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排序方式: 共有126条查询结果,搜索用时 31 毫秒
51.
京津冀水资源问题已经严重制约区域经济发展,定量分析研究区水源涵养生态服务供受关系,有助于深刻理解区域上下游之间的生态联系,促进区域生态公平,实现区域社会持续健康发展.利用降水储量法、水量平衡法及水源涵养生态服务供体区与受体区划分方法,分析2000-2010年京津冀净水源涵养量空间格局,划分研究区水源涵养生态服务供体区和受体区范围.结果表明:①冀北燕山山区净水源涵养量最高,年均值为65.24~81.35 mm,其次是冀西太行山山区,年均值为46.47~61.28 mm;净水源涵养量负值区主要分布在东部沿海和大中小城市,年均值为-130.46~-152.39 mm.②水源涵养生态服务供体区占研究区面积的41.42%,单位面积(m2,下同)平均净供水量为0.03~0.07 m3;水源涵养生态服务平衡区面积占25.01%;水源涵养生态服务受体区面积占33.57%,单位面积平均净需水量为0.18~0.41 m3,是供体区供水能力的6倍左右.③从流域来看,滦河流域的承德市为天津市、秦皇岛市及唐山市供应水资源,年均供水总量为23.7×108 m3;永定河流域的张家口市为北京市供应水资源,年均供水总量为5.3×108 m3;大清河流域的保定市为北京市及天津市西南部供应水资源,年均供水总量为8.2×108 m3;但子牙河流域和漳卫河流域供水能力严重不足.研究显示,燕山山区和太行山山区为水源涵养生态服务供体区,东部沿海和大中小城市为主要水源涵养生态服务受体区,水源涵养生态服务供体区净水源涵养能力不能满足水源涵养生态服务受体区需水量,整个研究区供受关系严重失衡. 相似文献
52.
成都电厂电子束烟气脱硫示范工程处理该厂200MW机组锅炉的30万Nm^2/h烟气。其脱硫率及脱硝率均超过80%及10%设计值,处理过程为干法,无废水废渣,副产品硫铵可用作化肥,过程对烟气SO2浓度及烟气量的变化有较好的适应性和负荷跟踪性。 相似文献
53.
程锦晖 《石油化工环境保护》2001,24(1):24-27
电子束法是一种能够同时脱硫、脱硝的烟气处理方法,具有脱硫、脱硝率高,副产品能够有效综合利用,不产生二次污染的特点,是一种先进的烟气处理技术。 相似文献
54.
Aerosol particles were collected in the situation of the widespread dust suspension on 21 February 1991 at Qira in the southern edge of the Taklamakan Desert, western China. The collected particles were examined by a transmission electron microscope equipped with an energy-dispersive X-ray (EDX) analyzer in order to obtain the size and elemental composition of individual mineral particles.On the basis of EDX analyses for 386 particles, mineral particles were present in high number fractions (>99%) of particles in the radius range of 0.1–4 μm. Particles mainly composed of silicates comprised 76% of mineral particles. “Ca-rich” particles were detected in 7% of all the particles. Ca in the particles would be present not only as CaCO3 but also as an internal mixture of CaCO3 and CaSO4. Particles containing halite (NaCl) were detected in number proportions of about 10% and were mainly present in the radius range of 0.5 μm. Some halite particles would be modified by chemical reactions with sulfuric acid. 相似文献
55.
Talarico L 《Environmental pollution (Barking, Essex : 1987)》2002,120(3):813-821
Thalli of the red alga Audouinella saviana were exposed to 600 microM Cd2+ (LC50), 1000 microM Cd2+ and 1500 microM Cd2+ (final concentrations) for 5, 10 and 15 days (each dose) by adding cadmium nitrate to the culture medium. Untreated thalli were set in triplicate as controls for each experiment. Ultrastructural modifications due to cadmium ad/absorption were observed by TEM/SEM electron microscopy. SEM-EDS X-ray microanalysis, definining the accumulation sites, was performed on cryoprepared samples. TEM studies showed striking changes in the plasmalemma of treated algae, which became irregular and convoluted. Electron-transparent exocytic vesicles, possibly related to cell wall polysaccharide synthesis, were observed. The appearance of ribosomes and Golgi bodies, not significantly present in the cytoplasms of untreated cells, suggested enhanced protein and carbohydrate biosynthesis. The cell walls lost their initial grooves and became smooth and thick. More or less electron-dense vesicular systems were formed. Electron-dense sphaeroids occurred in the plasmalemma-cell wall interface, in the cell wall itself and in nearby vesicular membrane systems. Many small vacuoles containing large metal complexes were formed. Complexes were then sequestered into a large vacuole. SEM observations demonstrated that the cell wall and the membrane systems were the most involved in the defense responses. EDS-X-ray microanalysis confirmed the presence of cadmium in these compartments. Chloroplasts, where no Cd2+ signal was detected, were the least affected organelles, showing only a partial disorganization after lengthy exposure to high Cd2+ concentrations. 相似文献
56.
研究了温度、pH值、电子供体种类及电子受体种类对反硝化的影响.试验结果表明,(1)在相同试验条件下,亚硝酸型反硝化与硝酸型反硝化的速率与硝态氮的浓度有关.在温度为25℃、pH为7的条件下,基质浓度<300mg/L时短程反硝化速率较快;基质浓度≥300 mg/L时,以NO3-为基质的反硝化速率较大.(2)具有大量碳源储存物(PHB)的细菌可实现快速的内源性反硝化脱氮,而处于饥饿状态的细菌的内源性反硝化效率极低. 相似文献
57.
Cheng Hou Xinbai Jiang Na Li Zhenhua Zhang Qian Zhang Jinyou Shen Xiaodong Liu 《Frontiers of Environmental Science & Engineering》2022,16(8):98
58.
Ru(Ⅲ) was employed as catalyst for aniline oxidation by permanganate at environmentally relevant pH for the first time. Ru(Ⅲ) could significantly improve the oxidation rate of aniline by 5-24 times with its concentration increasing from 2.5 to 15 μmol/L. The reaction of Ru(Ⅲ) catalyzed permanganate oxidation of aniline was first-order with respect to aniline, permanganate and Ru(Ⅲ), respectively. Thus the oxidation kinetics can be described by a third-order rate law. Aniline degradation by Ru(Ⅲ) catalyzed permanganate oxidation was markedly influenced by pH, and the second-order rate constant (ktapp) decreased from 643.20 to 2.67 (mol/L)^-1 sec^-1 with increasing pH from 4.0 to 9.0, which was possibly due to the decrease of permanganate oxidation potential with increasing pH. In both the uncatalytic and catalytic permanganate oxidation, six byproducts of aniline were identified in UPLC-MS/MS analysis. Ru(Ⅲ), as an electron shuttle, was oxidized by permanganate to Ru(Ⅵ) and Ru(Ⅶ), which acted the co-oxidants for decomposition of aniline. Although Ru(Ⅲ) could catalyze permanganate oxidation of aniline effectively, dosing homogeneous Ru(Ⅲ) into water would lead to a second pollution. Therefore, efforts would be made to investigate the catalytic performance of supported Ru(Ⅲ) toward permanganate oxidation in our future study. 相似文献
59.
不同香蒲预处理方式对水平潜流人工湿地脱氮的强化效果 总被引:1,自引:1,他引:0
针对水平潜流湿地脱氮过程中后端碳源不足导致反硝化脱氮效果不佳的问题,对湿地植物香蒲采用简单处理、酸热处理和碱热处理这3种预处理,探讨香蒲在不同预处理条件下静态释放规律和反硝化特性,基于碳源稳定释放特性及反硝化特性优选碱热处理香蒲作为人工湿地实验系统补给碳源,研究其对水平潜流人工湿地脱氮的强化效果.结果表明,香蒲不同预处理方式导致乙酸释放存在差异,造成碳源静态释放量存在明显差异,3种香蒲处理方式的平均COD释放量为碱热处理(89. 57 mg·L-1)酸热处理(67. 27 mg·L-1)简单处理(54. 45 mg·L-1).碱热处理香蒲硝氮去除率为75. 2%,明显高于酸热处理(67. 2%)和简单处理(23. 5%).水平潜流人工湿地中段投加碱热处理香蒲,能明显提高湿地脱氮效果,TN平均去除率对比空白对照湿地提高30. 3%,同时系统出水COD浓度不会显著提高,还能有效提高系统对污水中磷的去除效果,除磷效果相比空白组提高33. 9%. 相似文献
60.