共查询到20条相似文献，搜索用时 93 毫秒
1.
C. E. Lin P. K. A. Hong H. Y. Chiu R. Y. Surampalli C. T. Lin C. M. Kao 《International Journal of Environmental Science and Technology》2014,11(4):1017-1026
Remediation of heavy-metal-contaminated sediment is often hampered by the availability of heavy metals to the added chemical agents because the heavy metals are often shielded by the sediment matrix. Effective heavy-metal extraction technique becomes an important factor in enhancing the treatment efficiency. A novel extraction/washing technique utilizing chelating agent and elevated pressure in consecutive cycles of compression and decompression has been developed for heavy-metal-contaminated sediment washing in the presence of chelating agent. In this study, the optimal operational conditions of pressure-assisted cyclic washing of Cu-contaminated sediments (initial Cu concentration = 23.177 mg/kg) were determined in a laboratory-scale system. The control factors included applied pressure level, washing time, applied chelant [ethylenediamine-tertraacetic (EDTA)] concentration (0.01–0.5 M), pressure times, and application of consecutive batches washing. Results from the bench-scale study showed that up to 70 % of Cu can be removed from the sediments when 10 atm of pressure was applied for washing. The efficiency dropped to 55 % when the pressure dropped to 6 atm. Under the same operational conditions, the optimal cyclic washing time was 60 min. Results from the particle size analyses indicate that the mean particle size dropped from 100 to 50 μm after the pressure-assisted cyclic washing. Thus, cyclic pressure caused the fracture of sediment aggregates resulting in the exposure of Cu to chelating agents. With the assistance of pressure cyclic system, the total washing time and the amount of added chemical agent used can be significantly reduced. 相似文献
2.
气洗作用对油气组分影响的理论探讨 总被引：4，自引：1，他引：3
用PR状态方程定量计算和分析了部分常用地球化学参数随气洗次数的变化规律及这些参数与气洗方式之间的关系;定义了相对溶解度(α)和残留能力(h)的概念;推导出了凝析油和残留油中化合物含量比值与α、h之间的理论关系.从理论上证明,同一次气洗形成的凝析油中正构组分含量比值nCm/nCm 1必然大于残留油中nCm/nCm 1;同一油藏早期气洗凝析油中比晚期气洗凝析油中含有更丰富的轻质组分.并且给出了不同期次气洗凝析油中组分的变化规律.最后,用理论研究的结果探讨了松辽盆地古龙凹陷古31井Hl气层中凝析油的成因. 相似文献
4.
R. Sripriya A. Dutta P.K. Dhall M. Narasimha Vikas Kumar B.S. Tiwari 《International Journal of Mineral Processing》2006,80(2-4):177-188
A major operating cost in dense-medium separation is in replacement of lost medium solids. The loss of medium solids, being costly, plays a crucial role in determining the economics of any preparation operation. Coal washeries that employ dense-medium cyclones often attempt optimization of the processes by varying the vortex or the spigot diameter and the feed relative density. While these changes help in closer control of the separation process, they also result in medium losses due to changes in the medium split ratio (ratio of the medium flow rate in overflow to underflow). Since medium solids are lost by adhesion to products and as magnetic separator effluent, the effect of the change in medium split ratio on the drain-and-rinse screens and, hence, the magnetic separator circuit needs to be studied. In Tata Steel's coal washeries, at Jharkhand India, which employs primary and secondary dense-medium cyclones in series to produce clean coal, middlings and rejects, reducing the relative density of feed medium, had an insignificant effect on the medium split ratio. On the other hand, changing the cone ratio (ratio of the overflow diameter to the underflow diameter) changed the relative density and the flow rates through the cyclone outlets, thus affecting the performance of the magnetite recovery circuit.A systematic study through laboratory tests and a detailed plant sampling campaign helped in identifying the causes of magnetite loss. Upon implementation of the recommendations, the magnetite losses decreased, resulting in a saving of approximately US$27,500 per annum. The study also helped in evolving some checkpoints for plant operators for identifying magnetite losses. 相似文献
5.
注水开发过程中原油的水洗作用初探 总被引：2，自引：0，他引：2
注水开发过程中的水洗作用是一个以往被忽略,但又十分重要的问题.通过对3口井、时间间隔为20年的6个原油样品系统的地球化学测试与对比研究,探讨了注水开发过程中水洗作用对原油的改造作用以及各种地球化学参数的变化特征和规律.结果表明,在注水开发过程中,水洗作用对芳烃的影响远大于饱和烃,主要表现在芳烃组分的含量明显降低,一些芳烃类化合物的含量和芳烃参数也发生了显著的变化.认为这些变化是注水开发过程中原油遭受水洗作用的特征性标志,并对油源对比和油气运移等研究具有参考意义. 相似文献
6.
通过分析岩盐应力-溶解耦合效应对盐腔水溶建腔过程的影响,研究应力-溶解耦合作用下的盐腔水溶建腔机制。研究表明,在盐腔成腔过程中,应力-溶解耦合效应对盐腔形状的影响不可忽略;应力-溶解耦合作用下的盐腔水溶建腔机制在于溶蚀作用下在水的溶蚀影响范围内的腔壁围岩力学性质发生变化,同时,由于腔壁边界处围岩力学性质的改变,造成盐腔内部溶蚀过程发生变化,从而使盐腔形态发生改变;根据应力-溶解耦合作用下的盐腔水溶建腔机制,建立应力-溶解耦合作用下的盐腔水溶建腔计算方法;使用编制的应力-溶解耦合作用下的盐腔形态变化计算程序以及FLAC计算软件对水溶建腔过程进行计算。计算结果表明,相比于纯溶解作用,应力-溶解耦合作用下计算得到的盐腔形状与实际溶腔形状较为符合。该研究成果可为进一步研究储库盐腔水溶建腔机制提供理论依据和分析基础。 相似文献
7.
Ethylenediaminetetraaceticacid (EDTA) has been proven to be an efficient soil washing liquid to remove metal contaminants from soils. However, EDTA may cause secondary pollution due to its low biodegradability if it is not recycled or destroyed in the washing process. Thus, it is necessary to recycle and recover EDTA for sustainable use. In this paper, the extracting performance of fresh EDTA was firstly studied as a function of EDTA concentration, liquid/sediment (L/S) ratio and pH of the solution, and also extraction time. Then sodium tetraethylenepentamine-multi dithiocarbamate (TEPA-DTC), a heavy metals capturing agent, was synthesized on the base of the research of LIU-Lihua. Compared with Na2S and DDTC, TEPA-DTC shows strong chelating capacity, because it has functional groups of dithiocarbamate that could strongly chelate heavy metals and capture metal ions from Me-EDTA to form precipitates, allowing us to reclaim the EDTA during the process of soil washing. Three divalent heavy metals were investigated (Pb, Cd, and Cu). These three metals could almost precipitate completely with TEPA-DTC under the dosage of 300 mg/l, and EDTA was regenerated. The recovered EDTA was used again in three cycles of soil washing, and the amount of heavy metals extracted just slightly decreased each cycle. 相似文献
8.
9.
Weikun Song Jianbing Li Wen Zhang Xuan Hu Ling Wang 《Environmental Earth Sciences》2012,66(5):1487-1496
A series of laboratory experiments were carried out in this study to investigate the remediation of phenanthrene contaminated
soil using ultrasound and soil washing. The results indicated that ultrasound and soil washing could significantly enhance
the remediation efficiency of each other. The performance of the combined ultrasonic and soil washing process was then investigated,
and the impacts of four experimental variables including the initial concentration of phenanthrene in soil, sonication time,
pH of washing solution, and washing flow rate were examined using an orthogonal experimental design method. The analysis of
variance (ANOVA) of experimental results revealed that the initial phenanthrene concentration, sonication time and soil washing
flow rate showed significant effects (P ≤ 0.05) on the remediation efficiency. A pseudo-first-order kinetics model was developed for describing the remediation process,
and a maximum remediation efficiency of 69.5% was observed in the study after 20 min of treatment under the experimental conditions.
Therefore, the results indicate that the combined ultrasonic and soil washing process could represent a promising technology
for the effective remediation of phenanthrene contaminated soil. 相似文献
10.
对于石灰岩地层出水量小于5m^3／h的机井，采取单一的洗井增水方法效果一般不明显。笔者经过多年的研究与应用，提出了先对井孔进行爆破，然后利用盐酸与二氧化碳联合洗井的综合洗井增水技术，则往往能够取得较好的增水效果．一般增水率在60％以上。该项技术为石灰岩山区小水量的机井的开发提供了技术保证，具有广阔的发展应用前景。 相似文献
11.
油田废弃井改造是实现二次开发、重复利用资源的有效方式。东濮106井为中原油田废弃井,经过对目的层(即奥陶系碳酸盐岩热储层)以酸洗方式进行酸化改造,现已改造为地热井。经过多次配伍实验,酸液体系选择缓速有机酸系列(15%HAc),该酸液具有反应速度慢、作用距离大、二次伤害低等优点;缓蚀剂浓度选定为0.5%;最终表面活性剂采用FC-01和ABS。选取15%HAc与0.5%缓蚀剂(B溶剂),并相应添加粘土稳定剂、表面活性剂和铁离子稳定剂等药品。该研究验证了改造方案和技术的可行性,并为今后废弃井改造酸洗液的选择提供了新思路。 相似文献
12.
水洗作用对油藏中烃类组成的影响 总被引：17，自引：4，他引：13
通过塔木盆地塔中１０井油层和水层石炭系储集岩烃类宏观组成和分子地球化学特征研究,认识到油层和水层中储集岩含油率和烃类族组成存在着明显的差异。水洗作用对饱和烃生物标志化合物尤其是二环倍半萜影响较大,水层中倍半萜烷化合物已被消耗殆尽,三环萜烷含量降低, 伽玛蜡烷含量则相对增加;孕甾烷、升孕甾烷和重排甾烷的含量亦相对降低。水洗作用导致储集岩烃类芳烃组成中二苯并噻吩系列化合物的含量显著下降,二环和三环多环 相似文献
13.
Response surface methodology approach to the optimization of oil hydrocarbon polluted soil remediation using enhanced soil washing 总被引：2，自引：0，他引：2
A. Kalali M.Sc. T. Ebadi A. Rabbani S. Sadri Moghaddam M.Sc. 《International Journal of Environmental Science and Technology》2011,8(2):389-400
One of the environmental concerns in recent decades is the prevalence of different pollutants in soil. Hence, the importance of remediation has led to the development of various methods to remediate polluted soil. Among these methods, soil washing has gained significant attention to treat polluted soils. In this paper, the response surface methodology was applied in order to determine the optimal conditions for total petroleum hydrocarbon remediation using nonionic surfactant Brij35 in soil environment. The effect of different factors in soil washing process including surfactant solution concentration and volume, washing time, age of pollution and frequency of washing are evaluated. The predicted values for total petroleum hydrocarbon remediation efficiency by the response functions are in a very close agreement with experimental data (R-2= 98.75 %). The second order model was developed as experimented response and optimal conditions were obtained by analyzing the contour and surface plots and also by solving the regression equation using LINGO 9.0 software. The optimal concentrations (8 g/L), volume of surfactant solution (500 mL), washing time (75 min), age of pollution (29 days) and frequency of washing (three times) are determined. In this optimal condition, the removal efficiency has been observed to be 93.54 % which conforms to the results of process optimization using response surface methodology. Based on the results, it can be concluded that the response surface methodology is a suitable approach to determine the optimal conditions of soil washing to remediate organic hydrophobic pollutants using the nonionic surfactant Brij35 from the soil. 相似文献
14.
Estimating wasteful water use from car washing points on the water supply system of Yaounde,Cameroon
Humphrey Ngala Ndi 《GeoJournal》2018,83(1):1-12
Regular access to pipe-borne water remains a challenge to urban dwellers in Cameroon in general and those in Yaounde in particular. From that backdrop, this paper estimates the quantity of water used in car washing in the city of Yaounde as a representation of some of the numerous irrational water uses in the city in spite of its scarcity. It argues that the amount of water lost in car washing in the absence of water conservation and recycling techniques can offset the domestic water shortages experienced in many neighbourhoods of Yaounde significantly. To achieve this, both qualitative and quantitative methods were applied. An exhaustive enumeration of car washing points was undertaken in the Yaounde VI subdivision of the city of Yaounde. Water sources were determined and the water quantities used on a daily basis estimated from water bills paid and volumetric capacities of water reservoirs in the washing stations. Car washing was observed to be a streetside activity in dominantly outlying residential areas where some vacant undeveloped land still existed with the CDE being the major water supplier notwithstanding the emergence of alternative sources. Over 198.122 m3 of water (0.2 % of daily water use in the city of Yaounde) was estimated to be consumed by car washing in Yaounde VI. With a huge water supply deficit, of 200,000 m3 on its estimated daily water needs of 311,000 m3, water losses via spillouts from car washing points represents a significant withdrawal from the system that could reduce the daily shortages experienced by numerous households in Yaounde. There is the strong need for a water use policy that internalizes micro water recycling schemes in public water use as a means of reducing water demand, harvesting and wastage. 相似文献
15.
Gross compositions and distribution of saturated and aromatic hydrocarbons in Carboniferous sandstone reservoire rocks in oil and water zones for Tzhong-10 well of the Zhongyang Uplift in the Tarim Basin were studied in dteail by means of Rock-Eval Pyrolysis,thin-chromatograph-flame ionization detection(TLC-FID),gas chromatography,gas chromatography-mass spectrometry.The results suggest that the gross composition of reservoir hydrocarbons between the oil zone and the water zone show significant differences,Water wahing has a dramatic effect on saturated hydrocarbon blomarkers,especially drimane series compounds,Drimane series compounds in the water zone have been depleted completely.However,the contents of tricyclic iterpanes and pentacyclic triterpanes tend to decrease slightly,but the water-zone reservoir hydrocarbons contian a large amount of gammacerane.This suggests that gammacerane be more resistant to water washing than diterpanes and homohopanes.The contents of pregnane,homopregrane,diasteranes relastively decrease as a result of water washing.Water washing has a noticeable effect on polycyclic aromatic hydrocarbon compounds,especially aromatic sulfur compounds,and the contents of dibenzothiophene series compounds and benzonaplyiothipophene decrease significantly as a result of water washing.However,the conterts of bicyclic and tricyclic aromatic hydrocarbons decrase slightly and those of tetracyclic and pentacyclic aromatic hydrocarbons,especially benzofluoranthene and benzopyrenes,increase markedly owing to adecrease in light aromatie hydrocarbons as a result of water washing. 相似文献
16.
I. Blanco-García M. Rodas C. J. Sánchez J. Alonso-Azcárate 《Environmental Geology》2007,52(6):1097-1115
This work presents the main characteristics of 97 quarry wastes, collected in 23 gravel pits, from the Jarama river area, Madrid province, Spain. In this area, more than 2.5 × 106 ton of silty-clay waste are generated every year, and no applications have as yet been defined for them. This work is the first systematic study of the fine fractions generated from the Jarama river quaternary deposits, playing part in the comprehension of this complex terrace systems. Quartz, potassium feldspar, plagioclase, calcite, and complex mixtures of phyllosilicates, such as smectite, illite, kaolinite, chlorite and illite/smectite mixed layer, have been detected. Two sets of waste which are recognized according to the calcite content, have been directly related with the terrace level beneficed in the Jarama river, and the position along the valley. Calcite concentrates in the wastes produced in the lower course, where Henares and Tajuña tributaries promote an extensive change in the geochemistry of underground water, and locally, in the petrology of quarried conglomerates. This clear distinction by location between calcite-bearing and calcite-free wastes is essential for potential applications, such as soil conditioning, raw materials for brick or tiles, etc. The wastes studied can be considered as a potential source of industrial raw materials because of their uniformity and large volume. This suggestion is now being carried out, with an attempt at assessing the possibilities of using these mining wastes as ceramic raw materials. 相似文献
17.
菲律宾迪纳加特岛汇洋镍铬矿区的红土残坡积型铬铁矿规模为大中型,原矿中铬矿品位w（Cr2 O3）＞2.5％,铬矿石的含泥量很高,红土团块在水中较难碎散.调查后认为,对残坡积红土型铬铁矿的洗选可以利用当地的水源、地貌、木材、劳力等有利条件,制定洗选工艺流程：洗选作业利用自然坡度修建运矿沟,敷设木质洗矿溜槽,用水流冲洗脱泥;粗精矿进入双螺旋槽式洗矿机继续脱泥,粗粒级矿粒从上部排出机体,进入溜槽冲洗后获得粗粒级精矿;细粒级粗精矿从底部排矿口排出,经螺旋溜槽抛去尾矿,进入摇床进行选别,获得细粒级精矿. 相似文献
18.
河北开滦矿区煤洗选过程中 15种主要有害微量元素的迁移和分配特征 总被引：5，自引：2，他引：3
以河北开滦矿区晚古生代煤及其洗选产品为例,运用电感耦合等离子体质谱 (ICP-MS)和冷原子吸收光谱 (CV-AAS)方法对煤中主要微量有害元素 (包括 Be、 Cr、 Co、 Ni、 Cu、 Zn、 Ga、 As、 Se、 Mo、 Tl、 Pb、 Th、 U和 Hg)的含量及其在洗选过程中的迁移和分配特征进行了研究.通过对开滦矿区 10个矿井 47个煤层刻槽样品主要有害微量元素含量的统计,发现开滦矿区晚古生代煤中 Cr、 Ni、 Cu、 Zn、 Pb和 As富集.通过对原煤精煤中煤尾煤煤泥两套系列样品的分析,发现主要有害微量元素在精煤中都有不同程度的脱除,中煤中相对富集的元素有 Se和 Th,明显被脱除的元素有 Co和 Tl.除 Tl以外,尾煤中主要微量有害元素均有不同程度的富集,以 As的富集率最高,可达 34.4%, Hg的富集率最低,为 1.1%.煤泥中所有微量有害元素均相对富集,以 Hg的相对富集率最高,达 78.4%.因此,如果对尾煤和煤泥加以利用,需要特别关注 As和 Hg等微量有害元素对环境的影响.主要微量有害元素在洗选过程中的分配行为主要受控于它在煤中的赋存状态. 相似文献
19.
土壤砷污染已成为我国严重的环境问题,淋洗法是修复土壤砷污染较为有效的手段之一。文中以砷污染土壤为研究对象,运用2种环境友好的淋洗剂KH2PO4和草酸进行振荡淋洗实验,探究两种淋洗剂对不同砷污染土壤的淋洗效果,在此基础上,通过2种不同的体外方法 (physiologically based extraction test,PBET;in vitro gastrointestinal,IVG),探索其生物可给性及对人体的健康风险。结果显示,KH2PO4和草酸对土壤中砷有不同程度的去除,草酸对土壤砷的去除率较高,平均去除率为54.3%。运用PBET方法得到的土壤砷的生物可给性高于IVG方法,KH2PO4淋洗后土壤砷的生物可给性高于草酸。与草酸相比,KH2PO4淋洗会在一定程度上增加土壤砷的健康风险。不同in vitro方法对不同淋洗剂修复后效果有不同的评估结果,应该根据不同的淋洗剂选择较为保守的体外方法来评估淋洗后土壤的生物可给性及健康风险。 相似文献
20.
A combined mathematical geophysical model for prediction of pyrite oxidation and pollutant leaching associated with a coal washing waste dump 总被引：3，自引：0，他引：3
F. Doulati Ardejani Ph.D. B. Jodieri Shokri M.Sc. A. Moradzadeh Ph.D. E. Soleimani Ph.D. M. Ansari Jafari Ph.D. 《International Journal of Environmental Science and Technology》2008,5(4):517-526
The waste produced by coal washing process produces many environmental problems. In this study, the pollution problems associated with the waste produced by Alborz Sharghi Coal Washing Plant was investigated by mathematical modeling. The study area is located at 11 km. to Razmjah coal region and 45 km. to Tehran-Mashhad road in the north part od Iran. To achieve the goal, a few samples were taken from different depths at three points on the waste dump in order to investigate pyrite oxidation and pollution generation. The samples were then analysed, using an AA-670 Shimadzu atomic absorption to determine the fraction of pyrite remained within the waste particles. A numerical finite volume model using Phoenics package has been developed to simulate pyrite oxidation and pollution generation from the Alborz Sharghi coal washing waste dump. The pyrite oxidation reaction is described by the shrinking-core model. Gaseous diffusion is the main mechanism for the transport of oxygen through the waste. The results of numerical modelling were compared with the field observations and close agreement was achieved. A simple mathematical model incorporating advection and hydrodynamic dispersion processes was also presented in order to verify the results of geophysical time-laps method showing transportation of the pollutants through the downstream of the waste dump. Both mathematical model and geophysical time-laps method are agreed in the identification of pollutant transport emanated from the waste dump. The results of such investigations can be used for designing an effective environmental management program. 相似文献