The vacuum ultraviolet (VUV) process, which can directly produce hydroxyl radical from water, is considered to be a promising oxidation process in degrading contaminants of emerging concern, because of no need for extra reagents. In this study, the influencing factors and mechanism for degradation of diethyl phthalate (DEP) by the VUV process were investigated. The effects of irradiation intensity, inorganic anions, natural organic matter (NOM), and H₂O₂ dosage on the performance of VUV process were evaluated. The results showed that DEP could be more efficiently degraded by the VUV process compared with ultraviolet (UV)-254-nm irradiation. The presence of HCO₃⁻, NO₃⁻ and NOM in the aqueous solutions inhibited the degradation of DEP to a different degree, mainly by competing hydroxyl radicals (HO•) with DEP. Degradation rate and removal efficiency of DEP by VUV process significantly enhanced with the addition of H₂O₂, while excess H₂O₂ dosage could inhibit the DEP degradation. Moreover, based on the identified seven oxidation byproducts and their time-dependent evolution profiles, a possible pathway for DEP degradation during the VUV process was proposed. Finally, the ecotoxicity of DEP and its oxidation byproducts reduced overall according to the calculated results from Ecological Structure Activity Relationships (ECOSAR) program. The electrical energy per order (EE/O) was also assessed to analysis the energy cost of the DEP degradation in the VUV process. Our work showed the VUV process could be an alternative and environmental friendly technology for removing contaminants in water.

In this study, a simple submersible device was tested to remove and recover Cd(II), Cu(II), Pb(II), and Zn(II) from model wastewater and real natural water. To obtain this device, fine particles (< 0.1 mm) of a new hybrid adsorbent based on the mesoporous carbon and Fenton-modified humic acids were fixed onto a highly porous polymeric matrix. The hybrid adsorbent was characterized by various methods. The main mechanism for Cd(II), Cu(II), Pb(II), and Zn(II) adsorption by the hybrid adsorbent is chemosorption by surface functional groups, the total concentration of which was found to be 1.56 mmol g⁻¹. The adsorption capacity depends on pH, and at pH 6.0, it has the following order (mmol g⁻¹): Cu(II) (1.14) > Pb(II) (0.86) > Zn(II) (0.59) > Cd(II) (0.50). The possibility of applying a submersible device for the removal and recovery of these metals from multi-metal wastewaters and reservoirs was studied. A high efficiency of metal removal (95–99.9%) and recovery (85–99%) from wastewater remained in at least six consecutive adsorption–desorption cycles. Effective removal of metals from the water of a contaminated reservoir contributed to the rapid restoration of the phytoplankton organisms after their oppression by metals. Thus, the use of a submerged device with the new hybrid adsorbent can be an effective way of remediating wastewaters and natural waters contaminated with metals.

Geogenic dust is one of the most important environmental hazards in Iran. This study investigated the concentration, contamination level, potential sources, and ecological risk and human health assessment of Shiraz atmospheric dust, the largest city in southern Iran. Contents of atmospheric dust sediments geochemistry were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). The mean concentrations of the elements in atmospheric dust are Zn (106.6 mg/kg), Cr (98.4 mg/kg), Ni (68.1 mg/kg), Cu (40.5 mg/kg), Pb (30.6 mg/kg), As (4.5 mg/kg), and Cd (0.28 mg/kg). Except As and Cd, levels of all other elements in dust sediments samples were higher than corresponding background world soils. In comparison with the concentrations of studied heavy metals in Shiraz urban street dust, the concentrations of heavy metals in Shiraz atmospheric dust were substantially at low levels. Based on Enrichment Factor (EF) and Geo-accumulation index (Igeo), Shiraz atmospheric dust is moderately to minimally polluted by selected heavy metals. The values of risk index (RI) for seven heavy metals in all dust samples were 146.2 and 130.8, which were lower than 150, indicating that ecological risks posed by studied elements in atmospheric dust were moderate. Human health risk assessment (non-carcinogenic) suggested that of the three exposure pathways, ingestion of atmospheric dust was the major pathway exposure to heavy metals in dust, followed by skin contact. The hazard index (HI) values for all studied heavy metals decreased in the following order: Cr > Pb > Ni > Cu > Zn > Cd for both children and adults. Cr and Ni contribute most to health risk posed by atmospheric dust exposure for both children and adults, and Cd, Zn, and Cu have smaller contributions. The result of cancer risk assessment suggested that Cr, Ni, and Cd were all below the safe level. Principal component analysis (PCA) indicated that grouped Cd, Ni, and Zn and grouped Cr, Cu, and Pb could be controlled by two different types of anthropogenic source. Whereas, As and Zn were controlled by both human and geogenic sources.

Dispersants including Tween 20, Tween 40, Tween 60, and polyacrylic acid (PAA) were used to modify nanoscale zero-valent iron (nZVI). All dispersants dispersed nZVI effectively. PAA-modified nZVI was more stable than nZVI that was modified with Tween surfactant. Iron nanoparticles that were prepared using 0.5–5.0% (vol%) of PAA remained in suspension for more than 2 h. nZVI that was modified using Tween surfactant remained in suspension for 30–60 min, and there was complete sedimentation of bare iron in 10 min. When 2.0–5.0% (vol%) of Tween surfactant was used, the stability of the nZVI that was modified using Tween 20 was much better than that for nZVI that was modified using Tween 40 or Tween 60. The results for the transportation test show that nZVI that was prepared using 2% (vol%) of Tween 20 exhibited the best mobility in porous media. Approximately 83–90% of TCE was degraded by bare, PAA-modified, and Tween 20-modified nZVI, and about 63–67% of TCE was removed by nZVI that was modified using Tween 40 and Tween 60 during 20 days of reaction. The production of cis-dichloroethene (DCE) and 1,1-DCE demonstrates that TCE is removed via reductive dechlorination. The results of this study show that PAA- and Tween 20-modified nZVI are more practical for in situ remediation because they exhibit good mobility and degrade TCE effectively.

Over the past years, there were dramatic improvements in identifying and assessing various feedstocks for the production of biodiesel fuels. To promote a particular feedstock as a renewable source of energy, it is important to analyze their energy, economic, and engine performance characteristics. The current work attempts to evaluate the net energy and economic indices for both fossil diesel and coconut-blended diesel (B20) considering the diesel consumption by the Indian railways. Further, we present the experimental results of a multi-cylinder diesel engine operated with neat coconut biodiesel (B100) and fossil diesel at various load and speed conditions. The engine experiments reveal that the coconut biodiesel exhibits leaner combustion and shorter ignition delay than fossil diesel. Lower amount of carbon monoxide, hydrocarbon, and smoke emission is observed in the case of coconut biodiesel, with higher levels of nitric oxide (14%) and fuel consumption than diesel. The coefficient of variation in indicated mean effective pressure is within the range of better driveability zone for both the fuels at all test conditions. Overall the engine performance, emission and combustion results with neat coconut biodiesel are favorable with a penalty in NO emission at high load conditions. The techno-economical study highlights higher production cost per liter of B20 than the cost of fossil diesel. However, the net energy ratio (NER) for B20 is 1.021, favoring higher output than diesel and thus lowers the dependency on crude oil.

Ecosystem-based management is one of the strategies to protect the coastal areas. One of the key elements is phytoplankton community composition since it represents a good indicator of anthropogenic pressures. This identifies the seasonal patterns of phytoplankton, and its alterations by the stress factors induced by human activities are highly valuable. This research represents the first attempt to study that 476 km of western Mediterranean coastal belongs to the Valencian Community (Spain) based on the phytoplankton composition approach. The water samples during a 5-year period (6757 water samples) were taken to determine its phytoplankton group’s dynamics and its relationship with anthropogenic stressors by means of a series of plots and statistical analyses. Diatoms are the group that most contribute to the whole community composition with two periods of maximum abundance. The Prasinophyceae and Cryptophyceae show unimodal patterns varying its maximum values depending on the season. The picocyanobacteria group exhibited the clearest and best-defined pattern. Other groups have no clear seasonal pattern and become abundant in areas of higher anthropogenic pressure. Graphical abstract Figure A contains poor quality of text in image. Otherwise, please provide replacement figure file.A new graphical abstract, with higher quality is attached.

China is a vast country with a wide range of difference in local customs and practices, whose governments at all levels have certain flexibility in policy formulation and implementation accordingly. Therefore, it is necessary to compare the impacts of environmental regulations (ERs) on subjective well-being (SWB) in different areas, which was totally overlooked by many scholars. Combining environmental regulations data with subjective well-being data from CGSS (2015), we conduct an empirical study on the linear and non-linear relationships between three different types of ERs and SWB in this study, then, we further verify the lag effects because of the time lag–related policies. Research results provide support that (1) in the eastern region, when command-and-control regulations(CMCER) and market-based regulations (MBER) have a reversed “U”-shaped curve connection with SWB, informal regulations (INFER) would reduce subjective well-being, and (2) for the central region, a “U”-shaped curve relationship exists between CMCER with SWB, while MBER and INFER have no significant impact, and (3) in the western region, MBER can promote SWB more sharply, and CMCER and INFER play negative roles in SWB improvement. Finally, by comparing the hysteresis results of different regions, we find that INFER and MBER are required to be strengthened for all above regions. In addition, implementation of CMCER is the highlight point for western region. Our findings have meaningful policy implications and the government should develop appropriate environmental regulations based on local conditions.

The Bi-SnO₂/C electrocatalytic membrane was fabricated via a simple electrochemical reduction and hydrothermal method. Under the action of electric field, the Sn²⁺ and Bi³⁺ were firstly adsorbed and reduced to metallic Sn and Bi on the carbon membrane surface by cathodic reduction reaction, and the Bi-SnO₂/C membrane was obtained subsequently through hydrothermal oxidation process. Confirmed by SEM, TEM, XRD, and XPS characterizations, the nano-Bi-SnO₂ is homogeneously distributed on the membrane surface and is firmly attached to the carbon membrane via C–O–Sn chemical bond. Through CV, LSV, and EIS electrochemical analysis, the Bi-SnO₂/C membrane possesses the higher electrocatalytic activity and stability than carbon membrane. Therefore, the Bi-SnO₂/C membrane could continuously efficiently remove and inactivate Escherichia coli in water through flow-through mode. As a result, the sterilization efficiency can reach more than 99.99% under the conditions of cell voltage 4 V, flow rate 1.4 mL/min, and E. coli initial concentration 1.0 × 10⁴ CFU/mL, owing to the synergistic effect of the membrane separation and electrocatalytic oxidation. Moreover, it was found that the oxidation groups of ⋅OH radicals generated by Bi-SnO₂/C membrane play the crucial role for bactericidal performance. This work presents a low-cost, highly active, and stable electrocatalytic membrane towards continuous bacterial inactivation, which exhibits promising potential in water disinfection and is beneficial for practical large-scale applications.

Emission of greenhouse gas is a global environmental problem. In recent years, China has been facing growing international pressure because of its large energy consumption and elevated greenhouse gas emissions. As the capital of China, Beijing is central to the study of carbon emission reduction since its carbon emissions have ranked at the forefront nationwide. The existing literature mainly revolves around carbon emissions of a few specific years, and there is a lack of trend study of multiple years in Beijing. This paper, based on the input-output method, calculates carbon emissions in Beijing by carbon footprints; the changing trend analysis was carried out by researching available statistical data of three years, 2002, 2007, and 2012, from the perspective of the entire city of Beijing and from that of urban and rural residents’ consumption. The reasons for the changing trends of total carbon emission in Beijing have also been analysed using the Structural Decomposition Analysis (SDA) model. Results show that the total direct carbon footprint as well as the urban and rural direct carbon footprints of residents’ consumption in Beijing is all increasing gradually. The direct carbon footprint of urban residents’ consumption is mainly produced by electricity, gasoline, and heating power, while that of rural residents’ consumption is mainly produced by raw coal and electricity. The indirect carbon footprint of residents’ consumption in Beijing is increasing gradually, and that of urban areas is higher than that of rural areas. The compositions of indirect carbon footprints of rural and urban residents’ consumption are consistent, and both come mainly from the transportation and communication industry, housing, food, culture, education, entertainment, etc. The SDA results show that the per capita consumption level is the main driving factor for the increase of the indirect carbon footprint of Beijing residents’ consumption, and the intensity of CO₂ emission is the main inhibiting factor. Finally, suggestions for reducing carbon emissions from urban and rural perspectives have been put forward.

Heavy metal contamination, one of the greatest global problems, not only endangers humans and animals but also negatively affects plants. New trends, the production and industrial applications of metals in nanoforms, lead to release of large amounts of nanoparticles into the environment. However, the influence of nanoparticles on living organisms is not well understood. Cadmium is a heavy metal not essential for plants, and to its phytotoxicity also contributes its chemical similarity to zinc. It has been recorded that zinc at low concentrations reduces the toxicity of cadmium, but our results with ZnO nanoparticles did not proved it. In contrast, ZnO nanoparticles significantly increased the negative effect of cadmium, which was reflected mainly in changes in the content of photosynthetic pigments.