Aiming at addressing serious pollution in the No. 30106 fully mechanized coal mining face of Shiquan Coal Mine during coal cutting process, the spraying device between hydraulic supports was improved through the combination of experimental analysis, numerical simulation, and field measurement, and a novel wind-assisted centralized spraying dedusting device was developed. The newly developed device could make the formed spraying field more concentrated on the dust-producing source around the coal shearer’s drum, and thus significantly enhanced the spraying performance. According to numerical simulation results, the spraying performance reached the optimum at a hydraulic pressure of 8 MPa for the spraying device and an air pressure of 1 MPa for the pneumatic motor; under these optimal conditions, the droplet concentration in the spraying field around the coal cutter drum was as high as 24.85 g/m³, and the formed high-concentration spraying field could basically cover the whole section in the spraying field from coal wall to the support pillar. Field measured results revealed that, at a hydraulic pressure of 8 MPa and an air pressure of 1 MPa, the dust suppression rate around coal cutter driver reached up to 87.96%, suggesting that the developed wind-assisted centralized spraying dedusting device had remarkable dust suppression performance and could effectively improve the operating environment in the fully mechanized mining face. Graphical Abstract In this paper, we have designed a novel wind-assisted centralized spraying dedusting device and studied the optimal spray parameters. Firstly, the nozzles were selected according to the multi-factor experimental platform for measuring the spraying field’s atomization characteristics. Secondly, we had a numerical simulation of the fully mechanized mining face. And the third, we tested the effect of dust removal.

The effects of manganese content, carrier calcination temperature, and catalyst calcination temperature of manganese-based zirconium pillared intercalated montmorillonite (Mn/Zr-PILM) catalysts were investigated for low-temperature selective catalytic reduction of NOₓ by NH₃ (NH₃-SCR) in the metallurgical sintering flue gas. The physicochemical properties of these catalysts can be characterized by X-ray diffraction (XRD), N₂ adsorption-desorption isotherm, and temperature-programmed desorption of ammonia (NH₃-TPD). The 10Mn/Zr400-PILM(300) catalyst had the highest NOₓ conversion under excess oxygen conditions (15 vol% oxygen) and reached 91.8% NOₓ conversion at 200 °C. It was found that when the loading of manganese was 10 wt.%, the catalyst had the highest catalytic activity and the manganese-active component was highly dispersed on the Zr-PILM surface. The optimal calcination temperature of the Zr-PILM was 400 °C because the catalyst pore size was concentrated at 1.92 nm and the catalyst had the most acidic sites. And the optimum calcination temperature of the catalyst was 300 °C. This was because excessive calcination temperature promoted the manganese oxide polymerization and reduced the catalytic activity of the catalyst.

Cellulose and lignin belongs to refractory organic matters in the traditional composting. In this research, the degradation of lignocellulose in dairy cattle manure was investigated through adding calcium oxide (CaO) and superphosphate (SSP). In the presence of CaO and SSP, the degradation rate of cellulose and lignin were improved by 25.0% and 8.33%, respectively. The results indicated that the pH value in system would be slightly higher with the addition of CaO and SSP. Besides, the pH value of all cow manure piles were about 8.4 after composting rotten, which could be well neutralized by the gradually acidified soil in the southwest of China with the full effect of fertilizer released. In addition, the abundance of Bacillales, Actinomycetes, and Thermoactinomycetaceae in the experimental groups (AR) was slightly better than that in the control groups (CK) during composting, which led to a conclusion that an elaborate physical–chemical–multivariate aerobic microorganism evolution model of cellulose degradation products (PCMC) was deduced and the physical–chemical–multivariate aerobic microorganism model of lignin cycle degradation (PCML) was developed.

In this study, we aimed at determining greenhouse gas (GHG) (CO₂, CH₄, and N₂O) fluxes exchange between the soil collected from sites dominated by different vegetation types (Calamagrostis epigeios, Phragmites australis, and Carex schnimdtii) in nitrogenous loaded riparian wetland and the atmosphere. The intact soil columns collected from the wetland were incubated in laboratory and continuously treated with [Formula: see text]-enriched water simulating downward surface water percolating through the soil to become groundwater in a natural system. This study revealed that the soil collected from the site dominated by C. epigeios was net CO₂ and N₂O sources, whereas the soil from P. australis and C. schnimdtii were net sinks of CO₂ and N₂O, respectively. The soil from the site dominated by C. schnimdtii had the highest climate impact, as it had the highest global warming potential (GWP) compared with the other sites. Our study indicates that total organic carbon and [Formula: see text] concentration in the soil water has great influence on GHG fluxes. Carbon dioxide (CO₂) and N₂O fluxes were accelerated by the availability of higher [Formula: see text] concentration in soil water. On the other hand, higher [Formula: see text] concentration in soil water favors CH₄ oxidation, hence the low CH₄ production. Temporally, CO₂ fluxes were relatively higher in the first 15 days and reduced gradually likely due to a decline in organic carbon. The finding of this study implies that higher [Formula: see text] concentration in wetland soil, caused by human activities, could increase N₂O and CO₂ emissions from the soil. This therefore stresses the importance of controls of [Formula: see text] leaching in the mitigation of anthropogenic N₂O and CO₂ emissions.

Atrazine, one of the most widespread herbicides in the world, is considered as an environmental estrogen and has potential carcinogenicity. In this study, atrazine was degraded on boron-fluorine co-doped TiO₂ nanotube arrays (B, F-TiO₂ NTAs), which had similar morphology with the pristine TiO₂ NTAs. The structure and morphology of TiO₂ nanotube samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-visible diffuse reflectance spectroscopy (DRS). It showed that the decoration of fluorine and boron made both the absorption in the visible region enhanced and the band edge absorption shifted. The efficiency of atrazine degradation by B, F-TiO₂ NTAs through photoelectrocatalysis was investigated by current, solution pH, and electrolyte concentration, respectively. The atrazine removal rate reached 76% through photoelectrocatalytic reaction by B, F-TiO₂ NTAs, which was 46% higher than that under the photocatalysis process. Moreover, the maximum degradation rate was achieved at pH of 6 in 0.01 M of Na₂SO₄ electrolyte solution under a current of 0.02 A and visible light for 2 h in the presence of B, F-TiO₂ NTAs. These results showed that B, F-TiO₂ NTAs exhibit remarkable photoelectrocatalytic activity in degradation of atrazine.

In this study, the catalytic activity and kinetic characteristics of the aromatic hydrocarbon dioxygenase system and the possibility of substituting its ferredoxin and ferredoxin reductase components were evaluated. The genes encoding toluene dioxygenase and toluene dihydrodiol dehydrogenase were cloned from Pseudomonas putida F1, and the corresponding enzymes were overexpressed and purified to homogeneity. Oxidative hydroxylation of toluene to cis-toluene dihydrodiol was catalyzed by toluene dioxygenase, and its subsequent dehydrogenation to 3-methylcatechol was catalyzed by toluene dihydrodiol dehydrogenase. The specific activity of the dioxygenase was 2.82 U/mg-protein, which is highly remarkable compared with the values obtained in previous researches conducted with crude extracts or insoluble forms of enzymes. Kinetic parameters, as characterized by the Hill equation, were vₘₐₓ = 497.2 μM/min, KM = 542.4 μM, and nH = 2.2, suggesting that toluene dioxygenase has at least three cooperative binding sites for toluene. In addition, the use of alternative ferredoxins and reductases was examined. Ferredoxin cloned from CYP153 could transfer electrons to the iron sulfur protein component of toluene dioxygenase. The ferredoxin could be reduced by ferredoxin, rubredoxin, and putidaredoxin reductases of CYP153, alkane-1 monooxygenase, and camphor 5-monooxygenase, respectively. The results provide useful information regarding the effective enzymatic biotreatment of hazardous aromatic hydrocarbon contaminants.

To insight the urban volatile organic compound (VOC) profiles and its contribution to ozone, four-time per day (8:00–9:00, 15:00–16:00, 19:00–20:00, and 23:00–24:00) off-line VOC samples were collected from 16th July to 28th July 2018 for a summer investigation campaign over Xi’an, China. The diurnal variation was significant that the lowest TVOC concentrations were observed in the midnight period (28.4 ± 25.6 ppbv) while the highest was shown in the morning (49.6 ± 40.1 ppbv). The differences of total non-methane VOCs (TVOCs) between weekdays and weekend were also significant that the weekend showed significantly high VOC levels than weekdays (p < 0.05) but did not lead to significant ambient O₃ increase (p > 0.05). Isopentane, a general marker for vehicle exhaust, showed descending concentrations from morning to midnight and good correlation with vehicle numbers on road, indicating a potential source to the VOCs at this site. The results from PMF proved that vehicular exhaust was the largest source to the VOCs in this study (64.4%). VOC categories showed a reverse sequence in abundance of concentrations and OFP contributions that alkenes showed the highest OFPs although with the lowest abundance in TOVCs due to their high reactivity in photochemical reactions. High OFPs from ethylene and isopentane indicated that vehicular emissions could be the largest potential OFP source in this site. OFPs from isoprene (from 1.85 to 13.4 ppbv) indicated that biogenic VOCs should not be negligible in urban Xi’an city when controlling O₃ pollutants. Comparison of two OFP methods was conducted and MIR method was proved to be more reasonable and scientific in summer Xi’an. Therefore, vehicular emission, the largest contributor to ambient VOCs and also OFPs, as well as biological source should be priority controlled in guiding VOC emissions and reducing O₃ control policies.

In this study, nine OPEs were measured in 60 street dust samples collected from the central province of Henan, China. The total concentrations of OPEs (∑₉OPEs) in street dust range from 2.77 to 505 μg/kg (median 59.3 μg/kg). Chlorinated OPEs are dominant in street dust with median concentration of 33.5 μg/kg, followed by aryl OPEs (median 9.05 μg/kg), and alkyl OPEs (median 6.19 μg/kg). No significant correlations are found between ∑₉OPEs and parameters, such as population (p = 0.931), population density (p = 0.602), car ownership (p = 0.618), and gross domestic product (p = 0.863). Principal component analysis (PCA) result reveals that road traffic could be a major source of OPEs in street dust because of their extensive use in various vehicles. The total average (median) and high-level exposure (95th percentile) of OPEs are 1.01 × 10⁻², 7.17 × 10⁻² ng/kg bw/d for adults and 6.03 × 10⁻², 0.43 ng/kg bw/d for children, respectively. Hazard quotient (HQ) values are 5–6 orders of magnitude lower than the acceptable risk level (HQ < 0.1), indicating there is still a low risk to local residents at current levels.

A series of MnOₓ/ACFN, Ce-MnOₓ/ACFN, and Fe-Ce-MnOₓ/ACFN catalysts on selective catalytic reduction (SCR) of NOₓ with NH₃ at low-middle temperature had been successfully prepared through ultrasonic impregnation method, and the catalysts were characterized by SEM, XRD, BET, H₂-TPR, NH₃-TPD, XPS, and FT-IR spectroscopy, respectively. The results demonstrated that the 15 wt% Fe₍₁₎-Ce₍₃₎-MnOₓ₍₇₎/ACFN catalyst achieved 90% NOₓ conversion (100~300 °C), good water resistance, and stability (175 °C). The excellent catalytic performance of the Fe₍₁₎-Ce₍₃₎-MnOₓ₍₇₎/ACFN catalyst was mainly attributed to the interaction among Mn, Ce, and Fe. The doping of Fe promoted the dispersion of Ce and Mn and the formation of more Mn⁴⁺ and chemisorbed oxygen on the surface of a catalyst. This work laid a foundation for the successful application of active carbon fiber in the field of industrial denitrification, especially in the aspect of denitrification moving bed. Graphic abstract

Increasing population and over-consumption are placing unprecedented demands on agriculture and natural resources. The Earth is suffering from global warning and environmental destruction while our agricultural systems are concurrently degrading land, water, biodiversity, and climate on a global scale. For a sustainable future, green certification, e-commerce, and environment education can boost low-carbon economy with decreasing carbon emissions, but very few researches address them for the hotel industry. This research studies the performance impact of e-commerce, international hotel chain, local hotel chain, and green certification for carbon emission reductions of international tourist hotels of Taiwan. It reveals that, after a sufficiently long time, there is an improvement in the environmental and economic performance of the green-certified hotel group. In addition, it reveals that, as recommended by the operation policy, the international hotel chain group together with e-commerce has better performance than local hotel chain. It is also discussed how to sustain the continuing improvement in low-carbon performance of the hotel industry.