过碳酰胺对土壤中三氯甲烷和四氯乙烯的降解作用

采用室内土培试验手段,研究了1种酸性土壤中施入过碳酰胺后对三氯甲烷（TCM）和四氯乙烯（PCE）的降解效果。试验结果表明：过碳酰胺对土壤中TCM和PCE都有一定的降解,且随着降解时间的延长,过碳酰胺对TCM和PCE的降解效果逐渐增加。8周后TCM和PCE的降解率分别为23.91%和87.83%,说明过碳酰胺对TCM的降解效果差于对PCE的降解。随着过碳酰胺质量浓度的增加,TCM和PCE的降解效率提高,但过碳酰胺质量浓度较大时,过碳酰胺的有效利用率会降低。100mg·kg^-1的Tween80的存在会抑制过碳酰胺对土壤中TCM和PCE的降解。     

表面活性剂对东北黑土中苯并[a]芘的增溶洗脱作用

研究了4种常见表面活性剂十二烷基苯磺酸钠(SDBS)、十二烷基硫酸钠(SDS)、Tween80和TritonX-100对东北农田黑土土壤中苯并[a]芘的洗脱修复效果。增溶试验结果表明,非离子表面活性剂Tween80和TritonX-100对苯并[a]芘的增溶能力显著高于阴离子表面活性剂SDBS和SDS。4种表面活性剂在单一和混合处理条件下均能不同程度地洗脱土壤中的苯并[a]芘,且洗脱率随着表面活性剂浓度的增加而增大。各表面活性剂洗脱能力大小顺序为Tween80-SDS(3:1)Tween80-SDS(1:1)Tween80-SDS(10:1)Tween80TritonX-100SDSSDBS,当Tween80和SDS质量比为3:1时对两受试土壤中苯并[a]芘的去除率分别达到最高的42.3%和44.8%,可见阴-非离子混合表面活性剂对土壤苯并[a]芘的洗脱效果好于单一表面活性剂。土壤老化70 d后,Tween 80和Tween 80-SDS(3:1)处理对苯并[a]芘的洗脱率相比老化仅14 d的土壤分别下降了20.5%和12.9%,表明土壤老化时间的增加可降低表面活性剂对苯并[a]芘的洗脱去除效果。     

塿土对阴-非离子表面活性剂的吸附特征研究

以平衡吸附法研究了塿土对阴离子表面活性剂（SDS）、非离子表面活性剂（TritonX-100、Tween80和Brij35）的吸附特征,考察了pH、阴-非离子表面活性剂混合对塿土吸附表面活性剂的影响。结果表明,非离子表面活性剂在塿土上吸附等温线均呈L型,且均符合Freundlich和Langmuir方程;塿土对SDS的吸附等温线呈LS型,可用Freundlich方程来描述;塿土对4种表面活性剂吸附量的大小顺序为Tween80〉SDS〉Brij35〉TritonX-100。当阴-非离子表面活性剂一起进入土壤中,SDS-Brij35之间的相互影响不大;TritonX-100与SDS相互作用较大,无论二者以何种方式混合都会使TritonX-100在塿土上的吸附量增加,SDS的吸附量下降;SDS与Tween80之间的相互作用最大,混合后吸附量均下降,但Tween80吸附量降低的幅度最大。pH对非离子表面活性剂的吸附影响不大,而随着pH的增加,塿土对SDS的吸附百分率明显下降;在pH为8.0时,塿土对非离子表面活性剂的吸附百分率达到80以上。因此在选择合适的表面活性剂进行有机污染土壤修复和治理时,考虑土壤的特性和表面活性剂的结构是非常重要的。     

柠檬酸-1-酰胺二乙烯三胺的制备及其修复土壤重金属离子的行为

为提高柠檬酸修复土壤重金属离子的能力,设计合成新型绿色柠檬酸基表面活性剂柠檬酸-1-酰胺二乙烯三胺,用FT-IR研究其结构,并探究其表面性能。结果表明,新型绿色柠檬酸基表面活性剂的临界胶束浓度低于柠檬酸,其稳泡力、起泡力及亲水亲油平衡值优于柠檬酸。同时开展表面活性剂浓度、pH值、振荡时间、Ca2+浓度影响表面活性剂对土壤重金属污染去除率的研究,结果表明,柠檬酸-1-酰胺二乙烯三胺对重金属去除率随浓度、振荡时间的增加而升高;随离子强度、pH值的增加而降低。柠檬酸-1-酰胺二乙烯三胺去除Cd2+、Pb2+离子的最佳工艺为:质量分数5.5%,pH值3.0,振荡时间10h,Ca2+离子浓度0.4mol/L。在此条件下,2种表面活性剂对土壤中Cd2+、Pb2+离子去除率均达最大,柠檬酸-1-酰胺二乙烯三胺对Cd2+、Pb2+离子最大去除率分别为69.25%和98.59%,去除效果优于柠檬酸。     

阴-非离子表面活性剂对黑土中DDTs的洗脱研究

采用室内序批试验研究了几种非离子及阴离子表面活性剂,以单一和组合2种方式对人工污染黑土中滴滴涕(DDTs)的洗脱特性及影响因素进行了对比分析。结果表明:非离子表面活性剂对DDTs的洗脱效果优于阴离子表面活性剂,其中Tween 60和Tween 80的洗脱效果最佳,最高洗脱率达33.2%~37.2%。将Tween 60与阴离子表面活性剂SDS按一定质量比例组合可提高洗脱效果,尤其在质量比为3∶1时的洗脱率比Tween 60单独处理时高20%以上。表面活性剂对DDTs洗脱率随土壤老化时间的延长而降低,而土壤老化时间对Tween 60-SDS组合洗脱能力的抑制程度小于对Tween 60洗脱能力的抑制程度。无机助剂Na2SiO3或Na2CO3的添加可显著促进DDTs的表面活性剂洗脱效果,其中1 000mg/L的Na2SiO3使单一及混合表面活性剂对DDTs的洗脱率提高至1.4倍左右。3种有机助剂的添加同样对4,4’-DDT洗脱率起到一定的强化作用,但强化效果略低于无机助剂,对洗脱效果的促进作用大小顺序为:正丙醇正丁醇正己醇。     

吐温类表面活性剂在黑龙江黑土中的吸附特性研究

采用平衡振荡法,研究黑龙江黑土对吐温类非离子表面活性剂(Tween20、Tween40、Tween60和Tween80)的吸附特征及影响因素。结果表明,在试验浓度范围内,吐温类表面活性剂在黑土上的吸附随着平衡质量浓度的增加而增加;各表面活性剂的吸附等温线均呈"S"型,可用Freundlich吸附模型来描述;在同一平衡质量浓度下,Tween20和Tween40在黑土中的吸附量高于Tween60和Tween80的吸附量;有机质含量高的土壤S1对表面活性剂吸附能力高于有机质含量低的土壤S2。通过H2O2氧化去除黑土中的有机质后,对表面活性剂的吸附量与原土相比变化不大,表明土壤矿物质和有机质都是吸附表面活性剂的重要成分。黑土对Tween80的吸附量随着温度的增加而增加,但随着体系pH值的增加而呈现逐渐下降的趋势。     

Tween 80对DDTs污染场地土壤的增溶洗脱效果研究

以苏南某滴滴涕类化合物（DDTs）污染场地土壤为研究对象,进行实验室批量洗脱试验,研究了环境友好型表面活性剂Tween 80对土壤中DDTs的增溶洗脱效果及其影响因素。结果表明,Tween 80显著地增加了DDTs表观溶解度,在临界胶束浓度（CMC）以上对DDTs的增溶曲线呈指数衰减函数关系,DDTs各组分洗脱量顺序为4,4′-DDT〉4,4′-DDD〉2,4′-DDD〉2,4′-DDT。Tween 80的浓度、洗脱次数及土壤吸附作用共同影响其对DDTs的洗脱效果。去离子水能有效去除土壤中残留Tween 80,Tween 80解吸附率最高可达72.66%,大大降低了Tween 80二次污染土壤的风险。Tween 80增溶和去离子水解吸附联合过程对DDTs洗脱效果产生显著的协同作用。10 000 mg·L^-1浓度条件下Tween 80对DDTs的去除率最高为72%,其次为8 000 mg·L^-1 的Tween 80水溶液,去除率为66.72%。采用8 000 mg·L^-1的Tween 80溶液进行土壤洗涤处理,结合其他修复技术,可能会是修复DDTs污染土壤的有效技术方案之一。     

表面活性剂与EDTA对雪菜吸收镉的影响

采用表面活性剂与螯合剂处理,强化雪菜吸收土壤镉的盆栽试验表明,影响植物吸收镉的主要因子是表面活性剂类型。阴离子型与非离子型表面活性剂的强化修复效果要优于阳离子型表面活性剂,其中以十二烷基硫酸钠和Tween80为好。表面活性剂与EDTA复合使用,可以降低土壤对镉的吸附(顺序依次为EDTA/DBSSEDTA/TX-100EDTA/CTABEDTADBSSTX-100CTAB),增加土壤对镉的解吸,进而促使土壤镉向植物转移,有利于强化镉污染土壤的植物修复。     

阴/非表面活性剂对菲污染砂土柱淋洗研究

采用玻璃土柱法比较研究了1000、2000、3000和4000mg·L^-1的阴离子表面活性剂十二烷基苯磺酸钠（SDBS）、非离子表面活性剂聚氧乙烯山梨糖醇酐单油酸酯（Tween80）及不同质量配比的混合表面活性剂（SDBS-Tween80）（S∶T=1∶1、1∶2和1∶4）对砂土中菲的柱淋洗。结果表明,SDBS对菲的淋洗曲线总体上呈现先上升到峰值而后下降的变化规律,且呈锯齿形波动;而Tween80与SDBS-Tween80对菲的淋洗曲线具有相似的规律,即淋出液中菲浓度随表面活性剂淋洗液孔隙体积数增大呈现急剧增大、达到峰值后逐渐降低的趋势。淋洗结束时（菲流出浓度接近于0时）,不同浓度的Tween80和SDBS-Tween80对菲的总去除率均可达90.5%以上,而4000mg·L^-1的SDBS对菲的总去除率则仅为76.4%。此外,随着Tween80或SDBS-Tween80浓度增大,菲浓度峰值增大,开始有菲淋出时,菲浓度峰值以及菲流出浓度接近于0时对应的孔隙体积数均减小。菲浓度峰值与表面活性剂浓度呈正相关,累积孔隙体积数与表面活性剂浓度呈负相关。在淋出液累计孔隙体积数相同时,同种表面活性剂对菲的去除率与表面活性剂浓度呈正相关。     

生物质炭引起的土壤碳激发效应与土壤理化特性的相关性

生物炭因含有丰富的惰性碳元素而被看作是一种极富应用前景的固碳材料，将其施入土壤后可以增加土壤稳定性碳库，减缓全球气候变化。前人研究表明，生物炭添加到土壤中后，将增加（正激发效应）或者减缓（负激发效应）土壤原有机碳的矿化速率。然而，生物炭对不同土壤的激发效应以及土壤性质与生物炭激发效应之间的关系还不明确。因此，本研究利用13C 稳定性同位素标记的小麦秸秆制作成生物炭，分别将等碳量的生物炭和标记秸秆添加到四种不同性质的土壤中，室内培养一年，测定生物炭及秸秆中的碳元素在不同土壤中的降解量及其对土壤原有机碳的激发效应量。研究结果表明：生物炭在黑土水稻土以及下位砂姜土水稻土中引发了显著的负激发效应，激发效应量分别为-284 mg/kg和-157 mg/kg，而在红壤水稻土以及低肥力红壤水稻土（长期定位不施肥的红壤水稻土）中引发正激发效应，激发效应量分别为33.3 mg/kg和58.0 mg/kg；秸秆在四种土壤中引发的激发效应量不同，均为正激发效应，正激发效应量远大于生物炭。生物炭激发效应量与土壤的Ec（r= -0.884）以及pH（r= -0.824）成极显著的负相关关系。生物炭-碳在不同土壤上的累积降解量存在显著差异，黑土水稻土中为15.6 mg/kg，红壤水稻土中为14.2 mg/kg，下位砂姜土以及低肥力红壤水稻土中相似，分别为10.4 mg/kg和9.92 mg/kg；秸秆-碳的累积降解量远大于生物炭-碳，其在低肥力红壤水稻土中的降解量显著低于其他三种土壤。生物炭添加在黑土水稻土中碳净损失量最低，下位砂姜土水稻土中次之，低肥力红壤水稻土中最高。研究表明，生物炭在土壤中的固碳效果不仅受到生物炭-碳自身降解速率的影响，还会受到生物炭引发的土壤碳激发效应量的影响。     

Effect of SDBS–Tween 80 mixed surfactants on the distribution of polycyclic aromatic hydrocarbons in soil–water system

Purpose

Enhancing desorption of hydrophobic organic contaminants from soils is a promising approach for the effective remediation of soils contaminated with organic compounds. The desorption efficiency of chemical reagent, such as surfactant, should be evaluated. In this study, the effect of mixed anionic–nonionic surfactants sodium dodecylbenzene sulfonate (SDBS)–Tween 80 on the distribution of polycyclic aromatic hydrocarbons in soil–water system was evaluated.

Materials and methods

Batch desorption experiments were employed to evaluate the distribution of polycyclic aromatic hydrocarbons (PAHs) and surfactants in soil–water system. PAHs and SDBS were determined by high-performance liquid chromatography, Tween 80 by spectrophotometry, and total organic carbon with a carbon analyzer.

Results and discussion

Sorption of PAHs to soil was increased at low surfactant concentration due to the effective partition phase on soil formed by sorbed surfactants. The mixture of anionic and nonionic surfactants decreased the sorption of surfactants to soil, increasing the effective surfactant concentration in solution and thus decreasing the sorption of PAHs on soil. Anionic–nonionic mixed surfactant showed better performance on desorption of PAHs from soil than single surfactant. The greatest desorption efficiency was achieved with low proportions of SDBS (SDBS/Tween80?=?1:9).

Conclusions

SDBS–Tween 80 mixed surfactant showed the highest desorption rate with low proportion of SDBS, which indicated that the addition of relative low amount of anionic surfactant could significantly promote the desorption efficiency of PAHs by nonionic surfactants. Results obtained from this study did provide useful information in surfactant-enhanced remediation of soil and subsurface contaminated by hydrophobic organic compounds.     

表面活性剂溶液清洗油污土壤试验研究

选用两种阴离子型表面活性剂十二烷基苯磺酸钠(LAS)和十二烷基硫酸钠(SDS)及两种非离子型表面活性剂Triton X-100和Tween 80,研究了临界胶束浓度(CMC)附近各表面活性剂溶液对柴油的增溶及一次性清洗油污土壤的能力。结果表明:在CMC附近,各表面活性剂对柴油的增溶能力大小顺序为SDSSDS>Triton X-100>Tween 80,两种阴离子型表面活性剂的清洗效果优于两种非离子型表面活性剂。     

Surfactant Enhanced Desorption of TNT from Soil

Surfactant enhanced desorption of 2,4,6-trinitrotoluene (TNT) from contaminated soils at a military site was investigated. Anionic (SDS and DOWFAX 8390), cationic (CTAC and CTAB), and nonionic (Tween 80 and Brij 35) surfactants were first tested at concentrations ranging from 0.1 to 1%. The anionic and nonionic surfactants were further tested at concentrations of up to 10%. Anionic surfactants, particularly SDS, provided the best desorption of TNT from the soil. There was not any increase in TNT desorption for both the nonionics and cationics at concentrations ranging between 0.1 to 1% and the extent of desorption was found to be lower than the TNT desorption only by water. The competition of the negatively charged soil surfaces for the positively charged cationics and the neutral nonionic surfactants may constitute the underlying reason. TNT was significantly desorbed when the concentrations of Tween 80, DOWFAX 80 and SDS were increased up to 10%.     

表面活性剂对植物修复有机污染土壤的增效作用及原理

Phytoremediation is becoming a cost-effective technology for the in-situ clean up of sites polluted with hydrophobic organic contaminants （HOCs）. The major factors limiting phytoremediation are the mass transfer, rate of plant uptake, and microbial biodegradation of HOCs. This article discusses the potential of surfactants to enhance desorption, plant uptake, and biodegradation of HOCs in the contaminated sites. Positive effects of surfactants on phytoremediation have been recently observed in greenhouse studies. The presence of some nonionic surfactants including polyoxyethylene sorbltan monooleate （Tween 80） and polyoxyethylene（23）dodecanol （Brij35） at relatively low concentrations resulted in significant positive effects on phytoremediation for pyrene-contaminated soil. However, the anionic surfactant （sodium dodecyl sulfate, SDS） and the cationic surfactant （cetyltrimethylammonium bromide, CTMAB） were not useful because of their phytotoxicity or low efficiency for surfactant-enhanced phytoremediation （SEPR）. The mechanisms of SEPR for HOC-contaminated sites were evaluated by considering experimental observations. In view of concerns about the cost effectiveness and toxicity of surfactants to plants, more research is needed to enhance the use of SEPR technology.     

Influence of Soil Granulometry on Pyrene Desorption in Groundwater Using Surfactants

The high hydrophobicity of polycyclic aromatic hydrocarbons (PAHs) is the main limiting factor for the remediation of soils and aquifers. Surfactants are amphiphilic substances which encourage the transfer of hydrophobic compounds from the solid to the liquid phase. While the interaction between organic matter and surfactants has been widely studied, there is a lack of knowledge concerning the relationship between surfactant efficiency and the granulometry of soil and/or geologic material. In this paper, three non-ionic surfactants (Tween 80, Gold Crew, and BS-400) were used to study the desorption of pyrene, chosen as a representative PAH, in soils with different grain size proportions (1%, 5%, 10%, and 20% of clay and silt) and no organic matter (<0.1%). The best quantity of surfactant to apply is closely related to the proportion of fine materials. Tween 80 gave better maximum desorption than Gold Crew and BS-400 (89%, 40%, and 36%, respectively). As an important proportion of aquifers show fine material above 1%, the effective critical micellar concentration obtained when applying surfactants to this type of geologic materials has to be higher than 150 mg L⁻¹ for Tween 80, and higher than 65 mg L⁻¹, and 100 mg L⁻¹ for Golf Crew and BS 400, respectively. Furthermore, results indicate that carrying out simple laboratory tests before the use of surfactants on a field scale is necessary to improve the efficiency and minimize the financial and environmental impact of its application.     

Influence of surfactant charge on antimicrobial efficacy of surfactant-stabilized thyme oil nanoemulsions

Thyme oil-in-water nanoemulsions stabilized by a nonionic surfactant (Tween 80, T80) were prepared as potential antimicrobial delivery systems (pH 4). The nanoemulsions were highly unstable to droplet growth and phase separation, which was attributed to Ostwald ripening due to the relatively high water solubility of thyme oil. Ostwald ripening could be inhibited by incorporating ≥75% of corn oil (a hydrophobic material with a low water solubility) into the nanoemulsion droplets. The electrical characteristics of the droplets in the nanoemulsions were varied by incorporating ionic surfactants with different charges after homogenization: a cationic surfactant (lauric arginate, LAE) or an anionic surfactant (sodium dodecyl sulfate, SDS). The antifungal activity of nanoemulsions containing positive, negative, or neutral thymol droplets was then conducted against four strains of acid-resistant spoilage yeasts: Zygosaccharomyces bailli, Saccharomyces cerevisiae, Brettanomyces bruxellensis, and Brettanomyces naardenensis. The antifungal properties of the three surfactants (T80, LAE, SDS) were also tested in the absence of thymol droplets. Both ionic surfactants showed strong antifungal activity in the absence of thymol droplets, but no antimicrobial activity in their presence. This effect was attributed to partitioning of the antimicrobial surfactant molecules between the oil droplet and microbial surfaces, thereby reducing the effective concentration of active surfactants available to act as antimicrobials. This study shows oil droplets may decrease the efficacy of surfactant-based antimicrobials, which has important consequences for formulating effective antimicrobial agents for utilization in emulsion-based food and beverage products.