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Efficient fluoride removal using Al-Cu oxide nanoparticles supported on steel slag industrial waste solid Texte intégral
2018
Blanco-Flores, Alien | Arteaga-Larios, Nubia | Pérez-García, Victor | Martínez-Gutiérrez, José | Ojeda-Escamilla, María | Rodríguez-Torres, Israel
A SSW/Al-Cu formed from an industrial solid waste and Al-Cu Nps are utilized for the removal of fluoride from aqueous solutions. The SSW/Al-Cu was obtained by a chemical reduction method. The SSW/Al-Cu was characterized by TEM, SEM, FT-IR, XRD, BET, and pHzₚc techniques. The Nps were formed as bimetallic oxides and deposited in the form of spheroidal particles forming agglomerations. The sizes of these particles range from 1 to 3 nm. The surface area and average pore width of SSW/Al-Cu were 2.99 m²/g and 17.09 nm, respectively. The adsorption kinetics were better described using the second-order model, pointing to chemical adsorption with an equilibrium time of 540 min. The thermodynamic parameters obtained here confirm the spontaneous and endothermic nature of the process. The percentage of fluoride removal was 89.5% using the four-bladed disk turbine, and computational fluid dynamics (CFD) modeling demonstrated that using the four-bladed disk turbine helped improve the fluoride removal process. The maximum adsorption capacity was 3.99 mg/g. The Langmuir-Freundlich model best describes the adsorption process, which occurred by a combination of mechanisms, such as electrostatic interactions between the ions involved in the process. This study proves that the chemical modification of this waste solid created an efficient bimetallic nanomaterial for fluoride removal. Furthermore, the method of preparation of these nanocomposites is quite scalable.
Afficher plus [+] Moins [-]Development of immunochromatographic assays for the detection of imidacloprid in soil chemical barrier Texte intégral
2018
Yang, Jiachuan | Yang, Qian | Deng, Jiaqi | Tao, Zhexuan | Hua, Xiude | Wang, Minghua
A soil chemical barrier is the most important and common way to control termites; fast and on-site detection methods are significant tools to verify pesticide content meeting the standard requirements. In this study, conventional and enhanced immunochromatographic assays (ICAs) containing two test lines (TLs) were developed to semi-quantitatively detect imidacloprid in soil chemical barrier, and detection results were quantified by a smart phone. According to the results, the disappearance concentrations of first TL (TL-1) and second TL (TL-2) in an enhanced ICA and conventional ICA were 5 and 20 ng/mL and 20 and 80 ng/mL with the naked eye. The sensitivity of TL-2 was four times that of TL-1 in both ICAs, consistent with the maximum and minimum concentration differences for imidacloprid in Jiangsu province’s “the technical regulation of assay and evaluation on chemical soil barrier of termite prevention treatment in buildings”. The results of TLs can be used to judge whether the amount of imidacloprid in soil chemical barrier meets the standard. Enhanced and conventional ICAs were available for further quantitative testing with a smart phone, and the limit of detection (LOD) was 0.74 and 3.17 ng/mL, respectively. Moreover, some soil chemical barrier samples from several areas in Wuxi, Jiangsu province, were used to test by ICAs and high-performance liquid chromatography (HPLC), and the results of ICAs correlated well with HPLC.
Afficher plus [+] Moins [-]Vitamin E alleviates phoxim-induced toxic effects on intestinal oxidative stress, barrier function, and morphological changes in rats Texte intégral
2018
Sun, Yuecheng | Zhang, Jing | Song, Wentao | Shan, Anshan
Phoxim is an organic phosphorus pesticide that remains easily in the environment, such as human food and animal feed. The objective of this study was to explore the effect of vitamin E on phoxim-induced oxidative stress in the intestinal tissues of Sprague-Dawley (SD) rats. Forty-eight Sprague-Dawley rats were randomly assigned to a control group and three treatment groups: treatment group 1 (phoxim: 20 mg/kg·BW), treatment group 2 (phoxim: 180 mg/kg·BW), and treatment 3 (vitamin E + phoxim: 200 mg/kg·BW + 180 mg/kg·BW). Phoxim was given by gavage administration once a day for 28 days. The results showed that phoxim significantly reduced jejunum villus height in rats (P < 0.05), and decreased the mRNA expression of junction protein genes of rats, including Occlidin and Claudin-4 (P < 0.05). Phoxim reduced GSH content and T-AOC level in the intestinal mucosa (P < 0.05). The mRNA expression levels of oxidative stress-related genes (Nrf2 and GPx2) were decreased. The mRNA expression of SOD was significantly increased. In addition, phoxim increased the level of interleukin-6 (IL-6) in jejunum mucosa and significantly reduced the level of IL-8 in ileum mucosas, while significantly increased TNF-α secretion. The mRNA expression levels of IL-1β, IL-6, and IL-8 were significantly decreased, and mRNA expression of TNF-α was significantly increased (P < 0.05). Phoxim also increased the DNA expression of total cecal bacteria and Escherichia coli, inhibited the DNA expression of Lactobacillus and destroyed the intestinal barrier. Two hundred milligrams per kilogram BW vitamin E reduced the effect of phoxim on intestinal structure, alleviated the oxidative stress in intestinal tissue, and decreased the level of TNF-α. The mRNA expressions of antioxidative stress genes (SOD and GPx2) were significantly increased. The DNA expression level of Lactobacillus was significantly increased. In conclusion, vitamin E helped reduce the toxicity of organophosphate pesticides, such as phoxim on rat intestinal tissue.
Afficher plus [+] Moins [-]Exposure to aged crumb rubber reduces survival time during a stress test in earthworms (Eisenia fetida) Texte intégral
2018
Pochron, Sharon | Nikakis, Jacqueline | Illuzzi, Kyra | Baatz, Andrea | Demirciyan, Loriana | Dhillon, Amritjot | Gaylor, Thomas | Manganaro, Alexa | Maritato, Nicholas | Moawad, Michael | Rajwinder Singh, | Tucker, Clara | Vaughan, Daniel
Solid waste management struggles with the sustainable disposal of used tires. One solution involves shredding used tires into crumb rubber and using the material as infill for artificial turf. However, crumb rubber contains hydrocarbons, organic compounds, and heavy metals, and it travels into the environment. Earthworms living in soil contaminated with virgin crumb rubber gained 14% less body weight than did earthworms living in uncontaminated soil, but the impact of aged crumb rubber on the earthworms is unknown. Since many athletic fields contain aged crumb rubber, we compared the body weight, survivorship, and longevity in heat and light stress for earthworms living in clean topsoil to those living in topsoil contaminated with aged crumb rubber. We also characterized levels of metals, nutrients, and micronutrients of both soil treatments and compared those to published values for soil contaminated with virgin crumb rubber. Consistent with earlier research, we found that contaminated soil did not inhibit microbial respiration rates. Aged crumb rubber, like new crumb rubber, had high levels of zinc. However, while exposure to aged crumb rubber did not reduce earthworm body weight as did exposure to new crumb rubber, exposure to aged crumb rubber reduced earthworm survival time during a stress test by a statistically significant 38 min (16.2%) relative to the survival time for worms that had lived in clean soil. Aged crumb rubber and new crumb rubber appear to pose similar toxic risks to earthworms. This study suggests an environmental cost associated with the current tire-recycling solution.
Afficher plus [+] Moins [-]Occurrence, distribution and composition of aliphatic and polycyclic aromatic hydrocarbons in sediment cores from the Lower Fox River, Wisconsin, US Texte intégral
2018
Brewster, Chase S. | Sharma, Virender K. | Cizmas, Leslie | McDonald, Thomas J.
The Lower Fox River is a 39 mile section which supports approximately 270,000 rural inhabitants across 18 counties, 303,000 metropolitan residents in Green Bay and Appleton, Wisconsin, and several large industrial complexes such as paper mills and power plants. This paper presents the distribution and concentrations of aliphatic (n-alkanes) and aromatic hydrocarbons (polycyclic aromatic hydrocarbons [PAHs]) as well as total organic carbon (TOC) in the Lower Fox River to identify the sources of hydrocarbon contamination. Excluding one outlier, percent TOC values were between 0.73 and 19.9% with an average value of 6.74%. Total n-alkanes ranged from 3.51 μg/g to 117 μg/g and showed a strong presence of odd carbon-numbered n-alkane ratios (range of C25 to C35), suggesting source input from terrestrial biomass. The mean polycyclic aromatic hydrocarbon (PAH) concentration was 24,800 ng/g. High molecular weight PAH concentrations dominated the distribution of hydrocarbon contaminants. Cross-plots of PAHs were used to compare diagnostic source ratios of benz[a]anthracene (BaA), chrysene (Chr), fluoranthene (Flu), pyrene (Pyr), anthracene (Ant), phenanthrene (Phe), indeno[1,2,3-cd]pyrene (InP), and benzo[g,h,i]perylene (BghiP) by depth and area. PAH ratios varied slightly with the core depth. Deeper core sections indicated the presence of biomass combustion while the upper core sections indicated combustion of both petroleum and biomass. The PAH toxicity of one core was estimated using toxicity equivalency factors, and the benzo[a]pyrene toxic equivalence quotient totaled 2,293 ng/g-dry wt. Levels of PAHs in sediments are compared with established regulatory values and recommendations are made.
Afficher plus [+] Moins [-]In situ co-precipitation preparation of a superparamagnetic graphene oxide/Fe3O4 nanocomposite as an adsorbent for wastewater purification: synthesis, characterization, kinetics, and isotherm studies Texte intégral
2018
Pu, Shengyan | Xue, Shengyang | Yang, Zeng | Hou, Yaqi | Zhu, Rongxin | Zhu, Wei
A superparamagnetic graphene oxide (GO)/Fe₃O₄ nanocomposite (MGO) was prepared by a facile in situ co-precipitation strategy, resulting in a prospective material for the application of graphene oxide in wastewater treatment. MGO was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The prepared adsorbent showed a high adsorption efficiency relevant to the purification of dye-contaminated wastewater and could be readily magnetically separated. The maximum adsorption capacity was ca. 546.45 mg g⁻¹ for the common cationic dye methylene blue (MB) and ca. 628.93 mg g⁻¹ for the anionic dye Congo red (CR). The adsorption processes fit the pseudo-second-order kinetic model well, which revealed that these processes may involve the chemical interaction between adsorbate and adsorbent. The thermodynamic parameters indicated that the adsorption reaction was an endothermic and spontaneous process. Furthermore, the prepared magnetic adsorbent had a wide effective pH range from 5 to 11 and showed good stability after five reuse cycles. The synthetic MGO showed great potential as a promising adsorbent for organic contaminant removal in wastewater treatment.
Afficher plus [+] Moins [-]Minimum tillage and organic fertilization for the sustainable management of Brassica carinata A. (Braun) in the Mediterranean environment Texte intégral
2018
Debiase, Giambattista | Traversa, Andreina | Montemurro, Francesco | Mastrangelo, Marcello | Fiore, Angelo | Ventrella, Gianrocco | Brunetti, Gennaro
In recent years, the massive exploitation of agricultural land intended to meet growing food demand has led to a reduction in soil fertility through the depletion of nutrients and organic matter. To implement sustainable agriculture, it is necessary to reduce soil tillage and use residual biomasses that are easily available in the region as soil amendments. Furthermore, it is important to test these residual biomasses in order to exclude a possible increase of heavy metals in soils due to the incorporation of the aforementioned biomasses. The current study aimed to evaluate the effects on soil fertility and health following the application of organic fertilizers combined with different soil tillage practices and the agronomic response of Brassica carinata A. (Braun). The soil tillage treatments consisted of conventional (CT) and minimum tillage (MT), whereas the fertilization treatments were mineral fertilizer (Nₘᵢₙ), municipal solid waste compost (Ncₒₘₚ), mixed compost and mineral fertilizer (Nₘᵢₓ), and sewage sludge (Nₛₛ). These treatments were compared with an unfertilized control (N₀). The Ncₒₘₚ and Nₛₛ treatments enhanced soil fertility, increasing the organic carbon and available phosphorus concentrations compared with N₀ and Nₘᵢₙ, whereas no significant difference was showed between the soil tillage treatments in terms of soil fertility. In addition, Nₛₛ did not show any significant difference compared to Nₘᵢₙ in terms of crop biomass, whereas this parameter appeared higher in CT compared with MT. A principal component analysis showed that the concentrations of toxic elements applied by the organic amendments did not change the dynamic equilibrium of the soil–plant system. Over the short term, the replacement of CT and Nₘᵢₙ with MT and Nₛₛ can be achieved, thus guaranteeing the sustainable cultivation of Brassica, without significant changes in heavy metal concentration in soil.
Afficher plus [+] Moins [-]Levels and gas-particle partitioning of hexabromocyclododecanes in the urban air of Dalian, China Texte intégral
2018
Li, Yan | Zhu, Xiuhua | Wang, Longxing | Gao, Yuan | Chen, Jiping | Wang, Wei | Dong, Xuewei | Li, Xiaoxiao
The concentrations of α-, β-, and γ-hexabromocyclododecane diastereomers (HBCDs) in gas phase and particulate phase of Dalian urban air, China, were monitored from September 2016 to August 2017 with high-volume active sampler. The total concentration of ∑HBCDs (gas phase + particulate phase) ranged from 15.47 to 43.57 pg m⁻³, with an average of 27.07 pg m⁻³, and 73.39–96.76% of the total HBCDs were found in the particulate phase. No matter in gas phase or in particulate phase, α-HBCD was the predominant component in all, and there was a good negative correlation between the relative contribution of α-HBCD to ∑HBCDs and that of γ-HBCD to ∑HBCDs. The average ratios of the air concentration of α-HBCD to γ-HBCD were comparable with those found in decorative polystyrene, which indicated that HBCDs in outdoor air of Dalian probably came from indoor air and ventilation air from inside of buildings coupled with the already present contamination in background air. There were clear seasonal differences in the HBCD concentrations. Spearman’s rank correlation analysis between the concentrations of HBCDs with meteorological parameters was conducted. The exposure risk of HBCDs was evaluated, which illustrated that the estimated exposure of HBCDs via the outdoor air in Dalian was well below the reference doses (200 ng kg⁻¹ bw day⁻¹) derived by the US National Research Council.
Afficher plus [+] Moins [-]MicroRNA-191, acting via the IRS-1/Akt signaling pathway, is involved in the hepatic insulin resistance induced by cigarette smoke extract Texte intégral
2018
Yang, Qianlei | Cui, Yan | Luo, Fei | Liu, Xinlu | Wang, Qiushi | Bai, Jun | Dong, Faqin | Sun, Qian | Lu, Lu | Xu, Hui | Xue, Junchao | Chen, Chao | Xiang, Quanyong | Liu, Qizhan | Zhang, Qingbi
Cigarette smoke causes insulin resistance, which is associated with type 2 diabetes mellitus (T2DM). However, the mechanism by which this occurs remains poorly understood. Because the involvement of microRNAs (miRNAs) in the development of insulin resistance is largely unknown, we investigated, in hepatocytes, the roles of miR-191 in cigarette smoke extract (CSE)-induced insulin resistance. In L-02 cells, CSE not only decreased glucose uptake and glycogen levels but also reduced levels of insulin receptor substrate-1 (IRS-1) and Akt activation, effects that were blocked by SC79, an activator of Akt. CSE also increased miR-191 levels in L-02 cells. Furthermore, the inhibition of miR-191 blocked the decreases of IRS-1 and p-Akt levels, which antagonized the decreases of glucose uptake and glycogen levels in L-02 cells induced by CSE. These results reveal a mechanism by which miR-191 is involved in CSE-induced hepatic insulin resistance via the IRS-1/Akt signaling pathway, which helps to elucidate the mechanism for cigarette smoke-induced T2DM.
Afficher plus [+] Moins [-]Municipal solid waste compost as a novel sorbent for antimony(V): adsorption and release trials at acidic pH Texte intégral
2018
Diquattro, Stefania | Garau, Giovanni | Lauro, GianPaolo | Silvetti, Margherita | Deiana, Salvatore | Castaldi, Paola
The ability of two municipal solid waste composts (MSW-Cs) to sorb antimony(V) in acidic conditions (pH 4.5) was investigated. Sorption isotherms and kinetics showed that both MSW-Cs could sorb antimony(V), even if in different amounts (~ 0.18 and 0.24 mmol g⁻¹ of Sb(V) by MSW-C1 and MSW-C2, respectively). These differences were ascribed to the chemical composition of composts, as well as to the total acidity of their humic substances. The Sb(V) sorption by both MSW-Cs followed a pseudo-second-order kinetic model, while the sorption isotherms data fitted the Freundlich model better than the Langmuir one. The humic acids extracted from composts contributed to 4.26 and 8.24% of Sb(V) sorption by MSW-C1 and MSW-C2 respectively. SEM-EDX spectra of the MSW-C+Sb(V) systems showed a certain association of Ca(II) with Sb(V), while sequential extraction procedures indicated that more than 80% of the Sb(V) sorbed was strongly retained by MSW-Cs. On the other hand, treatment with oxalic acid at pH 4.5 favored the release of more than 98 and 65% of the Sb(V) sorbed by MSW-C1 and MSW-C2 respectively, supporting a possible role of calcium in Sb(V) retention. The results from this study suggest that MSW-Cs could be used as amendments for the in-situ immobilization of Sb(V) in acidic-polluted soils.
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