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81.
针对农村玛瑙染色工业废水中存在高浓度Cr(Ⅵ)、SO42-和H+等污染严重、难处理的问题,基于玉米芯、花生壳和铁屑,分别构造了1#(玉米芯)、2#(花生壳)、3 #(铁屑+玉米芯)、4#(铁屑+花生壳)动态柱实验模型,研究了生物质材料及其与铁屑协同处理玛瑙染色废水中Cr(Ⅵ)、SO42-、H+的效果和机理.结果表明,铁屑+玉米芯、铁屑+花生壳动态柱对Cr(Ⅵ)、SO42-的平均去除率分别为95.97%、96.42%和72.17%和59.55%,高于玉米芯、花生壳动态柱的89.67%、90.74%和39.00%、28.73%的平均去除率,且具有较强的抗污染负荷变化和一定的pH值提升的能力.对比分析可见,经过铁屑强化的生物质动态柱对Cr(Ⅵ)、SO42-、H+有更好、更稳定的去除效果. 相似文献
82.
Transesterification of a mixture of vegetable oils with methanol using metal oxide catalysts derived from snail shell (SS) for biodiesel production was investigated. The metal oxides obtained from calcined snail shells in the temperature range of 650°–950 °C and modified by loading different potassium salts were used as a catalyst in the process. The catalysts were characterized by FT-IR, XRD, SEM-EDS, XPS and TGA. Catalytic activities of developed catalysts were also tested by Hammet indicator method and ion exchange method. The best calcination conditions were observed at 850°C for 4 hours based on biodiesel yield. The KF loaded snail shell gave highest biodiesel yield of 98 ± 1% in a batch reactor with highest basicity (15.9 mmoles/g) and basic strength measured by Hammet method. The optimized reaction conditions were: reaction temperature 65°C, reaction time 3 hours, methanol to oil molar ratio 9:1 and catalyst concentration 3wt%. Leaching and reusability tests confirm the stability of the catalyst as it encounters only 3% of leaching and small changes in catalytic activity up to five runs in terms of biodiesel yield. 相似文献
83.
A food industry waste, almond shell, was pyrolyzed under three different environment static, nitrogen, and steam to produce bio-oil and its derivatives. The oil yield obtained at pyrolysis temperature of 600°C was 24.23% in a static atmosphere, whereas it increased to 27.25% and 33.05% in nitrogen and steam atmospheres, respectively. The bio-oil obtained under steam atmosphere is very efficient due to the production of high liquid and gas yields. Moreover, co-feeding steam during the pyrolysis altered the bio-oil structure by increasing the aliphatics and reducing the asphaltenes. Moreover, steam treatment also increases H/C and heating value of bio-oils. According to the obtained results, steam pyrolysis is an alternative option for future applications in refineries. 相似文献
84.
地震动差动作用下大跨度空间网壳结构的反应分析 总被引:1,自引:0,他引:1
选取100 m跨度的双层柱面网壳结构为研究对象,采用时程分析法,分别进行了结构在单向和三向地震行波输入作用下的反应分析,并针对多种视波速情况进行了研究,考查了地震动不同输入情况下结构杆件内力的分布特点,对其进行了对比分析,为大跨网壳结构的抗震设计提供了理论依据。研究表明,考虑行波效应会使结构部分构件内力有一定程度的提高,多维地震作用比单维地震作用下结构的杆件内力大。由此得出结论:对于大跨度空间网壳结构,应该进行多维非一致输入下的地震反应分析;为保证抗震安全,应对可能出现的地面视波速进行全面分析。 相似文献
85.
Four populations of the native annual grassTriplasis purpurea were surveyed on coastal beaches along the south shore of Staten Island, NY, to determine the potential of this species to
colonize shoreline habitats mostly devoid of other vegetation. If the species can establish and maintain dense populations,
it may have conservation value for urban beaches disturbed by human activities. For two populations, survivorship, growth,
and reproduction were monitored at different distances from shore to determine the ability of this species to maintain viable
populations. At three sites,T. purpurea occurred in >75% of all quadrats and the highest density was 1195 plants/m2 at 74 m from shore in one recently disturbed site. Density generally increased with increasing distances from shore at low
tide (from ca. 40–90 m). Plants showed the greatest growth and reproduction at close distances to shore (30–40 m); part of
this effect was due to density in one population, but when density effects were removed statistically, there still remained
a decline in growth and reproduction with increasing distance from shore. Improved vigor nearest to shore may be due to continual
sand deposition. Survivorship showed a Type I pattern, with low mortality throughout the growing season. By colonizing newly-deposited
and continually shifting sands,T. purpurea can contribute to the earliest stages of ecological succession along disturbed beaches in eastern North America and may be
valuable to the development and management of urban coastal plant communities. 相似文献
86.
Four populations of the native annual grassTriplasis purpurea were surveyed on coastal beaches along the south shore of Staten Island, NY, to determine the potential of this species to
colonize shoreline habitats mostly devoid of other vegetation. If the species can establish and maintain dense populations,
it may have conservation value for urban beaches disturbed by human activities. For two populations, survivorship, growth,
and reproduction were monitored at different distances from shore to determine the ability of this species to maintain viable
populations. At three sites,T. purpurea occurred in >75% of all quadrats and the highest density was 1195 plants/m2 at 74 m from shore in one recently disturbed site. Density generally increased with increasing distances from shore at low
tide (from ca. 40 – 90 m). Plants showed the greatest growth and reproduction at close distances to shore (30 – 40 m); part
of this effect was due to density in one population, but when density effects were removed statistically, there still remained
a decline in growth and reproduction with increasing distance from shore. Improved vigor nearest to shore may be due to continual
sand deposition. Survivorship showed a Type I pattern, with low mortality throughout the growing season. By colonizing newly-deposited
and continually shifting sands,T. purpurea can contribute to the earliest stages of ecological succession along disturbed beaches in eastern North America and may be
valuable to the development and management of urban coastal plant communities. 相似文献
87.
88.
青岛南海岸海水浴场的旅游环境质量评价 总被引:9,自引:1,他引:9
通过分析比较青岛市南海岸各海水浴场的旅游环境条件存在的问题,对浴场的旅游环境质量进行了评价,其中石老人海水浴场的旅游环境质量最高,环境条件最好,本文还对南海岸海水浴场治理和管理提出了建议。 相似文献
89.
The occurrence of antibiotics in the environment has recently raised serious concerns regarding their potential threat to human health and aquatic ecosystem. A new magnetic nanocomposite, Fe304@C (Fe304 coated with carbon), was synthesized, characterized, and then applied to remove five commonly-used sulfonamides (SAs) from water. Due to its combinational merits of the outer functionalized carbon shell and the inner magnetite core, Fe3O4@C exhibited a high adsorption affinity for selected SAs and a fast magnetic separability. The adsorption kinetics of SAs on Fe304 @ C could be expressed by the pseudo second-order model. The adsorption isotherms were fitted well with the Dual-mode model, revealing that the adsorption process consisted of an initial partitioning stage and a subsequent hole-filling stage. Solution pH exerted a strong impact on the adsorption process with the maximum removal efficiencies (74% to 96%) obtained at pH 4.8 for all selected SAs. Electrostatic force and hydrogen bonding were two major driving forces for adsorption, and electron-donor-acceptor interactions may also make a certain contribution. Because the synthesized Fe304@C showed comprehensive advantages of high adsorptivity, fast magnetic separability, and prominent reusability, it has potential applications in water treatment. 相似文献
90.