaptations of the soil microbiome to drought, rain and wildfire. Sequencing of the 16S rRNA gene was carried out for three significant conditions: drought and forest fires (“Fire”), after the first recorded rains (“First_Rain”), and during the rainy season (“Rainy”). It has been shown that under the “Fire” condition, there was a predominance of Phylum Actinobacteria, followed by Proteobacteria and Firmicutes. With the advent of the rainy season, “First_Rain,” there was a change in the predominant taxonomic groups, with a higher prevalence of members of Proteobacteria and Firmicutes. During the rainy season, Proteobacteria and Firmicutes continued as the most prevalent groups. However, it was noted that in this period, there was an increase in bacterial diversity when compared with other periods analyzed. These results show how environmental factors influence adaptations in microbial communities. This allows for a better understanding of how to link the structure of the microbial community to the performance of ecosystems, and assist in preventing the consequences of increased frequency of wildfires, and long periods of drought.

Pheromones are increasingly used as alternatives to pesticides to protect vineyards against L. botrana, a key grape pest. To diffuse (7E,9Z)-7,9-dodecadien-1-ylacetate, the L. botrana pheromone, passive, or aerosol dispensers are commonly applied. This paper deals with another method based on spraying an aqueous formulation, Lobesia Pro Spray, containing the pheromone encapsulated in a resin. The objectives were to assess the ability of vine leaves to act as pheromone dispensers and to check that encapsulation protects the plant from pheromone penetration. Laboratory testing based on an emission cell combined with airborne pheromone measurements by active sampling on sorbent tubes followed by ATD-GC–MS analysis was developed to accurately characterise the release of the pheromone into the air. Release kinetics analysis performed on the vine leaves showed a high pheromone release (about 30% of the sprayed quantity) the first day of the test. The release rate then decreased rapidly to reach about 650 mg/day/ha after 4 days. Kinetic modelling showed that it would be possible to maintain an effective airborne concentration of pheromone for approximately 12 days. Release tests were also carried out on glass, PVC and blotting paper. The results obtained showed that the vine leaves behaved as a non-absorbent material, implying that the pheromone used in the Lobesia Pro Spray formulation did not penetrate the plant. These first results prove the feasibility of using vine leaves as pheromone dispensers for a sprayed formulation and the ability to optimise the treatment conditions (dose and frequency) through laboratory testing.

In this study, the use of natural adsorbents, such as zeolite (clinoptilolite), leonardite, and duckweed (Lemna minor, L. 1753) was investigated for the regulation of optimum water qualities in freshwater aquaculture. The study was carried out in 3 experiments in triplicate. In the first experiment, aquarium fish feed (35% protein) was used as the ammonia source at 3 different rates (0.2, 0.4, and 0.6 g feed per 500 mL of tap water). In the second experiment, clinoptilolite (C) and leonardite (L) mixture (C:L = 1:2) were added to balance excessive ammonia. In the third experiment, duckweed (1.5 g/500 mL) was added to aquaria (10 cm in diameter) in a way to cover the surface area, and the ammonium adsorption of duckweed at low NH₄⁺-N concentrations was determined with 9 measurements. In this study, NH₃ values reached their peaks (0.19 mg/L) at the end of 1st experiment, in which ammonia values originating from the unconsumed feed were determined. In the 2nd experiment, NH₃ values began to decline (0.06 mg/L) with the addition of natural adsorbents (zeolite + leonardite) and were decreased to 0.003 mg/L with the addition of duckweed in experiment III, where natural adsorbents started to reach saturation. When the data obtained at the end of this study were evaluated, it was determined that all 3 natural materials had a positive effect on water parameters in aquaculture systems. As a result, it was determined that in high concentrations of zeolite + leonardite mixture and in low concentration of duckweed there had been a good removal efficiency.

Accompanied with the increasing complicated global value chain (GVC) networks is the carbon emission transfers among countries. Utilizing the complex network analysis alongside quadratic assignment procedure (QAP), this paper detects the community structure and influencing forces of the emission transfers under GVCs. The results imply that the bipolar structure of the network transformed gradually to tripolar owing largely to the surging of carbon emissions from China. Evidence on the existence of environmental Kuznets curve (EKC) in the emission transfers from high-income countries to low-income countries, and a U-shape relationship transfers in the reverse direction, suggesting that growing carbon emissions from both low- and high-income countries transferred to other high-income countries gradually. Gaps in technology, especially in patent applications, between source and destination countries played an important role therein.

As a result of extreme modifications in human activity during the COVID-19 pandemic, the status of air quality has recently been improved. This bibliometric study was conducted on a global scale to quantify the impact of the COVID-19 pandemic on air pollution, identify the emerging challenges, and discuss the future perspectives during the course of the ongoing COVID-19 pandemic. For this, we have estimated the scientific production trends between 2020 and 2021 and investigated the contributions of countries, institutions, authors, and most prominent journals metrics network analysis on the topic of COVID-19 combined with air pollution research spanning the period between January 01, 2020, and June 21, 2021. The search strategy retrieved a wide range of 2003 studies published in scientific journals from the Web of Sciences Core Collection (WoSCC). The findings indicated that (1) publications on COVID-19 pandemic and air pollution were 990 (research articles) in 2021 with 1870 citations; however, the year 2020 witnessed only 830 research articles with a large number 16,600 of citations. (2) China ranked first in the number of publications (n = 365; 18.22% of the global output) and was the main country in international cooperation network, followed by the USA (n = 278; 13.87% of the global output) and India (n = 216; 10.78 of the total articles). (3) By exploring the co-occurrence and links strengths of keywords “COVID-19” (1075; 1092), “air pollution” (286; 771), “SARS-COV-2” (252; 1986). (4) The lessons deduced from the COVID-19 pandemic provide defined measures to reduce air pollution globally. The outcomes of the present study also provide useful guidelines for future research programs and constitute a baseline for researchers in the domain of environmental and health sciences to estimate the potential impact of the COVID-19 pandemic on air pollution.

Chlorinated ethene (CE) groundwater contamination is commonly treated through anaerobic biodegradation (i.e., reductive dechlorination) either as part of an engineered system or through natural attenuation. Aerobic biodegradation has also been recognized as a potentially significant pathway for the removal of the lower CEs cis-1,2-dichloroethene (cDCE) and vinyl chloride (VC). However, the role of aerobic biodegradation under low oxygen conditions typical of contaminated groundwater is unclear. Bacteria capable of aerobic VC biodegradation appear to be common in the environment, while aerobic biodegradation of cDCE is less common and little is known regarding the organisms responsible. In this study, we investigate the role of aerobic cDCE and VC biodegradation in a mixed contaminant plume (including CEs, BTEX, and ketones) at Naval Air Station North Island, Installation Restoration Site 9. Sediment and groundwater collected from the plume source area, mid-plume, and shoreline were used to prepare microcosms under fully aerobic (8 mg/L dissolved oxygen (DO)) and suboxic (< 1 mg/L DO) conditions. In the shoreline microcosms, VC and cDCE were rapidly degraded under suboxic conditions (100% and 77% removal in < 62 days). In the suboxic VC microcosms, biodegradation was associated with a > 5 order of magnitude increase in the abundance of functional gene etnE, part of the aerobic VC utilization pathway. VC and cDCE were degraded more slowly under fully aerobic conditions (74% and 30% removal) in 110 days. High-throughput 16S rRNA and etnE sequencing suggest the presence of novel VC- and cDCE-degrading bacteria. These results suggest that natural aerobic biodegradation of cDCE and VC is occurring at the site and provide new evidence that low (< 1 mg/L) DO levels play a significant role in natural attenuation of cDCE and VC.

Rate constants of chlorine atom (Cl•) reactions (kCₗ•) determined using a large variation of experimental methods, including transient measurements, steady-state and computation techniques, were collected from the literature and were discussed together with the reaction mechanisms. The kCₗ• values are generally in the 10⁸–10⁹ mol⁻¹ dm³ s⁻¹ range when the basic reaction between the Cl• and the target molecule is H-atom abstraction. When Cl• addition to double bonds dominates the interaction, the kCₗ• values are in the 1 × 10⁹–2 × 10¹⁰ mol⁻¹ dm³ s⁻¹ range. In the kCₗ• = 1 × 10¹⁰–4 × 10¹⁰ mol⁻¹ dm³ s⁻¹ range, single-electron-transfer reactions may also contribute to the mechanism. The Cl• reactions with organic molecules in many respects are similar to those of •OH, albeit Cl• seems to be less selective as •OH. However, there is an important difference, as opposed to Cl• in the case of •OH single-electron-transfer reactions have minor importance. The uncertainty of Cl• rate constant determinations is much higher than those of •OH. Since Cl• reactions play very important role in the emerging UV/chlorine water purification technology, some standardization of the rate constant measuring techniques and more kCₗ• measurements are recommended.

The seed extract of Abelmoschus esculentus (AE), also known as Okra, was used as a source of reducing and capping agents to synthesized biogenic titanium dioxide nanoparticles (TiO₂ NPs) due to its rich flavonoid contents. The synthesized AE-TiO₂ nanoparticles were further evaluated by the effect of loading of TiO₂ NPs and irradiation time on the photocatalytic degradation of methylene blue dye. The synthesized TiO₂ NPs were then characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDS), Fourier transformed infrared (FTIR) spectroscopy, Raman spectra, UV–visible spectrophotometry, and particle size distribution (PSD). The findings confirmed the successful synthesis of the spherical anatase phase of TiO₂ NPs, as well as the existence of phytochemicals in the extract, which were involved in the capping/stabilization of NPs. The synthesized TiO₂ NPs were found to be 60–120 nm in size and almost uniformly distributed throughout the sample. The photocatalytic activity measured in a 300 mL cylindrical photochemical reactor and irradiated with 250 watts UV lamp was investigated based on methylene blue degradation. Effects of irradiation time and catalyst loading were elucidated and correlated with the characteristics of the catalysts. The findings revealed that the synthesized TiO₂ NPs were well-dispersed, stable, and could achieve more than 80 % degradation in 240 min of irradiation with 90 mg/L of AE-TiO₂ NPs loading compared to only 70 % by the commercial one. These results suggested that AE-TiO₂ NPs possesses significant catalytic activity, and the photocatalytic process could be used to degrade, decolorize, and mineralize the methylene blue dye. The polyphenolic tannins present in the extract were the reason behind the desirable characteristics of the nanoparticles and better photocatalytic activity of AE-TiO₂ NPs.