共查询到19条相似文献，搜索用时 148 毫秒
1.
通过实验研究筛选出一种经济可行的用于修复Cr(Ⅵ)污染地下水的PRB反应介质。实验以Cr(Ⅵ)污染地下水为研究对象,选用MB、Fe0、粉煤灰和活性炭4种材料进行PRB介质筛选的静态实验,选取处理效果好且经济的MB作为PRB反应介质进行动态修复实验。结果表明:以MB作为PRB反应介质可以使Cr(Ⅵ)的质量浓度从0.50 mg/L降低到0.05 mg/L以下,达到地下水水质Ⅲ类标准;且MB具有吸附量大、固液分离容易、无解吸、无二次污染等优点。以MB作为PRB反应介质修复Cr(Ⅵ)污染的地下水是可行的。 相似文献
2.
重非水相液体(DNAPLs)泄漏进入土壤-地下水环境成为长期污染源,给人类健康及生态环境带来严重威胁。将四氯乙烯(PCE)作为特征污染物,通过二维砂箱实验探究饱和非均质介质中PCE的运移分布,及Tween 80溶液对PCE的去除效果。采用透射光法监测运移与修复过程,定量评估PCE的修复效率。结果表明,由于PCE无法克服毛细压力,在低渗透性介质上方聚积污染池;由于拉断效应,PCE在运移路径上以离散状形式存在。离散状PCE与Tween 80溶液的有效接触面积大,易被优先溶解去除,控制着修复效率。Tween 80溶液对离散状PCE修复效果显著,可作为有效的修复溶剂选用。 相似文献
3.
铀污染地下水分布于世界多国,其危害备受关注。本文基于溶胶-凝胶法制备方解石负载羟基磷灰石复合材料(CLHC),通过静态与动态对比试验,探讨了PRB活性介质对水中铀离子的吸附机理和去除效果。试验结果表明,制备的CLHC表面被羟基磷灰石覆盖,对铀离子具有较强的吸附能力。当U的初浓度为5.0 mg/L、试验周期为2 h、溶液pH值为4、CLHC用量为0.5 g/L时,CLHC可以吸附水中所有的铀离子。CLHC对铀离子的吸附过程可以用Langmuir等温吸附模型、粒子内扩散吸附动力学模型和准二级吸附动力学模型较好地进行描述。石英砂负载羟基磷灰石与CLHC相比,后者具有更强的吸附能力,而且具有更长的使用寿命。CLHC在吸附铀的过程中没有价态变化,其对铀离子的吸附主要为离子交换的化学吸附。本研究的成果可为可渗透反应墙被应用于铀污染地下水修复提供试验依据。 相似文献
4.
凹凸棒石黏土(凹土)对重金属类污染组分具有较强吸附作用,但受原状凹土固液难以分离的制约,目前尚未应用于实际工程。本文利用海藻酸钠对酸改性凹土进行造粒,通过静态批实验分析了其对Sr和Cs的吸附性能,并利用柱迁移实验分析动态迁移规律。结果表明,Sr和Cs浓度为100 mg/L,投加量为10 g/L时,120 min内达到平衡,造粒后的凹土颗粒对Sr和Cs去除率分别为40.4%和45.9%,造粒作用引起吸附效能低于凹土原土,具有明显负效应;柱实验结果表明,吸附剂用量为10.0 g、流速为10 m L/min时Sr和Cs的去除率达到41.8%和61.5%,随流速增加或降低,去除率均减小。因此,海藻酸钠造粒改性凹土颗粒可作为含Sr和Cs废水处理的备选材料。 相似文献
5.
以天然钙基膨润土和燃料废弃物粉煤灰为原料,工业淀粉为致孔剂,采用挤出-滚圆技术,制备了粉煤灰/膨润土复合颗粒吸附剂,并用于含Pb~(2+)溶液的吸附。研究了吸附时间、pH、投样量和溶液初始浓度对吸附性能的影响。结果表明,采用挤出-滚圆法制得的复合颗粒吸附剂大小均匀,表面没有裂纹,具有良好的机械强度。吸附实验中,在投样量10.0 g/L,溶液pH为6,吸附时间120 min,溶液初始浓度100 mg/L时,复合颗粒吸附剂对Pb~(2+)的去除率达到97.40%,吸附量为9.74mg/g。热力学实验表明吸附剂对Pb~(2+)的吸附更符合Langmuir吸附等温模型。 相似文献
6.
为查明土著微生物活动对高砷地下水形成的影响,利用河套平原高砷地下水中分离出的土著微生物(YH002)进行了微宇宙实验研究.实验结果表明: 高砷地下水中加入的葡萄糖提供了微生物生长所需要的碳源,微生物大量繁殖,分泌的有机酸使溶液的pH值降低.在缺氧条件下,溶液中的OD值最高达到了0.189,pH值最低为6.22;在有氧条件下,OD值最高达到了0.286,pH值最低为6.04.溶液中As(III)的初始质量浓度为74 μg/L,占总砷质量浓度的11.2%,在加入微生物和葡萄糖后,在缺氧和有氧条件下,As(III)的质量浓度分别为278 μg/L和310 μg/L,占总砷质量浓度的42%和47%.微宇宙实验说明地下水中的土著微生物能将As(V)还原成As(III). 相似文献
7.
巯基棉分离富集-荧光分光光度法测定地下水中的痕量硒 总被引：4，自引：2，他引：4
在盐酸介质中,利用巯基棉分离富集地下水中痕量硒,然后在HC l-HNO3混合酸溶液及沸水浴加热条件下解脱富集的硒。通过测定2,3-二氨基萘与Se(Ⅳ)反应生成4,5-苯并苤硒脑的荧光强度,进而实现地下水中痕量硒的测定。实验表明,荧光光度法测定硒的线性范围为0~1.0μg,最低检测浓度为0.03μg/L,应用此法测定0.1μg/L硒的地下水,相对标准偏差小于7%,回收率达91%~105%,可满足地下水中硒的测定要求。 相似文献
8.
实验以大洋多金属结核浸出渣(66%,质量分数)为主要原料、高岭土(21%)为粘结剂、蛭石(13%)为膨胀剂,研制出用于动态吸附废水中重金属离子的浸出渣颗粒。以造粒后的颗粒为吸附剂动态处理含Cu2 的模拟废水,研究发现溶液浓度、流速、pH值对动态吸附效果的影响,选定浸出渣颗粒动态处理重金属废水的工艺参数:造粒后浸出渣颗粒的比表面积为18.61 m2/g,当模拟废水中Cu2 溶液的初始浓度为27 mg/L、pH=5.35、出口流速为10 ml/h时,每克浸出渣颗粒可动态处理模拟废水114.3 ml,处理后溶液中阳离子的浓度≤0.5 mg/L,实验效果明显。 相似文献
9.
《矿产与地质》2017,(2)
阳离子表面活性剂十六烷基三甲基溴化铵可以有效对天然硅藻土进行有机改性,获得有机改性硅藻土。有机改性硅藻土对富含甲基橙、酸性绿溶液的吸附实验研究结果表明,在相同条件下,改性硅藻土对甲基橙的吸附效果比较好,对酸性绿的吸附效果不是很理想,但也远远高于硅藻土原土对这两种阴离子的吸附效果。在室温条件下,当甲基橙溶液的浓度为20mg/L时,改性硅藻土投加量为0.2g、pH值为4、吸附时间为80min,改性硅藻土对其的吸附效果较好;在室温条件下,当染料酸性绿溶液的浓度为20mg/L时,改性硅藻土投加量为0.15g、pH值为4、吸附时间为80min,改性硅藻土对其的吸附效果较好;两种阴离子的吸附过程均符合Freundlich模型。基于n值对比分析,改性硅藻土对甲基橙的吸附属于优惠吸附,而对酸性绿的吸附属于非优惠吸附。 相似文献
10.
《地下水》2017,(4)
铬作为重要的工业原料,在工业生产中占据非常关键的位置,对我国工业的发展具有较为关键的作用。但是铬在生产的过程中会产生铬渣,这种物质是重污染资源,对周围环境影响严重,特别是地下水,铬通过土壤渗透到地下水中,对人体在成严重的危害。在进行水污染的处理中,传统抽出法消耗时间较长,效率较低,地下水净化效果较差,需采用科学的方法对地下水中铬污染进行全面控制,通过对PRB修复试验技术在地下水中铬污染方面的分析,对PRB修复技术中反映介质及修复技术介质吸附原理进行探讨,发现在研究地下水铬污染方面,PRB修复技术更加科学合理,在治理地下水过程中能达到良好效果,为地下水整体质量提高创造良好条件。 相似文献
11.
Sorptive removal of ibuprofen from water using selected soil minerals and activated carbon 总被引：1，自引：1，他引：0
S. K. Behera S. Y. Oh H. S. Park 《International Journal of Environmental Science and Technology》2012,9(1):85-94
Pharmaceuticals have gained significant attention in recent years due to the environmental risks posed by their versatile application and occurrence in the natural aquatic environment. The transportation and distribution of pharmaceuticals in the environmental media mainly depends on their sorption behavior in soils, sediment?Cwater systems and waste water treatment plants, which varies widely across pharmaceuticals. Sorption of ibuprofen, a non-steroidal anti-inflammatory drug, onto various soil minerals, viz., kaolinite, montmorillonite, goethite, and activated carbon, as a function of pH (3?C11), ionic strength (NaCl concentration: 0.001?C0.5?M), and the humic acid concentration (0?C1,000?mg/L) was investigated through batch experiments. Experimental results showed that the sorption of ibuprofen onto all sorbents was highest at pH 3, with highest sorption capacity for activated carbon (28.5?mg/g). Among the minerals, montmorillonite sorbed more ibuprofen than kaolinite and goethite, with sorption capacity increasing in the order goethite (2.2?mg/g)?<?kaolinite (3.1?mg/g)?<?montmorillonite (6.1?mg/g). The sorption capacity of the selected minerals increased with increase in ionic strength of the solution in acidic pH condition indicating that the effect of pH was predominant compared to that of ionic strength. An increase in humic acid concentration from low to high values made the sorption phenomena very complex in the soil minerals. Based on the experimental observations, montmorillonite, among the selected soil minerals, could serve as a good candidate to remove high concentrations of ibuprofen from aqueous solution. 相似文献
12.
H. Sepehrian M. Samadfam Z. Asadi 《International Journal of Environmental Science and Technology》2012,9(4):629-636
In this paper, the sorption of uranium onto nanoporous silica adsorbent in the presence of nitrate, sulfate, chloride, fluoride and phosphate was studied. The effect of contact time between the nanoporous sorbent and aqueous solution, pH and initial concentration of uranium was also investigated. Uranium sorption onto nanoporous silica adsorbent is a very fast process as sorption rate increases with pH increment. Optimum pH for uranium sorption was 4?C8. Experimental sorption isotherm is successfully described by Langmuir and Freundlich models. The results obtained by batch experiments showed that the presence of high concentration of nitrate, sulfate, chloride and phosphate anions alone had no interference with uranium recovery. However, the presence of fluoride ions (>250?mg/L) decreases uranium sorption by about 55?%. The results also showed that the presence of phosphate ions (about 300?mg/L) in solution could remove fluoride interference completely. Finally, the efficiency of the nanoporous silica adsorbent for uranium recovery from wastewater of the uranium conversion facility was investigated. 相似文献
13.
14.
Behavior of metals (Cu,Zn and Cd) in the initial stage of water system contamination: Effect of pH and suspended particles 总被引：1，自引：0，他引：1
The fate of potentially harmful metals (PHM) after their entry into an unpolluted fresh water body depends on the physicochemical and biological parameters of the aquatic ecosystem. This paper considers the effect of pH and suspended particles (SP) on the behavior of Cu, Zn and Cd when they enter a fresh water reservoir. In a field experiment, four mesocosms were constructed in the Novosibirskoye Reservoir to allow systematic variation of SP concentration (15 or 250 mg/L) and pH (8.5 or 6.5). The initial concentrations of Cu, Zn and Cd in the mesocosms were 1000, 1000 and 200 μg/L, respectively. Natural bottom sediments were used to provide additional mineral SP, and water hyacinth was used as a floating plant species. Over 11 days, measurements were made of several indicators: residual metal concentration in solution ([PHM]w); metal concentration in SP ([PHM]s); primary productivity of the phytoplankton community; mass of settled SP; PHM concentration in settled SP; and PHM bioaccumulation by water hyacinth. The ratio [PHM]w/[PHM]s in the water varied in the order Cu < Zn < Cd and was higher at pH 6.5 than at pH 8.5. This observation reflects different PHM sorption (Cu > Zn > Cd) onto mineral SP and PHM biosorption by planktonic organisms. Phytoplankton acts as a renewable source of organic SP and plays an important role in metal removal from the water in the mesocosms. After 11 days the residual concentrations of Cu, Zn and Cd in the mesocosm without SP addition (initial SP concentration was 15 mg/L) were 272, 355 and 84 μg/L, respectively. The residual concentrations of Cu, Zn and Cd in mesocosms with SP addition were 57, 100 and 14 μg/L at pH 8.5 and 80, 172 and 20 μg/L at pH 6.5, respectively. Therefore, addition of SP resulted in faster and more complete removal of metals into the bottom sediments. Floating plants (water hyacinth) accumulated PHM (Cu > Zn > Cd) more effectively at pH 8.5 than at pH 6.5, and PHM concentrations in the roots were higher than in settling SP. The general trends of PHM removal from contaminated water via sedimentation and bioaccumulation are compared with changes of metal speciation in solution. 相似文献
15.
零价铁去除Cr(Ⅵ)的一系列批实验结果表明：水溶液中发生的氧化还原反应符合准一级反应；对于相同粒度的铁屑(比表面积2．89m^2／g)，固液比由05g／100mL增加到2．0g／100mL，Cr(Ⅵ)质量浓度达到排放标准所需反应时间从26．7min降为3．6min；在固液比相同、原水中Cr(Ⅵ)质量浓度不超过30mg／L时，原水质量浓度增大，达到饮用水标准的反应时间增加；其他条件相同，升高温度可提高零价铁与Cr(Ⅵ)的反应速率。 相似文献
16.
Pushpa Kumari Parul SharmaShalini Srivastava M.M. Srivastava 《International Journal of Mineral Processing》2006
The present study explores the unexploited sorption property of the shelled Moringa oleifera seeds (SMOS) for decontamination of arsenic from water bodies. Sorption studies (batch experiments) result into the standardization of optimum conditions for removal of 60.21% As(III) and 85.60% As(V) as follows: biomass dosage (2.0 g), metal concentration (25 mg/L), contact time (60 min) and volume of the test solution (200 ml) at pH 7.5 and 2.5, respectively. The adsorption data are fitted with Langmuir isotherm. Surface area has been measured using BET surface area analyzer. Morphological changes observed in scanning electron micrograph of native and treated SMOS indicates the existence of biosorption process. Fourier transform infrared spectrometry of exhausted seed biomass highlights protein/amino acid–arsenic interactions responsible for sorption phenomenon. Regeneration has also been attempted for several cycles with a view to restore the sorbent to its original state. The sorption capacity of the regenerated biomass remained almost constant after three cycles of sorption process, suggesting that the lifetime cycle was sufficient for continuous application. The findings open up new avenues in the decontamination of arsenic using SMOS from arsenic contaminated water, as domestic and environment-friendly safe technology. 相似文献
17.
Taicheng An Hui Chen Huiying Zhan Kun Zhu Ronny Berndtsson 《Environmental Geology》2005,47(4):467-474
A laboratory study was executed to investigate the effect of surfactants to enhance sorption of polycyclic aromatic hydrocarbon (PAH) contaminants in loess soil. Phenanthrene and naphthalene were chosen as organic contaminant indicators in loess soil modified by the cation surfactant hexadecyltrimethylammonium (HDTMA) bromide. The kinetic behavior of sorption during transport in natural and modified loess soil was studied. The results indicated that sorption rate in the cation surfactant modified loess soils was at least 3 times faster than that of the natural soil. A first-order kinetics model fitted the sorption data well for both soils. The sorption rates of the two organic compounds were related to their primary residual quantity on the soils. The experiments showed that sorption amounts approached constant values approximately within 30 and 90 min for naphthalene and phenanthrene at 298–318 K, respectively. The rate constants, however, displayed negative correlation with increasing temperature. With changing temperature, the activation energy was calculated at –6.196–1.172 kJ/mol for naphthalene and –28.86–15.70 kJ/mol for phenanthrene at 298–318 K. The results can be used to predict the sorption kinetics of phenanthrene and naphthalene in loess soils, and in a wider perspective, be used to better understand the transport of petroleum contaminants in the soil environment. 相似文献
18.
M. A. Ashraf M.Phil M. J. Maah I. Yusoff Ph.D. 《International Journal of Environmental Science and Technology》2010,7(3):581-590
Unfertilizable fruiting buds of mango plant Mangifera Indica L, an agrowaste, is used as a biomass in this study. The efficacy of the biosorbent was tested for the removal of lead, copper, zinc and nickel metal ions using batch experiments in single and binary metal solution under controlled experimental conditions. It is found that metal sorption increases when the equilibrium metal concentration rises. At highest experimental solution concentration used (150 mg/L), the removal of metal ions were 82.76 % for lead, 76.60 % for copper, 63.35 % for zinc and 59.35 % for nickel while at lowest experimental solution concentration (25 mg/L), the removal of metal ions were 92.00% for lead, 86.84 % for copper, 83.96 % for zinc and 82.29 % for nickel. Biosorption equilibrium isotherms were plotted for metal uptake capacity (q) against residual metal concentrations (Cf) in solution. The q versus Cf sorption isotherm relationship was mathematically expressed by Langmuir and Freundlich models. The values of separation factor were between zero and one indicating favourable sorption for four tested metals on the biosorbent. The surface coverage values were approaching unity with increasing solution concentration indicating effectiveness of biosorbent under investigation. The non-living biomass of Mangifera indica L present comparable biosorption capacity for lead, copper, zinc and nickel metal ions with other types of biosorbent materials found in literature and is effective to remove metal ions from single metal solutions as well as in the presence of other co-ions with the main metal of solution. 相似文献
19.
由于三峡水库水位消落区具有特殊的水文特征和发达的农业耕作管理,该地区成为库区磷释放的一个敏感地带.对消落区土壤磷释放特征的研究对保护水库水质有着重要的意义.模拟三峡水环境的磷浓度,对消落区中典型土壤类型进行淹水模拟实验,研究发现,在0.1～1.6 mg/L的水体磷浓度范围内,土壤磷释放特征呈现出3种模式,即释放型、吸附型和释放/吸附型.水土界面的磷行为主要取决于土壤EPC0与水体中磷浓度的关系.当土壤EPC0高于初始磷浓度时则以释放为主;低于初始浓度则以吸附为主.借助土壤磷素水平与EPC0的相关关系,以Olsen-P为评价指标,可确定三种模式的阈值.当土壤Olsen-P含量高于123 mg/kg时,土壤为释放型,这类土壤的分布区是磷污染源区;当土壤Olsen-P含量低于14.4 mg/kg时,土壤为吸附型,这类土壤分布区不易成为磷释放源;当土壤的Olsen-P含量介于二者之间时,土壤属于释放/吸附型,这类土壤存在源-汇之间的动态转化. 相似文献