Chapmanharmon2165

The results point out that the Antarctic region is no longer a clean and isolated environment from human pollution.Particulate-bound mercury (PBM) is a global environmental concern owing to its large dry deposition velocities and scavenging coefficients, both of which drive Hg into terrestrial and marine ecosystems. PBM observation studies have been widely conducted over East Asia, but comparable studies in Peninsular Southeast Asia (PSEA) remain scarce. This is the first study reporting PBM concentrations for Ho Chi Minh City (HCMC), the biggest metropolitan area in Vietnam. A total of 222 samples were collected in 2018 and contained an average PBM10 (particulate matter - PM with diameter ≤10 μm) concentration and Hg mass fraction (i.e. PBM/PM) of 67.3 ± 45.9 pg m-3 and 1.18 ± 1.12 μg g-1, respectively. Although PBM concentration was lower than those reported in Chinese megacities, the Hg mass fraction was similar to those in China, suggesting strong enrichment from anthropogenic Hg emissions in HCMC. Traffic-induced particulate emission and deposition processes were major factors governing PBM temporal variation at our site. In addition, the prevailing southwest monsoon winds brought air masses that passed through industrial areas and were associated with a higher Hg mass fraction. Statistically significant positive correlations (R2 = 0.11-0.52, p less then 0.01) were observed for PBM with PM and the Hg mass fraction, indicating similar PM and Hg sources or oxidized Hg adsorption onto PM via gas-particle partitioning. Moreover, PCA results revealed a higher contribution of primary sources than secondary sources to PBM concentration variability in HCMC. A health risk assessment indicated that the PBM concentrations at HCMC posed minimal non-carcinogenic risks (HI less then 1) for children and adults, but dermal contact may act as an important exposure route since lightweight clothing is common among residents. This PBM dataset over PSEA, a region with high atmospheric Hg emissions, provides a valuable resource for the Hg scientific community to improve our understanding of Hg biogeochemical cycle.Photocatalysis is considered an economical, environmentally friendly, and effective technology for removing pollutants. The construction of Z-Scheme heterojunctions has been identified as one of the feasible solutions capable of enhancing the photocatalytic activity. Herein, a series of visible light responsive photocatalysts (NiIn2S4/UiO-66 composites) with excellent activity and stability were prepared by using a solvothermal process. It is found that 20 mg L-1 of tetracycline (TC) could be almost completely degraded under visible light irradiation within 1 h, when the mass ratio of NiIn2S4 to UiO-66 is 0.51 (NISU-0.5) and the solution pH = 11. In addition, after six cycles, the degradation rate of tetracycline photocatalyzed by NISU-0.5 still reach up to 90%. Ultraviolet photoelectron spectra (UPS), X-ray photoelectron spectra (XPS) and electron spin resonance measurements (ESR) confirm the formation of the Z-Scheme heterostructure between NiIn2S4 and UiO-66. The synergistic effect between built-in electric field, energy band bending and coulomb interactions in interface of Z-Scheme heterojunction is conducive to restrain the recombination of photogenerated electrons and holes, which greatly improve the photocatalytic activity. In conclusion, this study offers a new thought for design and synthesis of Z-Scheme heterojunctions and provides a cost-effective strategy for solving environmental pollution and energy problems in the future.The conventional adsorbent fabrication methods involve complicated processes and may cause secondary contaminations. Therefore, an effective eco-friendly method is required for the fabrication of heavy metal adsorbents using inexpensive and eco-friendly materials without secondary pollution during their process. In this study, nanofibrous membranes (NFMs) were fabricated via green electrospinning of poly(vinyl alcohol) (PVA), a hydrophilic polymer, and their water resistance was improved through simple heat treatment without using additional additives. Then, nanofibrous heavy metal adsorbents were prepared by dip-coating the NFMs in an aqueous solution of tannic acid (TA), a natural polyphenol. First, the adsorption/desorption behavior of TA on PVA NFMs during the TA coating process was investigated. In addition, the effects of TA coating on the mechanical properties and heavy metal adsorption characteristics of the PVA NFMs were analyzed. The TA coating significantly increased the mechanical strength, heat resistance, and heavy metal (Pb(II)) adsorption capacity of the PVA NFM. The Pb2+ adsorption amount of TA-coated PVA NFMs exhibited about 5-7 times higher than those of other heavy metal ions, indicating excellent selectivity for Pb2+. In addition, the TA-coated PVA NFMs retained >70% of its initial adsorption capacity even after four cycles of adsorption/desorption, indicating its reusability.The graphite-phase carbon nitride (g-C3N4) photocatalytic materials were prepared by one-step calcination method to degrade methylene blue (MB) and potassium butyl xanthate (PBX) under visible light irradiation. The prepared g-C3N4 photocatalytic materials were investigated in detail by various characterizations, and the experiments showed that the graphitic phase carbon nitride photocatalytic materials were successfully prepared by the one-step calcination method. The material possesses excellent optical properties and strong visible light absorption, thus achieving photocatalytic degradation of MB and PBX. The catalyst dosage, pH, the initial concentration of pollutants have important effects on photocatalytic activity of MB and PBX. selleck products The photocatalytic degradation efficiency was 98.99% for MB and 96.83% for PBX under the optimal conditions (catalyst dosage, initial pollutant concentration and pH value were 500 mg L-1, 20 mg L-1 and 7, respevtively). The photocatalytic mechanisms on MB and PBX were elucidated. ·OH was the key specie for MB, while ·O2- was the key specie for PBX. This study advances the development of photocatalytic technology for mineral wastewater.Bisphenol A (BPA) is regarded as an endocrine disruptor associated with negative health effects in animals and humans. Laccase from white-rot fungus can enable BPA oxidation and auto-polymerization to circumvent its biotoxicity, but the work concerning the effect mechanisms of divalent and trivalent metal ions (MIs) on BPA polyreaction have rarely been reported. Herein, Trametes versicolor laccase-started BPA conversion within 1 h followed pseudo-first order kinetics, and the rate constant (kprcs) and half-life were respectively 0.61 h-1 and 1.14 h. The presence of Ca2+, Mg2+, Cu2+, Pb2+, Cd2+, Zn2+ and Al3+ exhibited insignificant impact on BPA removal, whereas Fe2+, Fe3+ and Mn2+ had a strong inhibiting effect. Compared with MI-free, the kprcs values of BPA respectively lowered 34.4%, 44.3% and 98.4% in the presence of Fe2+, Fe3+ and Mn2+. Enzymatic activity and differential absorption spectrum disclosed that the inhibitory actions were accomplished by two different mechanisms. One is Fe2+ was preferentially oxidized into Fe3+ that restrained laccase activity at the initial stage of reaction, and subsequently, the formed Fe3+ complex bound with laccase T1-Cu site and thus impeded the single-electron transfer system. The other is Mn2+ was instantly oxidized by laccase to generate Mn3+-citrate complex, which completely consumed the dissolved O2 in solution and consequently terminated BPA removal. Considering environmental bioremediation, T. versicolor laccase-enabled auto-polymerization is a simple and convenient candidate to eliminate BPA in enzymatic wastewater treatment, however the effects of Fe2+/Fe3+ and Mn2+ on BPA decontamination should be cautiously assessed.Coal and coal-based products (by-products), along with other fossil fuels should be used with caution because of their impact on human health and the global climate. In the light of the environmental impact these fossil fuels cause, it's essential to understand the elemental configuration of coal-derived samples and their impact on the ecosystem. Some reports in past have described, geochemical and mineralogical physiognomies of fly-ash and their impact on the environment. However, a comprehensive investigation of various aspects of fly ash like geochemistry, mineralogy, morphology, and toxicological effects has been very sparse and the present study reports the above aspects. The ICP-OES studies confirm the presence of various elements (Al, Ca, Fe, Mg, Na, P, S, Si, and Ti) in the samples. The XRD analysis exposed the presence of minerals like Quartz, H-Hematite, Anatase, Muscovite, and Rutile, in addition to the various phases such as amorphous and crystalline in the fly-ash. Specific samples also possessed Ilmenite which is uncommon in many other samples. Chromium and lead, the well-known heavy metals to cause soil and water pollution in the neighbourhood were found to be existing in higher concentrations in the fly-ash samples, whereas cadmium was found to be the least among the toxic elements found in the samples. The samples were subjected to FE-SEM analysis, which reveals the presence of irregularly shaped minerals and unburnt carbon known to reduce the burning efficiency of coal, especially in power plants. Toxicology studies reported in the work suggested that fly-ash is toxic to the environment at higher concentrations than at lower concentrations.Nanoplastics (NPs) ( less then 1 μm) have gradually attracted worldwide attention owing to their widespread occurrence, distribution, and ecosystem risks. Few studies have explored the interaction between NPs and heavy metals in crops. In this study, we investigated the influence of polystyrene nanoplastics (PSNPs; 10 mg/L and 100 mg/L) and cadmium (2 mg/L and 10 mg/L) on the physiological and biochemical indices of maize plants, grown in Hoagland solution with contaminants, for 14 days. The fresh weight and growth of the maize plants were significantly reduced after exposure to high concentrations of PSNPs and Cd (p less then 0.05). Specifically, the fresh weight decreased by 30.3% and 32.5% in the PSNPs and Cd treatment, respectively. Root length and shoot length decreased by 11.7% and 20.0%, and by 16.3% and 27.8%, in the PSNPs and Cd treatment, respectively. However, there were no significant effects on the fresh weight and growth of maize plants as Cd levels increased from 2 to 10 mg/L in the presence of PSNPs. Polystyrene nanoplastics alleviated the phytotoxicity of Cd in maize. Scanning electron microscopy (SEM) showed that PSNPs and Cd could enter maize roots and were transported upwards to the leaves through the vascular bundle. The activities of peroxidase (POD) and catalase (CAT) in maize leaves increased significantly under high concentrations of PSNPs, whereas superoxide dismutase (SOD) activity decreased (p less then 0.05). The differences in SOD activity may be related to the absence of microelements such as Zn, Fe, and Mn. This study provides a scientific basis for further exploration of the combined toxicological effects of heavy metals and NPs on the environment.