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Bentzen Tucker posted an update 4 days, 12 hours ago
Copper-containing minerals have been extensively used in Fenton-like processes for degradation of pollutants and have exhibited great potential for environmental remediation. This work reports the first use of copper sulfide (CuS), a typical Cu-mineral, for the activation of peroxymonosulfate (PMS) for pollutant degradation; the study also elucidates the underlying mechanism of these processes. Copper sulfide effectively activated PMS to degrade diethyl phthalate (DEP). Electron paramagnetic resonance, free radical quenching, X-ray photoelectron spectroscopy, X-ray diffraction analyses and DFT calculations confirmed that ≡Cu (I)/≡Cu (II) cycling on the surface of CuS provided the main pathway to activate PMS to produce highly oxidative species. Unlike conventional sulfate radical-based PMS activation processes, hydroxyl radical (•OH) were found to be the dominant radical in the tested CuS/PMS system, which performed more efficiently than an alternative •OH-based oxidation system (CuS/H2O2) for DEP degradation. In addition, the presence of anions such Cl- and NO3- has limited inhibition effects on DEP degradation. Overall, this study provides an efficient pathway for PMS-based environmental remediation as well as a new insight into the mechanism of PMS activation by Cu-containing minerals.Evaluating the decomposition-based change dynamics of various elements in plant litter is important for improving our understanding about their biogeochemical cycling in ecosystems. We have studied the concentrations of major, trace, and rare earth elements (REEs) (34 elements) in green tissue litter, and soil and their dynamics in the decomposing litters of successional annual fleabane (Erigeron annuus) and silvergrass (Miscanthus sinensis). Concentrations of major and trace elements in the litter of annual fleabane were 1.02-2.71 times higher compared to silvergrass. For REEs the difference between the two litter types for elements studied was in the range of 1.02-1.29 times. Both the litters showed a general decrease in the concentrations of elements in the initial stages of decomposition (60-90 days). All the major and trace elements (except for Na) in silvergrass showed a net increase in concentration at the end of the decomposition study (48.9-52.5% accumulated mass loss). Contrastingly, a few trace elements (Mn, Mo, Sr, Zn, Sb, and Cd) in annual fleabane showed a net decrease in their concentrations. For REEs, there was an increase in concentrations as well as in net amounts in both litter types. Similarities observed in the dynamics together with high and significant correlations among them likely suggest their common source. The higher concentrations of REEs in soil likely suggest its role in the net increase in REEs’ concentrations and amount in litter during decomposition.Petroleum resource development has generated a global legacy of millions of active and decommissioned energy wells. Associated with this legacy are concerns about wellbore integrity failure and leakage of fugitive gas into groundwater and atmosphere. Selleck IK-930 The fate of fugitive gas in the shallow subsurface is controlled by sediment heterogeneity, hydrostratigraphy and hydraulic connectivity. We characterized the shallow subsurface at a site in northeastern British Columbia, Canada; a region of extensive petroleum resource development. We collected 13 core profiles, 9 cone-penetrometer profiles, 58 sediment samples and 4 electrical resistivity profiles. At the site, a ~ 12 m thick layer of low-permeability diamict (10-8 m/s) overlays a more permeable (10-6 – 10-4 m/s) but highly heterogeneous sequence of glacigenic sand, clay and silt. We develop a conceptual hydrostratigraphic model for fluid flow in this system in the context of fugitive-gas migration. Driven by buoyancy forces, free-phase gas will move upward thrphere.Environments polluted with excessively high levels of antibiotics released from manufacturing sites can act as a source of transferable antibiotic resistance (AR) genes to human commensal and pathogenic bacteria. The aim of this study was to evaluate AR of bacteria isolated from the Sava river sediments (Croatia) at the discharge site of effluents from azithromycin production compared to those from the upstream site and isolates collected in Croatian hospitals. A total of 228 environmental strains of azithromycin-resistant bacteria were isolated and identified, with 124 from the discharge site and 104 from the upstream site. In addition, a total of 90 clinical, azithromycin-resistant streptococcal and staphylococcal isolates obtained from the Croatian Reference Center for Antibiotic Resistance Surveillance were analyzed. PCR screening of isolates on 11 relevant macrolide-resistance genes (MRGs) showed that discharge isolates had greater detection frequencies for 4 gene targets (ermB, msrE, mphE and ermF) comps reservoirs for clinically relevant macrolide-resistance genes.Investigating the drivers of phenotypic and genetic divergence can reveal the underlying processes and strategies that species adopt in rapidly changing environments. However, knowledge of adaptive strategies and the underlying mechanisms is lacking for the majority of taxa, especially those living in habitats sensitive to climate change. Here, we investigated 20 populations of a Tertiary-relict tree species, Euptelea pleiospermum (Eupteleaceae), scattered in a mountain riparian habitat in China. We integrated genetic, growth, and reproductive traits, and evaluated the relative contributions of climatic and soil factors on genetic and functional trait divergence. The E. pleiospermum populations were divided into south and north genetic clusters, and there were significant differences in leaf density and seed mass of adult trees between the two. The spatial pattern of genetic divergence resulted from effects of both isolation by distance (IBD) and isolation by environment (IBE), whereas the divergence of growts are likely the main ecological factors shaping plant divergence in montane riparian regions.In this study, biochar R550, obtained from rice husk charred at 550 °C, was used to detoxify Cr(VI) and organic pollutant p-nitrophenol (PNP) with the cooperation of sulfite, simultaneously. Cr(VI) was mainly reduced by sulfite, and the reduction was accelerated by biochar. Also, the reactive oxygen species formed in-situ as a result of enhanced oxidation of sulfite with Cr(VI)/R550 system and the activation of O2 by R550, led to the degradation of PNP. Production of the radicals viz., SO3-, SO4- and OH was followed by Electron Paramagnetic Resonance (EPR) study, and the predominant role of SO4- towards PNP degradation was confirmed by radical quenching tests. The reaction completed biochar sample was undergone the X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR) spectral analysis, which suggested that the carboxyl group of the biochar triggered and enhanced the reactivity of Cr(VI) via coordination linkage, which in turn activated the sulfite and converted the SO32- into SO4- to a higher extent by overcoming the undesirable transformation of SO32- to SO42-.