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•Fluorescence “turn-on” FL-DFNS particles for Hg2+/Hg+ ions were prepared.•FL-DFNS@CS microbeads with Hg2+/Hg+ ions detecting ability are obtained.•FL-DFNS particles could be used to ...remove Hg2+/Hg+ ions.•FL-DFNS@CS microbeads could be used to remove Hg2+/Hg+ ions as well.
Dendritic fibrous nano-silica (DFNS) possesses unique porous structure, making it an outstanding candidate for heavy metal adsorption and separation. It is interesting to introduce natural polymer (chitosan) into DFNS and produce natural materials-based porous DFNS. Initially, in this work, DFNS underwent modification to enlarge size and enrich with -C≡C bonds. And then, NH2-naphthalimide fluorophore was click-reacted with the modified DFNS, forming fluorescent DFNS (FL-DFNS). Eventually, chitosan was integrated into FL-DFNS using diacyl chloride, generating the organic–inorganic fluorescent composite micro-beads (FL-DFNS@CS-3). FL-DFNS acts as a “turn on” sensor for Hg2+/Hg+ ions, showing up to 5 times fluorescence increase. Also, it exhibited effective mercury adsorption. Due to its porous structure, it demonstrated good performance in adsorbing and separating Hg2+/Hg+ ions, achieving removal ratios of 98.8 % and 96.1 %, and adsorption capacities of 196.2 mg/g and 180.4 mg/g, respectively. It reached effective adsorption equilibrium within 15 min and was reusable up to seven times. Overall, this work confirms the practical applicability of FL-DFNS and FL-DFNS@CS micro-beads for identifying and removing Hg2+/Hg+ ions. Further exploration is worthy to explore its potential in environmental science and engineering.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•A novel Hg(II)-volatilizing fungus showed bioremediation potentials.•The mer-mediated detoxification system was responsible for Hg(II) volatilization in fungus.•Resistance of DC-F11 ...to Hg(II) was generally a multisystem collaborative process.
Bioremediation of Hg-contaminated soil using microbe-based strategies is a promising and efficient method as it is inexpensive and not harmful to the environment. In this study, a novel Hg(II)-volatilizing fungus Penicillium spp., DC-F11 was isolated and showed bioremediation potential for reducing Hg(II) phytotoxicity, total Hg, and exchangeable Hg in Hg(II)-polluted soil. Subsequently, the mechanisms of Hg(II) volatilization and resistance involved were investigated using multiple complementary techniques. The fungal cells could detoxify Hg(II) by extracellular sequestration via adsorption and precipitation. Moreover, a comparative transcriptome analysis uncovered the primary intracellular adaptive responses of the DC-F11 to Hg(II) stress, including mer-mediated detoxification system, thiol compound metabolism, and oxidative stress defense and damage repair metabolism. These results showed that the resistance of DC-F11 to Hg(II) was generally a multisystem collaborative process. Here, we report, for the first time, that the mer-mediated detoxification system was responsible for Hg(II) volatilization in fungus. These findings provide a better understanding of the mechanisms involved in Hg(II) volatilization and resistance that occur in fungi and also provide a strong theoretical basis for the future application of fungi in the bioremediation of Hg-polluted environments.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•One-step crosslinking fabrication of hyperbranched chitosan composite, called HPFC.•Selective removal of Hg(II) ions with high efficiency over a wide pH range.•Concentration of ...Hg(II) ions can be decreased from 798 mg/L to 0.02 mg/L.•HPFC can adsorb up to 1594 mg/g Hg(II) ions from aqueous solution.•DFT calculations reveal selective adsorption nature of HPFC towards Hg(II) ions.
A cost-effective adsorbent for highly efficient removal of mercuric Hg(II) ions from aqueous media remains a great challenge. Herein, a novel polymer-based adsorbent of hyperbranched polyethylenimine functionalized carboxymethyl chitosan semi-interpenetrating network composite (HPFC) was fabricated through a facile one-step crosslinking reaction. Notably, the as-prepared adsorbent demonstrated ultra-high adsorption capacity toward the removal of Hg(II) ions. Upon treatment with 20 mg-dosage of HPFC in an aqueous medium (20 mL), the concentration of Hg(II) is decreased from 798.1 mg/L to 0.02 mg/L, which is below the national drainage standard of 0.05 mg/L for industrial wastewater in China. A kinetic study shows that the adsorption of Hg(II) ions follows the pseudo-second-order model, indicating chemical adsorption between Hg(II) ions and HPFC. The maximum adsorption capacity is 1594 mg/g, which is higher than that of many other currently known natural polymer-based adsorbent. Furthermore, this adsorbent exhibits excellent selectivity for removing Hg(II) ions, and the selectivity coefficient to Hg(II) ions is 3–4 orders of magnitude higher than that to Cu(II) ions, Cd(II) ions and Pb(II) ions, respectively. Based on the measurements of Fourier transform infrared spectrum (FTIR) and X-ray photoelectron spectroscopy (XPS) and the density functional theory (DFT) calculations, the adsorption mechanism was proposed. The removal of Hg(II) ions by HPFC is mainly controlled by the interaction between Hg(II) ions and nitrogen functional groups (i.e., amine and imine groups). Significantly, HPFC has superior reusability and could be easily regenerated and reused multiple times. The developed HPFC adsorbent holds high potential in remediating water polluted with Hg(II) ions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Hg contamination is a critical environmental problem, and its remediation using cost-effective and environmentally friendly methods is highly desirable. In this study, a multi-metal-resistant ...bacterium showing strong Hg(II) volatilization ability, Pseudomonas sp. DC-B1, was isolated from heavy metal-contaminated soils. DC-B1 volatilized 81.1%, 79.2% and 74.3% of the initial Hg2+ from culture solutions with initial Hg2+ concentrations of 5.1, 10.4, and 15.7 mg/L, respectively, within 24 h. Microcosm experiments were performed to investigate the remediation of Hg(II)-spiked soils inoculated with DC-B1 coupled with sawdust biochar amendment. The efficiency of Hg removal from two types of soil samples with different properties and an initial Hg(II) content of approximately 100 mg/kg was enhanced 5.7–13.1% by bio-augmentation with inoculation of the bacterial strain DC-B1, 5.4–10.7% by amendment of 4% (w/w) biochar, and 10.7–23.2% by the combination of DC-B1 and biochar amendments over an incubation period of 24 d over the efficiency in the control treatment under flooded conditions. Longer root lengths were observed in lettuce grown in the treated soils than in lettuce from the control soil, confirming the bioremediation efficacy of the two bioagents for soil Hg contamination.
•A multi-metal-resistant Pseudomonas sp. strain showing strong Hg(II) volatilization ability, DC-B1, was isolated.•Hg content in flooded soils was reduced spontaneously, which was further enhanced by DC-B1 inoculation.•Amendment with sawdust biochar facilitated the microbial remediation of Hg(II) in the soil.•Bacterium-mediated Hg(II) volatilization coupled with biochar amendment has high potential for soil Hg remediation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
A facile method was used to prepare two-dimensional MXene for the treatment of heavy metal ions in wastewater. The adsorbent has good selectivity for the adsorption of Hg (Ⅱ) in mixed divalent ...cationic metal solutions due to a large number of oxygen-containing functional groups on the surface of the material. The adsorption of mercury was tested using mercuric chloride and mercury nitrate solutions. The Langmuir maximum adsorption capacity of the adsorbent at a pH of 5.0 and a temperature of 30 °C is 1057.3 mg/g (mercuric nitrate) and 773.29 mg/g (mercuric chloride), respectively. The adsorbent also maintains a high adsorption capacity at low pH (pH = 2.0). The removal rate of mercury-containing wastewater within 100 mg/L is nearly 100%. The chemical species of Hg-containing ions at different pH and temperatures was studied. It was found that the adsorbent could maintain a high adsorption capacity for different forms of Hg-containing ions.
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•The High maximum adsorbance is 1057.332 mg/g (mercuric nitrate) and 773.294 mg/g (mercuric chloride).•Efficient selective adsorption of Hg (Ⅱ) even in extreme acid solutions).•Excellent reutilization performance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We evaluated a 14-year trend (2003–2017) in mercury (Hg) concentrations and fluxes in six litterfall categories (needles, bark, twigs, cones, lichen, and a mixture of unidentified fragments) at six ...research plots situated in two central European unmanaged mountain forest stands, dominated by mature Norway spruce. One of the stands (catchment of Plešné Lake, PL) was infested by bark beetle and all mature spruces died at three of four research plots during the study. One PL plot and two plots in the second stand (catchment of Čertovo Lake, CT) were intact and used as a control. At the intact plots, the litterfall Hg deposition averaged 45 and 32 μg/m2/year in the PL and CT catchments, respectively, while bulk precipitation Hg deposition was an order of magnitude lower (2.6 μg/m2/year). In the individual litter categories, Hg concentrations averaged 223, 195, 126, 81, 79 and 30 μg/kg in lichen, unidentified fragments, bark, twigs, needles and cones, respectively. As a result of decreasing European Hg emissions, Hg concentrations in most litter categories decreased from 2003 to 2017. Consequently, the litter-associated Hg flux to the forest floor decreased from 66 to 23 μg/m2/year during 2003–2017. The litterfall mass fluxes exhibited no trends at the intact plots. In contrast, the litter-associated Hg flux increased 5-fold after tree dieback due to elevated litterfall, averaging 218 μg/m2/year Hg at the PL infested plots during 2004–2009. The relative contribution of individual litter categories to the total Hg flux shifted from needle to bark and twig dominance. Starting in 2010, Hg flux decreased to pre-disturbance levels for the following decade. The tree mortality in the PL catchment provided a unique opportunity to evaluate changes in litter-associated Hg fluxes to the forest floor during and after natural tree dieback.
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•We assessed mercury in separate components of spruce litterfall for 14 years.•Lichen Hg concentrations were the highest of five litterfall components measured.•Hg concentrations in spruce litterfall decreased by 66% since 2003 at one Czech site.•Forest dieback increased litterfall with a shift from needles to twigs and bark.•Atmosphere-sourced Hg correlated with soil-sourced N, Al and Fe in litterfall.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The Cretaceous-Paleogene (K-Pg) boundary mass extinction is commonly attributed to the Chicxulub impact and/or the Deccan Traps (DT) volcanism, but the underlying trigger remains uncertain. The lack ...of detailed identification of the DT eruptive pluses impedes the full assessment of their relationship to the K-Pg boundary mass extinction. Here we present the first mercury (Hg) chemostratigraphy records on the paleo Asian plate, coupled with climatic and biotic data, to constrain the effects of the DT on the Late Cretaceous climate change and mass extinction. In northern China, a total Hg (THg) spike follows warming caused by the DT volcanism and corresponds to the significant species losses. Our study suggests that this most intense pulse of the DT (~50 kyr duration) occurred just before the K-Pg boundary and suggests that it contributed to the end-Cretaceous mass extinction in northern China.
•The first mercury (Hg) concentration and isotope record of the Cretaceous-Paleogene (K-Pg) boundary in the paleo Asian plate.•Hg anomaly close to the K-Pg boundary derived from a volcanic source coupling with biotic losses.•Deccan Traps LIP volcanism contributed to the end-Cretaceous mass extinction in northern China.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this article, carbon nanoparticles (CNPs) were used as a novel fluorescent sensing platform for highly sensitive and selective Hg
2+ detection. To the best of our knowledge, this is the first ...example of CNPs obtained from candle soot used in this type of sensor. The general concept used in this approach is based on that adsorption of the fluorescently labeled single-stranded DNA (ssDNA) probe by CNP via
π–
π stacking interactions between DNA bases and CNP leads to substantial dye fluorescence quenching; however, in the presence of Hg
2+, T–Hg
2+–T induced hairpin structure does not adsorb on CNP and thus retains the dye fluorescence. A detection limit as low as 10
nM was achieved. The present CNP-based biosensor for Hg
2+ detection exhibits remarkable specificity against other possible metal ions. Furthermore, superior selectivity performance was observed when Hg
2+ detection was carried out in the presence of a large amount of other interference ions. Finally, in order to evaluate its potential practical application, Hg
2+ detection was conducted with the use of lake water other than pure buffer and it is believed that it holds great promise for real sample analysis upon further development.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this contribution, a novel mesoporous CuO/ZnO heterojunctions were fabricated and designed through a wet chemical process in the presence of F127 surfactant. TEM image of mesoporous CuO/ZnO ...heterojunction showed a homogeneous size distribution with uniform spherical with particles size ~20 nm. The surface area of pristine ZnO NPs was estimated to be 200 m2/g, which reduced to 175 m2/g at 4% CuO/ZnO heterojunction. The synthesized CuO/ZnO heterojunctions were exhibited to effectively reduction and removal of Mercury (Hg(II)) ions through visible light. The optimized mesoporous 3% ZnO/CuO heterojunction exhibited the highest photoreduction efficiency compared to commercial P-25 and pristine ZnO NPs. The photoreduction/removal efficiency of Hg(II) over 3%CuO/ZnO heterojunction was reached up to 100% within 60 min, which is ~14 and ~24 times higher than P-25 and pristine ZnO NPs, respectively. The rate constant of mesoporous 3% ZnO/CuO heterojunction is better 30 and 54 order magnitudes than that compared with P-25 and pristine ZnO NPs, respectively. This is explained by the mesoporous CuO/ZnO heterojunctions greatly promotes the utilization light rate owing to its characteristic architecture, increases the surface area and pore volumes, promoting mass diffusion and providing more active sites, enhances the photoinduced electrons transfer the as a result of the formation of p-n types CuO/ZnO heterojunctions. Nevertheless, the photocatalysts were readily reused and recovered for five cycles without significant loss of photoreduction efficiency.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Sulfur-functionalized PAMAM dendrimer/magnetic Fe3O4 were fabricated.•The maximum adsorption capacity of the adsorbent for Hg(II) and Ag(I) were 0.8 and 1.29 mmol∙g−1.•Adsorption ...mechanism was demonstrated by combing experiment and DFT calculation.•The hybrid materials can be reused with good reusability.
Heavy metal ions pollution in water system has been imposing serious damage to aquatic ecosystem and public health. Efficient and selective capture of targeted metal ion from water is a great challenge and the focus of extensive research. Herein, sulfur-functionalized polyamidoamine (PAMAM) dendrimer/magnetic Fe3O4 hybrid materials were constructed for capturing Hg(II) and Ag(I) from water solution. The as-prepared adsorbents were fully characterized and the factors that influence the adsorption performance were investigated. The maximum adsorption of Fe3O4@SiO2-M2 were 0.8 and 1.29 mmol∙g−1 for Hg(II) and Ag(I). The hybrid materials display good adsorption selectivity and 100% selective adsorb Hg(II) with the presence of Ni(II), Mn(II), and Zn(II). Adsorption mechanism suggests sulfur groups play the predominant role during the capture of Hg(II). These hybrid materials exhibit excellent regeneration property and can be reused with practical application value.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
