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541.
Yongsheng Zhang Lilin Zhao Ruitao Guo Na Song Jiawei Wang Yan Cao William Orndorff Wei-ping Pan 《环境科学学报(英文版)》2015,27(7):156-162
In this study, the mercury adsorption characteristics of HBr-modified fly ash in an entrained-flow reactor were investigated through thermal decomposition methods. The results show that the mercury adsorption performance of the HBr-modified fly ash was enhanced significantly. The mercury species adsorbed by unmodified fly ash were HgCl2, HgS and HgO. The mercury adsorbed by HBr-modified fly ash, in the entrained-flow reactor, existed in two forms, HgBr2 and HgO, and the HBr was the dominant factor promoting oxidation of elemental mercury in the entrained-flow reactor. In the current study, the concentration of HgBr2 and HgO in ash from the fine ash vessel was 4.6 times greater than for ash from the coarse ash vessel. The fine ash had better mercury adsorption performance than coarse ash, which is most likely due to the higher specific surface area and longer residence time. 相似文献
542.
Min Song Chenchen Chi Min Guo Xueqing Wang Lingxiao Cheng Xueyou Shen 《环境科学学报(英文版)》2015,28(2):157-162
The pollution status and characteristics of PAEs(phthalate esters) were investigated in indoor air of offices, and PAEs of both gas-phase and particulate-phase were detected in all the samples. The concentration(sum of the gas phase and the particulate phase) was4748.24 ng/m3, ranging between 3070.09 and 6700.14 ng/m3. Diethyl phthalate, dibutyl phthalate, and di(2-ethylhexyl) phthalate were the most abundant compounds, together accounting for 70% of the ∑ 6PAEs. Dividing the particulate-phase PAEs into four size ranges( 2.5, 2.5–5, 5–10, 10 μm), the result indicated that PAEs in PM2.5were the most abundant,with the proportion of 72.64%. In addition, the PAE concentration in PM2.5correlated significantly with the total particulate-phase PAEs(R2= 0.85). Thus, the amount of PAEs in PM2.5can be estimated from the total amount of particulate-phase PAEs using this proportion. In a comparison between the offices and a newly decorated study room, it was found that pollution characteristics were similar between these two places. Thus, it is implied that the PAE concentration decreased by 50% 2 yr after decorating. 相似文献
543.
The aim of the study was to prepare a porous sound-absorbing material using steel slag and fly ash as the main raw material, with coal powder and sodium silicate used as a pore former and binder respectively. The influence of the experimental conditions such as the ratio of fly ash, sintering temperature, sintering time, and porosity regulation on the performance of the porous sound-absorbing material was investigated. The results showed that the specimens prepared by this method had high sound absorption performance and good mechanical properties, and the noise reduction coefficient and compressive strength could reach 0.50 and 6.5 MPa, respectively. The compressive strength increased when the dosage of fly ash and sintering temperature were raised. The noise reduction coefficient decreased with increasing ratio of fly ash and reducing pore former, and first increased and then decreased with the increase of sintering temperature and time. The optimum preparation conditions for the porous sound-absorbing material were a proportion of fly ash of 50% (wt.%), percentage of coal powder of 30% (wt.%), sintering temperature of 1130°C, and sintering time of 6.0 hr, which were determined by analyzing the properties of the sound-absorbing material. 相似文献
544.
The concentrations of phthalate esters(PAEs) in Chinese hospitals were investigated by simultaneously determining concentrations of gas- and particle-phase PAEs. PAEs were detected in two third-class first-grade hospitals, two second-class first-grade hospitals, and a community health service center. Hospital drugstores had the highest concentration(24.19 μg/m3), which was 1.54 times that of newly decorated houses. The second highest concentration was found in the transfusion rooms, averaging 21.89 μg/m3; this was followed by the concentrations of PAEs in the nurse's workstations, the wards, and the doctor's offices, with mean concentrations of 20.66, 20.0, and 16.92 μg/m3, respectively. The lowest concentrations were found in the hallways(16.30 μg/m3). Of the six different kinds of PAEs found, major pollutants included diethyl phthalates, dibutyl phthalates, butylbenzyl phthalates and di(2-ethylhexyl) phthalates, comprising more than 80% of all PAEs present.Meanwhile, a comparison between different wards showed that PAE concentrations in the maternity wards were 1.63 times higher than in the main wards. Based on known health hazards, our results suggest that the PAEs seriously influence the health of the pregnant women and babies; therefore, it is of great importance to take the phthalate concentrations in hospitals into consideration. In addition, hospital indoor air was more seriously contaminated than the air of newly decorated houses. 相似文献
545.
546.
能源利用、环境保护与可持续发展问题的研究已成为一个重要课题。本文讨论了以高能耗为特征的北京市工业可持续发展问题,选取北京市可持续发展实验区的怀柔区和石景山区作为主要研究对象,针对实验区工业领域典型企业进行广泛调研,分析了高能耗工业企业能源利用情况及其特点。研究结果表明,怀柔和石景山可持续发展实验区均呈现能源消费高度集中的主要特征。此外,对代表性企业实施的余热回收和水资源循环利用等节能改造方案进行深入研究,并进行技术经济分析。继续深入挖掘潜力,为"十二五"期间可持续发展实验区工业节能工作的深化和细化奠定基础。 相似文献
547.
548.
549.
目的:对职业卫生评价工作中石化企业外操岗位噪声40 h等效声级计算方法进行探讨.方法:通过对现行标准中每周40 h等效声级计算方法进行简化,得到简化的40 h等效声级公式.结果:与现行标准中每周40 h等效声级计算方法相比,简化的40 h等效声级计算方法得出的结果与之完全一致.结论:简化的40 h等效声级公式计算更为简单,提高了评价人员的工作效率. 相似文献
550.
通过定位监测和样品跟踪采集,在旱季对喀斯特小流域连续20天无前期降雨的一场暴雨(累计降雨量64mm)水文水化学过程进行了动态监测,并分析了相关的影响因素。结果表明,小降雨事件(8.5mm)未能引起溪流水位、电导率及温度的明显变化,而当累计降雨量达到35.5mm后溪流水开始响应。此后,溪流水文水化学参数对降雨快速响应,除硝态氮外,电导率(EC)、δ18 O、Ca2+迅速降至最低值,雨水稀释作用对其水化学变化起主要作用。通过对溪流新旧水比例进行划分发现,降雨前期和后期,溪流以旧水补给为主,而在水位快速上涨阶段,新水比例达到34%左右。两次降雨过程中,在溪流水水位升高的情况下,水体中硝态氮浓度仍然表现出高于雨前浓度的趋势。该研究为该区旱季小流域水资源利用和污染物防治方面提供了一定理论依据。 相似文献