The photocatalytic degradation of methylene blue (MB) in aqueous solutions and under visible light was investigated with dispersed and supported zinc oxide (ZnO) as catalysts. The ZnO catalyst was successfully impregnated in asymmetric alumina hollow fibers by the simple vacuum-assisted dip-coating method. According to energy-dispersive analyses, the photocatalyst was homogenously distributed in the substrate. A strong correlation was observed between the initial dye concentration and the efficiency of the supported photocatalyst. For the initial MB concentration of 5 mg L⁻¹ and catalyst dosage of 1 g L⁻¹, the photocatalytic system with both dispersed and supported catalysts reached almost 100% of MB degradation. The photocatalytic process followed the pseudo-first-order kinetic model, and, for the initial MB concentration of 5 mg L⁻¹, the apparent constants were 0.05415 and 0.00642 min⁻¹ for suspended and supported catalysts, respectively. The treated MB solutions presented low phytotoxicity to the germination Lactuca sativa seeds with germination indexes greater than 80% after irrigation with the treated MB solutions. The produced supported ZnO catalyst showed suitable photocatalytic stability even after several reuse cycles.

Forestry pest management includes biological and chemical methods of pest control. Using insecticides and natural enemies can be compatible in forest pest management programs. The compatibility of the predatory stink bug Podisus distinctus with the insecticide indoxacarb, used in forestry, needs to be evaluated in Brazil. This study investigated the mortality, survival, respiration, preference, prey consumption, and locomotor activity of P. distinctus adults exposed to indoxacarb. In concentration-mortality bioassays, the lethality of indoxacarb (LC₅₀ = 2.62 g L⁻¹ and LC₉₀ = 6.11 g L⁻¹) was confirmed in P. distinctus adults. The survival rate was 100% in predator insects not exposed to indoxacarb, declining to 40.7% in predator insects exposed to 2.62 g L⁻¹ and 0.1% in predators treated with 6.11 g L⁻¹. Indoxacarb reduced the respiration of P. distinctus from 18.45 to 14.41 µL CO₂ h⁻¹ at 2.62 g L⁻¹ for up to 3 h after insecticide exposure, inhibiting food consumption and displaying hyperexcitation. The harmful effects of indoxacarb to the natural enemy suggest that it should be better assessed for use with P. distinctus for pest management in forestry.

There is a rising concern that air pollution plays an important role in the COVID-19 pandemic. However, the results were not consistent on the association between air pollution and the spread of COVID-19. In the study, air pollution data and the confirmed cases of COVID-19 were both gathered from five severe cities across three countries in South America. Daily real-time population regeneration (Rₜ) was calculated to assess the spread of COVID-19. Two frequently used models, generalized additive models (GAM) and multiple linear regression, were both used to explore the impact of environmental pollutants on the epidemic. Wide ranges of all six air pollutants were detected across the five cities. Spearman’s correlation analysis confirmed the positive correlation within six pollutants. Rt value showed a gradual decline in all the five cities. Further analysis showed that the association between air pollution and COVID-19 varied across five cities. According to our research results, even for the same region, varied models gave inconsistent results. For example, in Sao Paulo, both models show SO₂ and O₃ are significant independent variables, however, the GAM model shows that PM₁₀ has a nonlinear negative correlation with Rₜ, while PM₁₀ has no significant correlation in the multiple linear model. Moreover, in the case of multiple regions, currently used models should be selected according to local conditions. Our results indicate that there is a significant relationship between air pollution and COVID-19 infection, which will help states, health practitioners, and policy makers in combating the COVID-19 pandemic in South America.

China’s Loess Plateau Region (LPR) plays a significant role in national ecological security and development. Due to the advantage that relates environment with economy, eco-efficiency has become an important indicator of sustainable analysis. Using cross-level panel data for the period 2006–2017, this paper studied LPR’s static eco-efficiency and dynamic performance through a combined application of DEA super-efficient slack-based measure and Malmquist Productivity Index at multi-scales. LPR’s eco-efficiency was found to experience a slight increase during the study period. The value decreased roughly from east to west, with high eco-efficiency mainly distributed in provincial cities and resource-based cities. The decomposition of the Malmquist Index indicated that technological change contributed most to the improvement of eco-efficiency in the LPR. Besides, this paper explained the variations of eco-efficiency based on the integrated input-output indicators and TOBIT regression model. Economic scale, population density, government regulation, technical innovation, and openness degree were identified as positive influencing factors, while the structure of the industry and land-use intensity were found to have negative impacts on eco-efficiency. Resource-based cities were found to have stronger potentials for eco-efficiency improvement than non-resource-based cities. This paper revealed the characteristics of LPR’s eco-efficiency from three perspectives: a spatiotemporal perspective, a macro-meso-micro perspective, and a static-dynamic perspective. The findings of this study hold important implications for policy makers.

Composites of titanium (IV) oxide combined with montmorillonite (MMT) with various TiO₂/MMT were prepared for photocatalysis application. The prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance UV–visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). The main influential factors such as the TiO₂/MMT dose, calcined temperature, and pH value of the solution were studied. The main intermediates of phenol degradation were determined by high performance liquid chromatography (HPLC). The results showed that the average size of TiO₂ nanoparticles was decreased from 22.51 to 10.66 nm through the immobilization on MMT. The components in the interlayer domain were replaced by titanium pillars, and the pillaring reaction proceeded in the interlayer domain, the basic skeleton of MMT was unchanged, and TiO₂ was dispersed on the surface of the MMT. When the initial concentration of phenol is 10 mg/L, the phenol solution pH is 6, and the UV light irradiation time is 240 min; the phenol degradation rate of 30%TiO₂/MMT composite is 89.8%, which is better than MMT (11.5%) and pure TiO₂ (58.8%). It shows that TiO₂ loaded on MMT improves its photocatalytic activity. The phenol reaction process detected by HPLC showed that it had undergone through hydroquinone and benzoquinone, and finally converted into maleic acid and carbon dioxide and small molecules. The possible photocatalysis mechanism is presented.

In this research paper, sustainable technologies that are plasma surface treatment and digital printing of wool and cotton fabrics with herbal inks are implemented for ecological outcomes. One of the significant objectives was to study the plasma surface modification and its implication on fabric absorbency, K/S values gained, and the fastness properties of the resultant herbal fabrics. The wash fastness to colour change was studied wherein plasma surface treatment remarkably improved wash fastness ratings from 1–2 to 3–4 obtained on inkjet printed wool and cotton fabrics. These findings were supported by data gained from optical tensiometer, ATR-FTIR, drop test and SEM justifying the enhanced wettability of the modified fabrics. The factorial experiment was designed for this segment of research, and it was further validated with ANOVA one-way test. The concluding parametric study with plasma surface modification yielded the probability value of 0.000463 and actual power of 0.99 which is reassuring. The ecological characterisation and assessment of functional properties of the herbal fabrics are suggested for the forthcoming study.

Microbial fuel cell (MFC) is a recommended treatment to remediate hexavalent chromium (Cr(VI)) in wastewater. In this study, a wood carbon (WC) electrode was introduced in MFC to enhance the Cr(VI) removal efficiency. WC electrode in MFC completely removed Cr(VI) as compared to the carbon cloth (31.12%) and carbon felt (34.83) within 48 h of operation at 20 mg L⁻¹ of Cr(VI) concentration. The maximum power density of WC electrode was 62.59 mW m⁻² higher than 0.115 and 3.154 mW m⁻² of carbon cloth and felt respectively. The specific surface area of WC increased to 158.47 m⁻² g⁻¹ after high-temperature carbonization, and electrochemical tests indicate it has higher electrocatalytic ability. Therefore, WC might be a good electrode material to effectively remove Cr(VI) and generate bioelectricity simultaneously.

The requirements for better understanding of marine metal geochemistry continually emphasize precise and accurate quantitative determination of elements in surface seawater matrix. While precise results are attained with most of the modern analytical instruments, the accuracy of quantitative results falls short unless the interferences caused from the high salinity of seawater are eliminated. In this study, the mass fractions of 22 elements in the surface seawater samples collected from the coastal part of west Antarctica were determined using an accurate and reliable quantification method. In this method, magnesium hydroxide (Mg(OH)₂) precipitation was performed using N,N-diethylethanamine (C₆H₁₅N) prior to determination by inductively coupled plasma – mass spectrometry system and the utility of method was studied by spiking experiments into seawater matrices. Percent recovery values of selected elements were varied between 86.0 and 129.9% with satisfactory precision levels (RSD ≤ 17.7%). Following the acceptable recovery results, the analytical method was used to determine the quantities of elements in surface seawater samples. In the samples, significant levels of aluminum, vanadium, and molybdenum were detected while the levels of heavy metals including As, Sb, Cd, Cr, Pb, and Bi were below the detection limit. The results suggest the absence of a continual contamination process in the coastal region of Horseshoe and Faure Islands. Concerning the limited data available in literature, the results may contribute for reliable evaluation of the distribution levels of selected elements in Antarctica.

Harmful algal blooms (HABs) are a worldwide problem with substantial adverse effects on the aquatic environment as well as human health, which have prompted researchers to study measures to stem and control them. Meanwhile, it is key to research and develop monitoring methods to establish early warning HABs. However, both the current monitoring methods and control methods have some shortcomings, making the field application limited. Thus, we need to improve current approaches for monitoring and controlling HABs efficiently. Based on the freshwater system features in China, we review various monitoring and control methods of HABs, summarize and discuss the problems with these methods, and propose the future development direction of monitoring and control HABs. Finally, we envision that it can combine physical, chemical, and biological methods to inhibit HAB expansion in the future, complementing each other with advantages. Further, we promise to establish a long-term strategy of controlling HABs with various algicidal bacteria co-cultivate for field applications in China. Efforts in studying algicidal bacteria must be increased to better control HABs and mitigate the risks of aquatic ecosystems and human health in China.

The impacts of the Batts drain on two chronically exposed fish (O. niloticus and C. gariepinus) were assessed using multiple biomarkers. Concentrations of metals in water and sediments (Cu, Zn, Fe, Cd, Pb, and Al) showed significant elevations near the Batts discharges (site 2) compared to the reference site (site 1). The liver and gills of fish collected from site 2 showed marked elevations in the catalase, superoxide dismutase, glutathione peroxidase, and thiobarbituric acid reactive substance levels. In addition, significant reductions in glutathione-reduced contents were also recorded. Tissue and species-specific antioxidant responses were associated with excessive generations of reactive oxygen species, which were visualized fluorescently. Various histological alterations were observed in the gills and livers of both species. These alterations varied between compensatory responses (ex: epithelial thickening and lifting) and irreversible damage (ex: necrotic degeneration). Based on the level of lipid peroxidation and the frequency of histopathological modifications, O. niloticus demonstrated greater resistance to the same level of pollution than C. gariepinus. Using integrated biomarkers to evaluate the real impacts of untreated discharges of the Batts drain is applied for the first time on the selected fish species at the studied sites.