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11.
中国NOx控制制度研究 总被引:2,自引:0,他引:2
中国NOx污染呈现总量逐年增加的趋势,已成为大气污染治理的主要内容.从NOx的控制制度、排放指标上对我国现行NOx控制体系进行了分析,并对我国进一步完善NOx控制制度及标准提出了建议.主要建议有(1)降低NOx控制标准适应当前环境状况;(2)应用科学方法,制订合理的NOx总量控制标准和制度;(3)制订氮氧化物排放标准;(4)浓度控制和总量控制结合.总量控制的实施要注意污染物排放标准制定的政策取向;总量控制法的基本原理和程序;总量控制结合排放标准控制. 相似文献
12.
《环境科学学报(英文版)》2023,35(3):319-331
Oxidation-absorption technology is a key step for NOx removal from low-temperature gas. Under the condition of low O3 concentration (O3/NO molar ratio = 0.6), F-TiO2 (F-TiO2), which is cheap and environmentally friendly, has been prepared as ozonation catalysts for NO oxidation. Catalytic activity tests performed at 120°C showed that the NO oxidation efficiency of F-TiO2 samples was higher than that of TiO2 (about 43.7%), and the NO oxidation efficiency of F-TiO2-0.15 was the highest, which was 65.3%. Combined with physicochemical characteristics of catalysts and the analysis of active species, it was found that there was a synergistic effect between F sites and oxygen vacancies on F-TiO2, which could accelerate the transformation of monomolecular O3 into multi-molecule singlet oxygen (1O2), thus promoting the selective oxidation of NO to NO2. The oxidation reaction of NO on F-TiO2-0.15 follows the Eley-Rideal mechanism, that is, gaseous NO reacts with adsorbed O3 and finally form NO2. 相似文献
13.
《环境科学学报(英文版)》2023,35(3):309-318
Accurate quantification of dissolved organic nitrogen (DON) has been a challenge due to the cumulative analytical errors in the conventional method via subtracting dissolved inorganic nitrogen species (DIN) from total dissolved nitrogen (TDN). Size exclusion chromatography coupled with an organic nitrogen detector (SEC-OND) has been developed as a direct method for quantification and characterization of DON. However, the applications of SEC-OND method still subject to poor separations between DON and DIN species and unsatisfied N recoveries of macromolecules. In this study, we packed a series of SEC columns with different lengths and resin materials for separation of different N species and designed an independent vacuum ultraviolet (VUV) oxidation device for complete oxidation converting N species to nitrate. To guarantee sufficient N recoveries, the operation conditions were optimized as oxidation time ≥ 30 min, injection mass (sample concentration × injection volume) < 1000 µL × mg-N/L for macromolecular proteins, and neutral pH mobile eluent. The dissolved O2 concentration in SEC mobile phase determined the upper limit of VUV oxidation at a specific oxidation time. Compared to conventional HW50S column (20 × 250 mm), HW40S column (20 × 350 mm) with mobile phase comprising of 1.5 g/L Na2HPO4·2H2O + 2.5 g/L KH2PO4 (pH = 6.85) could achieve a better separation of DON, nitrite, nitrate, and ammonia. When applied to river water, lake water, wastewater effluent, groundwater, and landfill leachate, the SEC-OND method could quantify DON as well as DIN species accurately and conveniently even the DIN/TDN ratio reached 0.98. 相似文献
14.
The influence of source and timing of nitrogen fertilizers on yield and nitrogen use efficiency of four sweet potato cultivars 总被引:2,自引:0,他引:2
R. O. Ankumah V. Khan K. Mwamba K. Kpomblekou-A 《Agriculture, ecosystems & environment》2003,100(2-3):201
Nitrogen (N) availability is a very important determinant of crop yield. It is also one of the most expensive inputs in crop production. Thus, the efficient management of N by farmers with limited resource is a very important part of successful soil and crop management system. A field study was conducted on a Norfolk sandy loam soil at the George Washington Carver Agricultural Experiment Station, Tuskegee, AL, to evaluate the influence of fertilizer source and timing on the yield of four sweet potato [Ipomoea batatas (L.)] cultivars. Two N sources (urea, CO(NH2)2 and ammonium nitrate, NH4NO3), four sweet potato cultivars (‘Georgia Jet’, GA-Jet; ‘TU-82-155’, TU-155; ‘TU-1892’; and ‘Rojo Blanco’, Rojo-Bl) and three times (zero, single, and split applications) were used in a factorial designed experiment. Plants were harvested after 80 and 120 days and total and marketable yields determined. Nitrogen recovery efficiency, yield efficiency and physiological efficiency were also determined. Total and marketable yields of early maturing cultivars were significantly higher than of late maturing cultivars (P<0.05). The single application of N resulted in significantly higher yield in storage roots than split application (P<0.05). Physiological efficiency values were highly correlated with total marketable yields. Recovery rates increased with time. Late maturing cultivars tended to have higher N recovery and physiological efficiency than early maturing cultivars. These results suggest that cultivar maturity group should play an important part in N fertilization recommendations for sweet potato. 相似文献
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17.
In this study, in order to research the synergistic inhibition effect of nitrogen and ultrafine water mist on gas explosion in a vented duct, a semi-confined transparent chamber was designed with the size of 120 × 120 × 840 mm, and the experiments were carried out with stoichiometric methane/air premixed mixture (fraction of methane: 9.5%), adding different fractions of nitrogen and ultrafine water mist. The experimental results showed the following: The combination of nitrogen and ultrafine water mist had a synergistic inhibiting effect on methane/air explosion, which was preferable to the single use of any kind. With the increase of spraying time of water mist and fraction of nitrogen, the initial shape of the explosion flame became snakelike, and at the same time the peak flame propagation speed and peak overpressure decreased significantly. When the nitrogen fraction was increased to 10% and the mist spraying time was increased to 2min, synergistic inhibiting effect on overpressure was high efficient. However, with the increase of spraying time of water mist and fraction of nitrogen going on, the amount of increase of explosion inhibition efficiency was gradually reduced. 相似文献
18.
Fredrik Wulff Christoph Humborg Hans Estrup Andersen Gitte Blicher-Mathiesen Mikołaj Czajkowski Katarina Elofsson Anders Fonnesbech-Wulff Berit Hasler Bongghi Hong Viesturs Jansons Carl-Magnus Mörth James C. R. Smart Erik Smedberg Per Stålnacke Dennis P. Swaney Hans Thodsen Adam Was Tomasz Żylicz 《Ambio》2014,43(1):11-25
The Baltic Sea Action Plan (BSAP) requires tools to simulate effects and costs of various nutrient abatement strategies. Hierarchically connected databases and models of the entire catchment have been created to allow decision makers to view scenarios via the decision support system NEST. Increased intensity in agriculture in transient countries would result in increased nutrient loads to the Baltic Sea, particularly from Poland, the Baltic States, and Russia. Nutrient retentions are high, which means that the nutrient reduction goals of 135 000 tons N and 15 000 tons P, as formulated in the BSAP from 2007, correspond to a reduction in nutrient loadings to watersheds by 675 000 tons N and 158 000 tons P. A cost-minimization model was used to allocate nutrient reductions to measures and countries where the costs for reducing loads are low. The minimum annual cost to meet BSAP basin targets is estimated to 4.7 billion €. 相似文献
19.
随着污水处理厂排到受纳水体标准的不断提高及区域污染物排放限值的要求,已建的污水处理厂需要提标改造提高排放标准。本文所提工程对现有的CASS池进行改造,通过投加悬浮填料形成CASS+MBBR工艺,其中TN污染物的去除率可提高到8%~15%间,其它污染物也能达到预期的设计标准。 相似文献
20.
Liang Lu Yuqi Jin Hongmei Liu Xiaojun Ma Kunio Yoshikawa 《Waste management (New York, N.Y.)》2014,34(1):79-85
Nitrogen evolution was studied during the co-combustion of hydrothermally treated municipal solid wastes (HT MSW) and coal in a bubbling fluidized bed (BFB). HT MSW blending ratios as 10%, 20% and 30% (wt.%) were selected and tested at 700, 800, 900 °C. Emissions of NO and N2O from blends were measured and compared with the results of mono-combustion trials. Moreover, concentrations of precursors like NH3 and HCN were also quantified. The results are summarized as follows: NO emissions were predominant in all the cases, which rose with increasing temperature. The blending of HT MSW contributed to the NO reduction. N2O emissions decreased with temperature rising and the blending of HT MSW also presented positive effects. At 30% HT MSW addition, both NO and N2O emissions showed the lowest values (391.85 ppm and 55.33 ppm, respectively at 900 °C). For the precursors, more HCN was detected than NH3 and both played important roles on the gas side nitrogen evolution. 相似文献