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1.
凹凸棒石催化氧化脱除柴油机尾气中的NOx   总被引:6,自引:0,他引:6       下载免费PDF全文
采用反应吸收法实验研究了天然凹凸棒石黏土、水和氢氧化钠等制备成的吸收液脱除柴油机尾气中氮氧化物(NOx)的特性.在吸收液的作用下,尾气中的NO经催化氧化和碱中和联合吸收过程而脱除.凹凸棒石黏土经稀土改性,可增强NOx的脱除效果.考察了吸收液的pH值、温度和稀土加入量等因素对NOx脱除效率的影响,并对其脱除机理进行了探讨.在最佳实验条件下,NOx脱除效率达90.6%.气相阻力为3.5kPa.  相似文献   

2.
针对废水含高浓度氯离子、高硬度的特点,采用"混凝沉淀——高精度过滤——均相淡化电渗析"工艺进行设计,并新建20000m~3/d示范工程。项目运行结果显示,该项目对废水中氯离子分离效果优越,分离率达到85%以上,淡液中氯离子可以稳定控制在设计要求的600mg/L以下,满足排放要求,吨水综合运行成本约2.3元,项目环保和经济效益显著。  相似文献   

3.
《中国环境科学》2005,25(5):0-0
 采用反应吸收法实验研究了天然凹凸棒石黏土、水和氢氧化钠等制备成的吸收液脱除柴油机尾气中氮氧化物(NOx)的特性.在吸收液的作用下,尾气中的NO经催化氧化和碱中和联合吸收过程而脱除.凹凸棒石黏土经稀土改性,可增强NOx的脱除效果.考察了吸收液的pH值、温度和稀土加入量等因素对NOx脱除效率的影响,并对其脱除机理进行了探讨.在最佳实验条件下,NOx脱除效率达90.6%.气相阻力为3.5kPa.  相似文献   

4.
中空纤维膜接触器分离烟气中CO2   总被引:12,自引:1,他引:12  
在中空纤维膜接触器试验台上利用模拟烟气进行CO2的分离试验,采用MDEA与MEA和MDEA与氨基酸盐2种混合吸收液,考察吸收液种类、浓度、CO2负荷和烟气CO2含量对脱除效率和传质速率的影响.结果表明,在MDEA水溶液中加入MEA或氨基酸盐作为添加剂,大大提高了脱除效率,改善了传质速率,相对于单一的MDEA吸收液,混合吸收液的脱除效率平均提高了200%,传质速率提高了238%,其中以MEA作为添加剂的混合吸收液的传质速率在2种混合吸收液中最好,传质速率最高可以达到1.7 mol·m-2·h-1.  相似文献   

5.
齐震  孙也  樊星  朱天乐 《环境科学学报》2014,34(12):3133-3137
分别采用Na Cl O2和Na2SO3溶液作为氧化液和吸收液,在自行设计的鼓泡塔反应系统进行了液相氧化-吸收脱除模拟烟气NOx的研究,考察了气相SO2浓度、Na Cl O2和Na2SO3投加量以及p H值等因素对NO氧化和NOx脱除的影响.结果表明,SO2会优先于NO与氧化剂反应,从而增大氧化剂消耗量.偏酸性条件有利于NO氧化,但酸性太强会导致Na Cl O2分解为Cl O2逸出.碱性吸收液对NO几乎不具吸收脱除效果,但共存NO2能促进NO的吸收脱除.SO2对NO2吸收脱除具有促进作用.  相似文献   

6.
芦澍 《环境工程》2013,(Z1):333-335,367
采用实验室模拟试验,对水泥窑协同处置垃圾焚烧飞灰处置技术中水洗预处理工艺及后续污水处理工艺进行了研究。试验考察了不同水洗方式、不同水洗比例(液固比为1,3,5,7,9,11)及水洗次数、添加改性剂等条件下飞灰中氯离子的去除效果;并对后续污水处理单元进行了初步研究。结果表明:水洗单元采用逆流二次漂洗对氯离子去除效果明显优于其他水洗方式,并节约用水量50%;在液固比为3:1进行洗灰时,对氯离子的去除率能到达90%以上,进一步增大液固比氯离子去除率没有显著提高;在后续污水处理单元中,通过中和、混凝、沉淀、过滤工艺,可以有效的去除重金属、钙离子含量,满足后续脱盐结晶单元要求。  相似文献   

7.
硫酸汞用于去除CODcr,测定中氯离子的干扰,但是硫酸汞是一种剧毒物质,对环境造成二次污染。因此本研究采用自制CODcr,环保消解液,通过在工作曲线的一系列标准溶液中加入与样品中相当量的氯离子进行消解比色,绘制工作曲线,通过回归方程直接扣除氯离子干扰。通过实验对比,自制CODcr,环保消解液能够达到进口试剂的消解效果,自制CODcr,环保消解液测定标准样品的相对误差在-1.25%~-456%之间,测定含氯污水的加标回收率在95.3%~105%之间。  相似文献   

8.
为解决生活垃圾填埋场的纳滤膜浓缩液和生活垃圾焚烧飞灰协同处置中淋滤条件对氯盐和重金属溶出效果的问题,采用北京市某生活垃圾填埋场的纳滤膜浓缩液在不同液固比和酸碱条件下淋滤北京市某生活垃圾焚烧厂的焚烧飞灰,探讨氯离子溶出及重金属的迁移特性. 结果表明:在液固比为12∶1、8∶1和4∶1条件下,焚烧飞灰中氯离子的总溶出率分别为81%、76%和61%,液固比越大,导致填料高度越低,氯离子溶出越充分;在液固比为4∶1条件下,纳滤膜浓缩液pH分别为3.20和10.70时,氯离子可与含氧阴离子竞争吸附位置,导致氯离子的总溶出率较未调节pH时大幅提升,增幅分别为81%和83%;不同液固比和酸碱条件下,采用XRD对淋滤灰渣分析发现,淋滤灰渣中均未检测到NaCl和KCl的矿物相. 改变纳滤膜浓缩液的pH为3.20和10.70后,淋滤灰渣中重金属Pb、Zn、Cu、Cr、Cd和Hg的浸出浓度均满足《危险废物鉴别标准 浸出毒性鉴别》(GB 5085.3—2007)和《生活垃圾填埋场污染控制标准》(GB 16889—2008)标准限值要求. 研究显示,纳滤膜浓缩液淋滤飞灰可脱除焚烧飞灰中的氯盐及部分重金属,淋滤灰渣经热处理后可焚毁截留纳滤膜浓缩液的有机物,热处理后灰渣有望实现安全资源利用.   相似文献   

9.
燃煤废气中二氧化硫转变成硫磺的研究   总被引:1,自引:0,他引:1  
用柠檬酸钠溶液吸收废气中的二氧化硫(SO_2)并还原成硫磺,吸收液中的硫磺分离后循环使用不外排。在SO_2脱除工艺中无需严格控制工艺条件如:烟道气中SO_2浓度的大小、气体温度、气体流速、液体流速等。实验证明该工艺具有SO_2去除率高、运行费用低、经济效益明显、不产生二次污染等优点,是脱除废气中SO2较理想的工艺。  相似文献   

10.
碱液吸收-催化氧化湿式脱硫是一种工艺流程简单的处理硫化氢的方法,这种方法能在脱除硫化氢的同时回收单质硫。本文研究碱液吸收-催化氧化湿式脱除硫化氢过程中,工艺条件对硫化氢脱除效果的影响。  相似文献   

11.
A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p < 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.  相似文献   

12.
The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.  相似文献   

13.
To demonstrate the existence of light thresholds in plant growth and to examine the effects of elevated CO2 on the shade tolerance of a tree species, an experiment consisting of a completely randomized design for a total of 96 yellow birch (Betula alleghaniensis Britton) seedlings was conducted with 3 light levels (2.9%, 7.7%, 26.1% of full sunlight)×2 CO2 levels (350 and 700±10 ppm) with 4 replications in a phytotron. The study proved that thresholds exist and they vary in different plant organs. In ambient CO2, the thresholds were 13.3%, 18.7%, 15.0%, 15.2%, and 15.6% of full sunlight for stem, leaf, root, total plant biomass, and the averaged value, respectively. In 700 ppm CO2, the corresponding thresholds were 16.7%, 21.3%, 18.1%, 21.7% and 19.5% for stem, leaf, root, total plant biomass, and the averaged value, respectively. The lowest threshold in the stem is an indicator of the minimal light intensity for regular growth for seedlings of this species. Below this threshold, light-stressful growth occurs. The result of a paired t-test indicated that the thresholds in elevated CO2 were significantly higher than in ambient CO2. This suggests that yellow birch will lose its moderate shade tolerance, evolutionally becoming a shade-intolerant species, and that it may become more difficult to naturally regenerate in the future.  相似文献   

14.
应用电子显微探针元素分析技术,对背角无齿蚌(Anodonta woodiana)的贝壳(棱柱层和珍珠层)进行了19种元素(Ag、Al、Au、Ca、Co、Cu、Fe、Hf、Mg、Mn、Mo、Na、Re、Se、Sn、Sr、Tl、V、Zn)分布特征的初步研究.元素面分布分析和定量线分析结果均直观而明显地表明:贝壳中Ca含量最高,Hf、Re、Mn、Al、Co、Fe、Sr、Cu和Na的含量较低,而Au、Mg、Tl、Zn、Sn、Ag、V、Mo和Se的含量甚少.Mn在珍珠层的分布高于棱柱层,壳顶区域的珍珠层的含量(0.087±0.045)%显著高于棱柱层(0.030±0.025)%(P<0.05),腹缘区域的珍珠层的含量(0.072±0.055)%亦显著高于棱柱层(0.044±0.025)%(P<0.05),而其余元素在贝壳中均匀分布.  相似文献   

15.
为探究青岛近海不同天气下气溶胶中金属元素的浓度分布特征,于2012年4~5月,2012年8月~2013年3月在青岛近海采集了总悬浮颗粒物(TSP)样品,利用电感耦合等离子体质谱法(ICP-MS)和电感耦合等离子体原子发射光谱法(ICPAES)分析了主要微量金属元素.结果表明,Al、Ca、Fe、Na、K和Mg是TSP中主要的金属元素,质量浓度占所测元素总浓度的94.2%.TSP及金属元素浓度月变化明显,Fe、Al、K、Ca、Mg、Zn、Ba、Mn、Ti、Sr和Li均在11月和1月浓度最高,Be、Sc、Co、Ni和Cr在1月最高,Na在8、11和2月较高,12月最低,Pb在1月和2月最高,8月和12月最低.富集因子表明Be、Co、Al、Ca、Fe、K、Mg、Mn、Sr和Ti主要受自然源影响,Li、Cr、Ni、Zn、Ba和Na除受自然源外,还受部分人为源影响,Pb主要来自人为源.不同天气状况对TSP及其金属元素浓度影响较大,除Ti外,所测元素浓度均在烟雾天最高.与晴天相比,烟雾天除Ti外,其余元素均升高,增幅为1~4倍,雾天Li、Be、Cr、Ni、Al、Fe、Mg和Mn变化不大,Pb和Na升高较多,Co、Ca和Ti降低较多,霾天Cr、Co和Ti降低,其余元素浓度升高,增幅为1~3倍.大部分元素在晴天富集因子最小,雾天富集因子最大.Ni、Zn、Ba、K、Na、Pb和Sr富集因子为晴<霾<烟雾<雾,Fe和Mn为晴<烟雾<霾<雾,Al和Mg为晴<雾<霾<烟雾,其余金属不同天气下富集因子的变化规律各不相同.  相似文献   

16.
通过大气环流向海洋大气边界层传输的人为源和陆源物质,明显改变了海洋气溶胶中痕量金属的组成.但基于开阔海域岛屿连续观测研究海洋气溶胶中痕量金属元素组成及其来源的研究较少.2010年3—5月在我国台湾北部东海海域彭佳屿岛采集了60个TSP(总悬浮颗粒物)样品,采用电感耦合等离子体质谱仪(ICP-MS)分析了19种痕量金属(Al、Fe、Ti、Y、Mn、Ba、Sr、Co、Cr、V、Ni、Tl、Zn、Sn、Pb、As、Cd、Sb、Se)的质量浓度.基于TSP中Al浓度、气团后向轨迹分析和美国国家宇航局CALIPSO卫星星载激光雷达扫描图像,将采集的TSP分为非沙尘TSP(不受沙尘影响的TSP)和沙尘TSP(受沙尘影响的TSP).沙尘TSP中所有痕量金属的浓度都高于非沙尘TSP,表明沙尘对彭佳屿岛TSP中痕量金属有贡献.结合富集因子、相关性分析和PMF模型研究结果表明,彭佳屿岛春季非沙尘TSP中Al、Fe、Ti和Y主要来源于地壳矿物,Mn、Ba、Sr、Co和Cr同时受地壳矿物和人为源的影响;沙尘TSP中Al、Fe、Ti、Y、Mn、Ba、Sr、Co和Cr主要来源于地壳矿物.V和Ni在彭佳屿岛春季非沙尘TSP中主要来源于燃料油燃烧,而在沙尘TSP中同时受燃料油燃烧和地壳矿物的影响.非沙尘TSP和沙尘TSP中,Tl、Zn、As、Sn、Pb、Cd、Sb和Se的来源相似.Tl主要源于交通和煤燃烧,Zn、Sn、Pb、Cd和Sb同时来源于交通、煤和燃料油燃烧,As主要来源于煤燃烧,Se则主要来源于煤和燃料油燃烧.研究显示,人为源释放到大气中的Tl、Zn、As、Sn、Pb、Cd、Sb和Se可以通过大气环流长距离传输至开阔海域.   相似文献   

17.
Earthworm toxicity tests are useful tools for terrestrial risk assessment but require a hierarchy of test designs that differ in effect levels (behavior, sublethal, lethal). In this study, the toxicity of chlorpyrifos contaminated soil on earthworms was assessed. In addition to the acute and chronic tests, an avoidance response test was applied. Earthworms were exposed to sublethal and lethal concentration of chlorpyrifos, and evaluated for acute toxicity, growth, fecundity and avoidance response after a certain exposure period. The test methods covered all important ecological relevant endpoints (acute, chronic, behavioral). Concentration of 78.91 mg/kg, chlorpyrifos caused significant toxic effects in all test methods, but at lower test concentrations, only significant chronic toxic effects could be observed. In the present study, chlorpyrifos had adverse effect on growth and fecundity in earthworm exposed to 5 mg/kg chlorpyrifos after eight weeks. The avoidance response test, however, showed significant repellent effects concentration of 40 mg/kg chlorpyrifos. For chlorpyrifos, concentration affecting avoidance response was far greater than growth and fecundity, it seemed likely that earthworms were not able to escape from pesticide-contaminated soil into the clean soil in field and hence were exposed continuously to elevated concentrations of pesticides.  相似文献   

18.
IntroductionAswangovernorate ,Egypt ,isfamousforbymonuments (Ancient,CopticandIslamic) .Thefoundationareofthefirstimportanceandcareshouldbetakentoseethattheyareconsolidatedandprotectedasforaspossiblefromtheinfiltrationofwater.Waterisamajorcauseofdamage ,no…  相似文献   

19.
In recent years, Dechloranes have been widely detected in the environment around the world. However, understanding and knowledge of Dechloranes in remote regions, such as the Arctic, remain lacking. Therefore, the concentrations of 5 Dechloranes in surface seawater, sediment, soil, moss, and dung collected from Ny-Ålesund in the Arctic were measured with the concentrations 93 pg/L, 342, 325, 1.4, and 258 pg/g, respectively, which were much lower than those in Asian and European regions. The mean ratios of anti-Dechlorane Plus (DP) to total DP (?anti) in seawater, sediment, soil, moss, dung, and atmospheric samples were 0.36, 0.21, 0.18, 0.27, 0.66, and 0.43, respectively. Results suggested that the main source of DP in seawater, sediment, soil, and moss was long-range atmospheric transport. However, the ratio identified in dung was different, for which the migration behavior of the organism is probably the main source of DP.  相似文献   

20.
In recent years, Dechloranes have beenwidely detected in the environment around the world. However, understanding and knowledge of Dechloranes in remote regions, such as the Arctic, remain lacking. Therefore, the concentrations of 5 Dechloranes in surface seawater, sediment, soil, moss, and dung collected from Ny-Ålesund in the Arctic were measured with the concentrations 93 pg/L, 342, 325, 1.4, and 258 pg/g, respectively, which were much lower than those in Asian and European regions. The mean ratios of anti-Dechlorane Plus (DP) to total DP (fanti) in seawater, sediment, soil, moss, dung, and atmospheric samples were 0.36, 0.21, 0.18, 0.27, 0.66, and 0.43, respectively. Results suggested that the main source of DP in seawater, sediment, soil, andmosswas long-range atmospheric transport. However, the ratio identified in dung was different, for which the migration behavior of the organism is probably themain source of DP.  相似文献   

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