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321.
Mitsuhiko Hat Jiraporn Chomanee Thunyapat Thongyen Linfa Bao Surajit Tekasakul Perapong Tekasakul Yoshio Otani Masami Furuuchi 《环境科学学报(英文版)》2014,26(9):1913-1920
The characteristics of the particles of the smoke that is emitted from the burning ofbiomass fuels were experimentally investigated using a laboratory-scale tube furnace and different types of biomass fuels: rubber wood, whole wood pellets and rice husks. Emitted amounts of particles, particle-bound polycyclic aromatic hydrocarbons (PAHs) and water-soluble organic carbon (WSOC) are discussed relative to the size of the emitted particles, ranging to as small as nano-size (〈70 nm), and to the rate of heating rate during combustion, differential thermal analysis (DTA) and thermogravimetric analysis (TG) techniques were used to examine the effect of heating rate and biomass type on combustion behaviors relative to the characteristics of particle emissions. In the present study, more than 30% of the smoke particles from the burning ofbiomass fuel had a mass that fell within a range of 〈 100 nm. Particles smaller than 0.43 μm contributed greatly to the total levels of toxic PAHs and WSOC. The properties of these particles were influenced by the fuel component, the combustion conditions, and the particle size. Although TC--DTA results indicated that the heating rate in a range of 10-20℃did not show a significant effect on the combustion properties, there was a slight increase in the decomposition temperature as heating rate was increased. The nano-size particles had the smallest fraction of particle mass and particle-bound PAHs, but nonetheless these particles registered the largest fraction of particle-bound WSOC. 相似文献
322.
延迟焦化焦粉夹带的原因及应对措施 总被引:1,自引:0,他引:1
详述了焦炭塔发生焦粉夹带的危害、原因及预防措施,描述了分馏系统焦粉的处理措施。 相似文献
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324.
本文对不同林分的土壤最大持水力、土壤毛管持水力、枯落物最大持水量和枯落物最大持水率进行分析,得出不同林分枯落物和土壤持水能力的关系. 相似文献
325.
Benying Su Meihua Zhou Hong Xu Xiujie Zhang Yonggeng Li Hua Su Bao Xiang 《环境科学学报(英文版)》2017,29(3):113-121
A field experiment was carried out to compare the responses to ozone(O_3) in two common herbaceous plant species, Plantago major L. and Sonchus oleraceus L., by building open-top growth chambers in situ to simulate O_3stress(+ O_3, 85 ± 5 ppb, 9 hr/day for 30 days) in a lowland habitat in Inner Mongolia, Northern China. Responses to O_3 of gas exchange,chlorophyll a fluorescence, leaf pigment content, antioxidant capability, soluble protein content, membrane lipid peroxidation and dark respiration(R_d) were analyzed. Results showed that elevated O_3 exposure significantly reduced the light-saturated net photosynthesis(P_(Nsat)), stomatal conductance(g_s) and transpiration rate(E) in both species. Although non-significant interactive effect between species and O_3 on P_(Nsat) was analyzed, the reduction in P_(Nsat) in S. oleraceus might be due primarily to the higher fraction of close PSII reaction centers and impaired activities of plant mesophyll cells as evidences by decreased maximum efficiency of PSII photochemistry after dark adapted state(F_v/F_m) and unchanged intercellular CO_2concentration(C_i). Besides, biochemical analysis showed that S. oleraceus had lower antioxidant ability compared to P. major. As a result, S. oleraceus was damaged to the larger extent in terms of lipid peroxidation and visible O_3 injury, indicating that S. oleraceus was more sensitive to O_3 than P. major. Our results indicated that wild herbaceous plant species growing in a lowland habitat in sandy grassland were sensitive to O_3 stress and S. oleraceus can be considered as one of the bio-indicators for high O_3 concentration in semi-arid grassland of northern China. 相似文献
326.
Zhao AQ Bao QL Tian XH Lu XC William JG 《Journal of environmental biology / Academy of Environmental Biology, India》2011,32(2):235-239
A nutrient solution experiment was conducted to investigate the effect of Fe and Zn supply on Fe, Zn, Cu, and Mn concentrations in wheat plants. The experiment used a factorial combination of two Fe levels (0 and 5 mg l(-1)) and three Zn levels (0, 0.1 and 10 mg I(-1)). The supply of Fe (5 mg l(-1)) and Zn (0.1 mg l(-1)) increased plant dry weight and leaf chlorophyll content compared to the Fe or Zn deficient (0 mg 11) treatments. However, excess Zn supply (10 mg l(-1)) reduced plant dry weights and leaf chlorophyll content. Iron supply (5 mg l(-1)) reduced wheat Zn concentrations by 49%, Cu concentrations by 34%, and Mn by 56% respectively. Zinc supply (10 mg l(-1)) reduced wheat Fe concentrations by an average of 8%, but had no significant effect on Cu and Mn concentrations. Stepwise regression analyses indicated that Zn, Cu, and Mn concentrations were negatively correlated with root- and leaf-Fe concentrations, but positively correlated with stem-Fe concentrations. Leaf-Mn concentrations were negatively correlated with root-, stem- and leaf-Zn concentrations. 相似文献
327.
In the process of mining activity, many kinds of heavy metals enter into soils with dust, causing serious contamination to the environment. In this study, six soils were sampled from cropland at different distances from a lead/zinc mine in Heilongjiang Province, China. The total contents of lead and zinc in the vicinal cropland exceeded the third level of environmental quality standard for soil in China, which indicated that soils in this area were moderately contaminated. Bacterial community diversity and population were greatly decreased when the concentrations of lead and zinc were beyond 1,500 and 995 mg kg(-1), respectively, as analyzed by plate counting and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The bands of DGGE patterns varied with the degree of contamination. The activities of soil urease, phosphatase, and dehydrogenase were negatively correlated with the concentrations of lead and zinc. The highest inhibitory effect of heavy metals on soil enzyme activities was observed in urease. It was noted that PCR-DGGE patterns combined with soil enzyme activity analysis can be indices for the soil quality assessment by heavy metal contamination. 相似文献
328.
The removal of biological nutrient from mature landfill leachate with a high nitrogen load by an internal circulation upflow sludge blanket (ICUSB) reactor was studied. The reactor is a set of anaerobic-anoxic-aerobic (A^2/O) bioreactors, developed on the basis of an expended granular sludge blanket (EGSB), granular sequencing batch reactor (GSBR) and intermittent cycle extended aeration system (ICEAS). Leachate was subjected to stripping by agitation process and poly ferric sulfate coagulation as a pretreatment process, in order to reduce both ammonia toxicity to microorganisms and the organic contents. The reactor was operated under three different operating systems, consisting of recycling sludge with air (A^2/O), recycling sludge without air (low oxygen) and a combination of both (A^2/O and low oxygen). The lowest effluent nutrient levels were realised by the combined system of A^2/O and low oxygen, which resulted in effluent of chemical oxygen demand (COD), NH3-N and biological oxygen demand (BOD5) concentrations of 98.20, 13.50 and 22.50 mg/L. The optimal operating conditions for the efficient removal of biological nutrient using the ICUSB reactor were examined to evaluate the influence of the parameters on its performance. The results showed that average removal efflciencies of COD and NH3- N of 96.49% and 99.39%, respectively were achieved under the condition of a hydraulic retention time of 12 hr, including 4 hr of pumping air into the reactor, with dissolved oxygen at an rate of 4 mg/L and an upflow velocity 2 m/hr. These combined processes were successfully employed and effectively decreased pollutant loading. 相似文献
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330.
Yao Xiaochen Zheng Guodi Cao Yun Yu Bao 《Environmental science and pollution research international》2021,28(36):49574-49587
Environmental Science and Pollution Research - The ecological floating beds (EFB) are widely used in water quality restoration because of its low cost, high efficiency, and green characteristics.... 相似文献