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241.
242.
以TiO2-P25及FeC2O4为前驱物制备了Fe3 掺杂TiO2光催化剂--Fe/TiO2.X射线衍射结果表明,500 ℃煅烧温度下的Fe/TiO2主要是锐态矿晶型,当掺Fe3 量为0.5%(质量分数,下同)时,Fe3 以取代掺杂形式进入TiO2晶格,而当掺Fe3 量达5.0%时,则出现α-Fe2O3的特征衍射峰;900 ℃煅烧温度下的Fe/TiO2则均为金红石晶型,掺Fe3 量达2.0%~5.0%时,出现Fe2TiO5的特征衍射峰.4-氯苯酚的光催化实验结果表明,煅烧温度及Fe3 掺杂量对Fe/TiO2的光催化活性有显著影响,以煅烧温度500 ℃及掺Fe3 量0.5%的Fe/TiO2为光催化剂,反应80 min,4-氯苯酚的降解率达100%,总有机碳去除率约95%. 相似文献
243.
The study of operating variables in soil washing with EDTA 总被引:7,自引:0,他引:7
Zou Z Qiu R Zhang W Dong H Zhao Z Zhang T Wei X Cai X 《Environmental pollution (Barking, Essex : 1987)》2009,157(1):229-236
This study discusses the operating variables for removal of metals from soils using EDTA, including the type of EDTA, reaction time, solution pH, dose, temperature, agitation, ultrasound and number of extractions. For As, Cd, Cu, Pb and Zn, the removal efficiency order was: H4-EDTA > Na2EDTA > (NH4)2EDTA. At low EDTA concentrations the removal increased progressively with increasing dose while above 0.4 mmol/g only small increases in extraction efficiency were observed. EDTA induced a two-step process including a rapid desorption within the first hour, and a gradual release in the following hours. The extraction efficiency of metals decreased with increasing pH in the range of 2-10. Consecutive extractions using low concentrations were more effective than a single extraction with concentrated EDTA if the same dose of EDTA was used. 相似文献
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246.
不同状态下的同一污泥胞外聚合物提取方法研究 总被引:8,自引:2,他引:6
以由厌氧污泥向好氧污泥转变前后2种不同状态下的污泥为研究对象,采用5种不同方法对污泥胞外聚合物(EPS)进行了提取实验。实验结果表明,NaOH法提取的EPS含量最高,但会导致胞内物质泄漏。CER和离心提取法较温和,但EPS产量不高。甲醛-NaOH和H2SO4法提取的EPS含量较高,且无大量细胞自溶发生,是有效的EPS提取方法。厌氧污泥转变为好氧污泥后蛋白质/多糖(PN/PS)比例有所增加,表明EPS各组分含量发生改变。红外分析表明厌氧污泥转变为好氧污泥前后EPS中主要组成成分没有发生改变,但各成分含量有所增加,特征明显的峰表明EPS中存在蛋白质、多聚糖。 相似文献
247.
MBR—NF处理印染废水 总被引:2,自引:2,他引:0
采用MBR—纳滤(MBR—NF)组合工艺处理印染废水。运行结果表明:MBR出水的COD、ρ(NH3-N)和TN分别为94,0.93,8.88mg/L,COD、NH3-N和TN的平均去除率分别为87%、95.8%和70.2%,出水水质满足GB4287—92《纺织染整工业水污染物排放标准》中的一级标准;再经NF处理后出水COD、色度、ρ(总Fe)、ρ(总Mn)和pH分别为11~30mg/L、2.3~7.4倍、0.065~0.095mg/L、0mg/L和8.06~8.21,水质可满足印染工艺回用要求。 相似文献
248.
火电厂烟气在线监测系统存在的主要问题及进一步加强在线监测工作的建议 总被引:1,自引:0,他引:1
火电厂燃煤过程排放的污染物是我国大气污染的主要来源之一,烟气排放连续监测系统(CEMS)是实现烟气排放连续监测有效的现代化仪器设备。介绍了目前我国火电厂烟气的CEMS主要存在的问题,并针对这些存在的问题提出了相应的解决方案。 相似文献
249.
Quantifying the Effect of Ecological Restoration on Soil Erosion in China’s Loess Plateau Region: An Application of the MMF Approach 总被引:5,自引:0,他引:5
Changbin Li Jiaguo Qi Zhaodong Feng Runsheng Yin Biyun Guo Feng Zhang Songbing Zou 《Environmental management》2010,45(3):476-487
Land degradation due to erosion is one of the most serious environmental problems in China. To reduce land degradation, the
government has taken a number of conservation and restoration measures, including the Sloping Land Conversion Program (SLCP),
which was launched in 1999. A logical question is whether these measures have reduced soil erosion at the regional level.
The objective of this article is to answer this question by assessing soil erosion dynamics in the Zuli River basin in the
Loess Plateau of China from 1999 to 2006. The MMF (Morgan, Morgan and Finney) model was used to simulate changes in runoff
and soil erosion over the period of time during which ecological restoration projects were implemented. Some model variables
were derived from remotely sensed images to provide improved land surface representation. With an overall accuracy rate of
0.67, our simulations show that increased ground vegetation cover, especially in forestlands and grasslands, has reduced soil
erosion by 38.8% on average from 1999 to 2006. During the same time period, however, the change in rainfall pattern has caused
a 13.1% ± 4.3% increase in soil erosion, resulting in a net 25.7% ± 8.5% reduction in soil erosion. This suggests that China’s
various ecological restoration efforts have been effective in reducing soil loss. 相似文献
250.
Ozonation of azo dye Acid Red 14 in a microporous tube-in-tube microchannel reactor: decolorization and mechanism 总被引:1,自引:0,他引:1
Despite the great success of time-weighted average passive sampling of hydrophobic contaminants, such as PCBs and PAHs, the sampling of polar organic compounds still presents a challenge because the equilibrium between water and most sampling phases is attained in a relatively short time. In this study, we proposed a new time-integrative sampler using in situ solvent extraction (TISIS) for polar organic chemicals. The sampler was composed of a 15 cm poly(dimethylsiloxane) (PDMS) tubing, with an internal diameter of 0.5 mm and wall thickness of 0.5 mm, through which an extraction solvent (acetonitrile) was passed. Four polar organic contaminants, caffeine, atrazine, diuron and 17α-ethynylestradiol, were chosen for the evaluation of the performance of the sampler. Without the use of in situ solvent extraction, the PDMS tubing when exposed to a constant aqueous concentration of the four model compounds was able to linearly accumulate those compounds for less than 12 h and equilibrium between the PDMS tubing and water was attained in 2 d under our laboratory conditions. However, TISIS when exposed to a constant aqueous concentration was able to linearly accumulate all the model compounds without any exposure time limitation. The measured sampling rates at three different extraction flow rates (0.2, 0.5, 1.5 mL min−1) were similar, regardless of the chemicals, indicating that the overall mass transfer from aqueous solution to the extraction solvent was most likely dominated by partitioning to the PDMS tubing and the internal diffusion within PDMS. In addition, a pulsed exposure experiment confirmed that TISIS operated in a time-integrative mode when the environmental concentration was highly fluctuated. 相似文献