Microplastic pollution is a significant and growing environmental issue. Recent studies have evaluated the atmosphere as an important pathway of microplastic contamination. Airborne microplastics can be transported long distances and accumulate in various terrestrial and aquatic environmental matrices, where they represent a threat to the biosphere. This review systematically summarizes the existing knowledge on airborne microplastics, including the different sampling and analytical techniques, occurrence and sources. We investigate the different sample collection techniques from street dust to indoor and outdoor air and examined sample preparation, pre-treatment and characterization techniques. We further explored the key factors with respect to their occurrence in the environment such as concentration levels, polymer composition, size distribution, shape and colour characteristics. The sources of airborne microplastics were also summarized. The results show that microplastics are ubiquitous in all atmospheric compartments including street dust and indoor and outdoor air at various concentrations, which is influenced by the community’s lifestyle choices, anthropogenic activities and meteorological conditions. Various forms of microplastics including spherules, film, fragments, fibres and granules were identified with fibrous microplastics being the most dominant. Additionally, microplastics of 20 different polymers and varying colour characteristic have been reported in studies focusing on airborne microplastic contamination. The size distribution of microplastics varied among the studied air compartments; however, they were mostly distributed towards the smaller size ranges, less than 1 mm. Our review highlights a need to consider atmospheric pathways in addition to soil and water migration dispersion processes for any holistic assessments of microplastic threats to the biosphere. Moreover, standardization of airborne microplastic sampling methods is needed to optimize the effectiveness of future work in this area. Graphical Abstract Microplastics in atmospheric environments

This study investigated the metabolic response of E. coli after exposure to TiO₂ and ZnO NPs under solar simulated irradiation. A total of 14 altered metabolites involved in two metabolic pathways were recognized using multivariate analysis. Polyamine, putrescine was elevated in ZnO-treated group, as an adaptation to oxidative stress in cells, whereas it was significantly reduced in TiO₂-treated group. Glycine levels also were elevated in both the treatment groups, showing cellular protection in cells after exposure. In addition, glycine, serine, and threonine metabolism and arginine and proline metabolism were altered in ZnO and TiO₂-treated groups respectively.

The industry sector is not only an important driving force for economic growth but also the largest sector of resource consumption and pollution emission. In this study, we first constructed a super-slack-based measure (Super-SBM) model including the resource consumption and undesirable outputs, and estimated the industrial environmental efficiency (IEE) in China from 2007 to 2016. Afterwards, based on the spatial autocorrelation test and the spatial Durbin model, the spatio-temporal evolution and the influencing factors of IEE were analyzed. The empirical results are obtained as follows: the average IEE from 2007 to 2016 was 0.5176. IEE in the east of China was the highest, whereas it was the lowest in the west. The spatial autocorrelation test showed that the regions with similar levels of IEE in China had significant spatial agglomeration, whereas the local spatial distribution of IEE was unbalanced. The high-high IEE agglomeration areas were located in Liaoning, Jilin, and Inner Mongolia. The low-low IEE agglomeration areas were concentrated in Gansu, Ningxia, and Sichuan. Finally, according to the spatial Durbin panel model and spillover effect decomposition, GDP, FDI, human capital, environmental governance investment, research and development investment, and urbanization have a positive impact on IEE. The industrial and energy consumption structures have a negative impact on IEE. Therefore, the central government should focus on balancing IEE of different provinces and regions, increasing investment in industrial pollution treatment, and encouraging FDI to improve IEE.

Trade openness is one of the main channels of globalization and technological transfers. In environmental economic literature, the implications of trade openness remain controversial and still could be potential drivers of carbon dioxide emissions. This study therefore explores the effect of trade openness in developed countries using EU-18 economies. We employed an econometric approach that accounts for cross-section dependence among study variables. The panel CIPS and CADF unit root show that the variables are stationary and the long-run relationship was confirmed in Westerlund cointegration tests. The mean group (MG) and augmented mean group (AMG) results show that trade openness increases CO₂-emissions in EU-18. Again, energy consumption and urbanization escalate emissions. The study confirmed the environmental Kuznets curve. Finally, pollution halo and pollution haven hypothesis were confirmed at both estimation methods. The Dumetriscu-Hurlin Granger causality test results confirmed bidirectional causality between trade openness and energy consumption and between trade openness and economic growth. Again, unidirectional Granger causality is running from trade openness and CO₂ emissions. Policy recommendations are further proposed.

The fixed-film sequencing batch reactor, or F-SBR, was developed to treat high organic compound levels and toxic cyanide concentrations in cassava wastewater. The performance of the F-SBR was compared with that of a conventional sequencing batch reactor, or SBR, that was operated with organic compound contents of 16,266.67–26,666 mg COD/L and 132.92–252.66 mg CN⁻/L. The cyanide and chemical oxygen demand removal efficiencies of the conventional SBR system were 42.61% and 36.83%, respectively, while those of the F-SBR were 77.95% and 74.43%, respectively; the cyanide removal efficiency reached 95.45% when the hydraulic retention time was increased to 5 days, and the F-SBR was very effective for the complete removal of cyanide when the hydraulic retention time was increased to 10 days. This effectiveness was similar to the effectiveness of chemical oxygen demand removal, which reached 40–78% efficiency with the F-SBR system. These results showed that the immobilization of cyanide-degrading bacteria such as Agrobacterium tumefaciens SUTS 1 and Pseudomonas monteilii SUTS 2 carried out with a polypropylene ring in a fixed-film aerobic system enhanced the performance of the reactor and can be successfully applied for cyanide and chemical oxygen demand removal from industrial wastewater with high cyanide and chemical oxygen demand concentrations. This study may provide a promising alternative technique that reduces economic operation costs in solving wastewater contamination problems.

Mesoporous silica impregnate with Cyanex 272 (bis/2,4,4-trimethylpentyl/phosphinic acid) extractant was immobilized into an alginate matrix to obtain a composite sorbent easy to use and applicable in fixed-bed column continuous systems. The sorption efficiency of this material was tested for the recovery of Eu(III) ions from aqueous solutions in batch and continuous mode. The competition among rare earths ions (europium, lanthanum, and lutetium) and among rare earths and calcium or sodium ions was investigated. High calcium concentrations strongly reduce the sorption capacity of the alginate matrix that composes the hybrid material and the Cyanex 272 impregnated into silica powder improves the rare earths’ sorption performance in this calcium charged media. The experimental breakthrough curves obtained were satisfactory fitted by Thomas model.

Polluted waters are an important reservoir for antibiotic resistance genes and multidrug-resistant bacteria. This report describes the microbial community, antibiotic resistance genes, and the genetic profile of extended spectrum β-lactamase strains isolated from rivers at, Pune, India. ESBL-producing bacteria isolated from diverse river water catchments running through Pune City were characterized for their antibiotic resistance. The microbial community and types of genes which confer antibiotic resistance were identified followed by the isolation of antibiotic-resistant bacteria on selective media and their genome analysis. Four representative isolates were sequenced using next generation sequencing for genomic analysis. They were identified as Pseudomonas aeruginosa, Escherichia coli, and two isolates were Enterobacter cloacae. The genes associated with the multidrug efflux pumps, such as tolC, macA, macB, adeL, and rosB, were detected in the isolates. As MacAB-TolC is an ABC type efflux pump responsible for conferring resistance in bacteria to several antibiotics, potential efflux pump inhibitors were identified by molecular docking. The homology model of their MacB protein with that from Escherichia coli K12 demonstrated structural changes in different motifs of MacB. Molecular docking of reported efflux pump inhibitors revealed the highest binding affinity of compound MC207-110 against MacB. It also details the potential efflux pump inhibitors that can serve as possible drug targets in drug development and discovery.

The present work is focused on the removal of NOx with reduced blue TiO₂ with Fe (blue Fe-TiO₂)- and Cu (blue Cu-TiO₂)-doped photocatalyst. TiO₂ was reduced via lithium in EDA (blue TiO₂). Fe and Cu ions were doped in the reduced TiO₂ (blue Fe-TiO₂ and blue Cu-TiO₂). The material resulted in a core-shell structure of amorphous and anatase phase. XPS suggests the existence of Ti³⁺ species and oxygen vacancies within the structure of TiO₂. Additionally, valence bond (VB)-XPS shows the generation of intermediate levels at the band edge of the doped photocatalyst. Photocurrent, electrochemical impedance spectroscopy and cyclic voltammetry confirmed the enhanced charge-separation process in doped reduced TiO₂. The photocatalysts were tested for the photo-oxidation of NOx. Blue Fe-TiO₂ reveals the efficiency of 70% for NO elimination and 44.74% for NO₂ formation. The improved efficiency of the doped photocatalyst is related to the re-engineered structure with Ti³⁺ species, oxygen vacancies, and charge traps. Electron spin resonance (ESR) measurement was carried out for blue Fe-TiO₂ to confirm the formation of reactive oxygen species (ROS). Furthermore, ion chromatography was used to investigate the mechanism of NOx oxidation. In conclusion, the doped blue TiO₂ has a strong tendency to photo-oxidize NOx gasses.

Diclofenac has been detected in water and terrestrial matrices, causing severe changes in the environment. This is due to the fact that it is one of the most widely used nonsteroidal anti-inflammatory drugs in the world. The advanced oxidation processes (AOPs) of photo-peroxidation and heterogeneous photocatalysis were tested in this work using UV-C and solar radiation to degrade diclofenac in aqueous solutions. To monitor the efficiency of the degradation processes an ultrahigh performance liquid chromatography with ultraviolet detection at a wavelength of 285 nm was applied. Both processes were found to be efficient (> 78%) after 60 min of treatment, being possible to determine the reaction kinetics for each one of them. Intermediate formation was also observed after 60 min which were also degraded by increasing the treatment time to 120 min. For the treatments using UV-C radiation, an order of 1.0 was observed, while the treatments that applied solar radiation obtained an order of 0.2 for the photocatalysis and 0.8 for photo-peroxidation.

This study investigated the impact of pyrolysis conditions on physical characteristics of date palm fronds biochars and their performances for aqueous uptake of anionic dyes—methyl orange (MO) and Eriochrome Black-T (EBT)—and cationic dyes—methylene blue (MB) and crystal violet (CV). Detailed characterization of the biochars revealed the formation of oxygen functionalities (C=O, C-O-C, and C-O), improved surface characteristics (surface area and pore volume) and high ash content at higher pyrolysis temperature and time. Biochar-derived date palm with a high surface area of 431.82 m²/g and a pore volume of 0.134 cm³/g was obtained at pyrolysis temperature and time 700 °C and 4 h, respectively. For all the four investigated dyes, the adsorption isotherm was mainly described by Redlich–Peterson isotherm model (R² > 0.95), while the adsorption kinetics well-fitted the pseudo-second order model. The biochar yielded fast dyes adsorption with maximum adsorption capacity for MB, EBT, MO, and CV dye of up to 206.61, 309.59, 163.132, and 934.57 mg/g at 200 mg/L dye concentration, respectively. The adsorption of cationic dyes was pH-independent indicating the involvement of pi–pi and chemical interactions. However, the uptake of the anionic dye was favorable at acidic conditions and was dominated by electrostatic interactions involving ion exchange and chemical reactions. The produced biochars exhibited excellent surface characteristics and enhanced adsorptive performance relative to other similar adsorbents. Thus, the direct pyrolysis of date palm fronds’ waste is a sustainable and economical approach of converting a huge quantity of wastes into excellent adsorbent for effective remediation of dye-contaminated water and wastewater.