排序方式: 共有39条查询结果,搜索用时 0 毫秒
31.
以电子元器件脱落为反应终点,研究了摩尔浓度分别为1.11、1.60、2.19、2.73、3.30、4.55 mol/L的硝酸浸提液中废印制电路板上Cu、Sn、Pb、Fe等金属的溶出规律。结果表明:(1)电子元器件脱落时间随硝酸浓度增大而缩短。(2)当硝酸摩尔浓度小于2.73 mol/L时,废印制电路板中Cu几乎不溶出。(3)废印制电路板中Sn和Pb总体随硝酸浓度增大溶出速率加快,反应初期溶出速率都较快,反应后期溶出速率变慢。(4)当硝酸摩尔浓度大于2.73 mol/L时,反应起始Fe迅速溶出达到一个较稳定的值,随着Sn和Pb的耗尽又一次迅速溶出,后一个迅速溶出规律与Cu一致。(5)在硝酸各浓度下,Sn、Pb溶出率一直高于80%且保持很好的一致性。Ni溶出率随着硝酸浓度的增大总体呈直线升高趋势,最终达到95%以上。当硝酸摩尔浓度小于3.30 mol/L时,Cu、Fe、Zn溶出率均为2%~3%;当硝酸摩尔浓度大于3.30 mol/L时,Cu、Fe、Zn溶出率最终分别约为50%、80%和93%。 相似文献
32.
本文综述了近年来国内外大量文献,对有关水体和大气中汞的存在形态、特性及水/气间汞交换通量的影响因素进行了总结,描述了目前国内外相关领域的研究现状,并对该领域下一步的研究方向进行了探讨. 相似文献
33.
利用2006-2010年上海市青浦区PM10和同期地面气象要素的监测资料,定量分析PM10的季节变化规律以及PM10与降雨量、大气湿度和风速之间的关系。分析结果表明:PM10浓度在夏季处于低值,冬季处于高值;5mm/d以上的降雨对PM10有显著的清除作用,且春夏季降雨的清除作用大于秋冬季节。PM10浓度与大气湿度基本呈负相关关系。风速在一定范围内有利于PM10的扩散但不至造成扬尘,春夏季节的适宜风速是1.5~3.5m/s,冬季的适宜风速是1.5~2.5m/s。 相似文献
34.
35.
采用自制厌氧反应器进行不同基质与苯胺黑药的共代谢特性研究。结果表明,经过72 d的驯化,反应器启动完成。在不同基质种类和比例条件下,蔗糖、乙酸钠、葡萄糖、淀粉和维生素C对苯胺黑药的厌氧降解有促进作用。当乙酸钠与苯胺黑药的质量比为2∶1 时降解效率最高,出水苯胺黑药浓度23.21 mg·L-1,降解率82.00%,出水COD为35.6 mg·L-1,去除率92.90%。对外加基质与苯胺黑药质量比为2∶1时的实验数据进行动力学分析,发现无外加基质组和共代谢基质为葡萄糖、蔗糖、淀粉和乙酸钠时,苯胺黑药的降解过程均符合一级动力学规律,而维生素C并不符合。反应速率常数的顺序为乙酸钠 > 淀粉 > 葡萄糖 > 蔗糖 > 空白。 相似文献
36.
Total mercury in wild fish in Guizhou reservoirs, China 总被引:2,自引:0,他引:2
Haiyu Yan Atle Rustadbakken Heng Yao Thorjorn Larssen Xinbin Feng Ting Liu Lihai Shang Thrond O. Haugen 《环境科学学报(英文版)》2010,22(8):1129-1136
The health hazard of mercury (Hg) compounds is internationally recognized, and the main pathways for methylmercury (MeHg) intake in humans are through consumption of food, especially fish. Given the large releases of Hg to the environment in China, combined with the fast development of hydropower, this issue deserves attention. Provided similar mobilization pathways of Hg in China as seen in reservoirs in North America and Europe one should expect increased Hg contamination in relation to future hydropower reservoir construction in this country. This study presents total Hg (THg) concentrations in wild fish from six Guizhou reservoirs, China. The THg concentrations in fish were generally low despite high background levels in the bedrock and depositions from local point sources. The over all mean ± SD concentration of THg was (0.066 ± 0.078) μg/g (n = 235). After adjusting for among-reservoir variation in THg, there were significant differences in THg among functional groups of the fish, assumed to re?ect trophic levels. Predicted THg- concentration ratios, retrieved from a mixed linear model, between the functional groups were 9:4:4:1 for carnivorous, omnivorous, planktivorous and herbivorous fish. This result indicated that MeHg accumulation may prevail even under circumstances with short food chains as in this Chinese water system. No fish exceeded recommended maximum THg limit for human consumption set by World Health Organization and the Standardization Administration of China (0.5 μg/g fish wet weight (ww)). Only six fish (2.5%) exceeded the maximum THg limit set by US Environmental Protection Agency (0.3 μg/g fish ww). 相似文献
37.
Methylmercury and sulfate-reducing bacteria in mangrove sediments from
Jiulong River Estuary, China 总被引:2,自引:0,他引:2
Hao Wu Zhenhua Ding Yang Liu Jinling Liu Haiyu Yan Jiayong Pan Liuqiang Li Huina Lin Guanghui Lin Haoliang Lu 《环境科学学报(英文版)》2011,23(1):14-21
Estuaries are important sites for mercury (Hg) methylation, with sulfate-reducing bacteria (SRB) thought to be the main Hg
methylators. Distributions of total mercury (THg) and methylmercury (MeHg) in mangrove sediment and sediment core from Jiulong
River Estuary Provincial Mangrove Reserve, China were determined and the possible mechanisms of Hg methylation and their
controlling factors in mangrove sediments were investigated. Microbiological and geochemical parameters were also determined.
Results showed that SRB constitute a small fraction of total bacteria (TB) in both surface sediments and the profile of sediments. The
content of THg, MeHg, TB, and SRB were (350 150) ng/g, (0.47 0.11) ng/g, (1.4 1011 4.1 109) cfu/g dry weight (dw), and (5.0
106 2.7 106) cfu/g dw in surficial sediments, respectively, and (240 24) ng/g, (0.30 0.15) ng/g, (1.9 1011 4.2 1010) cfu/g
dw, and (1.3 106 2.0 106) cfu/g dw in sediment core, respectively. Results showed that THg, MeHg, TB, MeHg/THg, salinity
and total sulfur (TS) increased with depth, but total organic matter (TOM), SRB, and pH decreased with depth. Concentrations of
MeHg in sediments showed significant positive correlation with THg, salinity, TS, and MeHg/THg, and significant negative correlation
with SRB, TOM, and pH. It was concluded that other microbes, rather than SRB, may also act as main Hg methylators in mangrove
sediments. 相似文献
38.
利用2006年-2010年上海市青浦区PM10和同期地面气象要素的监测资料,定量分析PM10的季节变化规律以及PM10与降雨量、大气湿度和风速之间的关系。分析结果表明:PM10浓度在夏季处于低值,冬季处于高值;5 mm/d以上的降雨对PM10有显著的清除作用,且春夏季降雨的清除作用大于秋冬季节。PM10浓度与大气湿度基本呈负相关关系。风速在一定范围内有利于PM10的扩散但不至造成扬尘,春季的适宜风速是1.5~3.5m/s,冬季的适宜风速是1.5~2.5 m/s。 相似文献
39.