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681.
硝基苯属于典型的难降解有机化合物,通过雾化-多相协同臭氧氧化技术对硝基苯废水的处理效果进行了分析研究.通过对实验中的主要影响因素进行分析,结果表明,液滴粒径对硝基苯降解速率常数具有负相关性;紫外灯功率、活性炭投加量和水温对硝基苯降解速率常数具有正相关性;pH值和臭氧投加量对硝基苯降解速率常数具有最佳值.雾化-多相协同臭氧氧化技术对硝基苯的降解过程遵从一级化学反应动力学方程.经验动力学方程为:C=C0exp(-4.54×10-6Q0.50G0.31W0.11t). 相似文献
682.
Chemical composition and source apportionment of PM10 and PM2.5 in different functional areas of Lanzhou, China 总被引:3,自引:0,他引:3
Xionghui Qiu Lei Duan Jian Gao Shulan Wang Fahe Chai Jun Hu Jingqiao Zhang Yaru Yun 《环境科学学报(英文版)》2016,28(2):75-83
To elucidate the air pollution characteristics of northern China, airborne PM_10(atmospheric dynamic equivalent diameter ≤ 10 μm) and PM_(2.5)(atmospheric dynamic equivalent diameter ≤ 2.5 μm) were sampled in three different functional areas(Yuzhong County,Xigu District and Chengguan District) of Lanzhou, and their chemical composition(elements, ions, carbonaceous species) was analyzed. The results demonstrated that the highest seasonal mean concentrations of PM_10(369.48 μg/m~3) and PM_(2.5)(295.42 μg/m~3) were detected in Xigu District in the winter, the lowest concentration of PM_(2.5)(53.15 μg/m~3) was observed in Yuzhong District in the fall and PM_10(89.60 μg/m~3) in Xigu District in the fall.The overall average OC/EC(organic carbon/elemental carbon) value was close to the representative OC/EC ratio for coal consumption, implying that the pollution of Lanzhou could be attributed to the burning of coal. The content of SNA(the sum of sulfate, nitrate,ammonium, SNA) in PM_(2.5)in Yuzhong County was generally lower than that at other sites in all seasons. The content of SNA in PM_(2.5)and PM_10 in Yuzhong County was generally lower than that at other sites in all seasons(0.24–0.38), indicating that the conversion ratios from precursors to secondary aerosols in the low concentration area was slower than in the area with high and intense pollutants. Six primary particulate matter sources were chosen based on positive matrix factorization(PMF) analysis, and emissions from dust, secondary aerosols, and coal burning were identified to be the primary sources responsible for the particle pollution in Lanzhou. 相似文献
683.
The anaerobic ammonium oxidation (anammox) process was successfully started up from conventional activated sludge using a hybrid bioreactor within 2 months. The average removal efficiencies of ammonia and nitrite were both over 80%, and the maximum total nitrogen removal rate of 1.85 kg N/(m3.day) was obtained on day 362 with the initial sludge concentration of 0.7 g mixed liquor suspended solids (MLSS)/L. Scanning electron microscope (SEM) observation of the granular sludge in the hybrid reactor clearly showed a high degree of compactness and cell sphericity, and the cell size was quite uniform. Transmission electron microscope photos showed that cells were round or oval, the cellular diameter was 0.6--1.0 μupm, and the percentage of the anammoxosome compartment was 51%--85% of the whole cell volume. Fluorescence in situ hybridization analysis (FISH) indicated that anammox bacteria became the dominant population in the community (accounting for more than 51% of total bacteria on day 250). Seven planctomycete 16S rRNA gene sequences were present in the 16S rRNA gene clone library generated from the biomass and affiliated to Candidatus Kuenenia stuttgartiensis and Candidatus Brocadia sp., a new anammox species. In addition, the average effluent suspended solid (MLSS) concentrations of outlets I (above the non-woven carrier) and II (below the non-woven carrier) were 0.0009 and 0.0035 g/L, respectively. This showed that the non-woven carrier could catch the biomass effectively, which increased biomass and improved the nitrogen removal rate in the reactor. 相似文献
684.
大亚湾核电站邻近海域大型底栖生物群落结构分析 总被引:1,自引:1,他引:1
2005年3月和7月对大亚湾核电站邻近海域的大型底栖生物进行了调查.春夏季两次调查共获底栖生物75种,环节动物种类数最多;平均生物量为42.13 g/m2,平均栖息密度为128.50 ind/m2.采用Bray-Curtis相似性系数聚类分析和多维排序尺度分析大型底栖生物群落,春夏季均划分出三个大型底栖生物群落,丰度生物量比较法分析认为个别生物群落可能处于中度扰动状态.不同季节相比较,大型底栖生物数量差别明显,春季生物种类数、生物量和丰度均高于夏季.春夏季生物群落发生了一定的变化,春季生物多样性好于夏季. 相似文献
685.
Jinshan Wei Lijie Duan Jian Wei Erhard Hoffmann Yonghui Song Xiaoguang Meng 《环境科学学报(英文版)》2021,33(3):135-144
Granular porous sorbents were normally used for heavy metals removal from water. To search for the new commercial sorbent and treatment strategy, an organic acrylic amine fiber (AAF) and phosphorus loading inorganic-organic AAF (P-AAF) were prepared and used for lead (Pb) removal from water. A new strategy of inorganic-organic coupling technology was proposed for Pb removal, based on the hypothesis of surface-induced precipitation mechanism. The AAF showed a Pb adsorption capacity of 417 mg/g from the Langmuir fitting, while the column filtration technology was further applied to measure the adsorption edge and applications. Effects of different initial Pb concentrations, hydraulic retention time, and co-existing P were considered in the filtration experiments. The presence of 0.8 mg/L P in water significantly improved the Pb breakthrough point from 15,000 to 41,000 bed volumes of water spiked with 85 µg/L Pb, while the P-AAF fixed bed showed better removal of Pb than AAF SEM/EDX and XRD spectra were employed for determining the surface functional groups and the formation of surface-induced precipitation of pyromorphite (Pb5(PO4)3OH) on AAF. This study verified the application of AAF sorbent for Pb removal and the enhanced effect of coating P on AAF, thus improved our fundamental understanding and application of the surface chemistry process of Pb with P. 相似文献
686.
687.
泾阳、临猗地震的地下流体异常特征 总被引:5,自引:3,他引:5
总结了1998 年泾阳Ms4.8 及临猗Ms 4.6 级地震的地下流体异常特征, 结果表明: 异常点数量有随震中距的增大而减少的趋势, 同时又受构造条件的制约; 异常时间以短临为主, 短期异常主要集中在震前3 个月左右, 临震异常出现在震前10 d 左右; 异常幅度与地震三要素关系不明显。 相似文献
688.
689.
TAN Jihu DUAN Jingchun HE Kebin MA Yongliang DUAN Fengkui CHEN Yuan FU Jiamo 《环境科学学报(英文版)》2009,21(6):774-781
The chemical characteristics (water-soluble ions and carbonaceous species) of PM2:5 in Guangzhou were measured during a typical
haze episode. Most of the chemical species in PM2:5 showed significant di erence between normal and haze days. The highest
contributors to PM2:5 were organic carbon (OC), nitrate, and sulfate in haze days and were OC, sulfate, and elemental carbon (EC)
in normal days. The concentrations of secondary species such as, NO3??, SO4
2??, and NH4
+ in haze days were 6.5, 3.9, and 5.3 times
higher than those in normal days, respectively, while primary species (EC, Ca2+, K+) show similar increase from normal to haze days by
a factor about 2.2–2.4. OC/EC ratio ranged from 2.8 to 6.2 with an average of 4.7 and the estimation on a minimum OC/EC ratio showed
that SOC (secondary organic carbon) accounted more than 36.6% for the total organic carbon in haze days. The significantly increase in
the secondary species (SOC, NO3??, SO4
2??, and NH4
+), especially in NO3??, caused the worst air quality in this region. Simultaneously,
the result illustrated that the serious air pollution in haze episodes was strongly correlated with the meteorological conditions. During
the sampling periods, air pollution and visibility had a good relationship with the air mass transport distance; the shorter air masses
transport distance, the worse air quality and visibility in Guangzhou, indicating the strong domination of local sources contributing to
haze formation. High concentration of the secondary aerosol in haze episodes was likely due to the higher oxidation rates of sulfur and
nitrogen species. 相似文献
690.
Jianrui Niu Haobin Liu Hengli Qian Jie Liu Mengyuan M Erhong Duan Lei Yu 《环境科学学报(英文版)》2020,32(2):260-272
In order to study their synergistic catalytic effects in toluene degradation, CuMn_2O_4/HTS-1(HTS-1 was a titanium silicon molecular sieve), Cu_(0.7)Mn_2Y_(0.3)O_x/HTS-1 and Cu_(0.7)Mn_2Ce_(0.3)O_x/HTS-1 catalysts were prepared by the impregnation method.The textural properties, redox properties and acidity of the catalysts were characterized by X-ray diffractometer(XRD),transmission electron microscopy(TEM), scanning electron microscopy(SEM), H_2 temperature-programmed reduction(H_2-TPR), X-ray photoelectron spectroscopy(XPS),frustrated total internal reflection(FT-IR), ammonium temperature-programmed desorption(NH_3-TPD) and pyridine adsorption internal reflection(Py-IR) measurements.The potential roles of Lewis acid sites(activating dioxygen) were discussed, and the experimental results indicated that the most efficient route for toluene degradation over Cu_(0.7)Mn_2Ce_(0.3)O_x/HTS-1(toluene conversion rate of 90%(T99) = 295℃) was ascribed to regulation of the synergistic effects of redox properties(activating molecular toluene) and Lewis acid sites(activating dioxygen).The Mars–Van–Krevelen(MVK) model was adopted to describe the reaction process of toluene oxidation, which gave an in-depth view into the toluene degradation over CuMn_2O_4/HTS-1, Cu_(0.7)Mn_2Y_(0.3)O_x/HTS-1 and Cu_(0.7)Mn_2Ce_(0.3)O_x/HTS-1.In addition, the synergistic effects between redox properties and Lewis acid sites were studied in detail. 相似文献