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1.
Sci Total Environ ; 751: 142293, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-33181995

RESUMO

The harm done to the environment by coal gangue was very serious, and it is urgent to adopt effective methods to dispose of coal gangue in order to prevent further environmental damage. Co-pyrolysis experiments of coal gangue (CG) and peanut shell (PS) were carried out using thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) under nitrogen atmosphere. The heavy metal was detected using the inductively coupled plasma-optical emission spectroscopy (ICP-OES). CG and PS were mixed according to the mass ratio of 1:0, 3:1, 1:1, 1:3 and 0:1. The samples were heated to 1000 °C at the heating rate of 10 °C/min, 20 °C/min and 30 °C/min. The comprehensive pyrolysis index (CPI) of CG, C3P1, C1P1, C1P3 and PS is 0.17 × 10-8, 9.75 × 10-8, 35.47 × 10-8, 100.94 × 10-8 and 192.72 × 10-8%2 ·min-2·°C-3. The kinetic parameters were calculated by model-free methods (Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose). The gas products generated at different temperatures during the pyrolysis experiment were detected by Fourier transform infrared spectrometer. The heating rate, temperature and mixing ratio are the input parameters of artificial neural network (ANN), and the remaining mass percentage of sample during the pyrolysis is the output parameter. The ANN model was established and used to predict thermogravimetric experimental data. The ANN18 model is the best model for predicting the co-pyrolysis of CG and PS.


Assuntos
Carvão Mineral , Pirólise , Biomassa , Carvão Mineral/análise , Cinética , Redes Neurais de Computação , Espectroscopia de Infravermelho com Transformada de Fourier
2.
J Environ Sci (China) ; 99: 239-248, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33183701

RESUMO

In this study, a high-efficiency cationic flocculant, P(DAC-MAPTAC-AM), was successfully prepared using UV-induced polymerization technology. The monomer Acrylamide (AM): Acryloxyethyl Trimethyl ammonium chloride (DAC): methacrylamido propyl trimethyl ammonium chloride (MAPTAC) ratio, monomer concentration, photoinitiator concentration, urea content, and cationic monomer DAC:MAPTAC ratio, light time, and power of high-pressure mercury lamp were studied. The characteristic groups, characteristic diffraction peaks, and characteristic proton peaks of P(DAC-MAPTAC-AM) were confirmed by fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), 1H nuclear magnetic resonance spectrometer (1H NMR), and scanning electron microscopy (SEM). The effects of dosage, pH value, and velocity gradient (G) value on the removal efficiencies of turbidity, COD, ammonia nitrogen, and total phenol by poly aluminum ferric chloride (PAFC), P(DAC-MAPTAC-AM), and PAFC/P(DAC-MAPTAC-AM) in the flocculation treatment of coal chemical wastewater were investigated. Results showed that the optimal conditions for the flocculation of coal chemical wastewater using P(DAC-MAPTAC-AM) alone are as follows: dosage of 8-12 mg/L, G value of 100-250 s - 1, and pH value of 4-8. The optimal dosage of PAFC is 90-150 mg/L with a pH of 2-12. The optimal dosage for PAFC/P(DAC-MAPTAC-AM) is as follows: PAFC dosage of 90-150 mg/L, P(DAC-MAPTAC-AM) dosage of 8-12 mg/L, and pH range of 2-6. When P(DAC-MAPTAC-AM) was used alone, the optimal removal efficiencies of turbidity, COD, ammonia nitrogen, and total phenol were 81.0%, 35.0%, 75.0%, and 80.3%, respectively. PAFC has good tolerance to wastewater pH and good pH buffering. Thus, the flocculation treatment of coal chemical wastewater using the PAFC/P(DAC-MAPTAC-AM) compound also exhibits excellent resistance and buffering capacity.


Assuntos
Carvão Mineral , Águas Residuárias , Acrilamida , Cátions , Floculação
3.
Chemosphere ; 262: 127846, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32777615

RESUMO

Data for source apportionment estimation was obtained from combustion of 11 types of biomass (rubber wood, palm kernel, palm fiber, sugarcane bagasse, sugarcane leaves, maize residue, rice stubble, rice straw, Xylocarpus moluccensis, Avicennia alba Blume and Rhizophora mucronata) and bituminous coal. Combustion was carried out in a tube furnace and emitted particulate matter (PM) was collected using a nanosampler that segregated particle sizes down to 0.1 µm. Emission factors of PM < 0.1 µm were in the range of 0.11-0.28 g kg-1 (∼1-8% of total PM), except in the case of Rhizophora mucronata, which had an emission factor of 0.071 ± 0.004 g kg-1 (∼18% of total PM). The dominant polycyclic aromatic hydrocarbons (PAHs) found on PM < 0.1 µm were chrysene from combustion of rubber wood, palm kernel, palm fiber, maize residue, Xylocarpus moluccensis, Avicennia alba Blume, Rhizophora mucronata and bituminous coal; benzo[b]fluoranthene from combustion of rice straw, sugarcane bagasse and sugarcane leaves; and benzo[k]fluoranthene from rice stubble combustion. The emission factors of PAHs bound to PM < 0.1 µm from biomass combustion ranged from 0.005 to 0.044 mg kg-1 and the emission factor from bituminous coal combustion was 0.1411 ± 0.0004 mg kg-1. The carcinogenic potency equivalent or benzo[a]pyrene equivalent was highest from bituminous coal combustion (0.1252 mg kg-1) and between 0.0019 and 0.0192 mg kg-1 from biomass combustion. However, emission factors of both PM and particle-bound PAHs from biomass combustion were affected by moisture content of biomass and moisture contents of biomass used in this study were quite low, ranging from 0.165 to 0.863%.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Biomassa , Carcinógenos/análise , Carvão Mineral/análise , Humanos , Tamanho da Partícula , Madeira/química
4.
Chemosphere ; 262: 127872, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32791370

RESUMO

Magnetite nanoparticles (Fe3O4 NPs) was firstly used to enhance pollutants removal during coal gasification wastewater (CGW) treatment in anaerobic digestion (AD) system. Bench-scale results revealed that 200 mg/L and 20-40 nm of Fe3O4 NPs addition resulted in a maximum removal capacity of total phenol (TPh) at a temperature of 36 °C and hydraulic retention time (HRT) of 36 h. Meanwhile, Fe3O4 NPs addition reduced the oxidation reduction potential (ORP) values and biological toxicity, and enhanced the stability of AD system. Pilot-scale results showed that the TPh and chemical oxygen demand (COD) removal efficiency (53% and 49%) were obtained with the optimal dosage of Fe3O4 NPs. Moreover, electron nanowires may be established with Fe3O4 NPs assisted to perform direct interspecies electron transfer (DIET) among Geobacter, Pseudomonas and Methanosaeta species, and finally enhanced the pollutants removal efficiency.


Assuntos
Resíduos Industriais , Nanopartículas de Magnetita/química , Indústria de Petróleo e Gás , Eliminação de Resíduos Líquidos/métodos , Anaerobiose , Análise da Demanda Biológica de Oxigênio , Reatores Biológicos , Carvão Mineral , Elétrons , Fenol , Fenóis , Pseudomonas , Águas Residuárias
5.
Environ Monit Assess ; 192(11): 715, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-33079243

RESUMO

The release of natural radioactive materials with the emission of fly ash as a result of coal burning in power generation plants is considered amongst the sources that elevate the technologically environmental radioactivity level. This research mainly concerns the assessment of various radiological parameters including excess lifetime cancer risk due to natural radioactive contents associated with fly ash emitted to the surrounding environment from the stack of 1320 Mw Sahiwal coal-fuelled power generation plant (CFPP). For this purpose, fifty-four soil samples were collected in a radius of 4 Km from CFPP and a highly background radiation-shielded HPGe system is used to measure radioactivity in the collected samples. The activity concentrations of radium-226, potassium-40, and thorium-232 in collected samples was found to be in the range of 20 to 138, 43 to 860, and 27 to 127 Bq/kg with average values of 66, 409, and 67 Bq/kg respectively. Activity concentrations of radium-226 and thorium-232 were observed significantly higher than UNSCEAR reported typical global average values. A significant decrease in the level of the aforementioned radionuclides in the collected soil samples was observed with increasing distance from the power plant, which is a clear indication for the elevation of radioactivity concentrations in the surrounding environment as a result of the operation of the CFPP. To assess the radiation dose delivered to the occupational workers and inhabitants living next to Sahiwal CFPP, absorbed γ-dose rate (Dγ), outdoor annual effective dose rate (EOutdoor), and excess lifetime cancer risk (ELCR) were estimated and these were found higher than the UNSCEAR recommended values of 59 nGy/h, 0.07 mSv/y, and 2.9 × 10-4 respectively. The outcome of this first systematic study is the assessment of potential radiological health risk to the occupational workers as well as the inhabitants living in the proximity of this CFPP.


Assuntos
Carvão Mineral , Radioatividade , Carvão Mineral/análise , Cinza de Carvão/análise , Monitoramento Ambiental , Humanos , Paquistão , Centrais Elétricas , Doses de Radiação
6.
Water Sci Technol ; 82(7): 1261-1271, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33079707

RESUMO

Floc structure plays an important role in the separation of coal wastewater. In this study, a camera-based method is used to evaluate quantitatively the structural characteristics of flocs generated by different coagulants and flocculants. The correlations between particle size, settlement velocity and effective density of coal tailings flocs are analysed. The results show that the statistical settling velocity increases linearly with floc size, while the effective density decreases with increase in floc size. Different flocculation mechanisms lead to diverse growth abilities of flocs. When the flocculant is used alone, the quality of the flocs generated by the flocculants, cationic polyacrylamide (CPAM) and non-ionic polyacrylamide (NPAM), is better than that generated by anionic polyacrylamide (APAM). However, the combination of trivalent cations and APAM yields a much better effect than that obtained using CPAM and NPAM. Flocs become larger and more compact when treated with a coagulant combined with a flocculant.


Assuntos
Carvão Mineral , Águas Residuárias , Cátions , Floculação , Tamanho da Partícula
7.
J Environ Qual ; 49(2): 256-267, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33016414

RESUMO

Fertilizer N losses from agricultural systems have economic and environmental implications. Soil amendment with high C materials, such as coal char, may mitigate N losses. Char, a coal combustion residue, obtained from a sugar factory in Scottsbluff, NE, contained 29% C by weight. A 30-d laboratory study was conducted to evaluate the effects of char addition on N losses via nitrous oxide (N2 O) emission, ammonia (NH3 ) volatilization, and nitrate (NO3 -N) leaching from fertilized loam and sandy loam soils. Char was applied at five different rates (0, 6.7, 10.1, 13.4, and 26.8 Mg C ha-1 ; char measured in C equivalent) to soils fertilized with urea ammonium nitrate (UAN) at 200 kg N ha-1 . In addition, there were two negative-UAN control treatments: no char (no UAN) and char at 26.8 Mg C ha-1 (no UAN). Treatment applied at 6.7 and 10.1 Mg C ha-1 in fertilized sandy loam reduced NH3 volatilization by 26-37% and at 6.7, 10.1, and 13.4 Mg C ha-1 in fertilized loam soils by 24% compared with no char application. Nitrous oxide emissions and NO3 -N leaching losses were greater in fertilized compared with unfertilized soil, but there was no effect of char amendment on these losses. Because NO3 -N leaching loss was greater in sandy loam than in loam, soil residual N was twofold higher in loam than in sandy loam. This study suggests that adding coal char at optimal rates may reduce agricultural reactive N to the atmosphere by decreasing NH3 volatilization from fertilized soils.


Assuntos
Amônia , Solo , Carvão Mineral , Fertilizantes , Volatilização
8.
Zootaxa ; 4838(1): zootaxa.4838.1.8, 2020 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-33056837

RESUMO

A fossil of a mayfly nymph that shows similarities with the modern genus Teloganella Ulmer, 1939 of the family Teloganellidae is recorded for the first time from the Indian subcontinent. It is systematically described from the Gurha lignite mine of Bikaner, Rajasthan which belongs to the Palana Formation (late Paleocene-early Eocene). As assignment of the fossil to a modern species of Teloganella is difficult due to indistinguishable location of gills in the impression, a new species, Teloganella gurhaensis Agnihotri et al., sp. nov. is instituted to include this fossil naiad resembling the extant Teloganella.


Assuntos
Ephemeroptera , Animais , Carvão Mineral , Fósseis , Índia , Ninfa
9.
Huan Jing Ke Xue ; 41(11): 4803-4812, 2020 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-33124224

RESUMO

In order to explore the pollution characteristics of the chemical components of atmospheric particulate matter in Nanjing Jiangbei New Area, size-resolved samples were collected from 2013 to 2014. The size distribution and seasonal variation of the chemical components of the particles were studied. The results showed that the total concentration of nine water-soluble ions in fine particles was higher in autumn and winter than in spring and summer, while the concentration of coarse particles was highest in winter. The ratio of NO3-/SO42- for the fine particles in winter was slightly higher than in the other three seasons, and lowest in the coarse particles. The trend of particle size distribution in spring, summer and autumn was consistent. The distribution of water-soluble ions was bimodal, and NO3- peaked at 0.65-1.1 µm in all four seasons. The peak radius of SO42- in the fine particles in summer and autumn was 0.43-0.65 µm, and the peak value in winter moved towards the coarser particles, while Na+ and Cl- mainly existed in the coarse particles. The charge equivalent of anion and anion indicated that the coarse and fine particles were alkaline and weakly alkaline, respectively. Organic carbon (OC) and elemental carbon (EC) mainly existed in the fine particles, with a bimodal distribution. The secondary organic carbon (SOC) in the fine particles in autumn and winter was significantly higher than in spring and summer. The ratio method further indicated that the carbonaceous component of the particulate matter in Nanjing Jiangbei New Area is mainly from the emissions of coal and biomass combustion, and vehicle exhaust.


Assuntos
Poluentes Atmosféricos , Aerossóis/análise , Poluentes Atmosféricos/análise , China , Carvão Mineral , Monitoramento Ambiental , Tamanho da Partícula , Material Particulado/análise , Estações do Ano
10.
Huan Jing Ke Xue ; 41(9): 3969-3975, 2020 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-33124276

RESUMO

This study updates a bottom-up high-resolution emission inventory and estimates the concentrations, emission factors, emissions, and performance values of China's power plants, based on the data from continuous emission monitoring systems and environmental statistics in 2018. The results show that the ultra-low emission policy has significant effects: the average concentrations of SO2, NOx, and PM in thermal power plants were 37.57, 56.71, and 7.41 mg ·m-3, respectively in 2018, which were 58.71%, 43.12%, and 60.79% lower than those in 2015. The average emission factors of SO2, NOx, and PM from coal-fired units in China were 0.3, 0.48, and 0.06 g ·kg-1, respectively, which were 55.2%, 36.84%, and 62.5% lower than those in 2015. The total emissions of SO2, NOx, PM, and PM2.5in thermal power plants were 721.4, 1183.8, 149.0, and 135.9 kt ·a-1, respectively, down by 41.32%, 19.29%, 48.12%, and 40.39% from 2015.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/análise , Poluição do Ar/análise , China , Carvão Mineral , Monitoramento Ambiental , Centrais Elétricas
11.
Huan Jing Ke Xue ; 41(8): 3563-3571, 2020 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-33124329

RESUMO

With the implementation of ultra-low-emission transformation in coal-fired power plants and other related industries in China, the concentrations of filterable particulate matter (FPM) and gaseous pollutants in exhaust gas from stationary sources have reduced significantly, while the emission of condensable particulate matter (CPM) remains a concern. In this study, the monitoring methods of FPM and CPM at a relatively low FPM concentration in exhaust gas from stationary sources in China and abroad were comprehensively analyzed. On the basis of existing research and experimental exploration, the monitoring methods of FPM and CPM were further studied. A direct condensation sampling and monitoring method for total particulate matter (TPM) in ultra-low-emission and high-humidity exhaust gas from stationary sources, which is suitable for the actual situation in China, was developed and established before being used to measure TPM in exhaust gas from a gas power plant in Beijing. The results showed that the emission concentration of TPM in the exhaust gas from the gas power plant was between 1.98 mg·m-3 and 3.77 mg·m-3 (average of 2.81 mg·m-3), whereas the average emission concentration of FPM was only 0.10 mg·m-3. The emission type of particulate matter in exhaust gas from the gas power plant was mainly CPM, which accounted for 93.8% to 99.2% of the TPM (average of 97.0%). The proportion of FPM to TPM ranged from 0.7% to 6.2% (average of 3.0%). The emission concentration of filterable CPM was slightly higher than that of FPM.


Assuntos
Poluentes Atmosféricos , Material Particulado , Poluentes Atmosféricos/análise , Pequim , China , Carvão Mineral , Monitoramento Ambiental , Umidade , Material Particulado/análise , Centrais Elétricas
12.
Huan Jing Ke Xue ; 41(10): 4462-4469, 2020 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-33124378

RESUMO

To explore the difference in the emission of air pollutants from coal stoves, five new and common residential coal stoves (square briquette, baffled heat exchange, heating and cooking integrated gasification positive burning, and gasification reverse burning stove) were selected. The emission level of major air pollutants was determined using simulated combustion in the laboratory for quantitatively evaluating the environmental effects of different coal stoves. Moreover, the factors and reasons for the differences were identified, and suggestions for the reduction of emission were proposed. The results showed that: ① the emissions of air pollutants from different coal stoves were significantly different; the heating and cooking integrated stove had the largest emission intensity (2.9 kg ·t-1) of air pollutants (SO2, NOx, and TSP), which was 1.6 times of the average value, and the square briquette stove had the lowest emission level, which was 65% of the average value. ② The emissions of gaseous pollutants from the coal stoves in different combustion stages also showed evident differences. In the high-fire stage, the NOx emission concentration of the square briquette stove was 0.49 mg ·m-3, which was 45%-72% lower than that of the other stoves; the SO2 emission concentration of the gasification reverse burning stove was 1.38 mg ·m-3, which was 28% lower than that of the other stoves. ③ The application technology and combustion type were the main factors affecting the emission levels of the coal stoves. The stove with square briquette technology and gasification reverse burning technology could have great environmental benefit. However, the cost of the two stoves was 20 and 18 thousand yuan, respectively, which was clearly higher than that of the other types of stoves. ④ Considering the difference in the emission of air pollutants from the different stoves, it was suggested to adopt differentiated economic policy and strict emission and product standards, promoting the use of energy-saving and environment-friendly coal stoves to reduce the emission of air pollutants from coal-fired stoves.


Assuntos
Poluentes Atmosféricos , Poluição do Ar em Ambientes Fechados , Utensílios Domésticos , Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Carvão Mineral/análise , Culinária , Material Particulado/análise
13.
Zootaxa ; 4859(2): zootaxa.4859.2.8, 2020 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-33056202

RESUMO

A new cosmocercid nematode species, Cosmocerca asansolensis sp. nov. (Ascaridida, Cosmocercidae) is described from an Indian bullfrog, Hoplobatrachus crassus (Jerdon, 1853), from Asansol town, Paschim Bardhaman district, West Bengal, India. This species is characterized by the presence of five pairs of plectanes supporting preanal papillae, absence of somatic papillae in females, and having one pair large postanal papillae, a single papilla on the upper lip of cloaca, a single papilla on the lower lip of cloaca and one pair adanal papillae in males and one pair postanal papillae in females. Spicules of the present species are equal, moderately sclerotized, knobbed and wide proximal end gradually tapering to a fine point distally. The gubernaculum is well sclerotized and Y-shaped. Cosmocerca asansolensis sp. nov. represents the 33rd species assigned to the genus, 8th from Oriental region and 6th species from India.


Assuntos
Ascaridídios , Nematoides , Animais , Anuros , Carvão Mineral , Feminino , Índia , Masculino
14.
Environ Monit Assess ; 192(11): 699, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33044641

RESUMO

The present study was intended to determine the potentially toxic elements (PTEs) concentration in fly ash (FA), soil, plant, and vegetable to assess the impacts of pollution on the nearby areas of coal-fired thermal power plant (TPP). The PTEs concentrations (mg/kg) in FA were Cr (48-74) > Pb (41-65) > Cd (7.4-9.7) > As (3.19-4.43) > Hg (0.518-0.598). The contamination factor (Cf) for Cd was highest in agricultural soil (Cf = 22) followed by roadside soil (Cf = 20), and forest soil (Cf = 15), which showed that the soil was strongly polluted due to the presence of Cd. The ecological risk index (ERI) in the topsoil of roadside area was also very high (1130), due to the high value of ecological risk factor of Cd (898) and Hg (213). The health risk associated with the intake of soil containing PTEs were also estimated by calculating hazard index (HI), and the values showed that the risk posed to children was minimum (HI < 1). But in case of roadside area, the HI was very close to one (0.975) indicating that the prolong exposure may pose severe health risk. The bioaccumulation coefficient of all PTEs for Albizia lebbeck and Madhuca longifolia were < 1, indicating less PTEs accumulation in the plant species. The hazard quotient of all PTEs (except of Hg) through vegetable consumption (Allium cepa and Raphanus sativus) was > 1, which signifies that the long-time consumption of contaminated vegetables may cause severe risk to the people.


Assuntos
Metais Pesados , Poluentes do Solo , Criança , Carvão Mineral , Monitoramento Ambiental , Humanos , Índia , Metais Pesados/análise , Centrais Elétricas , Medição de Risco , Solo , Poluentes do Solo/análise , Verduras
15.
PLoS One ; 15(9): e0238138, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32886664

RESUMO

Coal mining professionals in coal mining have recognized that the assessment of top coal release rate can not only improve the recovery rate of top coal, but also improve the quality of coal. But the process was often performed using a manual-based operation mode, which intensifies workload and difficulty, and is at risk of human errors. The study designs a assessment system to give the caving output ratio in top coal caving as accurately as possible based on the parameters adaptive Takagi-Sugeno (T-S) fuzzy system and the Levenberg-Marquardt (LM) algorithm. The main goal of the adaptive parameters based on LM algorithm is to construct its damping factor in the light of lowering of the objective function which is as taken as the index of termination iteration. The performance of the system is evaluated by Pearson correlation coefficient, Coefficient of Determination and relative error where the results of the Takagi-Sugeno method and the parameters adaptive Takagi-Sugeno method are compared to make the evaluation more robust and comprehensive.


Assuntos
Carvão Mineral , Sistemas Especialistas , Mineração/métodos , Lógica Fuzzy
16.
J Environ Manage ; 276: 111311, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32871465

RESUMO

Environment-friendly disposal of coal fly ash (CFA) is essential for sustainable development and cleaner production of electricity in thermal power plants. Although CFA has been employed for soil amelioration, direct application of CFA to soil may pose risks such as heavy metal contamination. This study investigated recycling of CFA through a novel method, which employs the ultrasonic treatment of CFA before its application. Physico-chemical properties of refuse dump soil and CFA were analysed. Subsequently, the effect of ultrasonic treatment on the physico-chemical properties of CFA was investigated. Different ultrasonic parameters (ultrasonic frequency, time interval, and temperature) were studied using response surface methodology. Finally, plant growth experiments were conducted to verify the feasibility of using ultrasonically treated CFA (UTCFA) for soil amelioration. The results show that untreated CFA cannot be used for soil amelioration due to its unsuitable high pH (10.20) and threatening concentrations of trace elements (6.80 mg/kg for Cadmium and 109.75 mg/kg for Arsenic). Ultrasonic treatment increases the soil amelioration properties of CFA by decreasing pH (to 8.50-9.20), decreasing concentrations of Cadmium and Arsenic (satisfying GB 15618-2018), and improving the water-holding capacity of CFA (reducing water loss). Plant indicators confirm the feasibility of using UTCFA for soil amelioration and suggest that the optimum UTCFA proportion is 20%. This study is a benchmark for the utilisation of ultrasonic treatment to improve the soil amelioration properties of CFA.


Assuntos
Cinza de Carvão , Metais Pesados , Carvão Mineral/análise , Cinza de Carvão/análise , Metais Pesados/análise , Solo , Ultrassom
17.
Bioresour Technol ; 318: 124055, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32911365

RESUMO

To discern influence of inorganic substances in coal on the co-utilization of coal and biomass, coal ash (CA) was added to biomass for pyrolysis. TG-FTIR and fixed bed reactor were used for pyrolysis of corn straw (CS) with CA. XRF and XRD were used to detect the reactants and products components, respectively. At constant heating rate. CA slightly promoted char and gaseous products formation. In the fixed bed reactor, the effect varied with temperature and CA addition ratio. The char and gas yields were changed due to the Si, Al, and other inorganic substances in CA. CS/CA = 1 had the greatest influence on char. Gas yield were reduced at 500-700 °C, but increased at 800 °C with a small proportion of CA. When CA was 1/10 of CS at 800 °C, the gas yield increased by 9.3%, and CH4, CO, and H2 increased by 26.1%, 8.4%, and 37.7%, respectively.


Assuntos
Pirólise , Zea mays , Biomassa , Carvão Mineral/análise , Cinza de Carvão , Temperatura Alta
18.
Medicine (Baltimore) ; 99(33): e21566, 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32872008

RESUMO

Metabolic syndrome (MetS) refers to the pathological state of metabolic disorders in the body's proteins, fats, carbohydrates and other substances. MetS is a systemic metabolic disease. Periodontal disease is also a part of systemic inflammatory diseases. Among Chinese patients with middle-aged and elderly MetS, the periodontal morbidity is very high, which is due to the involvement of inflammatory mediators in the pathogenesis of MetS and periodontal disease. The latter may also be a risk factor for the former's morbidity and promotion of disease progression. At present, there are not many investigations and studies on periodontal examination data and periodontal disease prevalence of patients with MetS. Coal mine workers, especially coal mine underground workers, have different work natures and different working environments. See related report.We will collect the clinical diagnosis and treatment information of the enrolled patients. We will focus on checking the incidence of periodontal disease and recording. Establish a database, check every 10 medical records, and make corrections in time to ensure data accuracy. We will popularize oral hygiene knowledge for the included patients and guide them to brush their teeth correctly and how to use dental floss. We will perform periodontal examination on the patients' teeth by site and record the plaque index, gingival sulcus bleeding index, periodontal pocket exploration depth and other indicators. We will repeat the above inspection items and record in the second and fourth weeks of the experiment.This study will explore the correlation between periodontal disease and MetS of coal mine workers. We aim to clarify the role and mechanism of MetS in the occurrence and development of periodontal diseases, guide the prevention of periodontal diseases, and thus reduce the prevalence of periodontal diseases. TRIAL REGISTRATION:: ClinicalTrials.gov, ChiCTR2000034177, Registered on 27 June 2020.


Assuntos
Carvão Mineral , Síndrome Metabólica/epidemiologia , Mineradores/estatística & dados numéricos , Doenças Periodontais/epidemiologia , Adulto , Glicemia , Pressão Sanguínea , Índice de Massa Corporal , China/epidemiologia , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade , Higiene Bucal , Índice Periodontal , Prevalência , Fatores de Risco , Fumar/epidemiologia , Adulto Jovem
19.
J Environ Sci (China) ; 97: 96-101, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32933744

RESUMO

Emission from burning coals is one of the major sources of the airborne particles in China. We carried out a study on the rare earth elements (REEs) in the inhalable particulate matter (PM10) emitted from burning coals and soil-coal honeycomb briquettes with different volatile contents and ash yields in a combustion-dilution system. Gravimetric analysis indicates that the equivalent mass concentration of the PM10 emitted from burning the coals is higher than that emitted from burning the briquettes. The ICP-MS analysis indicates that the contents of total REEs in the coal-burning PM10 are lower than those in the briquette-burning PM10. In addition, the contents of the light rare earth elements (LREEs) are higher than those of the heavy rare earth elements (HREEs) in the PM10 emitted from burning the coals and briquettes, demonstrating that the REEs in both the coal-burning and briquette-burning PM10 are dominated by LREEs. The higher contents of total REEs and LREEs in the coal-burning PM10 are associated with the higher ash yields and lower volatile contents in the raw coals. A comparative analysis indicates that the La/Sm ratios in the PM10 emitted from burning the coals and briquettes, being lower than 2, are lower than those in the particles from gasoline-powered vehicle emission.


Assuntos
Poluentes Atmosféricos/análise , Carvão Mineral/análise , China , Monitoramento Ambiental , Material Particulado/análise , Solo
20.
Chemosphere ; 258: 127310, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947673

RESUMO

We characterized the aerosol composition and sources of particulate matter (PM) in Sanmenxia, a polluted city located in the Fen-Wei Plain region of Central China. The PM2.5 concentration decreased by 18% from 72 µg m-3 in 2014 to 59 µg m-3 in 2019. All chemical species presented pronounced seasonal variations, with their highest concentrations in winter due to enhanced emissions and the frequent stagnant meteorological conditions. Nitrate was the major fraction of PM2.5 during all seasons (35-41%) except summer (25%), while sulfate was a dominant species in summer (29%) compared to other seasons (16-18%) from July 2018 to June 2019. The detailed analysis of a wintertime severe haze episode that lasted for approximately half a month demonstrated that secondary aerosols, including secondary organic aerosol, sulfate, nitrate, and ammonium, contributed 89% to non-refractory PM1 (NR-PM1), indicating the remarkable role of secondary aerosol formation in air pollution in Sanmenxia. Positive matrix factorization analysis further showed considerably enhanced low-volatility oxygenated organic aerosol (OA) and hydrocarbon-like OA during severe haze episodes, while significant contributions in semi-volatile oxygenated OA and coal combustion OA during clean periods. Severe pollution events in the city were generally associated with air masses from the southwest, and we also found that aerosol species, especially secondary aerosol species, showed distinct forenoon increases that were caused by the subsidence of air pollutants aloft. Our results highlight that future air quality improvement would benefit substantially from a more efficient control of gaseous precursors, particularly the NOx emissions from industry and vehicle emissions.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Poluição do Ar/análise , China , Cidades , Carvão Mineral/análise , Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Poluição Ambiental/análise , Hidrocarbonetos/química , Nitratos/análise , Óxidos de Nitrogênio/análise , Material Particulado/análise , Estações do Ano , Emissões de Veículos/análise
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