943 resultados para Organic compounds Properties Synthesis.
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A baseline environmental characterization of the inner Kachemak Bay, Alaska was conducted using the sediment quality triad approach based on sediment chemistry, sediment toxicity, and benthic invertebrate community structure. The study area was subdivided into 5 strata based on geophysical and hydrodynamic patterns in the bay (eastern and western intertidal mud flats, eastern and western subtidal, and Homer Harbor). Three to seven locations were synoptically sampled within each stratum using a stratified random statistical design approach. Three sites near the village of Port Graham and two sites in the footprint of a proposed Homer Harbor expansion were also collected for comparison. Concentrations of over 120 organic and metallic contaminants were analyzed. Ambient toxicity was assessed using two amphipod bioassays. A detailed benthic community condition assessment was performed. Habitat parameters (depth, salinity, temperature, dissolved oxygen, sediment grain size, and organic carbon content) that influence species and contaminant distribution were also measured at each sampling site. Sediments were mostly mixed silt and sand; characteristic of high energy habitats, with pockets of muddy zones. Organic compounds (PAHs, DDTs, PCBs, cyclodienes, cyclohexanes) were detected throughout the bay but at relatively low concentrations. Tributyltin was elevated in Homer Harbor relative to the other strata. With a few exceptions, metals concentrations were relatively low and probably reflect the input of glacial runoff. Relative to other sites, Homer Harbor sites were shown to have elevated concentrations of metallic and organic contaminants. The Homer Harbor stratum however, is a deep, low energy depositional environment with fine grained sediment. Concentrations of organic contaminants measured were five to ten times higher in the harbor sites than in the open bay sites. Concentration of PAHs is of a particular interest because of the legacy of oil spills in the region. There was no evidence of residual PAHs attributable to oil spills, outside of local input, beyond the confines of the harbor. Concentrations were one to ten times below NOAA sediment quality guidelines. Selected metal concentrations were found to be relatively elevated compared to other data collected in the region. However, levels are still very low in the scale of NOAA’s sediment quality guidelines, and therefore appear to pose little or no ecotoxicity threat to biota. Infaunal assessment showed a diverse assemblage with more than 240 taxa recorded and abundances greater than 3,000 animals m-22 in all but a few locations. Annelid worms, crustaceans, snails, and clams were the dominant taxa accounting for 63 %, 19%, 5%, and 7 % respectively of total individuals. Specific benthic community assemblages were identified that were distributed based on depth and water clarity. Species richness and diversity was lower in the eastern end of the bay in the vicinity of the Fox River input. Abundance was also generally lower in the eastern portion of the study area, and in the intertidal areas near Homer. The eastern portions of the bay are stressed by the sediment load from glacial meltwater. Significant toxicity was virtually absent. Conditions at the sites immediately outside the existing Homer Harbor facility did not differ significantly from other subtidal locations in the open Kachemak Bay. The benthic fauna at Port Graham contained a significant number of species not found in Kachemak Bay. Contaminant conditions were variable depending on specific location. Selected metal concentrations were elevated at Port Graham and some were lower relative to Kachemak Bay, probably due to local geology. Some organic contaminants were accumulating at a depositional site.
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植物源挥发性有机碳化合物(Volitale organic compounds, VOC)是大气VOC的主要来源,与对流层大气质量、大气化学密切相关。鉴于温带草地的分布范围很广,草地植物VOC释放潜力某种程度上影响植物源VOC的总释放量。另外,植物源VOC也是光合作用固定碳素的损失方式之一,可能在特定区域或生态系统中具有重要意义。基于上述想法,本文设计了四个方面的实验作为研究内容:1) 温带草地物种水平VOC释放潜力、及其与植物功能群的关系?2) 沙地植物物种水平VOC释放潜力、及其与植物功能群的关系?3) 沙地植物-草地植物VOC释放潜力存在显著性差异吗?4) 温带典型草地和退化草地的VOC释放速率如何?在生态系统水平,植物源VOC对温带草地碳循环的贡献多大? 在所测定的175种温带草地植物中,不同植物间异戊二烯和单萜释放潜力差异很大;除少数物种外,大多数植物的异戊二烯和单萜释放潜力都较低,尤其是典型草地的优势物种。在此基础上,作者探讨了分类学赋值方法对温带草地植被的可行性,并初步建立了锡林河流域温带草地植物的VOC释放目录(共277种植物)。另外,温带草地植物的异戊二烯和单萜释放潜力与植物功能群(植物生活型和水分功能群)具有一定的联系,尤其是植物生活型。总的来说,温带草原的优势生活型(物种),即多年生根茎禾草(或多年生丛生禾草),具有较低的异戊二烯和单萜释放潜力。各水分功能群间差异不显著,但中旱生植物、旱中生植物 (温带草原的优势功能群),具有较低的异戊二烯、单萜释放潜力。因此,温带草原退化过程中,那些具有较高VOC释放潜力的植物,重要性将会增加。 沙地植物种类组成非常丰富,不同物种间的异戊二烯和单萜释放潜力变异也很大。另外,沙地植物的异戊二烯和单萜释放潜力与其功能群间关系较密切,不同植物生活型间差异显著;其中也以多年生根茎禾草、多年生从生禾草的释放潜力最低,而乔木的释放潜力相对最高;该结论基本与草地的研究结论一致。然而,沙地植物的异戊二烯和单萜释放潜力与其水分功能群的关系比较模糊,中生植物具有更高的释放潜力,湿生植物的释放潜力较小。 通过对比沙地植物和草地植物的释放潜力,发现沙地植物的异戊二烯和单萜释放潜力比草地植物高,且这种差异整体上显著。另外,这种显著性差异,在不同植物生活型、水分功能群间也同样存在。沙地植物比对应的草地植物具有更高的异戊二烯和单萜释放潜力,最可能的原因:沙地正午的温度明显比草地温度高,前者实测温度可超过 45 ℃,这种经常性、周期性高温,促使沙地植物采用与草地植物不同的适应策略,即沙地植物通过释放更多的异戊二烯或单萜来减少其可能遭的热胁迫或热伤害,这种长期适应策略,使沙地植物具有更高的萜类化合物释放潜力。 本文还调查了温带典型草地生态系统和退化草地生态系统的异戊二烯和单萜释放速率,结果表明典型草地的标准异戊二烯和单萜释放速率分别为0.50 μgC g-1 h-1和0.69 μgC g-1 h-1;退化草地的标准异戊二烯和单萜释放潜力分别为0.32 μgC g-1 h-1和1.59 μgC g-1 h-1。总的来说,温带草地的异戊二烯和单萜释放速率都比较低,尤其是典型草地。整个生长季,典型草地释放的异戊二烯和单萜分别为31.6 mgC•m-2 和 70.4 mgC•m-2;退化草地的异戊二烯和单萜释放量分别为20.8 mgC•m-2 和 168.8 mgC•m-2。退化草地萜类化合物总释放速率远高于典型草地,尤其是单萜释放能力。过度放牧引起的草地退化,通过改变植被种类组成,对温带草地的异戊二烯和单萜释放速率产生显著影响;总体而言,温带草地退化将会使草地释放更多萜类化合物。 在温带草地生态系统中,Clost as VOC相对其NPP而言很小,在环境PAR和温度高时,它的贡献率相对较大;Clost as VOC约占典型草地生态系统NEP的5.32 %,退化草地生态系统NEP的0.23 %。植物源VOC释放所损失的碳素相对草地生态系统NPP而言几乎可以忽略不计;但是,相对其NEP,Clost as VOC还是具有一定的相关性。虽然,草地生态系统Clost as VOC对NPP或NEP的贡献率较小,但考虑到全球尺度植物源VOC的巨大释放速率,它在碳循环中的贡献率仍然不容忽视;在某些特殊的生态系统中,仍可能扮演重要角色。
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The effect of counter-ions on the coagulation of biologically treated molasses wastewater using iron-based coagulants was investigated. Parameters such as removals of chemical oxygen demand (COD) and color, and residual turbidity, were measured to evaluate coagulation performance. Experimental results showed that ferric chloride and ferric nitrate were more effective than ferric sulfate at optimal dosages, achieving 89 to 90% and 98 to 99% of COD and color removals, respectively, with residual turbidity of less than 5 NTU. High-performance size exclusion chromatography (HPSEC) results revealed differences in the removal of the molecular weight fraction of organic compounds using iron salts. Scanning electron microscopy (SEM) showed randomly formed coagulated flocs characterized with irregular, sheet-like shapes. Nitrate and chloride counter-ions had similar effects on coagulation performance compared to sulfate. Both FeCl3 and Fe(NO3)(3) yielded better results than Fe(SO4)(2) under underdosed and optimum dosage conditions. Coagulation efficiency was less adversely affected in the overdosed regions, however, if sulfate rather than chloride or nitrate was present. Water Environ. Res., 81, 2293 (2009).
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Coagulation/flocculation process was applied in the polishing treatment of molasses wastewater on a bench-scale. Important operating variables, including coagulant type and dosage, solution pH, rapid mixing conditions as well as the type and dosage of polyeletrolytes were investigated based on the maximum removal efficiencies of chemical oxygen demand (COD) and color, residual turbidity and settling characteristics of flocs. HPSEC was utilized to evaluate the removal of molecular weight fractions of melanoidins-dominated organic compounds. Experimental results indicate that ferric chloride was the most effective among the conventional coagulants, achieving 89% COD and 98% color eliminations; while aluminum sulfate was the least effective, giving COD and color reductions of 66% and 86%, respectively. In addition to metal cations, counter-ions exert significant influence on the coagulation performance since Cl--based metal salts attained better removal efficiency than SO42--based ones at the optimal coagulant dosages. Coagulation of molasses effluent is a highly pH-dependent process, with better removal efficiency achieved at lower pH levels. Rapid mixing intensity, rather than rapid mixing time, has relatively strong influence on the settling characteristics of flocs formed. Lowering mixing intensity resulted in increasing settling rate but the accumulation of floating flocs. When used as coagulant aids, synthetic polyelectrolytes showed little effects on the improvement in organic removal. On the other hand, cationic polyacrylamide was observed to substantially enhance the settleability of flocs as compared to anionic polyacrylamide. The effects of rapid mixing conditions and polymer flocculants on the coagulation performance were discussed. (C) 2009 Elsevier B.V. All rights reserved.
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The hydrolysis behaviors of polyferric sulfate (PFS) and ferric sulfate (FS) under conditions similar to raw wastewater were investigated and the coagulation of biologically pretreated molasses wastewater using PFS and FS was evaluated by studying coagulation efficiency, zeta potential and microscopic surface morphology of flocs. Experimental results show that the hydrolysis behavior of PFS is different from that of FS on the basis of ferron assay. In the case of FS, fast-reacting Fe(III) polymers were the dominant polynuclear species while large fraction of slow-reacting iron polymers is present in PFS. Despite slightly fewer dosages of PFS required as compared to FS, there is no marked difference in the coagulation of molasses effluent between PFS and FS, especially at the optimum dosages. Both coagulants destabilize organic compounds predominantly through charge neutralization-precipitation mechanism. Hydrolysis rate of PFS in synthetic solution is appreciably different from that in raw wastewater. This may due to the effect of sulfate anion introduced as counter-ion as well as depolymerization of larger polymeric Fe(III) species by the organic ligands present in molasses effluent.
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The aim of this study was to examine the effects of chemical nonylphenols (NPs) on the antioxidant system of Microcystis aeruginosa strains. The degradation and sorption of NPs by M. aeruginosa were also evaluated. High concentrations of NPs (1 and 2 mg/l) were found to cause increases in superoxidase dismutase (SOD) and glutathione-S-transferase (GST) activities and in glutathione (GSH) levels. These results suggest that toxic stress manifested by elevated SOD and GST levels and GSH contents may be responsible for the toxicity of NPs to M. aeruginosa and that the algal cells could improve their antioxidant and detoxification ability through the enhancement of enzymatic and nonenzymatic prevention substances. The observed elevations in GSH levels and GST activities were relatively higher than those in SOD activities, indicating that GSH and GST contributed more in eliminating toxic effects than SOD. Low concentrations of NPs (0.05-0.2 mg/l) enhanced cell growth and decreased GST activity in algal cells of M. aeruginosa, suggesting that NPs may have acted as a protecting factor, such as an antioxidant. The larger portion of the NPs (> 60%) disappeared after 12 days of incubation, indicating the strong ability of M. aeruginosa to degrade the moderate persistent NP compounds. The sorption ratio of M. aeruginosa after a 12-day exposure to low nominal concentrations of NPs (0.02-0.5 mg/l) was relatively high (> 30%). The fact that M. aeruginosa effectively resisted the toxic effects of NPs and strongly degraded these pollutants indicate that M. aeruginosa cells have a strong ability to adapt to variations in environmental conditions and that low and moderate concentrations of organic compounds may favor its survival. Further studies are needed to provide detailed information on the fate of persistent organic pollutants and the survival of algae and to determine the possible role of organic pollutants in the occurrence of water blooms in eutrophic lakes.
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Perfluorinated organic compounds (PFOCs) are emerging persistent organic pollutants (POPs) widely present in the environment, wildlife and human. We studied the cellular toxicology of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) on oxidative stress and induction of apoptosis in primary cultured hepatocytes of freshwater tilapia (Oreochromis niloticus). Cultured hepatocytes were exposed to PFOS or PFOA (0, 1, 5, 15 and 30 mg L-1) for 24 h, and a dose-dependent decrease in cell viability was determined using trypan blue exclusion method. Significant induction of reactive oxygen species (ROS) accompanied by increases in activities of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) were found, while activities of glutathione peroxidase (GPx) and glutathione-S-transferase (GST) were decreased. Glutathione (GSH) content was reduced following treatment of PFOA and PFOS. A dose-dependent increase in the lipid peroxidation (LPO) level (measured as maleic dialdehyde, MDA) was observed only in the PFOA exposure groups, whereas LPO remained unchanged in the PFOS exposure groups. Furthermore, a significant activation of caspase-3, -8, -9 activities was evident in both PFOS and PFOA exposure groups. Typical DNA fragmentation (DNA laddering) was further characterized by agarose gel electrophoresis. The overall results demonstrated that PFOS and PFOA are able to produce oxidative stress and induce apoptosis with involvement of caspases in primary cultured tilapia hepatocytes. (c) 2007 Elsevier B.V. All rights reserved.
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Water solubility enhancements of six phthalates (five aliphatic phthalates and one phenyl phthalate) by cetyltrimethylammonium bromide (CTAB) and beta-cyclodextrin (beta-CD) were studied at 25 degreesC. The solubilities of these plithalates are remarkably enhanced by CTAB solutions above the critical micelle concentration (cmc). Only marginal enhancement of phthalate solubility was observed in solutions containing CTAB below its cmc and beta-CD at low concentrations (less than 5 mM). The solubility enhancements of the plithalates are proportional to the added amount of CTAB and beta-CD. Partition coefficients of the plithalates between monomeric CTAB surfactant and water (K-MN) and between CTAB micelle and water K-MC) were estimated from the experimental data. The mechanisms of solubility enhancements by CTAB and beta-CD were discussed. A log-linear equation was proposed and evaluated for the solubilization by CTAB below cmc, while the previously proposed linear partitioning model was questioned. The structures of the complexes formed between plithalates and beta-CD were proposed, and the formation constants were estimated. The values of log K-MC, log K-MN, and log Kbeta-CD of the plithalates were found to correlate linearly with the log K-OW of plithalates, with the exception of the solid phenyl phthalate.
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有机锗化合物具有广谱抗癌活性和低毒副作用,有关它们的合成、生物活性及应用研究引起了医药界和化学界的兴趣。但由于未注重有机基团的相关性,忽略了分子整体对抗癌作用的影响,至今尚未出现临床应用的高效低毒的有机绪抗癌新药,分子结构与抗癌活性关系及抗癌作用机理仍不清楚。因此,继续合成新型且具有结构可比性的有机锗抗癌活性化合物,研究药物与生物大分子DNA的相互作用、揭示有机锗化合物的结构与抗癌作用关系,具有重要的理论意义和应用价值。为此,本论文就以下几个方面开展了研究工作。1、合成了4种有机锗二元杂环化合物一有机锗喳琳醋和有机锗蔡酚醋化合物。根据它们的光谱性质讨论了其结构特征,该类化合物具有与Ge-132类似的空间结构,即具有-Ge-O-Ge-O-聚合网络大环结构。由于保留了有机锗倍半氧化物的基本结构,同时引入了能够与DNA有强烈相互作用的蔡酚和喳琳基团,可能会产生协同效应,使新化合物具有较强的抗癌活性和较好的选择性。2、在保留有机锗倍半氧化物的基本结构的基础上,引入了本身具有抗癌活性和光谱学性质,并且能够与DNA有相互作用的葱、葱醒、菲、荀、荀酮等三环有机基团,合成了16种未见报道的有机锗三元杂环化合物。以葱环为代表的杂环化合物,例如氮杂葱醌及氮杂葱并吡唑类化合物,作为重要的抗癌活性化合物,引起了药学界的极大兴趣。我们合成的新化合物,既保留了有机锗倍半氧化物的基本结构,又引入了葱环类化合物,进而使新化合物具有较强的抗癌活性和选择识别性。3、选择了8个药物小分子,分别应用UV-Vis、热变性(Melting)、荧光光I新型有机锗化合物的合成、抗癌活性及其与DNA的相互作用研究谱变化、粘度测定等方法,研究它们与3种DNA,即小牛胸腺DNA(CT-DNA)和2种人I合成的寡聚核昔酸[22一merspoly(dA·d劝和22一merspoly(dG·dC)]的相互作用。发现与DNA作用后,这些化合物的紫外吸收光谱均发生减色效应和红移现象,它们能使3种DNA的热变性温度(几)升高,粘度增加,说明化合物是以插入方式与DNA结合的。应用荧光滴定方法,求得了新化合物与DNA的结合常数,场在1护一105M一l范围内,属中等强度结合。进一步研究发现它们是以1:2(小分子/碱基对)的计量比与DNA碱基结合的。4、2种有机锗菲醋化合物(G一1、G一2)与DNA结合后,紫外吸收光谱产生减色效应和兰移现象以及荧光淬灭,对DNA的粘度基本无影响,它们是以沟槽结合方式与DNA发生作用的。发现G-1和G-2不仅能够增加三链DNA-Polv(dA·ZdT油的稳定性,并且能够促进Poly(dA.ZdT)22的形成。这一结果说明,某些结构的有机锗化合物可能以这种作用机理发挥抗癌作用,同时可以作为潜在的三链DNA稳定剂。5、研究了部分新合成的有机锗化合物(GK-1,GK-2,GN-1,GN-2,EK-1,EK-2,D-1,D-2,G-,G-2)对PC一3M和K562癌细胞的作用。GK-1,GK-2能够显著抑"制PC一3M细胞的增值,而且对细胞形态也产生了严重影响,显示了明显的细胞毒作用。流式细胞实验结果表明EK类化合物对PC-3M细胞周期有很大影响,发现对细胞增值的抑制作用发生在S期,即细胞内DNA合成期,细胞实验的结果也进一步验证了药物与DNA相互作用的事实。GN-1,GN-2,EK-1,EK-2,D-1,D-2,G-和G一2对K562细胞表现了较强的抑制作用,尤其GN-1和GN-2,效果更为明显,说明分子内有机锗链和其它基团的协向作用增强了整体化合物的生物学作用。6、有机锗二元杂环化合物与DNA的结合常数和体外抗癌活性明显高于有机锗三元杂环化合物,结合强度和抗癌活性之间呈现线形相关性。有机链中甲基的存在不利于有机锗二元杂环化合物与DNA的作用,同时降低了抗癌活性,而同样甲基的存在有利于有机锗三元杂环化合物与DNA的相互作用和抗癌功能的发挥。
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本文主要研究了沈阳市主要绿化树种银杏(Ginkgo biloba)和油松(Pinus tabulaeformis)挥发性有机物(Volatile Organic Compounds,VOCs)排放的日变化、季节变化规律,同时采用开顶箱法研究了高浓度CO2(700 µmol•mol-1)、O3(80 nmol•mol-1)及复合作用下城市主要绿化树种银杏、蒙古栎(Quercus mongolica)、油松、华山松(Pinus armandii)VOCs排放规律,揭示了城市中树木VOCs排放的变化规律及其对高浓度CO2和O3的响应,为研究城市森林对全球变化的响应与反馈提供了科学依据。 本实验建立的热解吸与气相色谱联用方法,最小检测量为4×10-10 g,具有较高的灵敏度和精确度,可满足对树木VOCs分析的要求。研究发现,银杏和油松VOCs的释放具有显著的日变化和季节变化规律,二者夜间均不排放异戊二烯。α-蒎烯为油松释放VOCs的主要成份,同时发现油松排放的α-蒎烯,β-蒎烯,莰烯和柠檬烯之间具有显著相关关系,说明这几种化合物在遗传控制上有某种共同效应或者具有相同的代谢途径。不同树种排放的VOCs组成明显不同,银杏及蒙古栎主要排放异戊二烯,而油松和华山松主要排放单萜;蒙古栎VOCs释放量显著高于其他树种。市区树木VOCs排放速率显著高于郊区,沈阳市主要绿化树种银杏和油松VOCs的年排放量分别为12.16 t和14.48 t。大气CO2和O3浓度升高条件下,树木VOCs释放规律和排放组成,受植物种类和生长季的影响;单独提高大气CO2或O3浓度可显著影响树木VOCs的释放和组成,但是二者复合作用没有显著影响。
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东北土壤有机P库潜力巨大,通过调控磷酸酶活性来提高P的植物有效性是一条可行之路。本文以东北典型黑土和棕壤为供试土壤,从几种公认比较有效的有机化合物中筛选出具有实际可操作性浓度的磷酸酶(磷酸单酯酶,磷酸二酯酶和磷酸三酯酶)激活剂,并确定其最适浓度,研究其对土壤磷酸酶活性调节效果及其动力学特性,结果表明: 1、不同低浓度的还原型谷胱甘肽(GSH)、三磷酸腺苷(ATP)、辅酶I、L-半胱氨酸、生化腐殖酸、碘解磷定(PAM)中,160mg•kg-1 GSH在15天内对黑土三种磷酸酶有较好的激活效果,作为筛选出的激活剂。通过浓度调节试验,进一步确定480mg•kg-1还原型谷胱甘肽对黑土磷酸酶活性在30天内有很好的激活效果。 2、480mg•kg-1的GSH能够提高黑土磷酸单酯酶、二酯酶活性,对三酯酶没有激活效果,而对棕壤只激活三酯酶;同样的处理下,黑土单酯酶和三酯酶,棕壤的二酯酶和三酯酶Vmax值显著大于对照,激活剂处理的棕壤单酯酶及黑土的二酯酶Km值显著小于对照。 3、GSH作用下的黑土和棕壤有效P含量都与对照无显著差异;黑土和棕壤的微生物量P仅在短时间内略高于对照,但不显著;黑土可利用性P含量没有提高,甚至有时显著低于对照;而棕壤则在第5、7天显著高于对照,其它天与对照无显著差异。
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本文采用热解吸与气相色谱联用技术对沈阳市主要绿化树种银中杨(Populus alba × berolinensis)、垂柳(Salix babylonica)、榆树(Ulmus pumila)、皂角(Gleditsia japonica)、丁香(Syringa oblate)和水腊(Ligustrum obtusifolium)植物源挥发性有机物(Biogenic Volatile Organic Compounds,BVOCs)排放的日变化、季节变化规律进行了观测,并估算了这6种树的BVOCs排放通量;同时采用开顶箱法研究了高浓度CO2(700 µmol•mol-1)、O3(80 nmol•mol-1)及二者复合作用下蒙古栎(Quercus mongolica)和油松(Pinus tabulaeformis)BVOCs排放规律。研究结果如下所示: (1) 6种绿化树种BVOCs的释放具有显著的日变化和季节变化规律,且夜间几乎均不排放异戊二烯。 (2) 不同树种排放的BVOCs组成明显不同,银中杨、垂柳和蒙古栎以排放异戊二烯为主;油松主要释放α-蒎烯;榆树、皂角和丁香以释放柠檬烯为主;水腊在不同时段其BVOCs组成情况变化较大,主要释放异戊二烯、柠檬烯和α-蒎烯;其中银中杨和垂柳的BVOCs释放量明显高于其它树种。 (3) 在实测数据基础上,估算出沈阳市6种主要绿化树种银中杨、垂柳、榆树、皂角、丁香和水腊在自然条件下的BVOCs年排放量分别为104.86tC,168.66tC,3.56tC,1.27tC,4.07tC和1.33tC。 (4) 大气CO2和O3浓度升高条件下,树木BVOCs释放规律和排放物组成受植物种类和生长季的影响;单独提高大气CO2或O3浓度可显著影响树木BVOCs的释放,二者的复合作用对BVOCs释放的影响主要介于两者单独作用的结果之间。
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猪场废水COD浓度高、氨氮浓度高、悬浮物浓度高,已成为农村面源污染的主要来源,并严重威胁到农村饮用水安全。猪场废水氨氮浓度高、处理难度大,如何采用经济高效的方法,去除氨氮使其达到排放标准,一直是猪场废水处理中面临的重要难题。 厌氧氨氧化是近年受到国内外水处理研究者广泛关注的新型生物脱氮技术,具有不需要外加有机碳源、节省供氧量、降低能耗等优点。虽然国内外研究者对厌氧氨氧化过程的脱氮机理、厌氧氨氧化菌的生理生化特性等进行了多方面的研究,但已有的报道大多以模拟废水为研究对象,以猪场废水为研究对象的报道,在国内外文献中极少有报导。 本论文以猪场废水为主要研究对象,考察了猪场废水的亚硝化过程、厌氧氨氧化的启动过程,并对亚硝化和厌氧氨氧化联合用于猪场废水脱氮进行了探索。 1.论文首先研究了猪场废水的亚硝化过程,考察了废水水质和主要运行条件对亚硝化过程的影响。实验表明:(1)亚硝化阶段反应时间为8到10h时,出水中氨氮和亚硝酸盐浓度比可达到1:1~1:1.23,满足厌氧氨氧化反应对二者比例的要求;达到前述要求时,氨氮去除率达到58.3~65.6 %,亚硝化率在整个过程均保持在97 %以上,COD去除率在59.2~68.6 %;(2)曝气量(溶解氧)对亚硝化过程影响显著,随着曝气量增大,达到厌氧氨氧化要求的氨氮与亚硝酸盐氮浓度比例所需水力停留时间τ越短,pH出现明显下降的时间越短;(3)τ对应的pH在7.8~8.1之间,无需进行pH调节即可满足厌氧氨氧化反应对pH的要求;(4)氨氮和COD降解过程遵循一级反应动力学,氨氮和COD降解的速率常数分别为0.0656~0.0724 1/h和0.0491~0.0664 1/h。 2.在进行亚硝化过程研究的同时,以模拟废水为试验对象,进行厌氧氨氧化启动研究。以反硝化污泥和养殖厂储水池厌氧底泥的混合污泥作为接种污泥,历时大约100天,培育出具有厌氧氨氧化活性的污泥,氨氮和亚硝酸盐氮最高进水浓度分别为223.8 mg/L和171.4 mg/L,去除率最高分别达48%和41.5%,此时二者消耗比例为1.33:1。 3.在猪场废水的亚硝化研究完成和厌氧氨氧化过程初步启动成功后,在模拟废水中逐步加入猪场废水的亚硝化处理出水,逐步实现亚硝化和厌氧氨氧化的组合。亚硝化出水添加到厌氧反应器后,厌氧氨氧化反应仍可继续进行,且去除效率逐步提高。研究发现添加的亚硝化出水中携带的亚硝化细菌在厌氧氨氧化菌膜外层生长并累积,增加了厌氧氨氧化反应基质的传质阻力,妨碍了厌氧氨氧化效率的提高。 4.亚硝化-厌氧氨氧化实际工程应用探索中,生物接触氧化池可在有效去除废水中的有机物的同时实现亚硝化,出水中氨氮和亚硝酸盐比例平均为1.10,可满足后续厌氧氨氧化的要求;在适宜的进水浓度和温度下,ABR池出现了厌氧氨氧化启动的迹象;研究同时发现,水质的波动和气温的变化是工程中影响厌氧氨氧化菌活性的重要因素。 论文的主要创新点在于:(1)以猪场废水为研究对象,以实现厌氧氨氧化为目标,对亚硝化过程进行了比较详细的考察,获得了亚硝化出水满足厌氧氨氧化要求的工艺条件,通过对其COD和氨氮降解过程的考察,得出亚硝化阶段COD降解和氨氮去除的动力学模型;(2)对亚硝化-厌氧氨氧化处理猪场废水进行了探索,确立了影响其污染物去除率稳定的重要因素。 论文的上述研究成果,为厌氧氨氧化技术的实用性研究提供理论依据。 Piggery wastewater, which is characterized by high concentration of COD、ammonium and suspend substance, has become a most important source of non-point source pollution and also severely threats drinking water security in rural area. How to discharge piggery wastewater with the ammonium concentration meeting standard by economical and effective method? This is the most urgent problem in piggery wastewater treatment. As a new biological nitrogen removal technology, Anammox process has been paid more and more attention by researchers all over the world. Anammox has advantages of no need of organic carbon addition, low oxygen consumption and energy consumption. Plenty of investigations have been carried out to the mechanism, physiological and biochemical characteristic of bacteria about Anammox. Most of researches focused on synthetic wastewater, there is rare report about its application in piggery wastewater. In this paper,experimental studies were performed to investigate Sharon process in treatment of piggery wastewater,the start up process of Annammox using synthetic wastewater were studied, the feasibility of applying Sharon-Anammox process in the nitrogen removal of piggery wastewater was evaluated. 1. Sharon process of piggery wastewater was firstly investigated to analyze the effects of water quality and main running parameters, which meet the NH4+-N to NO2--N ratio requirement of successive Anammox. Results showed: (1)During Sharon Process,after 8~10 hours’ reaction the NH4+-N to NO2--N ratio in effluent reached 1:1.0~1:1.23, when the removal percentage of NH4+-N was 58.3~65.6 %, a semi-nitration rate of above 97 % was achieved during the process; meanwhile 59.2~68.6 % of the COD was also removed. (2)The aeration rate(oxygen) had obvious effect on the hydraulic retention time(τ) which met the NH4+-N to NO2--N ratio requirement of Anammox. As aeration rate increased, the hydraulic retention time(τ) was shortened. (3) The pH corresponding to τ was between 7.8 and 8.1, thus it needed no artificial adjustment. (4) The reduction of ammonia and COD followed the first-order reaction kinetics. The velocity constants of ammonia and COD were 0.0656~0.0724 1/h and 0.0491~0.0664 1/h, respectively. 2. The startup of Anammox process using the artificial wastewater was performed simultaneously with Sharon. The aim was to investigate the running parameters of Anammox and make foundation for the combination stage. By using the mixture of denitrifying sludge and anaerobic sludge in tank of the breeding factory, sludge of Anammox activity was cultivated in UASB after 100 days. The removal percentage of NH4+-N and NO2-N were up to 48% and 41.5%, respectively, when the NH4+-N and NO2-N influent concentration were 223.8 mg/L and 171.4 mg/L, respectively, the NH4+-N and NO2-N removal rate was 1.33:1. 3. After investigation of Sharon and startup of Anammox, effluent of Sharon process was added into the synthetic wastewater to combine Sharon and Anammox step by step. It took some time after the addition of Sharon effluent that Anammox reaction continued and the removal rate kept increasing. It indicated that nitrifying bacteria were carried by the Sharon effluent cumulated in the outer layer of Anammox. This enhanced transfer resistance of Anammox reaction and the increasing removal rate was restrained. 4. In the bio-contact oxidation pond of practical project, Sharon process were carried out successfully and organic compounds were removed effectively. An average NO2-N/ NH4+-N rate of 1:1.0 was achieved in the effluent, which met the requirement of successive Anammox. Under condition of suitable influent concentration and temperature, there was evidence that Anammox could start up in ABR. The variety of wastewater and temperature had great affects on Anammox activity in practical engineering. Innovation of this paper: (1) The Sharon process for treating piggery wastewater was discussed in details. Technological parameters that met requirement of Anammox were obtained. The dynamic models of COD and ammonium removal in the process were educed. (2) Sharon-Ananmmox for treatment of piggery wastewater was investigated, and the primary influencing factors was studied. This paper could be a theoretical consult for research of Anammox utility.
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本文介绍了从厌氧间歇膨胀光合反应器内的活性污泥中分离并鉴定的泥生绿菌(Chlorobium limicola Nadson)S1,它属严格厌氧光能自养型细菌,在有硫化物和少量碳酸氢盐存在下,有广泛利用有机物的能力,它的最适生长温度为28-30℃,最适生长PH为6.5-7.0,且含有氢化酶。因此,它能与甲烷发酵菌共存而共同作用,达到废水净化之目的。通过光照(2#反应器)和黑暗(1#反应器)对比实验,表明了在光照条件下即有泥生绿菌S1存在下,反应系统能更好地降低CODcr、BOD5 和提高CH4 含量,在四个负荷段的运行中,2#反应器在后三个负荷段的甲烷含量能稳定在91.6%而1#反应器为87%,2#反应器的二氧化碳含量为4.5%而1#反应器为8.8%,于28.35g/l.d的负荷下,2#反应器CODcr去除率达83.4%,BOD去除率达74.53%,分别较1#反应器高10.8%,6.4%。COD去除率提高了14%,BOD去除率提高了9.3%。本试验的试验条件为:白天自然光照,晚上电源光照,光照强度为1000-2500lux,通过连续动态运转,并以恒定的流速将废液注入反应器中,进水PH控制在6.5-7.2,反应器厌氧,恒温室温度控制在30±1℃。为使整个试验中同一水质条件下进行,进水采用化学合成培养基。This paper reports a Chlorobium Liwicola S1's isolation and identification. It is a strictly anaerobic and photosynthetic autotrophic bacterium. Along with sulfidedepondent CO2 assiwilaton,a few simple organic compounds can be photoassimilated. Acetate is most effectively used. Its best conditons of growth are 28-30℃,PH 6.5-7.0, and it contains hydrogenase. So it can live with methanefermentative bacteria in order to treat wastewater. At the same time, the treatment of wastwater using Chlorobium Limicola S1 with methane-fermontative bacteria under dark anaerobic and light anaerobic conditions is studied. In contrast with 1# reactor-darken, 2# reactor-illuminated can lossen wastewater's CODcr, BOD5 and on hance CH4 content better. In the test, 2# reactor's CH4 content is stable at 91.6%, but 1# reactor's is 87%. The CO2 content of 2# reactor is 4.5%, but 1# reactor's is 8.8%. When the load of teatment is 28.35g/l.d, the COD removal effficiency is 83.4% and the BOD removal efficiency is 74.53% in 2# reactor. They are separately 10.8%, 6.4% higher than 1# reactor's.