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排序方式: 共有893条查询结果,搜索用时 62 毫秒
741.
Haiyan Chen Yiqun Zhang Bo Gao Yang Xu Qi Zhao Juan Hou Jin Yan Guijie Li Hui Wang Lan Ding Jie Ding Chun Zhao 《Environmental science and pollution research international》2013,20(12):8567-8578
Group-selective magnetic molecularly imprinted polymers (MMIPs) that can extract four widely used sulfonamide antibiotics and their acetylated metabolites from environmental water were synthesized in this study. The MMIPs with saturation magnetization value of 16.7 emu g-1 could be separated from the environmental water samples easily by the application of an adscititious magnetic field, reducing the time consumption of pretreatment. The extraction conditions were evaluated, and optimal extraction conditions were as follows: extraction time, 25 min; amount of polymers, 90 mg; washing solvent, 30 % methanol aqueous solution; and elution solvent, methanol–acetic acid (95:5, v/v). The target analytes were detected by liquid chromatography–tandem mass spectrometry, and the detection limits of the method are in the range of 0.38–1.32 ng L-1. The relative standard deviations of intra- and inter-day are in the range of 1.3–6.8 % and 1.7–9.1 %, respectively. The proposed method is suitable for the analysis of environmental water samples. 相似文献
742.
743.
In this paper, elimination of two types of organophosphorus pesticides (OPPs), chlorpyrifos and diazinon spiked in aqueous solution by ultrasonic irradiation was investigated. Results showed that chlorpyrifos and diazinon could be effectively and rapidly degraded by ultrasonic irradiation, and the degradation of both pesticides was strongly influenced by ultrasonic power, temperature and pH value. Furthermore, two and seven products for the degradation of chlorpyrifos and diazinon formed during ultrasonic irradiation have been identified by gas chromatography-mass spectrometry, respectively. The hydrolysis, oxidation, hydroxylation, dehydration and decarboxylation were deduced to contribute to the degradation reaction and the degradation pathway for each pesticide under ultrasonic irradiation was proposed. Finally, the toxicity evaluation indicated that the toxicity decreased for diazinon solution after ultrasonic irradiation, but it increased for chlorpyrifos solution. The detoxification of OPPs by ultrasonic irradiation was discriminative. 相似文献
744.
研究了皂土对CuSO_4的吸附性能,考察了溶液初始pH、无机电解质NaCl、MgCl_2和AlCl_3及乙二胺四乙酸(EDTA)和柠檬酸等因素对皂土吸附量的影响。实验结果表明:皂土对CuSO_4有很强的吸附能力;其吸附动力学曲线和吸附等温线分别符合准二级反应速率方程和Langmuir方程;饱和吸附量达29.85 mg/g;随溶液初始pH增大,吸附量增大;无机电解质NaCl、MgCl_2和AlCl_3以及EDTA和柠檬酸均可以抑制CuSO_4在皂土上的吸附。 相似文献
745.
含苯酚危险废物的改进型Fenton氧化处理研究 总被引:3,自引:1,他引:2
建立以EDTA钠铁作为催化剂的改进型Fenton氧化体系,研究改进型Fenton氧化处理含高浓度苯酚危险废物的影响因素、处理效果和控制参数。研究结果表明,针对含苯酚污染土壤的自配样,当EDTA钠铁投加量为2μmol/g,15%H2O2投加量为0.1 mL/g,体系含水率为33%左右,反应时间60 min时,苯酚(含量为2 mg/g)的氧化降解率可达90%以上,反应后的体系pH约为5.7,便于直接进行固化稳定化等后续处理。该处理过程较传统型Fenton体系温和、安全,且适用于中性pH的体系,可应用于高苯酚含量且以固相无机质为主体的危险废物的快速应急处理。 相似文献
746.
Zheng Fang Chen Tian Hou Ying Wang Nai'ang 《中国人口.资源与环境(英文版)》2010,8(1):88-96
This study explained the importance of environmental protection in tourism development and illustrated the relationship between recreational resource valuation and environmental consideration. We compare different models of travel cost method and reiterates long-time existing problems of multi-destination and treats of time opportunity cost (TOC). Taking Jiayuguan's cultural sights as an example, we establish an updated method called multi-destination zonal tourism cost method to evaluate the recreational values (RVs) of selected three cultural sights. We divide trip packages of Jiayuguan's tourists into 11 portfolios. Each portfolio can be seen as a separate commodity, and each commodity has its own demand curve. According to demand curves we can calculate consumer surplus (CS) of different portfolios of tourist destinations and later we sum up the total travel costs (including travel expenditure and TOC) and CS to come to the RVs of each portfolio. We then apply suitable proportions to calculate the RVs between different destinations in the portfolio. In the end, we add up all the RVs calculated for the objective destination. Using this method, we draw conclusions that Jiayuguan's RV in 2006 includes national and international values, summing up to 738.4762 million yuan. The tourist expenditure, CS and TOC of Jiayuguan is proportionating 62.96, 32.28 and 4.76%, respectively. This study is also an example of non-market valuation of cultural tourism resources. 相似文献
747.
油田含油污泥热解制备烟气脱硫剂 总被引:1,自引:0,他引:1
为实现油田含油污泥深度资源化,针对高含油的孤岛采油厂含油污泥采用热解处理,回收油气资源的同时将热解残渣制备成烟气脱硫剂。以苯吸附值和热解残渣含油率为基准对热解工艺进行了优化,对热解油品和残渣进行分析,热解残渣经过后续处理进行了烟气脱硫性能评价。通过正交实验得到热解最佳工艺条件为:氮气保护下,热解温度550℃,热解时间4h,升温速率10℃/min。此时苯吸附值为60.12mg/g,热解残渣含油率为0.29%。最佳工艺条件下,热解油品产率可达10%左右,回收率大于65%,热裂解作用明显,热解油品的品质较好,产生的不凝气体可以作为洁净燃料气;热解残渣经过后续处理,可用于脱除烟气中的SO2,吸附脱硫能力较好,穿透硫容达到3%以上。 相似文献
748.
Formation and removal of PCDD/Fs in a municipal waste incinerator during different operating periods
The PCDD/F concentrations and removal efficiencies achieved with air pollution control devices (APCDs) during different operating periods (start-up, normal operation, and shut-down) at an existing municipal waste incinerator (MWI) in Taiwan are evaluated via stack sampling and analysis. The MWI investigated is equipped with electrostatic precipitators (EP), wet scrubbers (WS), and selective catalytic reduction system (SCR) as APCDs. The sampling results indicate that the PCDD/F concentrations at the EP inlet during start-up period were 15 times higher than that measured during normal operation period. The PCDD/F concentration observed at shut-down period was close to that measured at normal operation period. The CO concentration was between 400 and 1000 ppm during start-up period, which was about 50 times higher compared with the normal operation. Hence, combustion condition significantly affected the PCDD/F formation concentration during the waste incineration process. In addition, the distributions of the PCDD/F congeners were similar at different operating periods. During the normal operation and shut-down periods, the EP decreases the PCDD/F concentration (based on TEQ) by 18.4-48.6%, while the removal efficiency of PCDD/Fs achieved with SCR system reaches 99.3-99.6%. Nevertheless, the PCDD/F removal efficiency achieved with SCR was only 42% during the 19-h start-up period due to the low SCR operating temperature (195 degrees C). 相似文献
749.
750.
几种金属氧化物TPS性能比较 总被引:4,自引:2,他引:2
通过程度升温硫化研究了CuO,Fe2O3,SnO2,MnO2,CaO及ZnO等金属氧化物的脱硫性能,对各种金属氧化物的TPS曲线进行比较发现,其硫化温度及速度都不相同,氧化锰的硫化温度最低,从345K开始有较强的硫化氢吸收峰出现;氧化铜的硫化在373K左右进行;对氧化铁和氧化锌,硫化从473K开始,而氧化锡的硫化在650K左右发生;氧化钙的硫化发生在735K。粒度对TPS曲线有较明显的影响,粒度减 相似文献