In this research work, the removal of chromium(III) ion (Cr³⁺) by raw materials such as zeolite (Z) and chert (CH) was investigated. The batch method was invested, using two concentrations in chromium(III) sulphate at 21.31mg/L and at 22mg/L in nitrate nonahydrate. In order to improve the porous structure, the specific surface area and the adsorbent capacity of these natural materials, a purification technique was undertaken, namely a chemical treatment of the used natural materials (zeolite and cherts) with NaCl was carried out. Thus, the obtained raw and purified materials were characterized through chemical analysis by X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and liquid nitrogen adsorption-desorption analyses by measuring the specific surface area (BET method). The results demonstrated that zeolite (Z) and chert (CH) are good adsorbents and that the purified materials have a potential adsorbent to reduce the chromium concentration for a maximum adsorbed amount (Qads) of about 2.72mg/g and 2.85mg/g, respectively for purified zeolite and chert (Z-p and CH-p) in chromium(III) nitrate and about 2.83mg/g and 2.48mg/g, respectively for purified zeolite and chert (Z-p and CH-p) in chromium(III) sulphate. These results revealed that natural zeolite and chert hold great potential to remove cationic heavy metal species from industrial wastewater. The kinetics adsorption was also examined using pseudo-first-order and pseudo-second-order kinetics models. The adsorption kinetics was best described by the pseudo-second-order.

Surfactant-enhanced air sparging (SEAS) technology has been widely accepted to remediate VOC-contaminated soil with medium or high permeability, while the remediation efficiency and mechanism in low permeability soil have been rarely explored, which is of great importance to the field implementation due to the heterogeneous stratigraphic distribution at site. For this purpose, the surfactant-enhanced single air channel sparging tests and solubilization/desorption tests are comprehensively designed and performed in this study. Results showed that the exhaust gaseous MTBE concentration is significantly lower, and the time to reach concentration equilibrium is longer for air sparging in low permeability soil, which could be modified with surfactant incorporation. The reduced MTBE concentration, enlarged remediation zone, and the total MTBE removal rate in the low permeability soil could be observed after implementing the SEAS technology and will be further enhanced with sparging pressure increasing. The mass transfer zone (MTZ) in low permeability soil is enlarged with the increased surfactant concentration, based on which an exponential growth relation is established for MTZ quantitative prediction. The improved remediation efficiency of SEAS technology on low permeability soil is confirmed to be controlled by the contaminant solubilization/desorption mechanism, rather than the surface tension reduction mechanism that was conventionally confirmed in medium or high permeability soil.

We investigated a single-cycle product supply chain in a game model, where a supplier is the leader. By innovatively introducing cleaner production fraudulent income perception factor into a game model, we studied the mechanism of the effect of enterprise social responsibility and environmental awareness on cleaner production fraud. The results showed that the income of retailers and suppliers changes under different perceptions of fraudulent income. That is, the value of cleaner production fraudulent income perception factor will affect the enterprise’s choice of differentiation strategy. When the enterprise’s sense of social responsibility is weak, it is more likely to choose cleaner production fraud. Conversely, under the constraints of high social responsibility, it more likely avoids production fraud. Regarding government supervision, the income of suppliers and retailers changes under different government penalties. Furthermore, a reasonable punishment for cleaner production fraud can reduce such violations. However, after the punishment reaches a level, the efficiency of supervision begins to decline. In views of that, improving enterprise social responsibility through institutional reform is a more effective way to reduce cleaner production fraud. To contribute to a healthy competitive market environment, government supervision should establish a feedback mechanism, and make timely adjustments.

This study aimed to evaluate the implementation of an advanced oxidation system based on UV radiation and UV/H₂O₂ for degradation of TCS and IBU in synthetic effluent. The assays occurred in a 2-L reactor, protected from external light and equipped with a UV lamp (λ = 254 nm). The effect of contaminant concentration, fractions of chemical species present, and mineralization were evaluated. In the UV/ H₂O₂ system, different concentrations of H₂O₂ were studied for oxidation of the contaminants. The kinetic experiments took place between 75 and 270 min of UV irradiation. The results showed > 99% oxidation of TCS in the direct photolysis system at pH 9.4 after 12 min. The degradation of IBU in the UV/H₂O₂ system, when 10 mg L⁻¹ of H₂O₂ was used, was 97.39% oxidation. We obtained k′ values of 0.189 min⁻¹ for TCS when its highest oxidation occurred and k′ values of 0.0219 min⁻¹ for IBU. The system was not able to completely mineralize the contaminants, presenting high values of TOC and COD after treatment, thus suggesting the occurrence of phototransformation.

Carbamazepine (CBZ) is one of the most widely used antiepileptic drugs in Malaysia. It was detected frequently in wastewater. The electrochemical treatment process has been applied for the degradation of CBZ using graphite–PVC as an anode under these conditions: 0.5 g sodium chloride (NaCl)) as supporting electrolyte, 5 V and 0–60 min electrolysis time in 100 mL of solution. However, 10,11-dihydro10-hydroxy carbamazepine (HDX-CBZ) and 10,11-epoxycarbamazepine (EPX-CBZ) as the main by-product have been analysed and quantified using liquid chromatography–time of flight/mass spectrometry (LC-TOF/MS). Both by-products were analysed in positive ionization mode, and they were separated on a chromatographic C18 column (5 μm, 2 mm × 150 mm) at a flow rate of 0.3 mL/min. Solid-phase extraction (SPE) was applied as a pre-concentration step for the enhancement of the sensitivity and detectability for both HDX-CBZ and EPX-CBZ by-products. Methanol (MeOH) has been selected as the best elution solvent for both by-products compared to methyl tertiary butyl ether (MTBE) and acetone (AC). However, the recovery was 85% and 92% for HDX-CBZ and EPX-CBZ by-products, respectively. The limit of quantification (LOQ) was 0.588 and 0.109 µg/L for HDX-CBZ and EPX-CBZ by-products, respectively. After 20 min of electrolysis time, both by-products HDX-CBZ and EPX-CBZ appeared at maximum concentrations of 343 and 144 μg/L then they were decreased to 17.2 and 9.8 μg/L, respectively, after 40 min. At the end of electrochemical treatment, both by-products were completely eliminated after 60 min.

Radon exhalation from soil and ores is among the most dangerous risks for the public health care. The impact becomes even more powerful when technological enhanced naturally occurring radioactive materials (TENORM) are used for public and private building. Here, we built a down-scaled model (a 1.0 m × 1.0 m × 0.5 m parallelepiped) of a dwelling, whose construction materials contain TENORM harvested in a site in Crotone (Italy). We observed an increase of the radon activity in the model when TENORM residues are employed, reaching a value around 120 Bq/m³, i.e. up to three times higher than the typical values of Crotone indoor environment, which ranges around 40 Bq/m³. These results have then been compared to a real use case. The correspondence found between the values of radon activity concentration in the model and in the use case suggests that estimating the radon concentration is a useful method to target TENORM presence inside buildings.

This study investigates the impact of urbanization and nonrenewable energy consumption on carbon emissions. The context of the analysis is 54 African Union countries from 1996 to 2019. For estimation, we use panel quantile regression (PQR) and fully modified ordinary least squares (FMOLS). Our regression results demonstrate that there is a positive correlation between urbanization and CO₂ emission. Further, our empirical results confirmed that nonrenewable energy consumption increases environmental pollution in African Union countries. The outcomes demonstrate the EKC hypothesis because at the initial stage of development, when economic growth increases, environmental pollution increases; after a threshold point, environmental pollution decreases as economic growth increases. It can find an inverted U-shaped relationship between economic growth and CO₂ emission. The findings also show that urbanization should be planned; otherwise, it can lead to environmental degradation in the long run. Africa continent takes strict action and builds a blueprint for efficient and effective energy production and consumption. The only solution to achieve green growth in Africa is to shift from fossil fuel energy supply to renewable energy supply.

This study is focused on analyzing the linkage between carbon dioxide (CO₂) emissions, renewable energy consumption (RE), foreign direct investment (FDI), national patents (NP), exports (X), imports (M), and gross domestic product (GDP) in Tunisia by using the time series data from 1980 to 2017. A unit root test and an autoregressive distributed lag (ARDL) model were applied to avoid bias caused by data mismatch and autocorrelation of time series data. Elasticity long-run test shows that renewable energy consumption, exports, and gross domestic product have a positive impact on CO₂ emissions, while foreign direct investment acts negatively on CO₂ emissions. Depending on the error correction term test, there is a long-run causality: from CO₂ emissions, renewable energy, foreign direct investment, exports, and gross domestic product to home patent. Findings of the short-run causality show that there is a unidirectional causality running from exports to CO₂ emissions and from exports to gross domestic product. Our results also show that Tunisia should encourage foreign direct investment because it seems to be an important factor in the mitigation of CO₂ emissions.

Roadside trees alter biotic and abiotic factors of plants diversity in an ecosystem. Rows of plants grow along the roadside due to the interplay between the arrival of propagule and seedling establishment, which depends on the road’s specifications, land pattern, and road administration and protection practices. A field study was conducted to measure the roadside tree diversity in the city of Karachi (Pakistan). A total of 180 plots, divided into three primary road groups, were surveyed. The highest quantity of tree biomass per unit area was found on wide roads, followed by medium roads. On narrow roads, the least biomass was detected. A single species or a limited number of species dominated the tree community. Conocarpus erectus was the most dominant non-native species on all types of sidewalks or roadsides, followed by Guaiacum officinale. A total of 76 species (32 non-natives and 44 natives) that were selectively spread along the roadsides of the city were studied. There was a significant difference in phylogenetic diversity (PD), phylogenetic mean pairwise distance (MPD), and phylogenetic mean nearest taxon distance (MNTD) among wide, medium, and narrow roads. Management practices have a significant positive correlation with diversity indices. Our study identified patterns of diversity in roadside trees in Karachi. It provides the basis for future planning for plant protection, such as the protection of plant species, the maintenance of plant habitats, and the coordination of plant management in Karachi.

Pollution of aquatic ecosystems with nonylphenol (NP) and butyltins (BuTs) is of great concern due to their effects on endocrine activity, toxicity to aquatic organisms, and extended persistence in sediments. The impact of contamination with NP and/or BuTs on the microbial community structure in marine sediments was investigated using microcosms and high-throughput sequencing. Sediment microcosms with NP (300 mg/kg) and/or BuTs (95 mg/kg) were constructed. Complete removal of monobutyltin (MBT) occurred in the microcosms after 240 days of incubation, while a residual NP rate was 40%. The content of toxic tributyltin (TBT) and dibutyltin (DBT) in the sediments did not change notably. Co-contamination of the sediments with NP and BuTs did not affect the processes of their degradation. The pollutants in the microcosms could have been biodegraded by autochthonous microorganisms. Significantly different and less diverse bacterial communities were observed in the contaminated sediments compared to non-contaminated control. Firmicutes and Gammaproteobacteria dominated in the NP treatment, Actinobacteria and Alphaproteobacteria in the BuT treatment, and Gammaproteobacteria, Alphaproteobacteria, Firmicutes, and Acidobacteria in the NP-BuT mixture treatment. The prevalence of microorganisms from the bacterial genera Halothiobacillus, Geothrix, Methanosarcina, Dyella, Parvibaculum, Pseudomonas, Proteiniclasticum, and bacteria affiliated with the order Rhizobiales may indicate their role in biodegradation of NP and BuTs in the co-contaminated sediments. This study can provide some new insights towards NP and BuT biodegradation and microbial ecology in NP-BuT co-contaminated environment.