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Quantitative Assessment of PM2.5 Sources and Their Seasonal Variation in Krakow Полный текст
2017
Samek, Lucyna | Stegowski, Z. | Furman, L. | Styszko, K. | Szramowiat, K. | Fiedor, J.
In industry areas of Poland such as Silesia or urban sites like Krakow and some other cities, the levels of pollutants frequently breach air quality standards. Particulate matter (PM) is the most important constituent of atmospheric pollution. Beginning on 1st February 2014 until 31st January 2015, the samples of fine particulate matter PM₂.₅ (aerodynamic diameter of particles less than or equal to 2.5 μm) were collected at a site in the south-eastern Krakow urban background area. During this period, 194 samples were taken. The samples showed daily variation of PM₂.₅ concentration. From these data, monthly variations were estimated and presented in this paper. Monthly integrated data are more representative for the Krakow urban background and show seasonal variation of PM₂.₅ pollution. The lowest monthly concentration value was found for August 2014—about 10 μg m⁻³, the highest for February 2014–70 μg m⁻³, whereas the average annual value was about 31 μg/m³. Utilizing X-ray fluorescence method, concentrations of 15 elements for each sample were determined and 8 inorganic ions were analyzed by ion chromatography. Additionally, the samples were analyzed for black carbon (BC). Receptor model PMF (positive matrix factorization) was used for source identification and apportionment. The modeling identified six sources and their quantitative contributions to PM₂.₅ total mass. The following sources were identified: combustion, secondary nitrate and sulfate, biomass burning, industry or/and soil and traffic. Finally, monthly variations of each source are presented.
Показать больше [+] Меньше [-]Synthesis and Metal-Ion Uptake Properties of a New Dithiocarbamate-Base Resin Полный текст
2017
Sarikahya, Hasan | Scalzo, Rachel D. | Alawaed, Abdulkhaliq | Niri, Vadoud | Damkaci, Fehmi
A new dithiocarbamate-base resin was synthesized utilizing the reaction between carbon disulfide and immobilized amines on the fully cross-linked side of the styrene-maleicimide (SMI) copolymer. The sorption characteristics of the synthesized resin for copper, lead, nickel, zinc, and cadmium ions were investigated, using atomic adsorption spectroscopy (AAS). The sorption capacity of the resin for each metal ion was studied as a function of pH and time. The optimum pH range for sorption of the metal ions was between 4 and 6. The capacity of the resin for the metal ions decreases in the following order: Cu(II) ≈ Pb(II) > > Zn(II) > Ni(II) > Cd(II). The sorption rate of the metal ions in the resin decreases in the following order: Zn(II) > Ni(II) > Cd(II) > Pb(II) > Cu(II). The affinity of the resin for the ions was also studied using a mixture of the heavy metal ions. The capacities of the new resin, especially for copper and lead, are significantly higher than previously studied resins. Additionally, it was shown that desorption of the captured ions from the resin within 24 h can be done using 1 M nitric acid solution.
Показать больше [+] Меньше [-]Remediation of Radiocesium-137 Affected Soil Using Napiergrass Under Different Planting Density and Cutting Frequency Regimes Полный текст
2017
Kang, Dong-Jin | Ishii, Yasuyuki | Tazoe, Hirofumi | Isobe, Katsunori | Higo, Masao | Hosoda, Masahiro | Yamada, Masatoshi | Tokonami, Shinji
This study investigated the use of napiergrass (Pennisetum purpureum Schum.) to remediate soils highly contaminated with radiocesium-137 (¹³⁷Cs) in the town of Namie, Fukushima Prefecture, which is located around 9 km northwest of the Fukushima Daiichi Nuclear Power Plant, Japan. Field experiments were performed to investigate the remediation effects using two sites (paddy or upland grassland) as replicates, three planting densities (low, medium, and high density), and two different cutting frequencies (cut once or twice a year) over 2 consecutive years. Napiergrass can be more efficient than sorghum for ¹³⁷Cs remediation. The maximum ¹³⁷Cs removal ratio (CR, %) in napiergrass achieved with high-density planting (11 plants m⁻²) was between 0.32 and 0.57%. However, cutting frequency did not affect the CR. Higher biomass leads to a dilution of ¹³⁷Cs in cutting frequency. Therefore, we suggest that the greatest CR could be achieved through a high above ground biomass (high-density planting).
Показать больше [+] Меньше [-]Influences of Coal Ash Leachates and Emergent Macrophytes on Water Quality in Wetland Microcosms Полный текст
2017
Olson, LeifH. | Misenheimer, JohnC. | Nelson, ClayM. | Bradham, KarenD. | Richardson, CurtisJ.
The storage of coal combustion residue (CCR) in surface water impoundments may have an impact on nearby water quality and aquatic ecosystems. CCR contains leachable trace elements that can enter nearby waters through spills and monitored discharge. It is important, therefore, to understand their environmental fate in affected systems. This experiment examined trace element leachability into freshwater from fly ash (FA), the most common form of CCR. The effects on water quality of FA derived from both high and low sulfur coal sources as well as the influences of two different emergent macrophytes, Juncus effusus and Eleocharis quadrangulata, were evaluated in wetland microcosms. FA leachate dosings increased water electric conductivity (EC), altered pH, and, most notably, elevated the concentrations of boron (B), molybdenum (Mo), and manganese (Mn). The presence of either macrophyte species helped reduce elevated EC, and B, Mo, and Mn concentrations over time, relative to microcosms containing no plants. B and Mo appeared to bioaccumulate in the plant tissue from the water when elevated by FA dosing, while Mn was not higher in plants dosed with FA leachates. The results of this study indicate that emergent macrophytes could help ameliorate downstream water contamination from CCR storage facilities and could potentially be utilized in wetland filtration systems to treat CCR wastewater before discharge. Additionally, measuring elevated B and Mo in aquatic plants may have potential as a monitoring tool for downstream CCR contamination.
Показать больше [+] Меньше [-]Functionalization of Cotton by RGO/TiO2 to Enhance Photodegradation of Rhodamine B Under Simulated Solar Irradiation Полный текст
2017
Landi, S. Jr | Carneiro, J.O. | Fernandes, F. | Parpot, P. | Molina, J. | Cases, F. | Fernandez, J. | Santos, J.G. | Soares, G.M. B. | Teixeira, V. | Samantilleke, A.P.
Reduced graphene oxide (RGO) and titanium dioxide (TiO₂) nanoparticles were immobilized on cotton textile substrates to produce self-cleaning textiles. Varying number of layers of RGO and TiO₂ nanoparticles were coated by a facile method, and their photocatalytic potential was evaluated by measuring the degradation rate of rhodamine B (Rh-B) in an aqueous solution in a photoreactor under simulated solar irradiation. X-ray diffraction (XRD) and zeta potential measurements of starting materials were studied as they are crucial for innovative methods of functionalization. The study confirms that it is possible to ensure a good adhesion of nanoparticles on textile samples without the use of a resin. The application of varying number of RGO and TiO₂ coatings has influence on photocatalytic properties of functionalized cotton textile substrates. The energy band gap of the samples reduces from 3.25 to −3.20 eV with the number of RGO coatings. All five de-ethylated intermediates of Rh-B during the photocatalytic degradation were identified using a high-performance liquid chromatography–mass spectrometry method. The experimental results show that, in general, the higher the number of RGO coatings is, the higher the photocatalytic efficiency (η) of the functionalized substrate is (η=87% for three RGO coatings on TiO₂).
Показать больше [+] Меньше [-]Conventional as well as Emerging Arsenic Removal Technologies—a Critical Review Полный текст
2017
Mohanty, Debasis
Arsenic poisoning from contaminated drinking water has evolved as one of the major health hazards in recent times. High concentrations of arsenic in water and soil have been found in many parts of the world. Developing countries like Taiwan, Chile, Argentina, Bangladesh, Nepal and Vietnam are most affected by the contamination of groundwater with arsenic. These countries also cannot afford expensive and large-scale treatments to remove arsenic from drinking waters to acceptable limits (10 ppb, as recommended by WHO and US EPA). The aim of this review is to summarize low-cost, effective conventional technologies currently described in the literature for arsenic removal that can be used in the third world and developing countries, compare them with the emerging technologies and discuss their advantages and disadvantages along with a brief analysis of arsenic chemistry.
Показать больше [+] Меньше [-]Application of Thermally Treated Crushed Concrete Granules for the Removal of Phosphate: A Cheap Adsorbent with High Adsorption Capacity Полный текст
2017
Kang, Ku | Lee, Chang-Gu | Choi, Jae-Woo | Hong, Seong-Gu | Park, Seong-Jik
The aim of this study was to investigate phosphate removal using crushed concrete granules (CCGs). The CCGs were thermally treated at different temperatures (300, 500, 700, and 900 °C) for 3 h under anoxic conditions. The results showed that CCGs thermally treated at 700 °C (700TT-CCGs) were the most effective for the removal of phosphate. The equilibrium adsorption data fitted well the Langmuir isotherm model with a maximum phosphate adsorption capacity of 21.522 mg/g, higher than that of granular adsorbents in the literature. In pH experiments, phosphate adsorption by 700TT-CCGs decreased as initial pH increased from 3 to 5, but sharply increased above pH 5 (final pH 9.1), which was favorable for the formation of calcium phosphate precipitate. The effect of competing anions on phosphate adsorption follows the order: HCO₃⁻ > SO₄²⁻ > NO₃⁻, which is consistent with the reverse order of the shared charge. Column experiments showed no breakthrough of phosphate in the column packed with half 700TT-CCGs and half sand for over 300 h. This study demonstrates that CCGs can be used for phosphate removal from aqueous solution after thermal treatment, which is a simple and cheap way to improve the phosphate removal capacity of CCGs.
Показать больше [+] Меньше [-]Post Plasma-Catalysis of Low Concentration VOC Over Alumina-Supported Silver Catalysts in a Surface/Packed-Bed Hybrid Discharge Reactor Полный текст
2017
Jiang, Nan | Qiu, Cheng | Guo, Lianjie | Shang, Kefeng | Lu, Na | Li, Jie | Wu, Yan
In this study, the degradation of benzene by the means of an optimized surface/packed-bed hybrid discharge (SPBHD) plasma combined with γ-Al₂O₃-supported MO ₓ (M = Ag, Mn, Cu, or Fe) catalysts in post plasma-catalysis (PPC) system. The effects of Ag loading amount and gas hourly space velocity (GHSV) for plasma-catalysis degradation of benzene have been systematically investigated. The experimental result showed that the benzene degradation was improved and the mineralization process was greatly enhanced towards total oxidation after the combination of plasma with all MO ₓ /γ-Al₂O₃ catalysts. The AgO ₓ /γ-Al₂O₃ catalyst exhibited the best catalytic activity in benzene degradation than the other catalysts in PPC system. The highest benzene degradation efficiency of 96% and CO ₓ selectivity of 99% can be obtained for AgO ₓ /γ-Al₂O₃ catalyst with optimum Ag loading amount and GHSV of 15% and 22,856 h⁻¹, respectively. Time course of benzene degradation during PPC process indicated that the plasma-induced catalytic activity of AgO ₓ /γ-Al₂O₃ catalyst was temporary rather than lasting over a period after the plasma off. FT-IR analysis results revealed that the intermediate products (such as CO, HCOOH) and unwanted by-products (O₃ and NO ₓ) generated in plasma process could be significantly inhibited by PPC process with AgO ₓ /γ-Al₂O₃ catalyst.
Показать больше [+] Меньше [-]Comparative Adsorption of Zn2+ from Aqueous Solution Using Hydroxylated and Sulphonated Biochars Derived from Pulp and Paper Sludge Полный текст
2017
Chaukura, Nhamo | Gwenzi, Willis | Mupatsi, Nyarai | Ruziwa, DeborahT. | Chimuka, Claudius
Thermally robust hydroxylated biochar (HBC) and sulphonated biochar (SBC) were synthesised from paper and pulp sludge (PPS) and used for the adsorption of Zn²⁺ from synthetic wastewater through batch experiments. FTIR analyses proved successful incorporation of the hydroxyl and sulphonic functional groups in HBC and SBC, respectively. The effects of initial solution pH, initial Zn²⁺ concentration, solution temperature and equilibrium contact time were investigated. The removal efficiency of Zn²⁺ increased with increase in both solution temperature and initial Zn²⁺ concentration. Adsorption of Zn²⁺ was greatest at pH 3. HBC and SBC removed 38–99% and 68–90% of Zn²⁺ from solution, respectively. Zn²⁺ adsorption on SBC followed both Langmuir (R ² = 0.994) and Freundlich isotherm models (R ² = 0.999), while adsorption on HBC followed the Freundlich model (R ² = 0.989). Zn²⁺ adsorption on both biosorbents followed pseudo-second-order kinetics (R ² = 0.994–0.999). The increase in enthalpy of adsorption indicated the adsorption process was endothermic and a decrease in Gibbs free energy signified the spontaneity of adsorption. Positive entropy change values imply that the adsorbed Zn²⁺ ions are randomly distributed over the adsorbent surface. The research demonstrated that although their adsorption mechanisms had salient differences, HBC and SBC can effectively remove Zn²⁺ from wastewater. Development of HBC and SBC from PPS provides potential low-cost biosorbents for water and wastewater, while simultaneously minimising the environmental and public health risks associated with current disposal practices of PPS.
Показать больше [+] Меньше [-]Nitrogen removal and microbial community shift in an aerobic denitrification reactor bioaugmented with a Pseudomonas strain for coal-based ethylene glycol industry wastewater treatment Полный текст
2017
Du, Cong | Cui, Chong-Wei | Qiu, Shan | Shi, Sheng-Nan | Li, Ang | Ma, Fang
An aerobic denitrification system, initially bioaugmented with Pseudomonas strain T13, was established to treat coal-based ethylene glycol industry wastewater, which contained 3219 ± 86 mg/L total nitrogen (TN) and 1978 ± 14 mg/L NO₃ ⁻-N. In the current study, a stable denitrification efficiency of 53.7 ± 4.7% and nitrite removal efficiency of 40.1 ± 2.7% were achieved at different diluted influent concentrations. Toxicity evaluation showed that a lower toxicity of effluent was achieved when industry wastewater was treated by stuffing biofilm communities compared to suspended communities. Relatively high TN removal (~50%) and chemical oxygen demand removal percentages (>65%) were obtained when the influent concentration was controlled at below 50% of the raw industry wastewater. However, a further increased concentration led to a 20–30% decrease in nitrate and nitrite removal. Microbial network evaluation showed that a reduction in Pseudomonas abundance was induced during the succession of the microbial community. The napA gene analysis indicated that the decrease in nitrate and nitrite removal happened when abundance of Pseudomonas was reduced to less than 10% of the overall stuffing biofilm communities. Meanwhile, other denitrifying bacteria, such as Paracoccus, Brevundimonas, and Brucella, were subsequently enriched through symbiosis in the whole microbial network.
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