In this work, synergistic effect of solar photocatalysis integrated with adsorption process towards the degradation of Congo red (CR) was investigated via two different approaches using a photocatalytic membrane reactor. In the first approach, sequential treatments were conducted through the adsorption by graphene oxide (GO) and then followed by photocatalytic oxidation using Fe-doped ZnO nanocomposites (NCs). In the second approach, however, CR solution was treated by photocatalytic oxidation using Fe-doped ZnO/rGO NCs. These nanocomposites were synthesized by a sol-gel method. The NCs were characterized by X-ray diffraction (XRD), photoluminescence (PL), Fourier transmission infrared (FTIR), ultraviolet–visible (UV-vis) spectroscopy, and field emission scanning electron microscopy (FESEM). It was observed that Fe-doped ZnO could enhance the photoactivity of ZnO under solar light. When Fe-doped ZnO were decorated on GO sheets, however, this provided a surface enhancement for adsorption of organic pollutants. The photocatalytic performances using both approaches were evaluated based on the degradation of CR molecules in aqueous solution under solar irradiation. Nanofiltration (NF) performance in terms of CR residual removal from water and their fouling behavior during post-separation of photocatalysts was studied. Serious flux declined and thicker fouling layer on membrane were found in photocatalytic membrane reactor using Fe-doped ZnO/rGO NCs which could be attributed to the stronger π–π interaction between rGO and CR solution.

Industrial hydrodesulfurization method has not been efficient for removal of dibenzothiophene (DBT) from petroleum distillates. Therefore, in this current study, adsorptive desulfurization (investigated in batch mode) was carried out using functionalized carbon nanotubes (FCNTs) to reduce the amount of DBT in a model diesel. Different techniques, such as, scanning electron microscope (SEM) equipped with energy-dispersive X-ray (EDX), were used to check the morphological structure and the elemental compositions of the adsorbent; Fourier transmission infrared (FTIR) was used to check the chemical functionalities of the adsorbent; and nitrogen physisorption at 77 K was used to check the surface area, pore size, and pore volume of the adsorbent. The results show that the FCNTs outperformed the non-functionalized carbon nanotubes (CNTs) during the desulfurization by about 10%, indicating the functionalization did improve the desulfurization performance of the CNTs. The % removal of DBT by the FCNTs and CNTs was 70.48 and 60.88%, respectively. It can be concluded that the acid treatment of CNTs enhanced its surface affinity for DBT, thus contributing to the improved adsorption performance of the adsorbent. The isotherm results show that Freundlich isotherm model described well the mechanism of the adsorption process for both CNTs and FCNTs. In addition, pseudo second-order kinetics describes the behavior of the adsorbents during the adsorption process. The results obtained in this study therefore show that functionalized CNTs could be efficient and potential adsorbent for removal of DBT in petroleum distillate (e.g., diesel), to meet up with the stringent policies regarding emission of sulfur oxides.

Traffic accident may bring vehicle fire in the street canyons. With its high temperature and numerous hazardous materials, the smoke produced by the vehicle fire may cause serious damage to the human body and the properties nearby, such as the glass curtain walls of buildings. The influence of the ambient air flow speed and street aspect ratio on the dispersion of fire smoke in street canyon has been analyzed by FDS software and theoretical analysis in this study. The impact of different windward building heights and different ambient air flow speeds u₀ on the fire smoke were investigated. The results show that the fire smoke tilts towards the opposing direction of the ambient air flow within the street canyon, while the ambient air flow is perpendicular to the windward building. The results indicate that the critical re-entrainment velocity decreases at first, and then increases until it attains a constant with the building height ratio H₁/H₂. Finally, a predictive model of the critical re-entrainment velocity was developed under different building height ratios H₁/H₂.

This study aims to investigate the validity of pollution haven hypothesis for the period from 1982 to 2013 in ten newly industrialized countries. For this purpose, we examine the relationship between real income, foreign direct investment, energy consumption, and ecological footprint using second-generation panel data methodology to take into account the cross-sectional dependence among newly industrialized countries. In doing so, the possible nonlinear relationship between foreign direct investment and environmental degradation is also searched. The results show that increased energy consumption and economic growth lead to increase in ecological footprint. Moreover, the U-shaped relationship between foreign direct investment and ecological footprint is confirmed in newly industrialized countries.

Lignite fly ash (FA) and waste rocks (WRs) were mixed in three different ratios (1:1, 1:3 and 1:5) and studied to compare the effects of adding FA on acid mine drainage generation from coal mining WRs, leachability of elements and the potential occurrence of the secondary minerals. FA mixed with WRs showed significant differences in pH levels compared to previous research. The 1:1 mixture performed best of all the three mixtures in terms of pH and leachability of elements, mainly due to the higher proportion of FA in the mixture. The pH in the 1:1 mixtures varied between 3.3 and 5.1 compared to other mixtures (2.3–3.5). Iron and SO₄²⁻ leached considerably less from the 1:1 mixture compared to the others, indicating that the oxidation of sulphides was weaker in this mixture. Aluminium leached to a high degree from all mixtures, with concentrations varying from mg L⁻¹ to g L⁻¹. The reason behind this increase is probably the addition of FA which, due to acidic conditions and the composition of the FA, increases the availability of Al. For the same reason, high concentrations of Mn and Zn were also measured. Geochemical modelling indicates that the 1:1 mixture performs better in terms of precipitation of Al³⁺ minerals, whereas Fe³⁺ minerals precipitated more in mixtures containing less FA. These results suggest that, with time, the pores could possibly be filled with these secondary minerals and sulphate salts (followed by a decrease in sulphide oxidation), improving the pore water pH and decreasing the leachability of elements. Since grain size plays a crucial role in the reactivity of sulphides, there is a risk that the results from the leaching tests may have been influenced by crushing and milling of the WR samples.

Copper (Cu) and norfloxacin (Nor) are frequently used as feed additives for animal growth promotion, which results in a great probability of Cu²⁺ and Nor coexisting in animal excretion and in soils. Sorption of Cu²⁺ and Nor on soil organic matter (SOM) can markedly affect their environmental fate. Thus, humic acid (HA), a major fraction of SOM, was chosen to investigate the cosorption behaviors of Cu²⁺ and Nor on HA under different solution chemistry conditions (pHs, ionic strengths, and foreign ions). The addition of Nor decreased the maximum adsorption capacity (Qₘ) of Cu²⁺ and an increasing effect was observed with increasing Nor concentration. Meanwhile, the addition of Cu²⁺ also markedly inhibited the sorption of Nor on HA. The Qₘ of Cu²⁺ increased with increasing pH from 3.0 to 5.0 whether Nor was present or not, but more addition of Nor led to less increment in Qₘ of Cu²⁺ at the same pH. The Qₘ of Nor was observed at pH 4.0 without Cu²⁺, but that was found at pH 5.0 and 3.0 with the addition of 20 and 100 mg L⁻¹ Cu²⁺, respectively. The sorption of Cu²⁺ on HA decreased with increasing ionic strength and followed an order of NaH₂PO₄ > Na₂SO₄ ≈ NaNO₃ at pH 5.0 whether Nor was present or not. Additionally, the higher valence cation had a stronger inhibition effect on Cu²⁺ sorption. The competition between Cu²⁺ and Nor for sorption on HA under the same conditions indicated that the coexistence of Cu²⁺ and Nor may enhance the feasibility of their mobility and environmental risk.

The aim of the study was to evaluate the content, occurrence, and leachability of arsenic (As), lead (Pb), and thallium (Tl) in wastes from coal cleaning processes with respect to the safe management of this waste. The study focused on wastes resulting from the wet gravitation and flotation processes employed for the purposes of coking coal cleaning in four coal mines situated in the Upper Silesian Coal Basin (Poland). The scope of the study included (i) determination of the content of these elements in the investigated wastes using atomic absorption spectrometry, (ii) evaluation of their mode of occurrence using electron microprobe analysis, and (iii) preliminary assessment of their leachability in deionized water. The content of the analyzed elements in the examined samples of coal waste was twice as high as the average content of these elements in the Earth’s crust. The contents of As and Pb, however, did not exceed their permissible contents in inert waste in accordance with Polish legal regulations based on EU directives. The limit on the content of Tl is not specified by these regulations, but its amount in the examined samples was similar to that occurring in the soils. Moreover, leaching tests have shown that these elements are hardly eluted from the analyzed material. Their content in the water leachates was generally lower than the detection limit of the analytical method, complying with the standards for good and very good water quality. Low leachability of these elements most probably results from their mode of occurrence in the investigated wastes. The chemical analysis using an electron microprobe and the analysis of the correlation between these elements, e.g., total and pyritic sulfur, have shown that Pb, As, and Tl are mainly found in sulfide minerals which are characterized by negligible solubility. In conclusion, the investigated hard coal processing waste does not constitute a threat to the environment and can be commercially used or safely neutralized, e.g., by landfilling.

Spotted bollworm, Earias vittella, is one of the most serious and devastating insect pests of vegetables and cotton. Currently, insecticides are necessary for its control in nearly all crop systems. In this paper, we evaluate the sub-lethal effects of lufenuron on biological traits and activity of detoxification enzymes: cytochrome P450 monooxygenases, esterase, and glutathione S-transeferase (GST) in second instar larvae of E. vittella. Results showed that sub-lethal concentrations (LC₁₅ and LC₄₀ of lufenuron), prolonged larval period (at LC₄₀ = 13.86 ± 1.22 day, LC₁₅ = 13.14 ± 1.15 day, control = 12.28 ± 0.7), pupal duration (LC₄₀ = 11.1 ± day, LC₁₅ = 11.8 ± 0.28 day, control = 9.40 ± 0.52), and extended mean generation time (LC₄₀ = 27.3 ± 0.43 LC₁₅ = 29.0 ± 1.19 day, control = 26.0 ± 0.65). Sub-lethal exposure significantly prolonged the pre-adult stage, decreased pupal weight, and reduced adult longevity in the parent (F₀) and F₁ generation. Moreover, the fecundity and egg viability were significantly lowered in parental and F₁ generations at both sub-lethal concentrations compared to the control. While no significant effects were noted on reproductive parameters such as the intrinsic rate of increase (r), finite rate of increase (λ), and net reproduction rate (R₀) of F₁ generation when compared to the control. Only mean generation time (T) in F₁ at LC₁₅ was significantly longer compared to the LC₄₀ and control (LC₄₀ = 3.79 ± 0.37, LC₁₅ = 32.28 ± 1.55 day, control = 29.79 ± 0.55). Comparatively, the activities of cytochrome P450 monooxygenases and esterase were higher than GST in treated populations. The increase in resistance development against insecticides may possibly because of elevated activity of detoxification enzymes. These results provide useful information for monitoring resistance in integrated pest management (IPM) programs for E. vittella.

Resistance to grain protectants in Tribolium castaneum (Herbst) is a serious threat to international grain trade. Frequent and overdose application of chemical insecticides is becoming a serious health hazard and cause environmental pollution. Resistance management approaches by using various synergists along with novel compounds has become more imperative to increase efficacy of environmentally safe insecticides. We have evaluated piperonyl butoxide (PBO) and emamectin benzoate mixtures for management of resistant field populations of T. castaneum. The collected strains had demonstrated 50 to 200% resistance already developed against emamectin benzoate as compared with deltamethrin susceptible reference strain. The inclusion of PBO along with emamectin significantly reduced this resistance by at least 28% and the LC₅₀ were lowered from 5.12 to 1.9 μg/ml with the highest synergism ration of 2.7 in resistant strain. Enzymatic assays clearly demonstrated that the specific activities of catalase and acetylcholinesterases were significantly decreased at an average of 80% and 60%, respectively, when PBO was included as a synergist at 1:2 ratio with emamectin benzoate. The results highlight the mechanism that renders the field population resistant to emamectin benzoate and suggests the synergistic role of piperonyl butoxide as a potent additive in grain protectants for resistance management.

Tobacco stalk, a common agricultural waste derived from the harvest of tobacco, caused serious environmental pollution in China. In this study, the performance of biomethane production and characteristics of four varieties of tobacco stalk were investigated for the first time. The results showed that the highest cumulative methane yield of 130.2 mL/g-VS was obtained from Nicotiana tabacum L., Yunyan114, which had lower lignin content than other varieties of tobacco stalk. Moreover, different kinetic models were used to describe the biomethane production process, and it was found that the modified Gompertz model was more suitable to simulate the anaerobic digestion (AD) of tobacco stalk. The findings of this study not only showed a feasible method for minimizing the pollution issues of tobacco stalk waste but also gave fundamental information for future AD application.