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471.
南京市城市污泥和工业污泥中典型矿质元素含量和形态分布研究 总被引:1,自引:0,他引:1
采用三态连续提取法研究南京市部分城市污泥和工业污泥中典型矿质元素的含量和形态分布,为污泥资源化的合理利用提供科学参考.结果表明,污泥总体呈高有机质、高氮磷、低K的相似性,但其理化性质如阳离子交换容量(CEC)、pH等有差异.污泥中不同矿质元素含量差异也较大,Fe的浓度最高,其次是Mg、Zn;且不同污泥间同一矿质元素含量的差异也较大.各元素的形态分布有一定差异,Cu主要分布在可氧化态,其酸溶/交换态和可还原态的百分率很低;Zn三态分布均较高;Mg、Mn主要分布在酸溶/交换态;Fe主要分布在残渣态.但三种提取形态百分率之和除Fe外均超过50%.研究同时表明,城市污泥和工业污泥中矿质元素形态分布无显著性差异. 相似文献
472.
473.
Microscale analytical methods for the quantitative detection of PCBs and PAHs in small tissue masses 总被引:1,自引:0,他引:1
Microscale methods (MM) were evaluated and compared to traditional methods (TM) for measuring polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in spiked and standard reference fish and mussel tissues. MMs are advantageous because they use small tissue masses (ca. 100 mg), and maintain sensitivity through reducing final extract volume (traditionally 1 ml) by an order of magnitude or more (40 μl—PCBs; 100 μl—PAHs). Procedural losses occurred in the MMs’ combined cleanup/primary evaporation step (19% PAHs; 6% PCBs), and the final extract concentration (14% PAHs; 22% PCBs). The PAH MM performed comparably to the TM. Although most PCBs had recoveries >50%, the PCB MM generally yielded lower recoveries than the TM. Average method detection limits were 0.6 μg/kg (TM) and 1.0 μg/kg (MM) for PCBs and 25.7 μg/kg (TM) and 27.7 μg/kg (MM) for PAHs. MMs described for PCB and PAH tissue samples are potentially viable alternatives to TMs, and could lead to cost savings in bioaccumulation/toxicity tests. 相似文献
474.
Takamitsu Otake Yoshie Aoyagi Takashi Yarita 《Journal of environmental science and health. Part. B》2013,48(5):423-427
The aim of this study was to assess the performance of a method of analyzing pesticides in rice by using pressurized liquid extraction (PLE) and to perform a preliminary monitoring by using that method. The instrumental quantification limit, instrumental detection limit, method quantification limit, and method detection limit were determined. PLE temperature was also optimized for 6 target pesticides. Mean recoveries of spiked rice with target pesticides (4 ng/g and 40 ng/g) were 83%–109% with the repeatability of the analysis, represented as relative standard deviations, ranged from 1.3% to 11% (n = 5) for PLE at 130°C. These results were satisfactory according to the method of positive list in Japan. In a preliminary analysis of 10 target pesticides in 54 commercial rice samples, ferimzone was detected in only one unpolished rice sample. 相似文献
475.
B. Vandecasteele K. Willekens A. Zwertvaegher L. Degrande F.M.G. Tack G. Du Laing 《Waste management (New York, N.Y.)》2013,33(11):2195-2203
Micronutrient content and availability in composts may be affected by the addition of wood chips or tree bark as a bulking agent in the compost feedstock. In the first part of this study, micronutrient levels were assessed in bark and wood of poplar and willow clones in a short-rotation coppice. Large differences between species were observed in bark concentrations for Cd, Zn and Mn. In the second part of the study, we aimed to determine the effect of feedstock composition and composting on Cd, Zn and Mn concentrations and availability. By means of three composting experiments we examined the effect of (a) bark of different tree species, (b) the amount of bark, and (c) the use of bark versus wood chips. In general, compost characteristics such as pH, organic matter and nutrient content varied due to differences in feedstock mixture and composting process. During the composting process, the availability of Cd, Zn and Mn decreased, although the use of willow and poplar bark or wood chips resulted in elevated total Cd, Zn or Mn concentrations in the compost. Cd concentrations in some composts even exceeded legal criteria. Cd and Zn were mainly bound in the reducible fraction extracted with 0.5 M NH2OH?HCl. A higher acid-extractable fraction for Mn than for Cd and Zn was found. Higher Cd concentrations in the compost due to the use of bark or wood chips did not result in higher risk of Cd leaching. The results of the pH-stat experiment with gradual acidification of composts illustrated that only a strong pH decline in the compost results in higher availability of Cd, Zn and Mn. 相似文献
476.
W. Spieszalski H. D. Niemczyk 《Journal of environmental science and health. Part. B》2013,48(5-6):575-588
Abstract An improved Gas Chromatographic method utilizing simple extraction and one‐step purification on solid phase extraction tubes was developed for analysis of trichlorfon as an intact insecticide compound in turfgrass thatch and soil. A Gas Chromatograph/Mass Spectrum (GC/MS) was used for confirmation of trichlorfon structure. The method readily determines trichlorfon in the presence of dichlorvos. Using an electron capture (EC) detector, the detection limits were 0.02 ppm in soil, 0.04 ppm in turfgrass thatch, and 0.09 ppm in soil, and 0.2 ppm in turfgrass thatch using an nitrogen phosphorus (NP) detector. 相似文献
477.
废催化剂中金属的回收 总被引:7,自引:0,他引:7
简述了含有铂、钒、镍金属组分的废催化剂来源及金属回收工艺,介绍了萃取法在金属回收中的应用。 相似文献
478.
用松香胺萃取处理含酚废水的研究 总被引:14,自引:0,他引:14
用松香胺萃取处理模拟含酚废水。研究了萃取剂组成、油水比、废水酸度对分配系数的影响,萃取温度、萃取时间对脱酚效率的影响,以及反萃剂的浓度、用量和反萃温度对反萃率的影响。 相似文献
479.
Biodiesel has emerged as one of the most promising renewable energy to substitute existing petroleum-derived diesel fuel being used in transportation sectors. Among the various feedstocks reported for biodiesel production, Moringa oleifera oil is becoming a promising replacement for conventional diesel fuel. Therefore, this work provides a comprehensive overview of the recent progress in biodiesel production from Moringa oleifera oil. The physicochemical properties, fatty acid composition of oil and methyl esters, oil extraction methods, esterification, and transesterification process, and purification methods employed in the biodiesel production have been discussed. 相似文献
480.
通过对代表性山区河流电厂的取水工程安全实例分析 ,根据取水方式不同 ,建议应采取的措施分为 :直接在天然河道上布置取水构筑物时 ,取水头部上下端加设三角形挡沙板 ,取水口上游设导沙丁坝 ,抬高取水头高程和进水底槛高程 ,并且可考虑设置两套取水系统 ,枯水期直接利用河道取水头取水 ,洪水期从移动式泵车取水 ;在河道上设置拦河低坝取水时 ,必须设置配套取水防沙设施 ,如排沙闸或冲沙闸 ,进水闸前设导沙坝 ,冲刷闸前设导沙坎 ,泄洪闸前设冲沙廊道和导流堤 ,还可在河道上设置潜水丁坝等。 相似文献