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991.
CuO/γ-Al_2O_3类Fenton试剂降解丁基黄药 总被引:1,自引:0,他引:1
CuO/γ-Al2O3类Fenton试剂是降解丁基黄药的优良试剂。该试剂与传统的Fenton试剂相比,提高了反应的pH值,可在较高pH(4~5)条件下反应,而传统的Fenton试剂的适宜pH值一般在3以下。采用单因素实验和正交实验相结合的方法研究了pH、催化剂投加量、过氧化氢投加量以及反应时间对丁基黄药降解效果的影响,并对催化剂的使用寿命进行了探讨。研究结果表明,反应的最佳条件为:pH为4~5,催化剂投加量为6 g/L,过氧化氢用量为30 mg/L,反应30min。在此反应条件下,丁基黄药的降解率达98%以上;影响丁基黄药降解效果的因素大小顺序为:pH〉反应时间〉H2O2用量〉催化剂投加量,其中pH对CuO/γ-Al2O3类Fenton试剂降解丁基黄药的影响最为显著。 相似文献
992.
Guor-Cheng Fang Hung-Che Chiang Yu-Cheng Chen You-Fu Xiao Yuan-Jie Zhuang 《Environmental Forensics》2014,15(4):296-305
This study characterized the dry deposition flux and dry deposition velocity (Vd) of metallic elements attached on particulate matter. Specifically, large particles (>10 μm), coarse particles (10 μm~2.5 μm), and fine particles (<2.5 μm) were studied at the Gong Ming Junior High School (Taichung Airport) and Taichung Harbor sampling sites in central Taiwan. Ambient air samples were collected to determine total suspended particulate matter (TSP), dry deposition plate (DDP), Vd, coarse particulate matter (PM2.5–10) and fine particulate matter (PM2.5), and metallic elements concentrations at the Airport and Taichung Harbor sites between June 17, 2013, and November 14, 2013. The results revealed that the average TSP, DDP, Vd, PM2.5–10, and PM2.5 particulate at the Airport were 54.55 (μg/m3), 902.25 (μg/m2-min), 17.11 (m/sec), 0.003 (μg/m3), and 0.010 (μg/m3), respectively; while these values at Taichung Harbor were 63.66 (μg/m3), 539.69 (μg/m2-min), 9.94 (m/sec), 0.003 (μg/m3), and 0.014 (μg/m3), respectively. In addition, the results showed that the average Cu and Pb concentrations were higher than Cr, Ni, and Cd for both the airport and harbor sampling sites. Furthermore, Cr, N, Cu, Cd, and Pb had the highest average concentrations versus those reported for other study areas, with one exception: The results obtained in Kacanik, Kosovo, during 2005. The average metallic elements concentrations order was Cu > Pb > Cr > Ni > Cd. 相似文献
993.
Global warming has greatly concerned the whole world.Owing to the limitation we currently have,it is still difficult to completely understand the mechanism and physical science of climate change.Now both certainty and uncertainty coexist in the understanding of climate warming.This paper aims to summarize certainties and uncertainties in climate-warming studies,which focus on seven key problems related to human activities,namely,global warming,atmospheric concentrations of greenhouse gases,relationship between greenhouse gas emissions and climate warming,climate models,future climate change,2?warming threshold and tipping point in the Earth's system.We should comprehensively take into account the level of certainty and uncertainty in our understanding of climate change while adapting to and mitigating global warming and adjusting our industrial structures accordingly.This would allow us to respond to change with certainty,while avoiding the risks associated with uncertainty. 相似文献
994.
Air sparging (AS) was explored for remediation of a petroleum contaminated semi-confined groundwater system in NE China. Physical, hydro-chemical and hydraulic behaviors in subsurface environment during AS were investigated with support of modeling to understand the hydrogeo-chemical impacts of AS on the aquifer. The responses of groundwater, dissolved oxygen and temperature indicated that the radius of influence of AS was up to 8–9 m, and a 3D boundary of the zone of influence (ZOI) was accordingly obtained with volume of 362 m3. Water mounding unlike normal observations was featured by continuous up-lift and blocked dissipation. AS induced water displacement was calculated showing no obvious spreading of contaminant plume under this AS condition. Slug tests were employed before and after AS to reveal that the physical perturbation led to sharp increase in permeability and porosity. Modeling indicated that the regional groundwater flow field was not affected by AS except the physical perturbation in ZOI. Hydro-chemically increase of pH and Eh, and reduction of TDS, electrical conductivity and bicarbonate were observed in ZOI during AS. PHREEQC modeling inferred that these chemical phenomena were induced by the inorganic carbon transfer during air mixing. 相似文献
995.
运用分子轨道理论考察甲酚的生物降解特性 总被引:1,自引:0,他引:1
运用分子轨道理论考察了甲酚同分异构体的生物降解特性。计算出最高占据轨道(HOMO)能量的大小,反映了甲酚同分异构体生物降解反应的难易程度,且结论与事实相符合。 相似文献
996.
固定化生物活性炭处理低浓度甲醇废水 总被引:11,自引:0,他引:11
将分离筛选得到的甲醇降解菌固定在颗粒活性炭上,组成固定化生物活性炭反应系统,研究该反应系统处理轻度污染含甲醇废水的最佳运行条件和运行效果,结果表明,固定化生物活性炭处理轻度污染含甲醇放心水的方法明显好于3种树脂和单纯活性炭吸附处理,反应系统的最佳运行条件是水力负荷0.84-0.77m^3(m^2.h),停留时间57-62min,pH7-8,温度20℃-30℃,溶解氧是去除甲醇的主要限制因子,甲醇含量为11.3-23.1mg/L时,去除率大90%,出水CODcr小于12mg/L。此外还研究了生物活性炭生物膜的一些特点,并分析了运行中活性炭吸附性能的变化。 相似文献
997.
998.
This study monitored atmospheric pollutants during high wind speed (> 7 m s−1) at two sampling sites: Taichung Harbor (TH) and Wuci traffic (WT) during March 2004 to January 2005 in central Taiwan. The
correlation coefficient (R
2) between TSP, PM2.5, PM2.5−10 particle concentration vs. wind speed at the TH and WT sampling site during high wind speed (< 7 m s−1) were also displayed in this study. In addition, the correlation coefficients between TSP, PM2.5 and PM2.5−10 of ionic species vs. high wind speed were also observed. The results indicated that the correlation coefficient order was
TSP > PM2.5−10 > PM2.5 for particle at both sampling sites near Taiwan strait. In addition, the concentration of Cl−, NO3
−, SO4
2−, NH4
+, Mg2+, Ca2+ and Na+ were also analyzed in this study. 相似文献
999.
Atmospheric aerosol particles and metallic concentrations, ionic species were monitored at the Experimental harbor of Taichung
sampling site in this study. This work attempted to characterize metallic elements and ionic species associated with meteorological
conditions variation on atmospheric particulate matter in TSP, PM2.5, PM2.5–10. The concentration distribution trend between TSP, PM2.5, PM2.5–10 particle concentration at the TH (Taichung harbor) sampling site were also displayed in this study. Besides, the meteorological
conditions variation of metallic elements (Fe, Mg, Cr, Cu, Zn, Mn and Pb) and ions species (Cl−, NO3
−, SO4
2−, NH4
+, Mg2+, Ca2+ and Na+) concentrations attached with those particulate were also analyzed in this study. On non-parametric (Spearman) correlation
analysis, the results indicated that the meteorological conditions have high correlation at largest particulate concentrations
for TSP at TH sampling site in this study. In addition, the temperature and relative humidity of meteorological conditions
that played a key role to affect particulate matter (PM) and have higher correlations then other meteorological conditions
such as wind speed and atmospheric pressure. The parameter temperature and relative humidity also have high correlations with
atmospheric pollutants compared with those of the other meteorological variables (wind speed, atmospheric pressure and prevalent
wind direction). In addition, relative statistical equations between pollutants and meteorological variables were also characterized
in this study. 相似文献
1000.
Is an adjusted rhizosphere-based method valid for field assessment of metal phytoavailability? Application to non-contaminated soils 总被引:1,自引:0,他引:1
Fang J Wen B Shan XQ Lin JM Owens G 《Environmental pollution (Barking, Essex : 1987)》2007,150(2):209-217
Previously recommended rhizosphere-based method (RHIZO) applied to moist rhizosphere soils was integrated with moist bulk soils, and termed adjusted-RHIZO method (A-RHIZO). The A-RHIZO and RHIZO methods were systematically compared with EDTA, DTPA, CaCl2 and the first step of the Community Bureau of Reference (BCR1) methods for assessing metal phytoavailability under field conditions. Results suggested that moist bulk soils are equally suited or even better than rhizosphere soils to estimate metal phytoavailability. The A-RHIZO method was preferred to other methods for predicting the phytoavailability of Ni, Cu, Zn, Cd, Pb and Mn to wheat roots with correlation coefficients of 0.730 (P<0.001), 0.854 (P<0.001), 0.887 (P<0.001), 0.739 (P<0.001), 0.725 (P<0.001) and 0.469 (P<0.05), respectively. When including soil properties, other extraction methods were also able to predict phytoavailability reasonably well for some metals. Soil pH, organic matter and Fe-Mn oxide contents, and cation-exchange capacity mostly influenced the extraction and phytoavailability of metals. 相似文献