表面活性剂对多环芳烃的淋洗修复

土壤是人类赖以生存和发展的物质基础和环境条件。但目前无论在发展中国家还是在发达国家土壤污染问题都很严重。土壤淋洗修复技术是一种行之有效的污染土壤治理技术,适合于快速修复受高浓度重金属和有机物污染土壤与沉积物。研究了Triton X-100、SDS、TW80对多环芳烃的增溶作用,以及不同比例的Triton X-100/SDS复合表面活性剂对多环芳烃的增溶作用效果。以沈阳炼焦煤气厂搬迁区为实例,研究了土壤与淋洗剂的固液比、淋洗剂的浓度和淋洗的振荡时间对土壤淋洗修复效果的影响。     

生物柴油基微乳液的制备及其对钢铁厂多环芳烃污染土壤的修复性能

针对场地土壤中高浓度多环芳烃较难去除的问题,利用微乳液具有界面张力低、增溶能力强和体系稳定的特点,制备了污染土壤淋洗修复剂。采用表面活性剂、助表面活性剂、生物柴油为主要组分制备微乳液,优化微乳液最佳组分配比及制备条件,并比较表面活性剂、复配表面活性剂、生物柴油和微乳液等不同类型淋洗剂对钢铁厂污染土壤中多环芳烃的去除效果。结果表明,最佳微乳液组分及pH条件为：7.7% Tween-80、7.7% TX-100、15.4%正丁醇、20.5%生物柴油、pH=7。在不同类型的淋洗剂中,微乳液淋洗剂对多环芳烃的去除率最高(89.7%),显著高于其他类型淋洗剂的效果。多环芳烃的去除率与淋洗剂和土壤的液固比、洗脱振荡时间等有关,确定的微乳液最佳修复条件为：液固比为4∶1、洗脱振荡时间为8 h。按混合表面活性剂与生物柴油比为6∶4制备的微乳液洗脱效果最佳。本研究结果可为高效去除污染土壤中多环芳烃打下基础。     

多环芳烃污染土壤的植物与微生物修复研究进展

概括介绍了多环芳烃污染土壤的植物修复、微生物修复和植物 微生物联合修复的原理、优缺点、影响因素及国内外研究进展 ,并对生物修复的未来发展进行了展望     

多环芳烃污染土壤生物修复的强化方法

生物降解是去除环境中多环芳烃(PAHs)的重要途径，通过采取一些强化措施，如使用表面活性剂，添加营养物质和提供共代谢底物等，可显著提高PAHs降解速度和程度，为生物修复技术的成功应用提供前提。在分析中，对近年来国内外在PAHs污染土壤生物修复强化方面的研究进展进行了综述。     

表面活性剂增效电动技术修复多环芳烃污染土壤

研究了电动修复过程中修复时间和表面活性剂Triton X-100、鼠李糖脂对多环芳烃芘污染土壤的修复效果的影响。结果表明,在电动修复过程中,随着修复时间的增加,芘的去除率相应提高。通过向电解液中添加表面活性剂Triton X-100,芘的去除率从11.64%提高到了23.42%,当在电解液中添加浓度为40倍CMC的鼠李糖脂后去除率升高至36.29%,阳极附近土壤甚至达到了92.49%,这表明Triton X-100和鼠李糖脂均能促进土壤中芘的溶解和迁移,鼠李糖脂的促进作用高于Triton X-100。     

多环芳烃污染土壤生物修复的强化方法

生物降解是去除环境中多环芳烃(PAHs)的重要途径,通过采取一些强化措施,如使用表面活性剂,添加营养物质和提供共代谢底物等,可显著提高PAHs降解速度和程度,为生物修复技术的成功应用提供前提。在分析中,对近年来国内外在PAHs污染土壤生物修复强化方面的研究进展进行了综述。     

污染土壤的淋洗法修复研究进展

污染土壤淋洗技术是修复污染土壤的一种新方法 ,是对污染土壤生物修复的一种补充 ,使污染土壤修复的系统化成为可能。淋洗法主要使用淋洗剂清洗土壤 ,使土壤中污染物随淋洗剂流出 ,然后对淋洗剂及土壤进行后续处理 ,从而达到修复污染土壤的目的。因为淋洗剂的种类和淋洗方式的不同 ,土壤淋洗法可分为许多种类。土壤淋洗法主要受土壤条件、污染物类型、淋洗剂的种类和运行方式等因素影响。综合考虑多方面因素 ,就有潜力设计出经济高效的土壤淋洗系统。土壤淋洗法有很多优点 ,尽管也存在一些问题 ,但其技术上的优势也是其他方法难以取代的 ,所以有良好的应用前景。     

污染土壤的淋洗法修复研究进展

污染土壤淋洗技术是修复污染土壤的一种新方法，是对污染土壤生物修复的一种补充，使污染土壤修复的系统化成为可能。淋洗法主要使用淋洗剂清洗土壤，使土壤中污染物随淋洗剂流出，然后对淋洗剂及土壤进行后续处理，从而达到修复污染土壤的目的。因为淋洗剂的种类和淋洗方式的不同，土壤淋洗法可分为许多种类。土壤淋洗法主要受土壤条件、污染物类型、淋洗剂的种类和运行方式等因素影响。综合考虑多方面因素，就有潜力设计出经济高效的土壤淋洗系统。土壤淋洗法有很多优点，尽管也存在一些问题，但其技术上的优势也是其他方法难以取代的，所以有良好的应用前景。     

植物混种原位修复多环芳烃污染农田土壤

通过比较实验前后土壤微生物主要类群数量、PAHs降解菌数量、土壤PAHs含量和植物不同部位PAHs含量变化,评价植物单种和混种野外原位修复多环芳烃(PAHs)污染农田土壤的效果。结果显示,150 d天生长期内,黑麦草/小麦混种及黑麦草/蚕豆混种修复效果最好,对土壤PAHs总量的降解率分别达到了59.4%和64.8%。同时,这2个混种处理土壤细菌、真菌和PAHs降解菌数量分别显著高于相应的小麦、蚕豆和黑麦草单种处理。植物不同部位PAHs含量高低次序为根部>茎叶≈籽粒。混种模式下,蚕豆和小麦不同部位PAHs含量比单种模式的不同程度降低,特别是籽粒部。植物混种模式不仅显著提高了土壤PAHs的降解率,还降低了农作物体内PAHs含量,实现了边生产边修复,在污染农田土壤修复领域有着广阔的应用前景。     

均匀电场下多环芳烃在土壤中的迁移

当循环电解液流速为800 mL/h,电解液为无菌水时,电渗流流量、菲和芘在土壤中迁移量在电压梯度为1 V/cm作用下比电压梯度为0.5 V/cm时要多;电动注入表面活性剂Tween80和HPCD均可以提高菲和芘在土壤中的迁移,注入Tween80和HPCD浓度分别为500和1 000 mg/L时,相应地Phe提高5.8倍和11.7倍、芘提高2倍和3.4倍;而BaP在水中的溶解度太小,电场作用和电动注入表面活性剂对BaP在土壤中的迁移量影响很小。为建立电动修复有机污染物污染提供了技术基础。     

Remediation of soil contaminated with dioxins by subcritical water extraction

The effectiveness of subcritical water extraction (SCWE) was examined for removing dioxins from contaminated soil. Most dioxins in the soil sample were reduced at 300 degrees C or more, but decreased dioxin concentrations were also observed at 150 degrees C. After 4 h of extraction, 99.4%, 94.5% and 60% of PCDDs were removed from samples at 350, 300 and 150 degrees C, respectively. It was also determined that degradation of dioxins had occurred, since the sum of dioxins in the soil plus water extracts after the experiments had considerably decreased. This study revealed that pressurizing is not essential for the removal of dioxins. Reduction was complete within 30 min at 350 degrees C; however, it took a much longer time at lower temperatures. The results of addition experiments in which OCDDs were added to different types of soil samples have shown that dechlorination is one of the major reaction pathways. After addition of OCDD to soil samples, experiments were carried out to examine in detail the degradation pathways of PCDDs. The removal rates and congener profiles varied among soil types. Although it was previously assumed that removal rates and congener profiles depended on the chemical components in soil, nonparametric statistical analysis revealed no significant relationship between the rate of reduction and elements present in the soil. It was confirmed from isomer patterns that dechlorination of the 2,3,7,8-positions in PCDDs takes place somewhat faster than for the 1,4,6,9-positions.     

Remediation of metal contaminated soil with mineral-amended composts

This study examined the use of two composts derived from green waste and sewage sludge, amended with minerals (clinoptilolite or bentonite), for the remediation of metal-contaminated brownfield sites to transform them into greenspace. Soils contaminated with high or low levels of metals were mixed with the mineral-enhanced composts at different ratios and assessed by leaching tests, biomass production and metal accumulation of ryegrass (Lolium perenne L.). The results showed that the green waste compost reduced the leaching of Cd and Zn up to 48% whereas the composted sewage sludge doubled the leachate concentration of Zn. However, the same soil amended with composted sewage sludge showed an efficient reduction in plant concentrations of Cd, Cu, Pb or Zn by up to 80%. The results suggest that metal immobilisation and bioavailability are governed by the formation of complexes between the metals and organic matter. The amendment with minerals had only limited effects.     

微生物菌剂对石油污染土壤的修复研究

在油田周围普遍存在着土壤盐渍化和石油污染双重问题.为了修复胜利油田周围的污染土壤,采取了淡水压盐、土壤翻耕、添加菌剂和营养盐等措施,测定了在修复过程中的水溶性盐、微生物、脱氢酶、石油含量等变化.结果表明,在修复过程中微生物数目、脱氢酶和石油降解率具有相关性,修复初期,三者均处于较高水平,随后微生物数目减少,脱氢酶活性降...     

高岭土模拟铜污染土壤电动力学修复

采用电动力学方法修复重金属污染土壤。研究中采用高岭土模拟铜污染土壤,结合电动力学修复理论,考察了不同电压、添加络合剂条件下铜的修复效果。结果表明,当电压强度为0．5V／cm时,最靠近阴极部分的土壤中Cu^2＋的C／C。为1．596,当电压强度为1V／cm时,C／C0为2．245,说明适当提高电压强度能够有效的增加Cu^2＋的迁移效果;土壤中未加入络合剂时,Cu^2＋大部分集中在第5段土壤中,C／C0为1．339,在土壤中加入络合剂以后Cu^2＋大部分集中在靠近阴极部分的土壤中,C／C。为1．716,说明在污染土壤中加入一定量的络合剂可以与Cu^2＋结合生成螯合物,提高Cu^2＋的迁移效果。     

PAHs污染土壤的热修复可行性

以某煤制气厂污染场地中16种US EPA优先控制多环芳烃（Σ16 PAHs）为目标污染物进行了热修复批量实验和可行性实验。热修复批量实验结果表明,当热修复温度为400 ℃、加热时间为8 h时,土壤中的Σ16 PAHs去除率达99.9%。热修复可行性实验选择重污染、中污染和轻污染土壤以400 ℃作为目标温度,恒温72 h进行实验。热修复前后不同程度污染土壤的Σ16 PAHs的总去除率均可达到99.9%,但重污染土壤浓度非常高,部分苯并类物质未达到修复目标值,需进一步延长加热时间或提高加热温度保证达到修复目标值。土壤土工参数影响分析结果表明,热修复后土壤颗粒粒径呈增大趋势,土壤稳定性、抗压强度均增强。此外,土壤中可溶性盐含量增多,盐渍化程度增大。     

Remediation of toxic metal contaminated soil by washing with biodegradable aminopolycarboxylate chelants

Ex situ soil washing with synthetic extractants such as, aminopolycarboxylate chelants (APCs) is a viable treatment alternative for metal-contaminated site remediation. EDTA and its homologs are widely used among the APCs in the ex situ soil washing processes. These APCs are merely biodegradable and highly persistent in the aquatic environments leading to the post-use toxic effects. Therefore, an increasing interest is focused on the development and use of the eco-friendly APCs having better biodegradability and less environmental toxicity. The paper deals with the results from the lab-scale washing treatments of a real sample of metal-contaminated soil for the removal of the ecotoxic metal ions (Cd, Cu, Ni, Pb, and Zn) using five biodegradable APCs, namely [S,S]-ethylenediaminedisuccinic acid, imminodisuccinic acid, methylglycinediacetic acid, DL-2-(2-carboxymethyl) nitrilotriacetic acid (GLDA), and 3-hydroxy-2,2′-iminodisuccinic acid. The performance of those biodegradable APCs was evaluated for their interaction with the soil mineral constituents in terms of the solution pH and metal-chelant stability constants, and compared with that of EDTA. Speciation calculations were performed to identify the optimal conditions for the washing process in terms of the metal-chelant interactions as well as to understand the selectivity in the separation ability of the biodegradable chelants towards the metal ions. A linear relationship between the metal extraction capacity of the individual chelants towards each of the metal ions from the soil matrix and metal-chelant conditional stability constants for a solution pH greater than 6 was observed. Additional considerations were derived from the behavior of the major potentially interfering cations (Al, Ca, Fe, Mg, and Mn), and it was hypothesized that use of an excess of chelant may minimize the possible competition effects during the single-step washing treatments. Sequential extraction procedure was used to determine the metal distribution in the soil before and after the extractive decontamination using biodegradable APCs, and the capability of the APCs in removing the metal ions even from the theoretically immobilized fraction of the contaminated soil was observed. GLDA appeared to possess the greatest potential to decontaminate the soil through ex situ washing treatment compared to the other biodegradable chelants used in the study.     

典型禾本科植物对石油污染土壤的修复作用

石油类污染物对土壤生态系统的结构与功能造成了较为严重的破坏,影响植物的生长,甚至直接影响到人类健康。选择典型禾本科植物 高粱和玉米,通过盆栽实验,种植于模拟石油污染的土壤中,植物成熟收割后,通过测定土壤中总石油烃的含量,植物体中多环芳烃和直链烷烃的含量,研究高粱和玉米对石油污染土壤的修复作用。结果显示：在种植高粱、玉米后,土壤中总石油烃含量明显降低,并且在收获的高粱、玉米植物体中直链烷烃和多环芳烃含量明显高于空白对照组（未检出）。说明高粱、玉米对石油烃具有一定的去除作用,且高粱对土壤中石油烃的去除作用高于玉米;高粱、玉米对土壤中的多环芳烃和直链烷烃具有一定的积累与富集作用。     

原位电阻热脱附修复氯代烃污染土壤

针对原位电阻热脱附(ISERH)技术基础性研究不足、缺乏小试设备研发等问题,利用自主研发ISERH设备,以1,2-二氯乙烷和氯苯为目标污染物,探究了ISERH过程中土壤温度变化及设定温度、加热时间、污染物种类、老化时间对污染物热脱附效果的影响.结果表明,在热脱附过程中氯代烃污染土壤的主要阴离子SO42-和Cl-含量分别...     

微波催化氧化修复技术处理有机氯污染土壤

采用微波催化氧化修复技术处理常州某农药厂有机氯农药污染场地和南通某化工厂有机氯污染场地土壤,考察不同参数条件下实验装置对污染土壤的处理效能。结果表明,在微波功率18kW、微波辐射时间20min、土壤处理量400kg/h、土壤含水率15%、活性炭添加量0.03kg/kg的最佳条件下,实验装置运行稳定,有机氯农药污染土壤中氯丹去除率可达70%左右;有机氯污染土壤中邻二氯苯、石油烃总量、1,2-二氯乙烷、苯酚去除率分别可达到99.98%、91.29%、98.52%、74.74%。研发的污染土壤微波催化氧化修复技术及实验装置对有机氯污染土壤的修复具有一定的普适性。     

Remediation of contaminated soil by a solvent/surfactant system

This study investigates a new approach using a solvent/surfactant-aided soil-washing process to improve the performance of conventional surfactant-aided soil remediation. Three surfactants (Brij 35, Tween 80, and SDS) and three organic solvents (acetone, triethylamine, and squalane) were used to evaluate the desorption performances of 4,4'-dichlorobiphenyl (DCB) out of three soils with different sorption characteristics. The performance improvement is likely due to better dissolution of the hydrophobic contaminants from the soil assisted by the solvent, and the formation of solvent-incorporated surfactant micelles, which increases both the size (i.e. capacity) and affinity of micelles for more effective contaminant extraction. The foc of soils were found to be important in determining the performance of a solvent/surfactant-aided soil-washing process. Judging from the experimental data and as verified by the two constants in the proposed soil-washing model, as the organic solvent is coexisting with the surfactant micelles, both the marginal soil-washing performance (right after the use of a very small amount of solvent compared to that of none) and the final soil-washing capacity are increased compared to those of a pure surfactant-aided washing process.