•Noble metal catalyst surpasses metal oxides on low-temperature activity.•Low-temperature activity determines the cost of catalysis application.•Hybrid treatments with catalysis are promising ...technologies for industrial VOCs pollution.
VOCs pollution is a complex issue involving a wide variability of pollutants that threatens human health and environment. Owing to the effective and economic characters, low-temperature (293–673K) catalytic oxidation (CO) has been extensively studied for VOCs removal in research and application fields. This review examines recent progress on the VOCs catalytic oxidation with noble metal and metal oxides catalysts, and the engineering features of regenerative catalytic oxidizer (RCO), recuperative catalytic oxidizer (CO), photocatalytic oxidizer (PCO) and hybrid treatment combining adsorptive concentration/ozonation/plasma with catalytic oxidizer. The aim was to analyze the factors that relate to the low-temperature activity of catalysts, and the efficiency and economy of manifold catalytic oxidizers. It can be concluded that improving low-temperature activity of catalysts, increasing thermal recovery efficiency of oxidizers and developing hybrid treatment technologies are most effective means to control practical VOCs pollution.
Abstract
The widely adopted “lamppost” thermal reprocessing model, in which the variable UV/optical emission is a result of the accretion-disk reprocessing of the highly fluctuating X-ray ...emission, can be tested by measuring interband time lags in quasars spanning a range of X-ray power. This work reports the interband time lag in an apparent X-ray-weak quasar, SDSS J153913.47+395423.4. A significant cross correlation with a time delay of ∼33 days (observed frame) is detected in the Zwicky Transient Facility
g
and
r
light curves of SDSS J153913.47+395423.4. The observed X-ray power seems to be too weak to account for the observed interband cross correlation with time delay. Hence the X-ray-weak quasar SDSS J153913.47+395423.4 is either intrinsically X-ray normal (but observationally X-ray weak), or the X-ray emission is not the only mechanism to drive UV/optical variability. In the former case, the required X-ray power is at least 19 times stronger than observed, which requires either an exceptionally anisotropic corona or Compton-thick obscuration. Alternatively, the corona-heated accretion-disk reprocessing or the EUV torus models may account for the observed time lags.
Excessive exploitation and massive coal mine closures have brought about extensive goafs in Shanxi where 8780 coal mines have been abandoned in the last 20 years. Acid mine drainage (AMD) poses ...severe environmental impact and has become a prominent problem in Shanxi abandoned coal mine areas, which has aggravated the shortage of water resources and threatened the safety of the local drinking water supply. The purpose of this review is to protect the precious water resources and maintain sustainable use in Shanxi coal mines and downstream. By retrieving and analyzing about 90 domestic and international publications, a critical review of the AMD research results in Shanxi abandoned coal mines is conducted from the perspective of the formation mechanism, migration and transformation, prediction, treatment and management. The results shows that pyrite is the prerequisite for the formation of AMD, oxygen is the inducement, water is the carrier, and Fe3+ and microorganisms are the catalyst. The roadway system and geological structure are the dominant control factors. Finally, current difficulties and future research are pointed out. It is necessary to further strengthen the systematic research on the geological and hydrogeological conditions of abandoned coal mines, and explore an efficient, cheap, environmental technology, and construct the pollution risk assessment model for the AMD treatment. This study provides a scientific basis for the comprehensive treatment and management of AMD in abandoned coal mines in Shanxi.
In this study, rod-like Co3O4 (Co3O4-rod) nanocatalyst was prepared by a modified precipitation method, which showed an excellent performance for formaldehyde oxidation to carbon dioxide and water. ...The light-off temperature (10% conversion) and the temperature for complete conversion of formaldehyde was at 60°C and 120°C, respectively. XPS and CO2-TPD analyses indicated that Co3O4-rod had abundant Co3+ and OH (hydroxyl) species on the surface compared with other morphologies of Co3O4 investigated (e.g. Co3O4-sheet and Co3O4-cube). It was proposed that Co3+ ions should be considered as active sites of good oxidation ability for formaldehyde catalytic oxidation.
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•Rod-like Co3O4 was synthesized by a modified precipitation method.•Rod-like Co3O4 shows good performance on low-concentration formaldehyde removal.•Abundance of Co3+ ions on rod-like Co3O4 surface exhibits high oxidation ability.•Hydroxyl species on the surface promote the activity of formaldehyde oxidation.
The red imported fire ant (
) is a worldwide invasive and dangerous insect that is controlled mainly by chemical insecticides. Plant-derived insecticidal compounds are generally better than synthetic ...insecticides for environmental compatibility and the biosafety of non-targets. The toxicity of the ethanol extract of
roots against
was evaluated under laboratory conditions. The ethanol extract showed toxicity against minor and medium workers of
with 7-day LC
values of 1426.25 and 2292.60 mg/L, respectively. By bioactivity-directed chromatographic separations using the minor worker as the test insect, two active compounds, matrine and sophocarpine, were isolated from the
total alkaloids; their chemical structure was identified by
C NMR data. Matrine showed toxicities against minor and medium workers with 7-day LC
values of 46.77 and 71.49 mg/L, respectively, and for sophocarpine, 50.08 and 85.87 mg/L, respectively. The two compounds could substantially reduce the foraging response, food consumption, and aggregation of
workers at a sublethal concentration of 15 mg/L. The present research suggests that
roots have potential as a natural control agent for red imported fire ants.
Abstract We use LCOGT observations (MJD 59434−59600) with a total exposure time of ≃50 hr and a median cadence of 0.5 day to measure the interband time delays (with respect to u ) in the g , r , and ...i continua of a highly variable active galactic nucleus (AGN), 6dFGS gJ022550.0-060145. We also calculate the expected time delays of the X-ray reprocessing of a static Shakura–Sunyaev disk according to the source's luminosity and virial black hole mass; the two parameters are measured from the optical spectrum of our spectroscopic observation via the Lijiang 2.4 m telescope. It is found that the ratio of the measured time delays to the predicted ones is 2.6 − 1.3 + 1.3 . With optical light curves (MJD 53650–59880) from our new LCOGT and archival Zwicky Transient Facility, Pan-STARRS, Catalina Sky Survey, and ATLAS observations, and Wide-field Infrared Survey Explorer (WISE) data (MJD 55214−59055), we also measured time delays between WISE W1/W2 and the optical emission. W1 and W2 have time delays (with respect to V ), 9.6 − 1.6 + 2.9 × 10 2 days and 1.18 − 0.10 + 0.13 × 10 3 days in the rest frame, respectively; hence, the dusty torus of 6dFGS gJ022550.0-060145 should be compact. The time delays of the W1 and W2 bands are higher than the dusty torus size–luminosity relationship of Lyu et al. By comparing the infrared and optical variability amplitude, we find that the dust-covering factors of the W1 and W2 emission regions are 0.7 and 0.6, respectively. Future broad emission-line reverberation mapping of this target and the results of this work enable us to determine the sizes of the AGN main components simultaneously.
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•The addition of iron increased valence state of manganese.•The addition of tungsten introduced new acid site.•High temperature selectivity is significantly improved.•Modified ...catalysts showed excellent SCR activity, selectivity and H2O resistance.
The influence of iron and tungsten in the Mn/Ti catalyst system on the activity and H2O induced deactivation was evaluated for the Selective Catalytic Reduction (SCR) of NO. The properties of the catalysts were characterized by physicochemical measurements, including BET surface area, X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), NH3 temperature-programmed desorption (NH3-TPD), NO oxidation, X-ray photoelectron spectroscopy (XPS) and in situ diffuse reflectance infrared spectroscopy (DRIFT) analyses. The results indicated that the addition of iron promoted surface species dispersion and increased valence state of manganese species, which enhanced the low-temperature activity. The addition of tungsten enhanced the acid sites and improved the thermal stability of the acid sites. Thus, the Mn10Fe10/W3Ti exhibited excellent NOx conversion and N2 selectivity during high temperature compared with Mn10/Ti and Mn10Fe10/Ti catalysts. Furthermore, the addition of tungsten exhibited excellent resistance to H2O induced deactivation. Accordingly, the co-addition of iron and tungsten with proper ratios to Mn/Ti resulted in excellent NOx conversion, N2 selectivity and H2O resistance.
Tumor-associated macrophages (TAMs) represent the M2-like phenotype with potent immunosuppressive activity, and play a pro-tumor role in pancreatic ductal adenocarcinoma (PDAC) biology. In this ...study, we investigated the role of the insulin-like growth factor binding protein 2 (IGFBP2) as a determinant of TAM polarity. Clinical data revealed that the levels of IGFBP2 correlated with M2 TAMs accumulation and disease progression in human PDAC. In vivo mouse model experiments showed that IGFBP2 promoted an immunosuppressive microenvironment and tumor growth in a macrophage dependent manner. Bioinformatics analysis of PDAC transcriptomes revealed a significant association between IGFBP2 expression and M2 macrophage polarization and signal transducer and activator of transcription 3 (STAT3) activation. Mechanistic investigations demonstrated that IGFBP2 augmented the expression and secretion of IL-10 through STAT3 activation in PDAC cells, which induced TAM polarization toward an M2 phenotype. IGFBP2-polarized M2 macrophages significantly increased Tregs infiltration and impaired antitumor T-cell immunity in a mouse model. Thus, our investigations have illuminated the IGFBP2 signaling pathway that contributes to the macrophage-based immunosuppressive microenvironment in PDAC, suggesting that blocking the IGFBP2 axis constitutes a potential treatment strategy to reset TAM polarization toward an antitumor state in PDAC.
•High IGFBP2 correlates with M2 TAM accumulation and disease progression in human PDAC.•IGFBP2 augments IL-10 by STAT3 activation in PDAC cells, inducing M2 TAM polarization.•IGFBP2-polarized M2 TAMs increase Treg infiltration and impair antitumor T-cell immunity.•Blocking IGFBP2 offers a potential strategy to reset TAM polarization toward an antitumor state in PDAC.
Photoelectrochemical（PEC） water splitting using solar energy has attracted great attention for generation of renewable hydrogen with less carbon footprint, while there are enormous challenges that ...still remain for improving solar energy water splitting efficiency, due to limited light harvesting, energy loss associated to fast recombination of photogenerated charge carriers, as well as electrode degradation. This overview focuses on the recent development about catalyst nanomaterials and nanostructures in different PEC water splitting systems. As photoanode, Au nanoparticle-decorated TiO2 nanowire electrodes exhibited enhanced photoactivity in both the UV and the visible regions due to surface plasmon resonance of Au and showed the largest photocurrent generation of up to 710 nm. Pt/Cd S/CGSe electrodes were developed as photocathode. With the role of p–n heterojunction, the photoelectrode showed high stability and evolved hydrogen continuously for more than 10 days. Further, in the Z-scheme system（Bi2S3/TNA as photoanode and Pt/Si PVC as photocathode at the same time）, a self-bias（open-circuit voltage Voc= 0.766 V） was formed between two photoelectrodes, which could facilitate photogenerated charge transfers and enhance the photoelectrochemical performance, and which might provide new hints for PEC water splitting. Meanwhile, the existing problems and prospective solutions have also been reviewed.
Caragana sensu lato (s.l.) includes approximately 100 species that are mainly distributed in arid and semi-arid regions. Caragana species are ecologically valuable for their roles in windbreaking and ...sand fixation. However, the taxonomy and phylogenetic relationships of the genus Caragana are still unclear. In this study, we sequenced and assembled the chloroplast genomes of representative species of Caragana and reconstructed robust phylogenetic relationships at the section level. The Caragana chloroplast genome has lost the inverted repeat region and wascategorized in the inverted repeat loss clade (IRLC). The chloroplast genomes of the eight species ranged from 128,458 bp to 135,401 bp and contained 110 unique genes. All the Caragana chloroplast genomes have a highly conserved structure and gene order. The number of long repeats and simple sequence repeats (SSRs) showed significant variation among the eight species, indicating heterogeneous evolution in Caragana. Selective pressure analysis of the genes revealed that most of the protein-coding genes evolved under purifying selection. The phylogenetic analyses indicated that each section forms a clade, except the section Spinosae, which was divided into two clades. This study elucidated the evolution of the chloroplast genome within the widely distributed genus Caragana. The detailed information obtained from this study can serve as a valuable resource for understanding the molecular dynamics and phylogenetic relationships within Caragana.
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