电动修复重金属污染土壤的研究进展

电动修复是当前重金属污染土壤原位修复研究领域的热点,首先详细阐述了电动修复技术的特点和修复效果的影响,如电场、电压、pH、离子强度等,并对电动修复与其它典型技术(如:淋洗、PRB、植物、微生物等)联合修复技术的特点和适应场地作了详细介绍;在此基础上,对电动修复重金属污染土壤技术的关键问题和发展方向作了展望,以期为电动修复的发展提供参考。     

不同电极电动修复铜镉复合污染土壤的研究

针对铜镉污染土壤问题,研究了不同电极材料对电动修复土壤效果的影响。采用不锈钢、石墨板、钛板、钛网四种不同电极对土壤进行修复。结果显示,石墨板电极对2种重金属的总去除率较好,Cu为40.34%,Cd为95.21%,且Cd的去除率明显高于Cu。另外,不同电极材料对修复过程中电流和处理后重金属形态分布的影响不大,其中石墨板电极电流稳定时的值为42mA,高于其他三种电极。     

改性生物炭材料对镉污染土壤的修复

以花生壳为原料,氨水和草酸为改性试剂进行浸渍改性制备改性生物炭,进行模拟Cd污染土壤的修复实验研究。实验结果表明改性生物炭结构粗糙多孔,层级间隙明显;比表面达342.212 8 m²/g;-NH₃和-COOH官能团成功在生物炭上负载。修复Cd²⁺污染土壤的最佳投加量为0.200 0 g,草酸改性生物炭和氨水改性生物炭对Cd去除率分别高达90.0%和96.5%,氨水改性生物炭效果更好。毒性淋滤实验表明经改性生物炭修复后土壤的毒性降低,研究结果可为Cd污染土壤的修复提供理论依据。     

不同电极电动修复铜镉复合污染土壤的研究

针对铜镉污染土壤问题,研究了不同电极材料对电动修复土壤效果的影响。采用不锈钢、石墨板、钛板、钛网四种不同电极对土壤进行修复。结果显示,石墨板电极对2种重金属的总去除率较好,Cu为40.34%,Cd为95.21%,且Cd的去除率明显高于Cu。另外,不同电极材料对修复过程中电流和处理后重金属形态分布的影响不大,其中石墨板电极电流稳定时的值为42mA,高于其他三种电极。     

重金属污染土壤化学钝化修复材料研究进展

土壤重金属污染严重威胁着人类的健康和生存环境。一直以来,由于土壤重金属污染的潜伏性、滞后性和复杂性,使之成为环境治理的重大挑战。在诸多土壤重金属污染修复治理技术中,化学钝化修复技术无疑是具有极大研究价值和实际应用价值的修复治理技术手段之一。本文综述了近些年来各类无机、有机、无机-有机复合以及新型化学钝化修复材料的研究进展,为进一步发展重金属土壤污染治理领域化学钝化修复材料的研究提供参考。     

生物钝化修复镉污染土壤研究进展

回顾了我国含镉土壤的场地修复。综述了利用生物钝化技术修复镉污染土壤的研究现状,重点探讨了微生物的代谢产物与镉产生硫化物或磷酸盐沉淀的微生物沉淀作用、微生物的细胞壁和其分泌的胞外聚合物直接吸附镉的微生物吸附作用以及镉离子透过微生物的细胞膜而被固定在细胞内的微生物摄取作用等生物钝化机理,并对有机钝化过程和无机钝化过程进行了介绍和评价。分析了镉在土壤中的离子交换态、碳酸盐结合态、铁锰氧化物结合态、有机结合态和残渣态等赋存形态以及土壤中pH值、氧化还原电位、有机质、共存重金属和微生物等因素对镉的生物可利用度的影响。最后阐述了生物钝化技术的优点以及该技术不能将重金属从土壤中永久去除的问题,指出生物钝化技术与其他修复方法相结合是其未来的发展方向。     

土壤镉污染的植物修复技术

镉在土壤中有稳定、积累和不易消除的特点,且可通过食物链富集使人体慢性中毒.植物修复技术是一种清除环境污染的绿色技术,具有成本低、不破坏土壤生态环境、不引起二次污染等优点,具有广阔应用前景.土壤镉污染植物修复技术有植物提取、植物挥发、植物稳定和植物促进等修复技术,在镉污染土壤的治理时,应根据土壤条件、污染的程度、预期的修复目标、时间限制、成本等因素加以综合考虑,选择合适的修复技术或组合,达到高效、低耗的双重效果.     

含磷材料钝化修复土壤重金属污染的研究进展

全球土壤重金属污染形势严峻,含磷材料被广泛应用于土壤重金属污染治理,其环境适宜性还需要更全面的评估。文章从钝化修复技术简介、含磷钝化修复材料分类、含磷材料钝化机理、总结与展望四个方面详细介绍了含磷材料在土壤重金属污染治理领域中的研究进展。同时指出含磷材料在钝化修复应用中的局限性,发展组合钝化剂是未来研究方向。     

腐植酸对电动法修复污染土壤的影响

室内模拟研究结果表明．电动修复苯胺污染土壤的过程中,若加入腐植酸会对试验结果有较大影响。当腐植酸浓度大于临界胶束浓度时．可起表面活性剂的作用,使苯胺在土壤中迁移增强并在阳极附近富集。当加入16．7mg／L腐植酸溶液时,苯酚在阳极的富集浓度可以达到未添加腐植酸的1．26倍。腐植酸还可以改变镍的迁移方向,使其在距阳极8cm处富集,富集浓度达到120％。     

铁基稳定化材料在重金属污染土壤修复中的应用

土壤重金属污染形势日益严峻,严重影响人类身体健康。铁基稳定化材料可有效稳定土壤重金属。本文从稳定化机理、材料理化性质等方面对铁基稳定化材料进行了介绍,并在最后对实际工程案例进行了分析。希望为铁基稳定化材料在土壤重金属稳定化领域的应用提供有用信息。     

土壤污染修复技术分析及其应用案例

概括了目前常用的土壤污染修复技术原理及其国内外相关工程应用的情况,分析不同修复技术存在的优缺点,以期为土壤修复技术的推广和应用提供一定参考。     

Electrode Configuration for Electrokinetic Restoration of Greenhouse Saline Soil

Electrokinetic restoration (EKR) of saline soil has been achieved successfully on a laboratory scale. In this study, the effectiveness of an electrokinetic system with one anode in the center of the electrokinetic cell and two cathodes at the end of the cell was investigated to simulate the EKR system, with electrodes installed in the ridge and furrow pattern of a field. Anions were transported toward the anode centered in the cell, and cations were moved toward both cathodes. Chloride and nitrate were almost completely removed from the soil; however, a certain amount of sulfate accumulated in the anode region. Although the voltage influenced the transport of salts in the soil, there was no significant increase in the reduction of electrical conductivity at a higher voltage gradient. The pattern of salt removal was symmetric around the center anode, and energy consumption was less than that of a normal system. This means that the system can be used effectively to remove salts from saline greenhouse soil.     

零价铁反应墙联合电动法修复铅锌矿区重金属复合污染农田土壤的试验研究

采用ZVI-EKR联用技术对Pb、Cu、Zn、As污染的农田土壤进行修复。与简单EKR技术对比,ZVI-EKR联用技术可以增加电流密度,零价铁比表面积大,铁粉在土壤和水的混合物中发生氧化还原反应和水解反应,生成氧化铁、四氧化三铁以及氢氧化铁胶体,能够吸附迁移到附近的重金属离子,提高电动修复的效率。     

In Situ Electrokinetic Removal of Salts from Greenhouse Soil Using Iron Electrode

An electrokinetic (EK) field study was performed on a pilot scale (2.2 × 3.3 × 0.3 m³, W × L × D) in a greenhouse by using Fe electrodes and bentonite backfill. When a constant voltage gradient was applied, the current intensity was affected by electrode position, and the soil temperature increased with the current intensity. After the EK treatment, the soil pH was little changed and the cations were hardly removed because of the ion exchange in the bentonite. However, the anions were mostly removed by electromigration, resulting in the reduction of the soil electrical conductivity. The field study demonstrated that in situ EK process is feasible for the remediation of greenhouse soils. In addition, the improvement of EK system and the role of bentonite backfill were discussed.     

腐植酸强化电动修复铅锌矿区复合重金属污染农田土的实验研究

电动修复实验中,通过加入络合剂腐殖酸,提高对水口山铅锌矿区农田土壤中铅、锌、镉、铜的去除效率。实验结果表明,当修复电压达到17.6 V·cm~(-1)的时候,修复时间为7天的时候,铅、镉、铜、锌的去除效率分别达到65.04%、94.92%、89.88%、91.05%。电动修复后,土壤中可交换态和碳酸盐结合态的Cd含量大大降低,减少了Cd的环境毒性影响。     

模拟Cd污染土壤的电动修复

文章研究电压、修复时间,添加新型绿色络合剂-PASP和缓冲液对电动修复实验效果的影响。结果表明,升高电压和加长修复时间都能提高Cd的迁移率。随络合剂浓度由2g,L升高到4g/L,阳极附近的迁移率由68．8％提高到78．5％,实验中在阴极加入醋酸后,阴极附近Cd的迁移率升高了12．3％,说明添加络合剂和醋酸可以提高修复效果。     

Electrokinetic Remediation. I. Modeling of Simple Systems

Abstract

A One-Dimensional Model Is Developed For Simulating The Electrokinetic Treatment Of Saturated Porous Media Contaminated With An Ionic Salt. Simulations Of Simple, Unenhanced Electrokinetic Treatment For The Removal Of A Nonamphoteric Salt Such As Cadmium Sulfate Exhibit A Severe Drop-Off In Electric Current And In Remediation Rate After About 50–60% Of The Cation Has Been Removed. Simulation Of Electrokinetic Treatment In Which The Oh^? Generated In The Cathode Compartment Is Partially Neutralized By The Addition Of Acid Show Rapid And Complete Removal Of The Cation. Partial Neutralization Of H⁺ In The Anode Compartment By Addition Of Base Results In Immobilization Of The Toxic Metal As The Solid Hydroxide, Although This Should Be A Useful Technique For The Removal Of Arsenate And Selenate.     

An Acidic Injection Well Technique for Enhancement of the Removal of Copper from Contaminated Soil by Electrokinetic Remediation Process

An experimental study constituting eight different tests was performed to investigate the effect of relevant factors on the remedial efficiency of electro-kinetic process applied to clean-up Cu contaminant from three types of Iraqi soil. An efficiency enhancement scheme was employed involving pH control, acid-injection wells, and optimized potential gradient as part of the investigative program. With pH controlled within the range 2.5-3, four acid-injection wells, and a potential gradient of 0.8 V/cm; overall clean-up efficiencies of 85%, 58%, and 34% were achieved for sandy, sandy loam, and silty loam soils, respectively.