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201.
Gemini1231双季铵盐选择性抑制赤潮生物生长的实验 总被引:3,自引:0,他引:3
以甲藻门的东海原甲藻、塔玛亚历山大藻、裸甲藻,黄藻门的赤潮异弯藻,硅藻门的中肋骨条藻等典型赤潮生物以及绿藻门的青岛大扁藻和亚心形扁藻2种非赤潮生物为研究对象,探讨了Gemini1231双季铵盐类表面活性剂的抑藻活性.结果表明,该表面活性剂在较低浓度下(0.2~0.5 mg·L-1时),对东海原甲藻、塔玛亚历山大藻和赤潮异湾藻等赤潮生物的生长表现出了明显的抑制作用.当该双季铵盐的浓度增至0.5 mg·L-1以上时,对中肋骨条藻的生长也表现出了一定的抑制作用.而在相同浓度范围内,对裸甲藻和所选用的2种非赤潮生物生长的影响不明显,表现出了抑藻作用的选择性.对各海洋微藻的脂肪酸组成分析表明,该表面活性剂的选择性抑藻作用与不同海洋微藻生物膜的脂肪酸组成,尤其是其多不饱和脂肪酸的含量明显相关. 相似文献
202.
羟基氧化铁催化臭氧氧化对滤后水卤乙酸生成势的影响 总被引:2,自引:0,他引:2
考察了滤后水经过单独臭氧氧化和羟基氧化铁(FeOOH)催化臭氧氧化后5种卤乙酸生成势(HAA5FP)的生成情况.研究了氧化时间、溴离子浓度、滤后水pH值、碱度和O3投量对2种氧化方式下HAA5FP的影响规律.发现该滤后水氯化后的HAA种类为二氯乙酸(DCAA)、三氯乙酸(TCAA)及溴离子存在时有二溴乙酸(DBAA).无溴离子存在时,催化臭氧氧化在5~20min内使得HAA5FP比臭氧氧化后的降低9.5%~18.3%.溴离子浓度增加使HAA5FP减少,催化臭氧氧化后HAA5FP也比臭氧氧化后低更多.中性pH时,催化臭氧氧化比臭氧氧化有更明显的控制HAA5FP的优势.重碳酸盐碱度升高使HAA5FP降低,且2种氧化后HAA5FP的差别减小.O3/TOC比值为0.45~1.43的臭氧投量范围内,催化臭氧氧化后HAA5FP比臭氧氧化后减少11.2%~28.0%.催化臭氧氧化对滤后水HAA5FP的影响与FeOOH催化臭氧生成羟基自由基的特点密切相关. 相似文献
203.
应用大鼠全胚胎培养方法探讨偏钒酸铵的致畸作用及其机理 总被引:1,自引:0,他引:1
本文通过NH4VO3体外大鼠全胚胎培养致畸实验研究,发现NH4VO3对大鼠胚胎具有直接胚胎毒性和致畸性,且具有显的剂量一反应和时间一效应关系,其作用机理可能与卵黄囊的功能受到钒化物的损害有关。 相似文献
204.
Paramee S Chidthaisong A Towprayoon S Asnachinda P Bashkin VN Tangtham N 《Environmental monitoring and assessment》2005,102(1-3):27-40
Wet deposition is one of the important sources of nitrogen input into the ecosystem. It also contributes to rain acidity in some environments. In this study we reported the annual as well as seasonal trends of nitrogen wet deposition at three locations in Thailand: Bangkok, Chiang Mai and Nan. Comparison of nitrogen wet deposition between in rural and in the urban areas was also made. Daily rainfall was measured and monthly rainwater was collected for nitrogen analysis during 1999–2002. The average NO3
– concentration in rainwater collected from the rural sites (60 km from urban area) was around 0.2–0.3 mg L–1, while that from the urban areas of Chiang Mai and Nan cities it was 0.4–0.5 mg L–1. NH4
+ concentration in rainwater showed the similar ranges to that of NO3
– , except at Nan where concentration was not significantly different between the urban and rural sites. On the other hand, the average concentrations of NO3
– were higher at Bangkok site than other sites, while concentration of NH4
+ was almost the same between Chiang Mai and Bangkok. Wet deposition of NO3
– at the rural sites of Chiang Mai and Nan ranged from 2.1 to 3.2 kg N ha–1 yr–1, while at the urban sites this ranged from about 6 kg N ha–1 yr–1 in Chiang Mai and Nan Cities to 8.6 kg N ha–1 yr–1 in Bangkok. Wet deposition of NH4
+ at the rural sites of Chiang Mai and Nan was about 2.4 to 3.6 kg N ha–1 yr–1 and at the urban sites of Chiang Mai, Nan and Bangkok this was 7.7, 4.9 and 8.1 kg N ha–1 yr–1, respectively. Thus, it was concluded that wet deposition of both nitrogen species was significantly higher at the urban sites than at the rural sites. 相似文献
205.
Sutton MA Asman WA Ellermann T Van Jaarsveld JA Acker K Aneja V Duyzer J Horvath L Paramonov S Mitosinkova M Tang YS Achermann B Gauger T Bartniki J Neftel A Erisman JW 《Environmental monitoring and assessment》2003,82(2):149-185
In the context of international efforts to reduce the impactsof atmospheric NH3 and NH4
+ (collectively, NHx), it is important to establish the link between NH3emissions and monitoring of NHx concentrations and deposition. This is equally relevant to situations where NH3emissions changes are certain (e.g. due to changed source sectoractivity), as to cases where NH3 abatement technologies havebeen implemented. Correct interpretation of adequate atmosphericmeasurements is essential, since monitoring data provide the onlymeans to evaluate trends in regional NH3 emissions.These issues have been reviewed using available measurements and modelling from nine countries. In addition to historic datasets,the analysis here considers countries where NH3 source sector activity changed (both increases and decreases) and countries where NH3 abatement policies have been implemented.In The Netherlands an `ammonia gap' was identified between the expected reduction and results of monitoring, and was attributedinitially to ineffectiveness of the abatement measures. The analysis here for a range of countries shows that atmospheric interactions complicate the expected changes, particularly sinceSO2 emissions have decreased at the same time, while at manysites the few years of available data show substantial inter-annual variation. It is concluded that networks need to beestablished that speciate between NH3 and aerosol NH4
+, in addition to providing wet deposition, and sample at sufficient sites for robust regional estimates to be established. Such measurements will be essential to monitor compliance of the international agreements on NH3 emission abatement. 相似文献
206.
207.
An equilibrator for sampling the partial pressures of halomethanes in seawater was designed and built, incorporating semipermeable membrane tubing to carry the gas phase. The equilibrator was tested for its ability to equilibrate chloromethane, bromomethane, iodomethane, and CFC-11. The residence time required for these halomethanes to equilibrate in the tubing (30 to 60 s) was determined experimentally. In a laboratory test, concentrations calculated from equilibrator measurements and based on published solubility values were found to differ by 6% to 16% from concentrations measured with a purge-and-trap apparatus, but uncertainties in the solubility values are likely to contribute significantly to the differences. In a comparison at sea, no significant difference was found between the semipermeable membrane equilibrator and another, more conventional equilibrator, except a 1.3% difference for CFC-11. This study demonstrates the feasibility of using semipermeable membranes in this and related applications. 相似文献
208.
MAP法沉淀回收装置的运行条件优化研究 总被引:2,自引:1,他引:1
采用一种简易的MAP回收装置,研究了间歇运行条件下反应时间和曝气量对MAP法除磷效果的影响,确定出最佳反应时间为90 min,最佳曝气量为1.2 L/min,相应的除磷率可达98.26%,沉淀回收率为74.54%。当增加一个漏斗形隔板分离反应区和沉淀区并连续运行时,除磷率和沉淀回收率分别为92.11%和63.66%。当不投加镁盐和铵盐而仅调控实际污泥脱水滤液的pH值为9.8时,其连续运行的平均除磷率和MAP回收率分别可达95.16%和70%,运行性能比较稳定。 相似文献
209.
210.
以聚乙烯醇与海藻酸钠为载体,包埋固定氨氧化细菌(AOB),研究温度、DO、初始游离氨(FA)、有机物等影响因素对其短程硝化稳定性的影响。结果表明,25~30℃时载体中氨氧化细菌占优势;DO宜控制在4.0~5.5 mg/L之间,既能满足细菌生长所需,又不至过度曝气,造成载体间的摩擦增大,减少其使用寿命;载体耐氨氮负荷能力强,同时可以抵御有机物对氨氧化细菌的伤害;当初始FA>6.5 mg/L时,氨氧化细菌的活性将受到抑制;富集氨氧化细菌的污泥包埋后氨氮去除率降低了7.5%;包埋载体在确保短程硝化作用的同时,在内部形成的缺氧区可实现反硝化脱氮,提高了系统氨氮的处理能力。 相似文献