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Preparation of a novel nano-Fe3O4/triethanolamine/GO composites to enhance Pb2+/Cu2+ ions removal Texte intégral
2019
In this paper, a magnetic nano-Fe₃O₄/triethanolamine/GO composite (TEA-GO-FE) was prepared by using graphene oxide (GO), triethanolamine (TEA), and ferric chloride. The result indicates that triethanolamine acted as an important role for the growing of Fe₃O₄ and adsorption ability of composite material. The synthesis mechanism of TEA-GO-FE was investigated through the medium of SEM-EDS, XRD, FT-IR, and TEM. The characterization results indicated Fe₃O₄ nanoparticles have been successfully loaded on the surface of graphene oxide and they were encapsulated by TEA and have excellent stability. According to the results of XRD, the general particle size of Fe₃O₄ on TEA-GO-FE was 27.5 nm. In order to understand the adsorption properties of TEA-GO-FE for Pb²⁺ and Cu²⁺, this article uses a static adsorption study method. The optimized adsorption conditions are as follows: pH = 5.0, temperature is 293.15 K, and the ion concentration is 100 mg/L. Under the optimized prerequisites, the adsorption capacities of Pb²⁺ and Cu²⁺ were 121.5 mg/g and 68.7 mg/g, separately. Through thermodynamic as well as kinetic studies, the adsorption process of Pb²⁺ and Cu²⁺ on TEA-GO-FE is a self-heating process.
Afficher plus [+] Moins [-]The use of vegetation, bees, and snails as important tools for the biomonitoring of atmospheric pollution—a review Texte intégral
2019
The continuous discharge of diverse chemical products in the environment is nowadays of great concern to the whole world as some of them persist in the environment leading to serious diseases. Several sampling techniques have been used for the characterization of this chemical pollution, although biomonitoring using natural samplers has recently become the technique of choice in this field due to its efficiency, specificity, and low cost. In fact, several living organisms known as biomonitors could accumulate the well-known persistent environmental pollutants allowing their monitoring in the environment. In this work, a review on environmental biomonitoring is presented. The main sampling techniques used for monitoring environmental pollutants are first reported, followed by an overview on well-known natural species used as passive samplers and known as biomonitors. These species include conifer needles, lichen, mosses, bees and their byproducts, and snails, and were widely used in recent research as reliable monitors for environmental pollution.
Afficher plus [+] Moins [-]Experimental characterization of multi-nozzle atomization interference for dust reduction between hydraulic supports at a fully mechanized coal mining face Texte intégral
2019
To analyze the distribution pattern concerning multi-nozzle interference spray particle granularity between hydraulic supports, the present study conducts atomization interference experimental characterization for three types of nozzles used in coal mines based on a Doppler laser interference spray dust suppression simulation experimental system. The results indicate that for single-nozzle atomization, the impact of spray pressure on spray droplet size is gradually subdued, and a spray pressure of 8 MPa yields the best result; compared with single-nozzle spray, the multi-nozzle atomization interference effect can downsize the spray field overlapping zone, leading to an improved uniformity of overall spray particle distribution. As the spray field overlapping coefficient k increases, the particle size of the interference spray field decreases first and then increases. As the spray field overlapping coefficient reaches 0.4, the distribution of spray droplet size is most concentrated, corresponding to the optimal atomized dust suppression effect. Practical testing indicates that the optimal spray field overlapping coefficient measured at a fully mechanized mining face agrees well with the experimental result. Under the optimal parameters, the average total dust and respirable dust suppression rates measured at various measuring points on the downwind side during support relocation reach 78.93% and 80.53%, respectively.
Afficher plus [+] Moins [-]A novel BiVO4-GO-TiO2-PANI composite for upgraded photocatalytic performance under visible light and its non-toxicity Texte intégral
2019
A novel non-toxic hybrid BiVO₄-GO-TiO₂-polyaniline (PANI) (BVGT-PANI) composite with superior photocatalysis was successfully prepared via a one-pot hydrothermal reaction. The structural and morphological characterizations of the synthesized compounds were analyzed by a series of techniques. We found excellent photocatalytic efficiencies for methylene blue (MB) and phenol degradation under visible light irradiation after adhering the PANI to the photocatalyst. The degradation rates of MB and phenol reach up to approximately 85% and 80%, respectively, after 3 h of irradiation. For photodegradation MB, BVGTA exhibit the highest kₐₚₚ rate constant of about 1.06 × 10⁻² min⁻¹, which is about 1.63-fold faster than BVG and 2.94-fold faster than BVGT. For photodegradation of phenol, BVGTA exhibits the highest kₐₚₚ rate constant, of about 8.86 × 10⁻³min⁻¹, which is about 1.2-fold faster than BVG and 1.96-fold faster than BVGT. Furthermore, vitro toxicity test against Bacillus subtilis and Staphylococcus aureus demonstrated that the nanophotocatalyst is non-toxic.
Afficher plus [+] Moins [-]A review for tannery wastewater treatment: some thoughts under stricter discharge requirements Texte intégral
2019
Zhao, Changqing | Chen, Wuyong
To meet the extremely strict requirements of tannery wastewater, scientists need to urgently devise novel methods for controlling the quality of tannery wastewater. With these methods, it would be easier to promote sustainable development in the tannery industry. In this article, we summarize the following aspects of tannery wastewater: (i) the sources and characteristics of tannery wastewater, (ii) the main treatment methods (primary, secondary, and tertiary treatments), and (iii) resource utilization status of wastewater. In a brief introduction, we describe how tannery wastewater is currently subjected to single-pollutant treatment methods that strive to remove various toxic chemicals, including total nitrogen, total phosphorus, chloride ion, chromic salts, sulfur-containing compounds, and dyes. The methods for treating tannery wastewater is proposed. We anticipate that by using a proposed combination treatment techniques, the effluents in tannery wastewater can eventually be controlled to satisfy the stricter standards of wastewater disposal. Moreover, we also focus our efforts on recycling wastewater.
Afficher plus [+] Moins [-]Assessing interactions, predicting function, and increasing degradation potential of a PAH-degrading bacterial consortium by effect of an inoculant strain Texte intégral
2019
Macchi, Marianela | Festa, Sabrina | Vega-Vela, Nelson E. | Morelli, Irma S. | Coppotelli, Bibiana M.
A natural phenanthrene-degrading consortium CON was inoculated with an exogenous strain Sphingobium sp. (ex Sp. paucimobilis) 20006FA yielding the consortium called I-CON, in order to study ecological interactions into the bacterial community. DGGE and proteomic profiles and analyses by HTS (High-Throughput Sequencing) technologies demonstrated inoculant establishment and changes on CON composition. Inoculation increased degradation efficiency in I-CON and prevented intermediate HNA accumulation. This could be explained not only by the inoculation, but also by enrichment in Achromobacter genus at expense of a decrease in Klebsiella genus. After inoculation, cooperation between Sphingobium and Achromobacter genera were improved, thereby, some competition could have been generated, and as a consequence, species in minor proportion (cheaters), as Inquilinus sp. and Luteibacter sp., were not detected. Sequences of Sphingobium (corresponding to the inoculated strain) did not vary. PICRUSt predicted a network with bacterial phylotypes connected with enzymes, showing functional redundancy in the phenanthrene pathway, with exception of the first enzymes biphenyl-2,3-diol 1,2-dioxygenase and protocatechuate 4,5-dioxygenase that were only encoded in Sphingobium sp. This is the first report where a natural consortium that has been characterized by HTS technologies is inoculated with an exogenous strain in order to study competitiveness and interactions.
Afficher plus [+] Moins [-]One-step synthesis of versatile magnetic nanoparticles for efficiently removing emulsified oil droplets and cationic and anionic heavy metal ions from the aqueous environment Texte intégral
2019
Lu, Ting | Qi, Dongming | Zhang, Dong | Zhang, Chuan | Zhao, Hongting
Versatile polyethyleneimine (PEI)-coated Fe₃O₄ magnetic nanoparticles (MNPs) have been synthesized by a one-step solvothermal method. The morphologies, structures, and properties of MNPs prepared for different reaction times have been characterized through various techniques. The synthesized MNPs were then used to separate emulsified oil and cationic and anionic heavy metal ions from the aqueous environment; moreover, the effects of the temperature, pH, and ionic strength of aqueous media, the solvothermal reaction time, and the number of reuse cycles on the removal efficiency have been investigated in detail. The results showed that pseudo-second-order kinetics and the Langmuir isotherm well described the adsorption processes of Cu(II) and Cr(VI). The Langmuir model yielded maximum adsorption capacities of 66.6 mg g⁻¹ for Cu(II) and 54.5 mg g⁻¹ for Cr(VI) at pH 5.0 and 25 °C. The synthetic MNPs could also efficiently separate diesel oil or olive oil droplets stabilized by sodium dodecyl sulfate from aqueous media. Moreover, these MNPs could be recycled five times without showing significant loss in separation efficiency. Notably, the synthesized PEI-coated MNPs could simultaneously separate emulsified oil and cationic and anionic heavy metal ions from multicomponent wastewater. Such versatile PEI-coated MNPs displayed good affinity towards emulsified oil and cationic and anionic heavy metal ions, showing great potential for practical applications in the treatment of complicated industrial wastewater matrices. Graphical abstract Simultaneous separation of emulsified oil and cationic and anionic heavy metal ions from aqueous media by using polyethyleneimine-coated Fe₃O₄ magnetic nanoparticles.
Afficher plus [+] Moins [-]Pollution intensity-dependent metal accumulation in ground beetles: a meta-analysis Texte intégral
2019
Tőzsér, Dávid | Magura, Tibor | Simon, Edina | Mizser, Szabolcs | Papp, Dalma | Tóthmérész, Béla
Survival of organisms in polluted habitats is a key factor regarding their long-term population persistence. To avoid harmful physiological effects of pollutants’ accumulation in organisms, decontamination and excretion could be effective mechanisms. Among invertebrates, ground beetles are reliable indicators of environmental pollution. Published results, however, are inconsistent, as some studies showed effective decontamination and excretion of pollutants, while others demonstrated severe toxic symptoms due to extreme accumulation. Using ground beetles as model organisms, we tested our pollution intensity-dependent disposal hypothesis for five pollutants (Cd, Cu, Mn, Pb, and Zn) among four soil pollution intensity levels (low, moderate, high, and extreme) by categorical meta-analysis on published data. According to our hypothesis, decontamination and excretion of pollutants in ground beetles are effective in lowly or moderately polluted habitats, while disposal is ineffective in highly or extremely polluted ones, contributing to intense accumulation of pollutants in ground beetles. In accordance with the hypothesis, we found that in an extremely polluted habitat, accumulation of Cd and Pb in ground beetles was significantly higher than in lowly polluted ones. These findings may suggest the entomoremediation potential of ground beetles in an extremely polluted environment.
Afficher plus [+] Moins [-]Selenium alleviates cadmium-induced inflammation and meat quality degradation via antioxidant and anti-inflammation in chicken breast muscles Texte intégral
2019
Tang, Kou-Kou | Li, Hui-Qin | Qu, Kui-Chao | Fan, Rui-Feng
Cadmium (Cd) as a widespread toxic heavy metal accumulates in animal food including chicken meat through food chain enrichment and finally threatens human health. Selenium (Se) is an essential mineral and possesses antagonistic effects on Cd-induced multiple organs’ toxicity in chickens. The objective of the present study was to reveal the antagonistic mechanisms of Se to Cd from the aspects of oxidative stress, inflammation, and meat quality in chicken breast muscles. Firstly, the results showed that Cd significantly elevated the levels of malondialdehyde (MDA), hydrogen peroxide (H₂O₂), and protein carbonyl, and declined the levels of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) to trigger oxidative stress in chicken breast muscles. However, Se treatment significantly alleviated Cd-induced oxidative stress by increasing the levels of GSH-Px, SOD, and CAT, and decreasing the levels of MDA, H₂O₂, and protein carbonyl. Secondly, Se obviously inhibited the expressions of Cd-activated inflammation-related genes including tumor necrosis factor (TNF-α), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), inducible nitric oxide synthase (iNOS), prostaglandin-endoperoxide synthase 2 (COX-2), and prostaglandin E synthase (PTGEs) in chicken breast muscles. Thirdly, meat quality-related parameters including pH₄₅ₘᵢₙ, ultimate pH (pHu), and drip loss were also detected, and the results showed that Se markedly recovered Cd-induced dropt of pH₄₅ₘᵢₙ and increase of drip loss in chicken breast muscles. In brief, these findings demonstrated that Se significantly alleviated Cd-induced oxidative stress and inflammation, and declined meat quality of chicken breast muscles.
Afficher plus [+] Moins [-]A study of “cancer villages” in Jiangsu Province of China Texte intégral
2019
Cheng, Yuanyuan | Nathanail, P. (Paul)
China’s economic boom has created many environmental and health challenges, including so-called cancer villages. This study, the first to use the lens of “cancer villages” at provincial level, examines the correlation between changes in Jiangsu cancer villages and economic and environmental quality indicators identified as being relevant, and hence to highlight environmental issues that should be mitigated to protect public health. Since 2001, 25 cancer villages have been reported in Jiangsu. The distribution pattern of these villages is of a cluster whose mean centre had moved from Suzhou city in 2001 to Taizhou in 2006 and 2011. By applying the buffer analysis tool of ArcGIS10.2.2 using 3-km and 5-km radius buffer, to examine the relationship between these cancer villages and the surrounding rivers, it was revealed that 76% of the villages fall within the 3-km buffer zone, and 88% are within the 5-km buffer zone. A fairly strong correlation between the cancer villages and annual GDP, as well as pollutant discharge, was found, with correlation coefficients of 0.94 for Jiangsu, 0.89 for Northern Jiangsu, 0.93 for Central Jiangsu, 0.83 for Southern Jiangsu and 0.64 for city level. The change of newly added cancer villages is significantly influenced by the discharge of sewage water (raising COD) and SO₂, and the peak of newly added cancer villages, as well as discharge of COD and SO₂ all occurred in 2005. For four cities, the total sewage water discharge and SO₂ emissions are consistent with the order of the distribution density of the villages. The phenomenon of cancer villages in China will gradually be resolved as the government takes effective measures to tackle environmental issues coupled with people’s increasing environmental and health awareness.
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