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Magnetite fine particle and nanoparticle environmental contamination from industrial uses of coal Полный текст
2018
Sutto, Thomas E.
Recently it has been shown that there are two types of magnetite particles in the human brain, some, which occur naturally and are jagged in appearance, and others that arise from industrial sources, such as coal fired power plants, and are spherical. In order to confirm the latter, the magnetic component of coal ash is first purified and characterized by XRD, showing that it is magnetite with an average particle size of 211 nm. Studies confirm the coal ash magnetic behavior, and that the magnetite is not bound to the other components of coal ash but exist as an isolatable component. SEM studies confirm that in the process of burning coal at very high temperatures for industrial uses, the magnetite formed is spherically shaped, as recent studies of brain tissues of highly exposed urban residents have found. As such, the use of coal for industrial applications such as coking in the production of steel and in power plants is indicated to be a major source of the spherical magnetic combustion-associated magnetite fine particle and nanoparticle environmental pollution. The capacity of these magnetic particles to penetrate and damage the blood-brain-barrier and the early development of Alzheimer's disease hallmarks in exposed populations calls for detail analysis of magnetic fine and nanoparticle distribution across the world.Summation: Industrial coal usage produces spherical magnetic particles and nanoparticles, identical to those associated with neurological disorders.
Показать больше [+] Меньше [-]CO2 reforming of CH4 on Ni-Al-Ox catalyst using pure and coal gas feeds: Synergetic effect of CoO and MgO in mitigating carbon deposition Полный текст
2018
Alabi, Wahab. O.
Mg-Al-Ox supported monometallic (Ni) and bimetallic (Ni-Co) catalysts with different compositions of Mg and Al were investigated for CO₂ reforming of CH₄, using both coal and pure gas feeds, to limit the emission of these environmental pollutant gases into the atmosphere. Results showed that all the catalysts were active for dry reforming reaction using both feeds. Reactants conversion, stoichiometric product selectivity, and resistance to carbon deposition of catalysts remarkably improved when the Mg/Al ratio was greater than 1. Characterization results revealed changes in the bulk structure, textural and surface properties as the Mg/Al ratio and composition of catalysts changed. Improved active metal reduction, metal-support and metal-metal interaction (in the bimetallic) were also noted in the catalysts with Mg/Al ratio greater than 1. With respect to feed composition, less carbon deposition was recorded in the corresponding catalysts using coal gas compared to the pure gas. Ni-Co interaction and their interaction with MgO facilitated better basicity, increased metal dispersion and smaller particle size in Ni-Co-Mg₁.₇-Al₁-Ox, which showed best catalytic performance with no carbon deposition in both feeds. These interactions and properties stabilized the Ni site, which made the Ni-Co-Mg₁.₇-Al₁-Ox, catalyst resistant to sintering and carbon deposition.
Показать больше [+] Меньше [-]Emission characteristics for gaseous- and size-segregated particulate PAHs in coal combustion flue gas from circulating fluidized bed (CFB) boiler Полный текст
2018
Wang, Ruwei | Liu, Guijian | Sun, Ruoyu | Yousaf, Balal | Wang, Jizhong | Liu, Rongqiong | Zhang, Hong
The partitioning behavior of polycyclic aromatic hydrocarbons (PAHs) between gaseous and particulate phases from coal-fired power plants (CFPPs) is critically important to predict PAH removal by dust control devices. In this study, 16 US-EPA priority PAHs in gaseous and size-segregated particulate phases at the inlet and outlet of the fabric filter unit (FFs) of a circulating fluidized bed (CFB) boiler were analyzed. The partitioning mechanisms of PAHs between gaseous and particulate phases and in particles of different size classes were investigated. We found that the removal efficiencies of PAHs are 45.59% and 70.67–89.06% for gaseous and particulate phases, respectively. The gaseous phase mainly contains low molecular weight (LMW) PAHs (2- and 3-ring PAHs), which is quite different from the particulate phase that mainly contains medium and high molecular weight (MMW and HMW) PAHs (4- to 6-ring PAHs). The fractions of LMW PAHs show a declining trend with the decrease of particle size. The gas-particle partitioning of PAHs is primarily controlled by organic carbon absorption, in addition, it has a clear dependence on the particle sizes. Plot of log (TPAH/PM) against logDp shows that all slope values were below −1, suggesting that PAHs were mainly adsorbed to particulates. The adsorption effect of PAHs in size-segregated PMs for HMW PAHs is more evident than LMW PAHs. The particle size distributions (PSDs) of individual PAHs show that most of PAHs exhibit bi-model structures, with one mode peaking in the accumulation size range (2.1–1.1 μm) and another mode peaking in coarse size range (5.8–4.7 μm). The intensities of these two peaks vary in function of ring number of PAHs, which is likely attributed to Kelvin effect that the less volatile HMW PAH species preferentially condense onto the finer particulates. The emission factor of PAHs was calculated as 3.53 mg/kg of coal burned, with overall mean EFPAH of 0.55 and 2.98 mg/kg for gaseous and particulate phase, respectively. Moreover, the average emission amount of PAHs for the investigated CFPP was 1016.6 g/day and 371073.6 g/y, respectively.
Показать больше [+] Меньше [-]Temporal-spatial characteristics and source apportionment of PM2.5 as well as its associated chemical species in the Beijing-Tianjin-Hebei region of China Полный текст
2018
Gao, Jiajia | Wang, Kun | Wang, Yong | Liu, Shuhan | Zhu, Chuanyong | Hao, Jiming | Liu, Huanjia | Hua, Shenbing | Tian, Hezhong
PM₂.₅ and its major chemical compositions were sampled and analyzed in January, April, July and October of 2014 at Beijing (BJ), Tianjin (TJ), Langfang (LF) and Baoding (BD) in order to probe the temporal and spatial characteristics as well as source apportionment of PM₂.₅ in the Beijing-Tianjin-Hebei (BTH) region. The results showed that PM₂.₅ pollution was severe in the BTH region. The average annual concentrations of PM₂.₅ at four sampling sites were in the range of 126–180 μg/m³, with more than 95% of sampling days exceeding 35 μg/m³, the limit ceiling of average annual concentration of PM₂.₅ regulated in the Chinese National Ambient Air Quality Standards (GB3095-2012). Additionally, concentrations of PM₂.₅ and its major chemical species were seasonally dependent and demonstrated spatially similar variation characteristics in the BTH region. Concentration of toxic heavy metals, such as As, Cd, Cr, Cu, Mn, Ni, Pb, Sb, Se, and Zn, were higher in winter and autumn. Secondary inorganic ions (SO₄²⁻, NO₃⁻, and NH₄⁺) were the three-major water-soluble inorganic ions (WSIIs) of PM₂.₅ and their mass ratios to PM₂.₅ were higher in summer and autumn. The organic carbon (OC) and elemental carbon (EC) concentrations were lower in spring and summer than in autumn and winter. Five factors were selected in Positive Matrix Factorization (PMF) model analysis, and the results showed that PM₂.₅ pollution was dominated by vehicle emissions in Beijing, combustion emissions including coal burning and biomass combustion in Langfang and Baoding, and soil and construction dust emissions in Tianjin, respectively. The air mass that were derived from the south and southeast local areas around BTH regions reflected the features of short-distant and small-scale air transport. Shandong, Henan, and Hebei were identified the major potential sources-areas of secondary aerosol emissions to PM₂.₅.
Показать больше [+] Меньше [-]Source apportionment of aerosol particles at a European air pollution hot spot using particle number size distributions and chemical composition Полный текст
2018
Leoni, Cecilia | Pokorná, Petra | Hovorka, Jan | Masiol, Mauro | Topinka, Jan | Zhao, Yongjing | Křůmal, Kamil | Cliff, Steven | Mikuška, Pavel | Hopke, Philip K.
Ostrava in the Moravian-Silesian region (Czech Republic) is a European air pollution hot spot for airborne particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and ultrafine particles (UFPs). Air pollution source apportionment is essential for implementation of successful abatement strategies. UFPs or nanoparticles of diameter <100 nm exhibit the highest deposition efficiency in human lungs. To permit apportionment of PM sources at the hot-spot including nanoparticles, Positive Matrix Factorization (PMF) was applied to highly time resolved particle number size distributions (NSD, 14 nm-10 μm) and PM₀.₀₉₋₁.₁₅ chemical composition. Diurnal patterns, meteorological variables, gaseous pollutants, organic markers, and associations between the NSD factors and chemical composition factors were used to identify the pollution sources. The PMF on the NSD reveals two factors in the ultrafine size range: industrial UFPs (28%, number mode diameter - NMD 45 nm), industrial/fresh road traffic nanoparticles (26%, NMD 26 nm); three factors in the accumulation size range: urban background (24%, NMD 93 nm), coal burning (14%, volume mode diameter - VMD 0.5 μm), regional pollution (3%, VMD 0.8 μm) and one factor in the coarse size range: industrial coarse particles/road dust (2%, VMD 5 μm). The PMF analysis of PM₀.₀₉₋₁.₁₅ revealed four factors: SIA/CC/BB (52%), road dust (18%), sinter/steel (16%), iron production (16%). The factors in the ultrafine size range resolved with NSD have a positive correlation with sinter/steel production and iron production factors resolved with chemical composition. Coal combustion factor resolved with NSD has moderate correlation with SIA/CC/BB factor. The organic markers homohopanes correlate with coal combustion and the levoglucosan correlates with urban background. The PMF applications to NSD and chemical composition datasets are complementary. PAHs in PM₁ were found to be associated with coal combustion factor.
Показать больше [+] Меньше [-]Air pollutant emissions and mitigation potential through the adoption of semi-coke coals and improved heating stoves: Field evaluation of a pilot intervention program in rural China Полный текст
2018
Liu, Yafei | Zhang, You | Li, Chuang | Bai, Yun | Zhang, Daoming | Xue, Chunyu | Liu, Guangqing
Pollutant emissions from incomplete combustion of raw coal in low-efficiency residential heating stoves greatly contribute to winter haze in China. Semi-coke coals and improved heating stoves are expected to lower air pollutant emissions and are vigorously promoted by the Chinese government in many national and local plans. In this study, the thermal performance and air pollutant emissions from semi-coke combustion in improved heating stoves were measured in a pilot rural county and compared to the baseline of burning raw coal to quantify the mitigation potential of air pollutant emissions. A total of five stove-fuel combinations were tested, and 27 samples from 27 different volunteered households were obtained. The heating efficiency of improved stoves increased, but fuel consumption appeared higher with more useful energy output compared to traditional stoves. The emission factors of PM2.5, SO2, and CO2 of semi-coke burning in specified improved stoves were lower than the baseline of burning raw coal chunk, but no significant NOx and CO decreases were observed. The total amount of PM2.5 and SO2 emissions per household in one heating season was lower, but CO, CO2, and NOx increased when semi-coke coal and specified improved stoves were deployed. Most differences were not statistically significant due to the limited samples and large variation, indicating that further evaluation would be needed to make conclusions that could be considered for policy.
Показать больше [+] Меньше [-]Long term trends in atmospheric concentrations of polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons: A study of Japanese cities from 1997 to 2014 Полный текст
2018
Hayakawa, Kazuichi | Tang, Ning | Nagato, Edward Gou | Toriba, Akira | Sakai, Shigekatsu | Kano, Fumio | Goto, Sumio | Endo, Osamu | Arashidani, Kei-ichi | Kakimoto, Hitoshi
Total suspended particulate matter (TSP) was collected during the summer and winter in five Japanese cities spanning Hokkaido to Kyushu (Sapporo, Kanazawa, Tokyo, Sagamihara and Kitakyushu) from 1997 to 2014. Nine polycyclic aromatic hydrocarbons (PAHs) with four to six rings, including pyrene (Pyr) and benzo[a]pyrene (BaP), were identified using high-performance liquid chromatography (HPLC) with fluorescence detection. Two nitropolycyclic aromatic hydrocarbons (NPAHs), 1-nitropyrene (1-NP) and 6-nitrobenzo[a]pyrene (6-NBaP), were identified by HPLC with chemiluminescence detection. A comparison of PAH and NPAH concentrations and [NPAH]/[PAH] ratios such as [1-NP]/[Pyr] and [6-NBaP]/[BaP] revealed the following characteristics in the five cities: (1) In Sapporo, Kanazawa, Tokyo and Sagamihara, the concentrations of PAHs and NPAHs were high at the beginning of the sampling period and then steadily decreased, with NPAHs decreasing faster than PAHs. The large initial [1-NP]/[Pyr] ratios suggest that the major contributor was automobiles but subsequent decreases in this ratio suggest decreased automobile contributions. (2) By contrast, PAH concentrations in Kitakyushu did not decrease during the sampling period, though concentrations of NPAHs decreased. The consistently smaller [1-NP]/[Pyr] ratio and larger [6-NBaP]/[BaP] ratio in Kitakyushu suggests that the major contributor of PAHs was not automobiles but iron manufacturing which uses a large amount of coal. The sudden increase in atmospheric PAH concentrations in the winter of 2014 may also be due to iron manufacturing.
Показать больше [+] Меньше [-]The effect of sewage sludge fertilization on the concentration of PAHs in urban soils Полный текст
2018
Wołejko, Elżbieta | Wydro, Urszula | Jabłońska-Trypuć, Agata | Butarewicz, Andrzej | Łoboda, Tadeusz
This paper analyses sources of sixteen PAHs – polycyclic aromatic hydrocarbons in urbanized areas by using selected diagnostic ratios. Simultaneously, an attempt was made to determine how sewage sludge changes PAHs content in urbanized areas soils. In the experiment three lawns along the main roads in Bialystok with different traffic intensity, three doses of sewage sludge and two years of study were considered. There was no effect of fertilization with sewage sludge on the sum of 16 PAHs in urban soil samples, nevertheless, the sum of 16 PAHs was reduced from 2.6 in 2011 to 2.3 mg/kg in 2012. Among 16 tested PAHs compounds, benzo[a]pyrene was the most dominant compound in samples collected in both years – about 15% of all PAHs. The results suggest that application of sludge into the soil did not influence the concentration of 2-3-ring, 4-ring and 5-6-ring PAHs. For the objects fertilized with a dose 150.0 Mg/ha, of sludge the total sum of potentially carcinogenic PAHs in the urban soil lowered by approximately 68% in comparison with the control plots. PAHs contamination of the urban soil samples resulted from the influence of coal, petroleum and biomass combustion. Moreover, PAHs can enter soil via at mospheric deposition.
Показать больше [+] Меньше [-]Fragrances and PAHs in snow and seawater of Ny-Ålesund (Svalbard): Local and long-range contamination Полный текст
2018
Vecchiato, Marco | Barbaro, Elena | Spolaor, Andrea | Burgay, Francois | Barbante, Carlo | Piazza, Rossano | Gambaro, Andrea
Polar regions are fragile ecosystems threatened by both long-range pollution and local human contamination. In this context, the environmental distribution of the Personal Care Products (PCPs) represent a major knowledge gap. Following preliminary Antarctic studies, Fragrance Materials (FMs) were analyzed in the seawater and snow collected in the area of Ny-Ålesund, Svalbard, to investigate local and long-range contamination. Polycyclic Aromatic Hydrocarbons (PAHs), including Retene, were determined in parallel to help the identification of the governing processes. Concentrations of FMs up to 72 ng L⁻¹ were detected in the surface snow near the settlement and at increasing distances, in relation to the prevailing winds. PAHs follow a similar scheme, with levels of Retene up to 1.8 μg L⁻¹, likely deriving from the occurrence of this compound in the coal dust due to the previous mining activities in the area. The snow seasonal deposition of FMs and PAHs was estimated in a snowpit dug at the top of the Austre Brøggerbreen glacier, indicating the long-range atmospheric transport (LRAT) of these compounds.
Показать больше [+] Меньше [-]Alteration behavior of mineral structure and hazardous elements during combustion of coal from a power plant at Huainan, Anhui, China Полный текст
2018
Tang, Quan | Sheng, Wanqi | Li, Liyuan | Zheng, Liugen | Miao, Chunhui | Sun, Ruoyu
The alteration behavior of minerals and hazardous elements during simulated combustion (100–1200 °C) of a raw coal collected from a power plant were studied. Thermogravimetric analysis indicated that there were mainly four alteration stages during coal combustion. The transformation behavior of mineral phases of raw coal, which were detected by X-ray polycrystalline diffraction (XRD) technique, mainly relied on the combustion temperature. A series of changes were derived from the intensities of mineral (e.g. clays) diffraction peaks when temperature surpassed 600 °C. Mineral phases tended to be simple and collapsed to amorphous glass when temperature reached up to 1200 °C. The characteristics of functional groups for raw coal and high-temperature (1200 °C) ash studied by Fourier transform infrared spectroscopy (FTIR) were in accordance with the result obtained from XRD analysis. The volatilization ratios of Co, Cr, Ni and V increased consistently with the increase of combustion temperature, suggesting these elements were gradually released from the organic matter and inorganic minerals of coal.
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