Reversible Solubilization of Typical Polycyclic Aromatic Hydrocarbons (PAH) by a Gas Switchable Surfactant

Surfactant‐enhanced remediation (SER) is one of the most effective remediation methods for polycyclic aromatic hydrocarbons (PAH) contaminated soils. However, mass deployment of SER has been restricted due to the shortage of the separation, recycle technology of the surfactant and its operation costs. This research mainly studied the reversibility of 2‐n‐lauryl‐1,1,3,3‐tetramethyl guanidine (DTMG) surfactant and its influence on reversible solubilization of typical PAH. Experimental results showed that the reversibility of the DTMG surfactant is excellent. The critical micellar concentration (CMC), surface tension and pH of DTMG in CO₂/N₂ conditions undergo reversible changes promptly. DTMG·CO₂ shows a strong solubilization capacity for PAH; the apparent solubilities of the selected PAH pyrene, phenanthrene and anthracene in 4 mmol/L of DTMG·CO₂ solution were about 32.4, 17.1 and 14.6 times higher than in water, respectively. The corresponding molar solubilization ratios were 5.4 × 10^?3, 2.80 × 10^?2 and 1.1 × 10^?3, much higher than those with DTMG. More than 50 % of the PAH in surfactant solutions could be released through gas control at each surfactant concentration, and improved release efficiency was achieved at low surfactant concentrations. In brief, such results in this work introduce a facile method to meliorate the SER technology.     

可逆表面活性剂十一烷基二茂铁三甲基溴化铵的合成、表征及其电化学行为的研究

以傅克反应与氨基化反应为主要方法,合成了阳离子型表面活性剂十一烷基二茂铁三甲基溴化铵(简称FTMA)。核磁共振氢谱与碳谱分析结果表明,FTMA的分子结构与理论结构相吻合,色谱纯度为97%;通过铂金板法测定了30℃下FTMA在还原态与氧化态(FTMA+)下的临界胶束浓度(CMC)分别为0.6 mmol/L与1.0mmol/L,两种状态表面活性发生了大幅度变化;采用循环伏安法考察了FTMA在0.2 mol/L L i2SO4溶液中的电化学性能,FTMA氧化峰和还原峰电位分别为0.457 0 V和0.416 8 V(vsSCE),峰电位之差ΔEp=40.2 mV,峰电流之比Ipa/Ipc=1.26,显示出良好的电化学可逆变化特性,并用电化学方法完成了FTMA在还原态与氧化态之间的转换。结果表明,FTMA可通过电化学"开关"控制其表面活性态和非表面活性态之间的可逆变换,是一种新型的可用于可逆增溶修复过程的表面活性剂。     

阳离子表面活性剂胶束和微乳液增溶过程的核磁共振谱法研究(英文)

运用高分辩NMR方法 ,研究了阳离子表面活性剂十六烷基三甲基溴化铵 (CTAB)胶束水溶液、KBr盐溶液对苯甲醇的增溶作用及CTAB/正丁醇 /10 %正辛烷 /水反向微乳液对丙烯酰胺(AM)的增溶作用。结果表明 ,在苯甲醇浓度低时苯甲醇主要增溶于CTAB胶束水溶液或KBr盐溶液的界面层 ,随着增溶物浓度的增大 ,苯甲醇主要增溶于胶束的栅栏层和胶束内核。在CTAB胶束水溶液中 ,当苯甲醇浓度达到 0 35 7(V/V)时 ,它沿烃链的增溶达到饱和 ,并开始进入胶束内核中心 ,并引起CTAB长链亚甲基峰分裂成两个单峰 ,一个在高场 ,一个在低场 ,而在CTAB胶束KBr盐溶液中 ,未得到长链亚甲基的分裂峰。在CTAB油包水 (W /O)微乳液中 ,通过 1H和 13CNMR谱讨论了丙烯酰胺与CTAB和正丁醇的相互作用 ,丙烯酰胺浓度较小时 ,其增溶在微乳液的Stern层 ,当丙烯酰胺与CTAB摩尔比接近 0 75时 ,丙烯酰胺分子增溶到栅栏层 ,并沿CTAB烃链进行分布     

食品中多环芳烃的快速荧光检测

建立了油炸、烧烤类食品中多环芳烃的同步荧光测定方法。样品经甲醇－氢氧化钾皂化,环己烷提取,硅胶柱净化,用同步荧光光谱测定。其多环芳烃（PAHs）的回收率为：83．98％～101．70％,相对标准偏差为：0．62％～1．42％。所建立的分析方法快速、简便,适合多环芳烃的检测分析。     

The Effect of Polycyclic Aromatic Hydrocarbons on the Structure of Organotrophic Bacteria and Dehydrogenase Activity in Soil

The objective of this article was to determine the structure of microbial communities and the activity of dehydrogenases in soil samples contaminated with four polycyclic aromatic hydrocarbons (PAHs), i.e., naphthalene, phenanthrene, anthracene, and pyrene, in the amount of 0, 1000, 2000, and 4000 mg kg^?1soil DM. Organic substances—cellulose, sucrose, and compost—were added to the samples in the amount of 0 and 9 g kg^?1soil DM. The experiment was performed in a laboratory on samples of loamy sand. Indices of colony development (CD) and eco-physiological diversity (EP) of organotrophic bacteria, soil resistance (RS), and soil resilience (RL) were calculated. Soil contamination with PAHs differentiated the structure of organotrophic bacteria, and the lowest CD and EP values were noted in soil samples containing pyrene. PAHs inhibited the activity of dehydrogenases, and pyrene exerted the most inhibitory effect on enzyme activity. Dehydrogenase activity was determined mainly by the applied PAH dose, the date of analysis and the type of organic substance added to soil. Low RL values indicate that exposure to PAHs induces long-term changes in dehydrogenase activity.     

Physico-Chemical Investigations of Mixed Micelles of Cationic Gemini and Conventional Surfactants: a Conductometric Study

The interaction of cationic gemini and cationic conventional surfactants by conductivity was systematically overviewed, paying attention to synergism observed in micellization. These mixed systems were found to show remarkable synergism in micelle formation. The experimental critical micelle concentration values being lower than the value predicted by ideal solution theory indicate that the mixed micellization is due to attractive interaction between the two components. Gemini/conventional systems form mixed micelle due to attractive interactions (negative β values). The values of micellar mole fraction of constituent 1 (X ₁) in surfactant mixtures are more than in the ideal state (X ₁ ^ideal ), which means that, the mixed micelles are rich in conventional surfactants in comparison to that in the ideal state.     

改进索氏提取器提取土壤中多环芳烃（菲、蒽、屈）

文章用改进索氏提取器与自动索氏提取器提取土壤中加标多环芳烃（菲、蒽、屈）,采用高效液相色谱法对提取液进行分离测定,并选择了流动相最佳比例。结果表明,采用改进索氏提取器,二氯甲烷作提取剂,氧化铝柱层析法纯化,并用HPLC—UVD测定可得到很好的效果。三种多环芳烃的平均加标回收率在78.7%~111%之间,且重现性较好。     

Isolation and some Properties of Bacteria that Degrade Polycyclic Aromatic Hydrocarbons

Four bacteria, which could grow on pyrene as the sole source of carbon, were isolated from soil from an urban area in Tokyo. One of them, strain H2-5, was a rod bacterium that was positive in gram staining and in acid-fast staining. The optimum growth temperature was 34-35°C, and the upper limit temperature for the growth was around 45°C. At a concentration of 1.3 μg/ml polycyclic aromatic hydrocarbon (PAH), H2-5 cells (45 μg dry weight/ml) grown on Tryptic Soy Broth made disappear 90% of pyrene in 12 hr, and Benzo(a)pyrene (BaP), Benz(a)-anthracene (BaA), and Benzo(ghi)perylene individually disappeared 60%, 25%, and 8%, respectively, in 3 days. PAHs in the extract by dichloromethane from airborne particles in approximately 5 m³ of air disappeared by the action of H2-5 as follows: pyrene, 100% in 3 days; BaA and BaP, 70% and 71%, respectively, in 4 days. Pyrene in tarry matter extracted from soil disappeared 88% in 4 days.     

固相萃取法和GC-MS联用检测石油污染物中17种多环芳烃

文章建立了一种检测石油污染物中多环芳烃的方法。该法采用商品化的硅胶和氧化铝混合填料固相萃取柱对样品中的烷烃和多环芳烃进行分组,实验结果表明,烷烃及多环芳烃的加标回收率在85.6%~104.9%,分组效率优越,可满足实验需求,消除了烷烃对多环芳烃检测的干扰。在该基础上,对石油样品进行净化处理,经过检测,可准确得到石油样品中多环芳烃的含量,石油样品中多环芳烃的加标回收率数据在85.3%~105.9%,RSD(n=5)范围为2.2%~7.3%,方法具有较好的重现性。本方法操作简便、选择性好、灵敏准确,可应用于石油样品中多环芳烃的检测研究。     

同位素稀释-气相色谱-质谱法同时测定化妆品中20种多环芳烃类化合物

建立了一种同位素稀释-气相色谱-质谱法同时测定化妆品中20种多环芳烃类化合物的方法。不同类型化妆品用环己烷以不同方法进行提取,然后采用GC-MS的选择离子模式对20种目标物进行定性、定量分析。方法具有良好线性,相关系数r均大于0.992,定量限为50μg/kg。各组分平均回收率在70.5%～114.5%,相对标准偏差在1.7%～13.6%。采用此方法测定了化妆品中多环芳烃的水平,发现某些化妆品中存在萘、1-甲基萘和2-甲基萘。     

Inclusion complexation of (11-ferrocenylundecyl)trimethylammonium bromide by β-cyclodextrin and its effects on electrochemical behavior of the surfactant

This report describes the influence of β-cyclodextrin complexation on thermodynamic and kinetic parameters of the electrode reaction of (11-ferrocenylundecyl)trimethylammonium bromide in aqueous media. The host attracted the reduced form having a less positive charge more strongly than the corresponding oxidized one. Thus, a hydrophobic interaction between the non-polar host cavity and the ferrocene moiety plays an important role in the inclusion complexation. Fast-scan voltammetric behavior of the amphiphilic ion suggested that inclusion-ejection processes practically attain equilibrium in the scan-rate range below 10 V s⁻¹, because of their fast rates. The relation between the peak current and peak potential leads to the conclusion that the enveloped guest exchanges no electrons directly with an electrode. The mean diffusion coefficient of the surfactant can be written as a linear combination of the contributions from a free monomolecular, a micelle-forming, and a host-bound surfactant. Since the binding affinity of the ferrocene moiety for the host cavity is much stronger than the aggregation force between the amphiphilic molecules in aqueous media, the host disrupts the micelles by incorporating the surfactant molecule into its cavity.     

多环芳烃菲和荧蒽半抗原的制备及量化计算

以多环芳烃菲和荧蒽为原料,分别与丁二酸酐发生傅克酰基化反应,制备γ-羰基-2-菲丁酸和γ-羰基-3-荧蒽丁酸,再经黄鸣龙还原制备半抗原2-菲丁酸和3-荧蒽丁酸,产品结构经熔点、IR和1HNMR表征。采用量子化学计算优化两种半抗原的分子构型,获得前线轨道、能量、电子分布及稳定性等信息,辅助半抗原的设计和筛选,为制备高特异性人工抗原奠定了基础。     

Health Assessment of Polycyclic Aromatic Hydrocarbon Mixtures: Current Practices and Future Directions

The U.S. EPA's Integrated Risk Information System (IRIS) program has initiated a health assessment for polycyclic aromatic hydrocarbon (PAH) mixtures. The IRIS program develops EPA consensus scientific positions on potential human health effects from chronic exposure to chemicals. Currently, the IRIS database contains health assessments for the toxic effects of exposure to coke oven emissions, creosote, diesel emissions, and 15 individual PAH compounds. As a whole, these assessments do not consider issues related to the environmental occurrence of PAH compounds as complex mixtures. Risk assessment of PAH mixtures has been hindered by a lack of information on the composition and toxicity of specific mixtures, the components that contribute most to toxicity, and the interactions and differences in mode of action between components. The state-of-the-science has advanced considerably in the past decade and will play a key role in the development of the health assessment. Consideration of these issues led to an EPA-sponsored Workshop on Approaches to PAH Health Assessment in October 2001. The current practices of the EPA regarding the health assessment of PAH compounds and future directions of the agency are discussed in this article.     

Source Allocation of Aliphatic and Polycyclic Aromatic Hydrocarbons in Particulate-Phase (PM10) in the City of Valdivia,Chile

The concentration and signature of n-alkanes (n-C₁₀ to n-C₃₃) and 18 PAHs were determined in air filters across a year period (2010) in an urban area of the city of Valdivia, Chile. Filter samples were extracted using sohxlet apparatus and analyzed by GC-MS techniques. Concentrations of total hydrocarbons ranged from 45–352 ng.m^?3 and total PAHs ranged from 2.93–78.01 ng.m^?3. Concentrations of hydrocarbons during the summer were high (288–352 ng.m^-3) and reduced when the autumn began (45–79 ng.m^?3) to then increase almost linearly to the next summer. The drop in concentration was attributed in part to the significant reduction of traffic when summer ends as tourists leave the city (about 9–15% of the total cars circulating). Results from the chemometric technique of Polytopic Vector Analysis (PVA) indicated three main sources for the alkanes: biogenic (terrestrial plants), signatures of oil combustion, and an unconfirmed source which is thought to come from non specific organic matter degradation. Total PAHs correlated well with total particulate matter with a R² = 0.94. Levels of PAHs in the atmosphere were higher during the winter (6.85–78.01 ng.m^?3) period than the rest of the year (2.93–36.30 ng.m^?3). PVA results indicate three key sources of PAHs and two of those sources derived from oil combustion and biomass burning.     

Multimedia and Spatial Distribution,Internal Accumulation and Source Diagnostics of Polycyclic Aromatic Hydrocarbons (PAHs) of the Luan River Basin,China

The distribution, composition, and source of 16 polycyclic aromatic hydrocarbons (PAHs) in the Luan River, China, were investigated in this study. The compositional profiles of PAHs in the three mediums represented different characteristics. In different land-use areas, compositional profiles of PAHs in water were familiar, while that in sediment and bank soil presented differences. The spatial distribution of PAHs indicated that the most polluted sites all gathered in the middle and lower reaches of the region, which was different from other rivers in China. The PAH data of bank soil were used for source identification. Both diagnostic ratios of selected PAHs and principal component analysis (PCA) with multiple linear regression (MLR) analysis were studied, suggesting mixed source of PAHs in the Luan River Basin.     

Recertification of Standard Reference Material (SRM) 1649, Urban Dust,for the Determination of Polycyclic Aromatic Hydrocarbons (PAHs)

The National Institute of Standards and Technology (NIST) recently issued SRM 1649a, Urban Dust, with certified and reference values for 44 polycyclic aromatic hydrocarbons (PAHs). This material is a recertification of SRM 1649 which was issued in 1982 with certified values for only five PAHs. The PAHs were determined using the following analytical techniques: (1) reversed-phase liquid chromatography with fluorescence detection (LC-FL) for analysis of the total PAH fraction, (2) reversed-phase LC-FL for analysis of isomeric PAH fractions isolated by normal-phase LC (i.e., multidimensional LC), and (3) gas chromatography/mass spectrometry (GC/MS) for analysis of the PAH fraction using three different stationary phases, each with different selectivity for PAH separations. The results from the different techniques are compared and discussed. SRM 1649a is currently the most extensively characterized environmental matrix SRM with respect to PAH constituents.     

Recovering phenanthrene from spiked sand by a combined remediation process of micellar solubilization and cloud-point extraction

A remediation process, which combines the micellar solubilization and the cloud-point extraction technique by a nonionic surfactant Tergitol 15-S-7, was used to decontaminate phenanthrene, as a model hydrophobic pollutant, from spiked sand samples. A first-order kinetics model was employed to describe the solubilization behavior of phenanthrene well. It was observed that presence of surfactant decreased the mass-transfer coefficient of phenanthrene from sand surface to surfactant solutions, however, higher solubilization rate was obtained due to enhanced aqueous solubility and, thus, the larger driving force resulted from solublization. Cloud-point extraction was used to concentrate the phenanthrene solubilized in the washing solutions in an attempt to minimize the amount of wastewater. The extraction was carried out, subsequently, at room temperature by adding sodium sulfate to suppress the cloud-point low enough to induce phase-separation of the surfactant-rich phase with a minimal phase volume from the coexisting water phase. Recoveries higher than 93% were achieved in the combined process of micellar solubilization and cloud-point extraction on ultimate removal of immobilized phenanthrene sorbed on sands. The results showed that this combined process is efficient in recovering phenanthrene sorbed and immobilized on sands from contaminated sites, and produces only minimal amount of wastewater, i.e. less than 3% of its original volume.     

Polycyclic Aromatic Hydrocarbons in Residential Soils from an Indian City near Power Plants Area and Assessment of Health Risk for Human Population

This article deals with the distribution, composition profiles, and possible sources of sixteen priority polycyclic aromatic hydrocarbons (PAHs) in residential soils from Korba district in Chhattisgarh State, India. Sixteen priority PAHs in soils were analyzed after ultrasonic extraction, silica gel column chromatographic cleanup, and quantitation was performed using HPLC-DAD. The concentrations of ∑16PAHs were within acceptable limits of soil quality guidelines and the study area got classified as weakly contaminated. The concentration of probable human carcinogenic PAHs in soils accounted for 10% of ∑16PAHs. The concentration of Benzo(a)Pyrene (BaP) accounted 1% to total PAHs. Benzo(a)pyrene Toxicity Equivalency (BaP_TEQ) for 16 PAHs was 30 ± 12 μg BaP_TEQ kg^?1. The composition profiles and molecular ratios of PAHs suggested mixed pyrogenic sources of PAHs from combustion of coal, wood, and vehicular exhaust emissions. Human health risk was assessed by calculating the lifetime average daily dose (LADD) and incremental life time cancer risk (ILCR) for human adults and children. Estimated ILCR was within safe limit (10^?6?10^?5), indicating low risk to human population. Potential risk to contaminated ground water from leaching of carcinogenic PAHs was assessed by estimating the Index of Additive Cancer Risk (IACR).     

Biodegradation of High Molecular Weight Polycyclic Aromatic Hydrocarbons Mixture by a Newly Isolated Fusarium sp. and Co-Metabolic Degradation with Starch

One native fungal strain, designated ZH-H2, was isolated from an agricultural soil contaminated by HMW-PAHs in a typical coal mining area of Hebei, China. The filamentous fungus was identified as a Fusarium sp. ZH-H2 was able to survive not only in the presence of the individual HMW-PAHs of Chry, BaA, B(K)F, BaP, DB(a,h)A, InP, InP and B(g,h,i)p but in the presence of a mixture of the above seven HMW-PAHs with a total concentration of up to 10 mg L^?1. Biodegradation experiments demonstrated that Fusarium sp. (ZH-H2) was able to degrade the aforementioned individual HMW-PAHs, with a degradation percentage of 77%, 85%, 91%, 42%, 56%, 42% and 38%, respectively, and degrade the aforementioned seven PAHs mixture with a degradation percentage of 48%. The effect of starch addition on the biodegradation efficiency of the PAH mixture was also investigated. The results showed a significant improvement in the degradation extent of the PAH mixture with the increase of starch concentration. The greatest degradation rate (DR; 89%) in 7 d was obtained when starch was added at 1.0 g L^?1, about 2-fold than was achieved without starch. This study implicates that Fusarium sp. (ZH-H2), a potential biodegrader, is suitable for practical field application in effective bioremediation of soils that have been simultaneously contaminated by several HMW-PAHs for a long time.     

季铵盐双子表面活性剂N,N’-双（十二/十四烷基二甲基）-1,4-对苯二甲基氯化铵盐的合成及性能

分别以十二烷基二甲基叔胺、十四烷基二甲基叔胺和对二氯苄(XDC)为原料,"一步法"合成了两种季铵盐双子表面活性剂,通过正交实验优化了合成条件,结果表明,当n(叔胺)∶n(XDC)=2.4∶1、反应温度75℃、反应时间2 h时,XDC转化率达到100%;产物结构经红外光谱(FTIR)、核磁共振氢谱(1HNMR)和碳谱(13CNMR)进行了确认。研究了其表面活性,结果表明:25℃时,碳链长度分别为12和14时,表面活性剂临界胶束浓度(CMC)分别为1.36×10-5和2.56×10~(-6)mol/L,表面张力(γCMC)分别为40.71和35.37 m N/m;p C20值分别为5.63和6.18;表面过剩吸附量(Γmax)分别为2.41×10~(-6)和3.09×10~(-6)mol/m~2;分子最小截面积(Amin)分别为0.69和0.54 nm~2。动态表面张力参数n值分别为0.85、0.74,t*分别为1.05和0.27 s,R1/2分别为14.11和69.79 m N/m/s,R=14的双子表面活性剂的动态表面张力优于R=12时。该季铵盐双子表面活性剂与结构相似的季铵盐表面活性剂如十六烷基三甲基溴化铵(CTAB)相比CMC低2个数量级。