Lead (Pb) is considered an important environmental contaminant due to its considerable toxicity to living organisms. It can enter and accumulate in plant tissues and become part of the food chain. In the present study, individual and combined effects of Bacillus sp. MN-54 and phosphorus (P) on maize growth and physiology were evaluated in Pb-contaminated soil. A pristine soil was artificially contaminated with two levels of Pb (i.e., 250 and 500 mg kg⁻¹ dry soil) and was transferred to plastic pots. Bacillus sp. MN-54 treated and untreated maize (DK-6714) seeds were planted in pots. Recommended doses of nutrients (N and K) were applied in each pot while P was applied in selective pots. Results showed that Pb stress hampered the maize growth and physiological attributes in a concentration-dependent manner, and significant reductions in seedling emergence, shoot and root lengths, fresh and dry biomasses, leaf area, chlorophyll content, rate of photosynthesis, and stomatal conductance were recorded compared with control. Application of Bacillus sp. MN-54 or P particularly in combination significantly reduced the toxic effects of Pb on maize. At higher Pb level (500 mg kg⁻¹), the combined application effectively reduced Pb uptake up to 42.4% and 50% by shoots, 30.8% and 33.9% by roots, and 18.4% and 26.2% in available Pb content in soil after 45 days and 90 days, respectively compared with that of control. Moreover, the use of Bacillus sp. MN-54 significantly improved the P uptake by maize plants by 44.4% as compared with that of control. Our findings suggest that the combined use of Bacillus sp. MN-54 and P could be effective and helpful in improving plant growth and Pb immobilization in Pb-contaminated soil.

Electrokinetic (EK) remediation combined with in situ chemical oxidation (ISCO) can be applied to low permeability organic contaminated soil. However, the effects of electrode configuration on EK-oxidation remediation remain unclear. In this study, EK-ISCO remediation of real polycyclic aromatic hydrocarbon (PAH)-contaminated soil under different electrode configurations was conducted. The results showed that increasing the number of anodes and electrode pairs in one-dimensional (1D) and two-dimensional (2D) electrode configuration was conducive to migration of oxidants into the system. The change in soil pH after remediation in 2D electrode configuration was not obvious, but the increase of soil electrical conductivity (EC) was higher than that of the 1D electrode configuration. The removal rates of PAHs in 2D electrode configurations (35.9–40.9%) were relatively higher than those of the 1D electrode configurations (0.54–31.6%), and the hexagonal electrode configuration yielded the highest pollutant removal efficiency, reaching 40.9%. The energy consumption under 2D electrode configuration was smaller than that under 1D electrode configuration, and the energy consumption of per gram removed PAHs in the hexagon configuration (66.74 kWh (g PAHs)⁻¹) was lowest in all electrode configurations. Overall, the results of this study suggest that 2D electrode configuration is better than 1D and hexagonal electrode configuration is an optimal electrode configuration.

Malaria is a dangerous disease affecting millions around the globe. Biosynthesized nanoparticles are used against a variety of diseases including malaria worldwide. Here, silver nanoparticles (AgNPs) synthesized from the leaf extracts of Indigofera oblongifolia have been used in the treatment of mice infected with Plasmodium chabaudi to evaluate the expression of iron regulatory genes in the spleen. Infrared spectroscopy was used to identify the expected classes of compounds in the extract. AgNPs were able to decrease the parasitemia nearly similar to the used reference drug, chloroquine. In addition, AgNPs significantly decreased the spleen index after infection. Moreover, the iron distribution was increased after the treatment. Finally, AgNPs could regulate the mice spleen iron regulatory genes, Lipocalin 2 (Lcn2), transferrin receptor 1 (TFR1) and hepcidin antimicrobial peptide (Hamp). Taken together, our findings indicate that AgNPs have antimalarial activity and can control the state of iron in spleen. We need further investigations to determine mechanisms of action of the AgNPs.

The adsorption process is one of the most promising alternatives for textile effluent treatment. Different materials have been used as adsorbents and most of them present hard recovery, increasing the process cost. In this work, polyethylene terephthalate (PET) waste bottles were used as a substrate for the formation of titanium dioxide (TiO₂-G5) films aiming at Reactive Black 5 removal by adsorption process. The TiO₂-G5/PET films were characterized by N₂ adsorption-desorption, zeta potential analysis, X-ray diffraction (XRD), and adherence test. The pH, adsorbent charge, and stirring effects were investigated. Initially, the effects of the adsorbent mass, pH of the solution, and stirring were studied, obtaining a maximum adsorptive capacity of 155.04 mg g⁻¹ in the greatest condition (4 mg, pH = 4 and no stirring). The experimental data were fitted by the Langmuir and Freundlich isotherms. The Langmuir model presented the greatest fit, evidencing monolayer adsorption for this process. The kinetic study showed a great fit between the adsorption process and the pseudo-first-order kinetic model, which presented a correlation coefficient of 0.982. The thermodynamic parameters—enthalpy (∆H = − 19.53 kJ mol⁻¹), entropy (∆S = − 50.26 J mol⁻¹ K⁻¹), and Gibbs energy (− 5.31, − 4.80, and − 4.30 kJ mol⁻¹ at 283.15 K, 293.15 K, and 303.15 K, respectively)—indicate a spontaneous and exothermic process. Finally, the regeneration by solar radiation exposure led to an efficient TiO2-G5/PET spent sheets recovery, exhibiting good stability after 5 cycles of use. Graphical abstract

In this study, activated carbons were prepared from bamboo via carbonization and successive KOH activation by tuning the post-treatment procedure. The resultant carbons possessed high surface area, high oxygen doping, and 3D hierarchical porous structure with interconnected micro-, meso- and macropores. These features resulted in ultra-excellent adsorption capacity for rhodamine B (> 1200 mg/g). Furthermore, the kinetic and isotherm experimental data were best described by pseudo-second kinetic model and Langmuir isotherm model, respectively. The adsorption of RhB onto the as-synthesized carbons was a spontaneous endothermic process. The π–π stacking, hydrogen bond, and acid-base interaction were proposed to account for the adsorption mechanism. Moreover, SiO₂ in bamboo-based carbon functioned as frameworks and its removal via alkali treatment led to the collapse of porous structure, decreasing surface area, pore volume, and O heteroatom doping, consequently dropping the adsorption performance. Overall, bamboo as an abundant and renewable biomass could be considered as a potential precursor for the production of excellent adsorbent for wastewater purification.

The concentrations of heavy metal (copper (Cu), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn)) were measured in Acer(A.) pseudoplatanus tree bark to evaluate its suitability as a bioindicator of air pollution in downtown Toronto, Canada. The analysis of digested tree bark samples was carried out by inductively coupled plasma optical emission spectrometry (ICP-OES) for Cu, Mn, Ni, Pb, and Zn, whereas a mercury analyzer was used to quantify Hg without sample pre-treatment. The concentrations of the analyzed heavy metals were found to be 26.4 μg g⁻¹ for Cu, 51.7 μg kg⁻¹ for Hg, 55.3 μg g⁻¹ for Mn, 6.55 μg g⁻¹ for Ni, 26.5 μg g⁻¹ for Pb, and 95.2 μg g⁻¹ for Zn. Analysis of background control tree barks (collected in a remote area) showed that maple tree barks in Toronto were strongly enriched with heavy metals, with their mean accumulation factors ranging between 1.88 (Mn) and 12.54 (Pb). The tree bark was also found to distinguish between impacted areas as the locations close to the roads with elevated vehicular traffic showed higher metal contents. Therefore, it could be concluded that A. pseudoplatanus tree bark is a good bioindicator of atmospheric heavy metal pollution.

BRICS are among the rising nations which drive economic growth by excessive utilization of resources and resulting in environment degradation. Although there is bulk of research on environmental Kuznets curve (EKC), very limited studies explored the scope in context of tourism in BRICS countries. So this research is conducted to explore the association of tourism, renewable energy, and economic growth with carbon emissions by using annual data of BRICS countries from the year 1995 to 2018. By using the recent approach of method of moments quantile regression (MMQR), the finding shows that tourism has stronger significant negative effects from 10th to 40th quantile while the effects are insignificant at remaining quantiles. Furthermore, an inverted U-shape EKC curve is also apparent at all quantiles excluding 10th and 20th quantiles. For renewable energy, the results are found negatively significant across all quantiles (10th–90th) which claim that CO2 emission can be reduced by opting renewable sources. Hence, the empirical results of the current study provide insights for policymakers to consume renewable energy sources for the sustainable economic growth and solution of environmental problems.

The current paper aimed at evaluating and optimizing the efficiency of energy use and mitigation of environmental pollution by minimizing the emissions and intensity of greenhouse gases (GHG) for farm production systems in Mashhad, Iran. The results indicated that the total values of consumed energy were equal to 28,648, 38,479, and 43,490 MJha⁻¹ for barley, canola, and forage corn, respectively. The highest rate of the consumed energy for all crops belonged to irrigation electricity, diesel fuel, and nitrogen consumption. The highest and lowest energy efficiencies were respectively achieved from forage corn and canola, while barley production led to the lowest GHG emissions. The estimation of GHG intensity demonstrated that canola with 53% took up the highest intensity, which was followed by barley (30%) and forage corn (17%). Since the intensity of GHG takes into account the amount of energy produced by each crop per hectare, this index is more suitable than GHG emissions for assessing environmental pollution. The results of optimal responses of the multiple goal programming (MGP) model revealed that the optimum evaluated cultivation areas (for meeting the goals of the study) for barley and forage corn were 10,088 and 3256 ha, respectively, while the MGP model generally eliminates canola from the cultivation plan. On the other hand, the plan proposed by the MGP model increases the total energy efficiency from 103,625 for the current systems to 105,169 for the optimized systems per year. Furthermore, the emissions and intensity of GHG were reduced by the model to 311,786 kgCO₂eq and 10 kgCO₂eq MJoutput⁻¹ per year, respectively.

The aim of this work is the employment of char waste in the synthesis of silicon foams for oil spill remediation and the comparison analysis with carbon nanotubes-filled foams. The foams are obtained by foaming a slurry constituted by a silicone matrix with CNT or char filler (7.7 wt%) in presence of a Sn-based catalyst. All the investigated materials present a foam morphology with an open/closed cell structure. Each foam was tested in three used common oils (kerosene, crude oil, and pump oil). Also, hydrophilic behavior of the foam was investigated. CNT showed a 700% sorption capacity in light oils (almost 7 gₒᵢₗ/gfₒₐₘ in kerosene); on the contrary, char foam evidenced the higher sorption efficiency in heavier oils; in particular, it reaches 130% in pump oil (1.3 gₒᵢₗ/gfₒₐₘ). All the filled foams are reusable. The reuse increases the foam efficiency and decreases the economic and environmental impacts.

This study explores the opportunities for irrigated agriculture in Khyber District of Former Federally Administered Tribal Area (FATA). Agriculture continues to be most important economic activity in Pakistan and former FATA is no exception. However, agriculture in the semi-arid Khyber District continues to suffer a decline due to excessive reliance on rainfall, which is drastically insufficient. Khyber District have large expanses of fertile land; however, farmers depend on unpredictable rain-fed agriculture, which has low productivity and food insecurity. There are a number of rivers in the region where great prospects exist for irrigated farming. Geographical information systems (GIS)-based multi-criteria analysis can be used to map areas with irrigation potential. The current study focused on different variables including soil texture, perennial rivers, land cover, topography, and dams. For this study, data was collected from diverse sources which include Google earth images, top sheets, land use land cover, soil texture map of FATA, and SRTM 30 Meter. The collected data was analyzed by using multi-criteria analysis in Arc GIS 10.2.2 by using MIF technique. The results of this research indicate that there is great potential for irrigated farming in the study area. Potential land for this purpose were divided into three categories, i.e., highly suitable which consisted of 678 km², or 26% of the total area; 1044 km² representing 40% were moderately suitable to irrigation; while the remaining 698 km² representing 27% were considered least suitable for irrigation. Likewise, 204 km² representing 7% were deemed unsuitable for irrigated agriculture mostly consisting of barren rocks. The results also illustrate how GIS as a tool can be used in the exploration of water resources in a scientific approach, thus making decision-making easier and more accurate.