Dispersion and immobilization of pollutants in Cretaceous sandstones where U ore was mined by sulfuric acid leaching     

Jan Holecek Jiri Muzak Tomas Paces 《中国地球化学学报》2006,25(B08):43-43

The uranium deposit Straz pod Ralskem in the northern part of the Czech Republic was exploited by underground acidic leaching between 1968 and 1996. More than 14000 tons of uranium were produced during this period. More than 4 million tons of H2SO4, 300 thousand tons of HNO3, 120 thousand tons of NH3 and other chemicals were injected in Cenomanian sandstones. The mining has resulted in a large contamination of ground waters. Lateral hydrodynamic dispersion of the pollutants and migration of pollutants across aquitard are a potential hazard to drinking water supply and to surface aquatic environment, Chemical leaching was done by forced circulation of a technological acid solution introduced to the sandstones through injection drill holes and withdrawal of the enriched resulting solution by production wells. The solution is reacting not only with uranium ore, but also with minerals of the rock environment. Hydrogen ions are replaced by uranium and other cations leached from the rock, especially Fe, Al, Be and As. Ammonia remaining after the precipitation of the yellow cake （ammonium diuranate） was rejected underground in spite of that it serves no purpose in the underground leaching. High concentrations of Al, Be, As and ammonium ions in ground water became the most serious ecological pollutant. Modelling of the hydrodynamic dispersion of the pollutants predicts the future risks to local water supplies in 200 to 500 years. A possible way to reduce the risk is an immobilization of the pollutants in deeper parts of the sandstone aquifer. We found that modeling of the geochemical reactions using classical hydrochemical models give unrealistic results because of formation of colloidal particles.  相似文献   

巢湖的稀土元素地球化学特征   总被引：1，自引：1，他引：1  

朱兆洲  王中良  高博  王仕禄 《地球化学》2006,35(6):639-644

采用液-液萃取法和ICP-MS测试技术对巢湖的溶解态稀土元素进行了分析。结果表明,巢湖的溶解态稀土的含量与世界淡水相当,丰水期的样品含量高于其他季节。pH值和悬浮物、胶体是控制巢湖水体中溶解态稀土含量的主要因素。巢湖的溶解态稀土的分布模式以平坦型为主,少数呈现重稀土富集。丰水期和枯水期的溶解态稀土的(La/Yb)N值从西半湖区到东半湖区呈现有规律性的逐渐增大,并且丰水期的(La/Yb)N值低于枯水期。在富营养化湖泊中,胶体和水生生物可能是造成这一现象的主要原因。  相似文献   

Speciation of Trace Elements in Acidic PoreWaters from Waste Rock Dumps by Ultrafiltration andIon Exchange Combined with ICPMS and ICPOES     

Alexander Pleßow  Hartmut Heinrichs 《Aquatic Geochemistry》2000,6(3):347-366

A speciation procedure developed on reactive acidicpore water samples from mining areas is presented.Methods with low consumption of solution are requiredthat allow rapid sample preparation to avoid equilibriumchanges as far as possible. The entire procedure includesonly three parallel separation steps. One aliquot is filteredthrough an 1 kd ultrafiltration membrane to separate traceelements adsorbed or complexed by colloids. One cationand one anion exchange are performed with two additionalaliquots to determine simple hydrated ions and smallinorganic complex ions. Commonly used procedures ofion exchange seem to be problematic. This new techniqueis based on a novel ion exchanger. Subsequently the threefractions obtained from the separation procedures and theoriginal pore water sample are analysed by ICPMS, ICPOES,ET-AAS, Flame-AAS, FES and IC to determine the concentrationsof the major ions and additionally up to 50 trace elements. Theinfluence of pH-values and several dissolved compounds iscontrolled in experiment series with synthetically preparedsolutions to reveal potential artifacts.  相似文献   

Colloid‘s influences on microalgae growth as a potential environmental factor     

赵新淮张正斌  刘莲生 《中国海洋湖沼学报》2003,21(3):270-279

The role of colloid as “colloid pump”in the ocean is well known. The important influence of colloid in seawater on the growth of microalga was found in our 1999--2000 study. Colloid concentrates were obtained by employing a cross-flow filtration system to ultrafilter seawater(which had been pre-filtrated by 0.45 μm acetate cellulose membrane) successively with different membranes. Ultrafiltration retentions (we called them colloid concentrates) together with control sample (seawater without colloid) were then inoculated with two species of microalgae and cultivated in selected conditions. Monitoring of microalgae growth during cultivation showed that all colloid concentrates had obvious influence on the growth of the microalgae studied. Addition of Fe(OH)3 colloid or organic colloid (protein or carbohydrate) to the control sample enhanced the microalgae‘s growth.  相似文献   

影响粘土胶体稳定性的因素研究   总被引：3，自引：0，他引：3  

赵红挺  马毅杰 《矿物学报》1993,13(2):182-189

本文研究了我国六种蒙脱石及高岭石和伊利石胶体的粘度和稳定性、探讨了胶体浓度、pH值和ESP的影响及其机理。  相似文献   

九龙江口水体中不同相态磷的环境化学行为研究          下载免费PDF全文

姜双城 《应用海洋学学报》2021,40(3):511-519

利用切向超滤技术分离和提取九龙江口水体中溶解相(粒径0.45μm)、胶体相(分子量 1 k Da,粒径0.45μm)和真溶解相(分子量1 k Da)的活性磷酸盐(SRP)和溶解态总磷(DTP),初步探讨了不同相中各形态磷的环境化学行为。研究表明,切向超滤过程的SRP和DTP系统空白分别为ND～0.001 mg/dm~3和ND～0.005 mg/dm~3,均未高于方法检出限;样品质量回收率为92.3%～100.0%,满足80.0%～120.0%质量技术要求。真溶解相中SRP、溶解态有机磷(DOP)和DTP占溶解相比例为65.3%～92.3%,存在形式以真溶解相为主;胶体相中SRP、DOP和DTP的含量分别为0.13～4.19、3.25～19.20μg/dm~3和3.39～23.40μg/dm~3,占溶解相比例为1.2%～17.0%;真溶解相和溶解相中的各形态磷含量主要受陆源输入控制。  相似文献   

滨海地下水交互带中的胶体运移行为研究综述          下载免费PDF全文

谭博  刘曙光  代朝猛  邓慧萍  周辉  丰莎 《水科学进展》2017,28(5):788-800

在分析国内外已有研究的基础上,综述滨海地下水交互过程中的胶体运移规律,重点阐述咸淡水驱替作用下胶体的宏观运移规律和微观作用机理。胶体在滨海地下水交互中可成为联系海-陆相的物质传输纽带,其运移行为主要受地下水水化学参数波动影响,受控于胶体类型与数量、表面电位及地下水pH、离子强度等因素,具有水动力、水环境多因子联合作用的特征,并在含水层中具有空间堵塞和团聚体结构改变的不确定性。未来关于滨海地下水交互带中的胶体行为研究应重视基础勘察,考虑胶体群体效应,结合滨海含水层对水动力、水化学条件的敏感性,研究胶体在多相体系中胶体运移的不确定性及其对污染物的协同运移作用,为滨海资源化研究构建统一分析体系和预测机制。  相似文献   

石油沥青质的吸附、沉淀机理及其影响因素   总被引：4，自引：0，他引：4  

田建锋  陈振林 《海相油气地质》2005,10(3):37-42

对于原油中石油沥青质的存在状态尚无统一认识,存在多种石油胶体体系理论模型。沥青质有两种方式从石油中分离出来,即吸附和沉淀,它们具有完全不同的机理。吸附的沥青质不能被溶解,要通过解吸才能消除,且解吸过程相对溶解而言很慢。沉淀是由于石油胶体体系的变化引起的,而吸附则是由石油胶体体系以及体系外的水介质环境和周围岩石矿物特征等所控制的。影响吸附的主要因素有:矿物本身的化学性质和结构特征、矿物质表面水层的性质、原油组成。影响沉淀的因素主要有:原油的组成、温度和压力、石油所处的状态、孔隙特征。低渗储层比高渗储层更容易导致沥青质的沉淀。  相似文献   

五种天然水体胶体相可酶解磷的含量及分布特征   总被引：3，自引：1，他引：2  

王芳  朱广伟  贺冉冉 《湖泊科学》2009,21(4):483-489

分别在太湖草型湖区胥口湾及藻型湖区梅梁湾采集水样,采用常规过滤与切向流超滤相结合的方法,将水体中的颗粒,胶体依据粒径大小分离,通过测定计算得到64-1μm,1-0.5μm,0.5-0.1μm,0.1μm-1nm,<1nm五个粒级的可酶解磷含量.同时采集太湖"引江济太"工程长江调水口--望虞河口水样、千岛湖水样及千岛湖下游河流型水库富春江段水样进行分析.结果显示,5种典型水体中颗粒相的可酶解磷含量占总可酶解磷含量的比重较高,胶体相的可酶解磷也占了相当的比重,是生物必需磷不可忽视的重要储库.望虞河口河水总磷0.216mg/L,可酶解磷含量达0.174mg/L,其输入可能对太湖水体生物有效磷浓度的增加起到重要的贡献,"引江济太"调水时具有一定生态风险.对于胶体范围的可酶解磷,胥口湾、望虞河的胶体态可酶解磷主要分布在较大、中胶体范围,梅梁湾和千岛湖的胶体态可酶解磷主要分布在中、微胶体范围,富春江水库的胶体态可酶解磷分布的相对比较均匀.  相似文献   

Modelling of colloidal particle and heavy metal transfer behaviours during seawater intrusion and refreshing processes          下载免费PDF全文

Bo Tan  Shuguang Liu  Chaomeng Dai  Hui Zhou  Zhenquan Hui  Guihui Zhong  Hong Zhang 《水文研究》2017,31(22):3920-3931

The proper management of coastal aquifers commonly requires an understanding of regional mass flow and complete seawater–freshwater circulation. In this study, time series observations of seawater intrusion and refreshing were conducted using a column experiment based on natural flow conditions in coastal groundwater and a sampled medium from a coastal sandy aquifer without chemical treatment. Ranges of hydrodynamic and hydrochemical variables were tested and analysed. The results showed that the zeta potential of suspended colloids in aqueous solution in an aquifer polluted with 0.5 g/kg of heavy metals exhibited an isoelectric point for pH values ranging from 5.70 to 6.07 when freshwater or seawater completely occupied the aquifer pores, which is representative of natural hydrochemical conditions. In this scenario, a high background concentration of heavy metals induced colloidal immobilization. Otherwise, seawater–freshwater circulation enabled colloid mobilization due to ionic strength and pH fluctuations. The migration of multiple heavy metals occurred at a characteristic time of approximately 1 pore volume after each intrusion stage began and when the peak rate of colloid release was reached. At these times, the colloid behaviour determined the quantity and pathway of heavy metal transport. On the basis of the influences of seawater and freshwater interactions, the quantity of mobilized particles generally decreased and was uniformly distributed in each fraction due to particle loss and decreased porous connectivity. We speculate that the decrease in the total surface area of the migratory colloids may cause colloid‐associated heavy metal transport to decrease. The experimental results provide a useful basis for testing coastal groundwater flow and mass transport models because these phenomena require full characterization to precisely evaluate the associated fluxes from the field scale to the microscopic dimension.  相似文献