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排序方式: 共有1534条查询结果,搜索用时 390 毫秒
871.
红壤对铬(VI)吸附特性的研究   总被引:1,自引:0,他引:1  
通过云南三类红壤对Cr(VI)吸附行为的研究。结果表明,红壤对Cr(VI)有明显的吸附作用,等温吸附曲线可以用Freundlich方程、Langmuir方程和Temkin方程描述。最大吸附量为红壤>赤红壤>砖红壤。酸度、温度和有机质对红壤吸附Cr(VI)均有影响。低pH值时吸附量随pH值升高略有增加,pH值超过某一限度,吸附量急剧下降,直至基本不吸附;温度低于40℃时,吸附量随温度升高而减少,但温度高于40℃时,吸附量不再减少;随有机质加入量的增加,吸附量减少,其相关性红壤和赤红壤达显著水准,砖红壤达极显著水准。  相似文献   
872.
黑龙江省同全国一样,虽然农村经济发展很快,但传统粗放的农村经济发展模式并没有得到根本的转变,许多环境问题日益突出,本文根据统计数据和现状调查,揭示了黑龙江省农村环境污染情况,分析了造成污染的原因,提出了保护农村环境,防治污染的建议.  相似文献   
873.
废弃水基钻井液固化处理研究   总被引:11,自引:5,他引:11  
废弃水基钻井液固化处理是当前油田环保急需解决的问题之一。研究利用油田的几种废弃水基钻井液,选择固化技术对其进行固化处理,探讨几种无机和有机添加剂对处理效果的影响,优选相对较好的添加剂配方,并对其固化机理作了初步分析。结果表明:采用无机胶凝剂和少量有机固化剂配制的复合型团化剂,固化效果较好,固化物的浸出液毒性均在GB3550-83控制的指标之内,成本低廉,收到较好的社会与经济效益。  相似文献   
874.
鸭绿江口再悬浮沉积物中汞的释放   总被引:4,自引:0,他引:4       下载免费PDF全文
报道了鸭绿江河口区悬浮物中汞含量随潮态的变化,并通过实验模拟研究了鸭绿江下浮污染沉积物中汞在海水作用下的释放机理。结果表明,在河口区,高潮时悬浮物中汞含量低于低潮时的含量,其原因除了海水中氯离子对悬浮物中汞的络合作用以及碱金属和碱土金属离子的交换作用外,还由于悬浮沉积物中汞主要以有机物,腐殖酸结合态存在,碱性海水能溶解腐殖酸,从而导致与腐殖酸结合态汞的释放。  相似文献   
875.
Organic and inorganic materials migrate downstream and have important roles in regulating environmental health in the river networks. However, it remains unclear whether and how a mixture of materials (i.e., microbial species) from various upstream habitats contribute to microbial community coalescence upstream of a dam. Here we track the spatial variation in microbial abundance and diversity in the Three Gorges Reservoir based on quantitative PCR and 16S rRNA gene high-throughput sequencing data. We further quantitatively assess the relative contributions of microbial species from mainstem, its tributaries, and the surrounding riverbank soils to the area immediately upstream of the Three Gorges Dam (TGD). We found an increase of microbial diversity and the convergent microbial distribution pattern in areas immediately upstream of TGD, suggesting this area become a new confluence for microbial diversity immigrating from upstream. Indeed, the number of shared species increased from upstream to TGD but unique species decreased, indicating immigration of various sources of microbial species overwhelms local environmental conditions in structuring microbial community close to TGD. By quantifying the sources of microbial species close to TGD, we found little contribution from soils as compared to tributaries, especially for sites closer to TGD, suggesting tributary microbes have greater influence on microbial diversity and environmental health in the Three Gorges Reservoir. Collectively, our results suggest that tracking microbial geographic origin and evaluating accumulating effects of microbial diversity shed light on the ecological processes in microbial communities and provide information for regulating aquatic ecological health.  相似文献   
876.
白腐真菌菌丝球形成的物化条件及其对铅的吸附   总被引:47,自引:1,他引:47  
为了探讨影响微生物菌丝球生长的物理化学因素和控制菌丝球大小的规律以及微生物吸附重金属的效果,对黄孢展齿革菌(Phanerochaetechrysosporium)呈球状体生长和用此菌丝球吸附水溶液中的Pb^2+进行了研究。  相似文献   
877.
The 6:2 FTS was the substitute for perfluorooctane sulfonate(PFOS) in the chrome plating industry in Japan. Electrochemical oxidation of 6:2 FTS was investigated in this study. The degradabilities of PFOS and 6:2 FTS were tested on the Ti/SnO2–Sb2O5–Bi2O3anode. The effects of current density,potential,and supporting electrolyte on the degradation of 6:2 FTS were evaluated. Experimental results showed that 6:2 FTS was more easily degraded than PFOS on the Ti/SnO2–Sb2O5–Bi2O3anode. At a low current density of 1.42 mA/cm2,6:2 FTS was not degraded on Ti/SnO2–Sb2O5–Bi2O3,while the degradation ratio increased when the current density ranged from 4.25 to 6.80 mA/cm2. The degradation of 6:2 FTS at current density of 6.80 mA/cm2 followed pseudo first-order kinetics with the rate constant of 0.074 hr-1. The anodic potential played an important role in the degradation of 6:2 FTS,and the pseudo first-order rate constants increased with the potential. The surface of Ti/SnO2–Sb2O5–Bi2O3was contaminated after electrolysis at constant potential of 3 V,while the fouling phenomenon was not observed at 5 V. The fouled anode could be regenerated by incinerating at 600°C. The intermediates detected by ultra-performance liquid chromatography coupled with a triple-stage quadrupole mass spectrometer(UPLC–MS/MS) were shorter chain perfluorocarboxylic acids. The 6:2 FTS was first attacked by hydroxyl radical,and then formed perfluorinated carboxylates,which decarboxylated and removed CF2 units to yield shorter-chain perfluorocarboxylic acids.  相似文献   
878.
官厅水库氮、磷污染及其控制途径   总被引:3,自引:0,他引:3  
官厅水库是北京地区担负多功能的重要水资源。过去曾对该水库的酚、氰、重金属污染做了许多调查研究。但很少涉及氮、磷污染问题。本项工作主要对该水库近年来氮、磷污染水平、污染的生态效应特别是富营养化问题,进行了较为系统的研究,根据实验结果进行了综合评价。在此基础上,应用生态学原理,提出了控制氮、磷污染的有效途径。  相似文献   
879.
Novel brominated flame retardants (NBFRs) were investigated in Arctic air and soil samples collected from Ny-Ålesund and London Island, Svalbard, during Chinese scientific research expeditions to the Arctic during 2014–2015. The concentrations of Σ9NBFRs in the Arctic air and soil were 4.9–8.7 pg/m3 (average 6.8 pg/m3) and 101–201 pg/g dw (average 150 pg/g dw), respectively. The atmospheric concentration of hexabromobenzene (HBB) was significantly correlated with that of pentabromotoluene (PBT) and pentabromobenzene (PBBz), suggesting similar source and environmental fate in the Arctic air. No significant spatial difference was observed among the different sampling sites, both for air and soil samples, indicating that the effects of the scientific research stations on the occurrence of NBFRs in the Arctic were minor. The fugacities from soil to air of pentabromoethylbenzene (PBEB), 2,3-dibromopropyl 2,4,6-tribromophenyl ether (DPTE), and decabromodiphenylethane 1,2-bis (pentabromophenyl) ethane (DBDPE) were lower than the equilibrium value, indicating a nonequilibrium state of these compounds between air and soil, the dominant impact of deposition and the net transport from air to soil. The correlation analysis between the measured and predicted soil-atmosphere coefficients based on the absorption model showed that the impact of the soil organic matter on the distribution of NBFRs in the Arctic region was minor. To the best of our knowledge, this work is one of the limited reports on atmospheric NBFRs in the Arctic and the first study to investigate the occurrence and fate of NBFRs in the Arctic soil.  相似文献   
880.
Toxicity of pyrene on the denitrifiers was studied by spiking an agricultural soil with pyrene to a series of concentrations (0-500 mg kg−1) followed by dose-response and dynamic incubation experiments. Results showed a positive correlation between potential denitrification activity and copy numbers of denitrifying functional genes (nirK, nirS and nosZ), and were both negatively correlated with pyrene concentrations. Based on the comparison of EC50 values, denitrifiers harboring nirK, nirS or nosZ gene were more sensitive than denitrification activity, and denitrifiers harboring nirS gene were more sensitive than that harboring nirK or nosZ genes. Seven days after spiking with EC50 concentration of pyrene, denitrifiers diversity decreased and community composition changed in comparison with the control. Phylogenetic analyses of three genes showed that the addition of pyrene increased the proportion of Bradyrhizobiaceae, Rhodospirillales, Burkholderiales and Pseudomonadales. Some species belonging to these groups were reported to be able to degrade PAHs.  相似文献   
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