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Результаты 2401-2410 из 4,309
Rapid total sulphur reduction in coal samples using various dilute alkaline leaching reagents under microwave heating: preventing sulphur emissions during coal processing Полный текст
2017
Mketo, Nomvano | Nomngongo, PhiliswaNosizo | Ngila, JaneCatherine
Currently in South Africa, online flue gas desulphurisation (FGD) is being utilized as one of the most effective methods for total sulphur reduction in coal samples during the combustion process. However, the main disadvantage associated with FGD is the formation of its by-products (FGD gypsum). The latter is mostly formed in low grade quality, thereby bringing secondary pollution problems and extra disposal costs. Therefore, the current study describes the development of total sulphur extraction in coal under microwave heating using different dilute alkaline solutions such as NaOH, NaOH-H₂O₂, NH₄OH, and NH₄OH-H₂O₂. The experimental conditions were as follows: 150 °C, 5 min and 10% (m/v or v/v) for temperature, extraction time and reagent concentration, respectively. The most effective alkaline reagent for coal desulphurisation was observed to be NaOH-H₂O₂ with total sulphur reduction of 55% (from the inductively coupled plasma-optical emission spectrometry (ICP-OES) results). The NaOH-H₂O₂ reagent also showed significant morphological changes in coal as observed from the SEM images and effective demineralisation as revealed by the powder X-ray diffractometer (P-XRD) results. Additionally, desulphurisation results obtained from the developed microwave-assisted dilute alkaline extraction (MW-ADAE) method were quite comparable with the published work. The proposed total sulphur reduction method is advantageous as compared to some of the literature reported coal desulphurisation methods as it requires a short period (5 min) of time to reach its completion. Additionally, the proposed method shows excellent reproducibility (% RSD from 0.5 to 1); therefore, it can be utilized for routine analysis. Graphical abstract ᅟ
Показать больше [+] Меньше [-]Response of anaerobic membrane bioreactor to the presence of nano-Bi2WO6: reactor performance, supernatant characteristics, and microbial community Полный текст
2017
Chen, Lin | Wang, Yue | Cao, Chuqing | Liu, Chang | Zhu, Liang
Considering the increasing incorporation of manufactured nano-material into consumer products, there is a concern about its potential impacts in biological wastewater treatment. In this study, the response of anaerobic sludge to the presence of Bi₂WO₆ nano-particles (NPs) was investigated in the anaerobic membrane bioreactor (AnMBR). As the concentration of Bi₂WO₆ in the reactor was controlled around 1 mg/L, there was no significant difference in effluent water quality or bacterial activities before and after NP exposure, partially due to the microbial-induced NP aggregation and stable complex formation. However, with the increasing dosage of Bi₂WO₆ from 5 to 40 mg/L, great influences on the AnMBR performance were observed, including the reduction of COD removal efficiency, inhibition of the mechanization step, increased production of soluble microbial products, and enhanced secretion of extracellular polymer substrates. Additional investigation with high-throughput sequencing was conducted, clearly demonstrating that Bi₂WO₆ NPs induced changes in the bacterial community.
Показать больше [+] Меньше [-]The level of toxic and essential trace elements in hair of petrochemical workers involved in different technological processes Полный текст
2017
Skalny, Anatoly V. | Kaminskaya, Galina A. | Krekesheva, Tatyana I. | Abikenova, Sholpan K. | Skalnaya, Margarita G. | Berezkina, Elena S. | Grabeklis, Andrei R. | Tinkov, Alexey A.
The objective of the investigation is comparative analysis of hair trace element content in workers of different departments of petrochemical plant. A total of 75 men working in office (engineers), and departments 1 (D₁), 3 (D₃), and 4 (D₄) of the petrochemical plant, as well as occupationally non-exposed persons, were examined. Hair trace element levels were analyzed using inductively coupled plasma mass spectrometry. The office workers were characterized by the highest hair As, Hg, Sn, I, and Si content as compared to the workers of other departments, whereas the level of those elements did not differ significantly from the control values. It is notable that hair Be levels in all employees of petrochemical plant were significantly lower, whereas Se content was significantly higher than that in unexposed controls. Hair toxic trace element content in workers directly involved in industrial processes did not differ significantly or was lower than that in the control group. At the same time, the highest levels of essential trace elements (Cr, Fe, and I) were observed in employees working in primary oil refining (D₁). Hair levels of Co, I, and Li were maximal in persons of sulfur and bitumen-producing division (D₄). The lowest levels of both essential and toxic trace elements in hair were detected in employees involved in production of liquefied gas, kerosene, and diesel fuel (D₃). The obtained data demonstrate that involvement in different technological processes in petrochemical complex differentially affect hair trace element content in workers.
Показать больше [+] Меньше [-]Exploring new DGT samplers containing a polymer inclusion membrane for mercury monitoring Полный текст
2017
Turull, Marta | Elias, Gemma | Fontàs, Clàudia | Díez, Sergi
A polymer inclusion membrane (PIM) made of cellulose triacetate as a polymer and the task specific ionic liquid (IL) trioctylmethylammonium thiosalicylate (TOMATS) was assembled as a new Diffusive Gradients in Thin film (DGT) device to test its efficiency as a binding phase for mercury (Hg) monitoring. The effect of IL content was assessed, showing that higher TOMATS percentage is better for short deployment studies (up to hours), whereas for long-term exposure (up to days), a lower content can be more suitable. Different configurations of PIM-DGT samplers have been tested under controlled conditions and compared with in-house DGT conventional ones, manufactured with thiol groups as resin layer, for the determination of labile Hg. According to our results, a nonlinear accumulation profile of Hg with deployment time for the different designs of PIM-DGT was observed, limiting the range of applicability of the DGT technique. Promising results for the efficient removal of Hg from aqueous solutions and/or environmental monitoring studies were obtained with TOMATS.
Показать больше [+] Меньше [-]Differential toxicity of arsenic on renal oxidative damage and urinary metabolic profiles in normal and diabetic mice Полный текст
2017
Yin, Jinbao | Liu, Su | Yu, Jing | Wu, Bing
Diabetes is a common metabolic disease, which might influence susceptibility of the kidney to arsenic toxicity. However, relative report is limited. In this study, we compared the influence of inorganic arsenic (iAs) on renal oxidative damage and urinary metabolic profiles of normal and diabetic mice. Results showed that iAs exposure increased renal lipid peroxidation in diabetic mice and oxidative DNA damage in normal mice, meaning different effects of iAs exposure on normal and diabetic individuals. Nuclear magnetic resonance (NMR)-based metabolome analyses found that diabetes significantly changed urinary metabolic profiles of mice. Oxidative stress-related metabolites, such as arginine, glutamine, methionine, and β-hydroxybutyrate, were found to be changed in diabetic mice. The iAs exposure altered amino acid metabolism, lipid metabolism, carbohydrate metabolism, and energy metabolism in normal and diabetic mice, but had higher influence on metabolic profiles of diabetic mice than normal mice, especially for oxidative stress-related metabolites and metabolisms. Above results indicate that diabetes increased susceptibility to iAs exposure. This study provides basic information on differential toxicity of iAs on renal toxicity and urinary metabolic profiles in normal and diabetic mice and suggests that diabetic individuals should be considered as susceptible population in toxicity assessment of arsenic.
Показать больше [+] Меньше [-]The influence of growth form and substrate on lichen ecophysiological responses along an aridity gradient Полный текст
2017
Paoli, Luca | Pinho, Pedro | Branquinho, Cristina | Loppi, Stefano | Munzi, Silvana
In this paper, we investigated whether growth form and substrate in lichens influence their physiological responses along an aridity gradient. Thalli of the foliose lichen Parmotrema perlatum and the fruticose lichen Ramalina canariensis were transplanted in selected rural/forested sites of Southern Portugal characterized by a different aridity index. Physiological parameters including photosynthetic performances, assimilation pigments, ergosterol content and sample viability were measured prior to exposure (winter) and after 6-month exposure (summer). Photosynthetic performances were also investigated in common native foliose and fruticose epiphytic lichens and in fruticose terricolous species. Both transplanted and native lichens showed a decrease in photosynthetic performances in summer and lower performances in sites classified as drier and higher performances in humid forested sites. No relevant differences occurred between epiphytic foliose and fruticose growth forms. However, terricolous fruticose samples showed a significant difference in humid and drier sites and between winter and summer, probably due to microclimatic conditions similarly to other biological crusts.
Показать больше [+] Меньше [-]Scenario analysis of the impacts of socioeconomic development on phosphorous export and loading from the Dongting Lake watershed, China Полный текст
2017
Hou, Ying | Chen, Weiping | Liao, Yuehua | Luo, Yueping
Socioeconomic development in lake watersheds is closely related with lake nutrient pollution. As the second largest freshwater lake in China, the Dongting Lake has been experiencing an increase in nutrient loading and a growing risk of eutrophication. This study aimed to reveal the likely impacts of the socioeconomic development of the Dongting Lake watershed on the phosphorous pollution in the lake. We estimated the contributions from different sources and sub-watersheds to the total phosphorous (TP) export and loading from the Dongting Lake watershed under two most likely socioeconomic development scenarios. Moreover, we predicted the likely permissible and actual TP loadings to the Dongting Lake. Under both two scenarios, three secondary sub-watersheds—the upper and lower reaches of the Xiang River watershed and the Dongting Lake Area—are expected to dominate the contribution to the TP export from the Dongting Lake watershed in 2020. Three primary sub-watersheds—the Dongting Lake Area, the Xiang River, and the Yuan River watersheds—are predicted to be the major contributors to the TP loading from the entire watershed. The two scenarios are expected to have a slight difference in TP export and lake TP loading. Livestock husbandry is expected to be the predominant anthropogenic TP source in each of the sub-watersheds under both scenarios. Compared to 2010, permissible TP loading is not expected to increase but actual TP loading is predicted to grow significantly in 2020. Our study provides methodologies to identify the key sources and regions of lake nutrient loading from watersheds with complex socioeconomic context, and to reveal the potential influences of socioeconomic development on nutrient pollution in lake watersheds.
Показать больше [+] Меньше [-]Variation in accumulation and translocation of di-n-butyl phthalate (DBP) among rice (Oryza sativa L.) genotypes and selection of cultivars for low DBP exposure Полный текст
2017
Cai, Quan-Ying | Xiao, Pei-Yun | Zhao, Hai-Ming | Lü, Huixiong | Zeng, Qiao-Yun | Li, Yan-Wen | Li, Hui | Xiang, Lei | Mo, Ce-Hui
Di-n-butyl phthalate (DBP) is a typical endocrine-disrupting chemical with higher detection frequency and concentration in agricultural soil (particularly in paddy-field soil of Guangdong Province) of China. In this study, a greenhouse experiment was conducted to investigate variation in uptake and accumulation of DBP by 20 rice cultivars and to screen low DBP-accumulating cultivars. DBP concentrations in plants varied greatly with rice cultivars, growth stages, and tissues. The highest DBP concentrations in both roots and shoots were observed at the ripening stage, with concentrations 2–100-fold higher than those at tillering, jointing, and flowering stages. At the ripening stage, DBP concentrations decreased in the order of leaf > root > stem > grain, and significant differences of DBP concentrations were observed among various rice cultivars. Moreover, the magnitude of variation in DBP concentrations among various cultivars was greater in stems and grains than in roots and leaves. The translocation factors of DBP from roots to stems and from shoots to grains were <1.0, and those from stems to leaves were almost >1.0. Overall, cultivars Yuxiangyouzhan, Jinnongsimiao, Tianyou 122, and Wuyou 380 accumulated relatively lower DBP in grains, resulting in lower DBP exposure. The DBP uptake and translocation pathways in rice require further investigation. Graphical abstract ᅟ
Показать больше [+] Меньше [-]The study on the evaluation of the pollution control situation of the sewage systems in the counties and cities of Taiwan by applying the VIKOR method Полный текст
2017
Kuo, Jun-Yuan
Currently, the pollution control situation of the sewage systems across Taiwan can be divided into the two major sewage systems, namely, industrial area sewage and public community sewage. When the counties and cities of Taiwan cannot effectively control the sewage pollution situation, ecological pollution of the environment and personal health damage would result. Therefore, evaluating the pollution control situation of the sewage systems can help the environmental protection authorities developing strategies for the pollution control of the sewage systems in the future. In this study, the Vise Kriterijumska Optimizacija I Kompromisno Resenje (VIKOR) method was applied to evaluate the pollution control situation of the sewage systems. The water sample test qualification rate, the emission permit issuance rate, and the staff setting rate of the dedicated wastewater treatment company were used as the pollution control evaluation indexes. According to the results, the use of the VIKOR method to evaluate the pollution control situation of the sewage systems is effective. In cities and counties in Taiwan, public community sewage systems, dedicated to pollution control case, the public community should be actively coached in emission control technology to upgrade sewage capacity, the issuance of discharge permits, and the staff setting rate of the dedicated wastewater treatment, to improve public community sewage pollution control system capabilities. In Taiwan, the industrial area sewage systems, dedicated to pollution control situations, must pay attention to business units in raw materials, spare part inventory, and machine supplier of choice, and we must choose to meet environmental supply chain of green suppliers, which would be effective in reducing effluent produce and improve water sample test qualification rate. The VIKOR value of Yilan County is 1.0000, which is the worst in the pollution control of all the industrial area sewage systems, followed by Taoyuan County (0.2253) and Kaohsiung City (0.1334). Other cities and counties of Taiwan have good performance in the pollution control of the industrial area sewage systems. The VIKOR value of Kinmen County is 1.0000, which is the worst pollution control among the all public community sewage systems, followed by Hsinchu County (0.7458) and New Taipei City (0.5527). Among the cities and counties with good pollution control of the public community sewage systems, the best is Chiayi County (0.0000), followed by Kaohsiung City (0.0159) and Hsinchu City (0.0352). Chiayi County is a good performance compromise between all VIKOR values (0.0000), whether in industrial or public community area pollution control sewage systems. Yilan County industrial pollution control has the poorest performance of all the industrial area sewage systems in Taiwan, but in the public community, it ranked as fourth place of all the public community area sewage systems in Taiwan. The VIKOR method proposed in this study can effectively evaluate the pollution control situation of the sewage systems, and serve as a reference for the environmental protection authorities in developing the strategies for the pollution control of the sewage systems.
Показать больше [+] Меньше [-]Influential impacts of combined government policies for safe disposal of dead pigs on farmer behavior Полный текст
2017
Chen, Xiujuan | Qiu, Guangqian | Wu, Linhai | Xu, Guoyan | Wang, Jianhua | Hu, Wuyang
Improper disposal of dead pigs by pig farmers may have an adverse impact on the ecological environment and food safety. In this paper, disposal of dead pigs by pig farmers in four main pig production provinces in China (Jiangsu, Anhui, Hubei, and Hunan) was empirically investigated. Then, pig farmers’ awareness and evaluation of current combined government policies for the safe disposal of dead pigs were analyzed. Furthermore, the influential effects of combined government policies on the disposal of dead pigs by pig farmers were examined using Decision-Making Trial and Evaluation Laboratory (DEMATEL). Results indicated that the issue of disposal of dead pigs by farmers was very complex and was influenced by the combination of subsidy and compensation, facility and technology, and supervision and punishment policies. The findings also indicated that the different types of policies had different effects and interacted with each other. Among these three combinations, supervision and punishment policies were the most influential policies and facility and technology policies were in most urgent need to improve for regulating the current state of the disposal of dead pigs by farmers. These findings have implications for sustainable pig production.
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