Kinetics and physicochemical studies of surfactant enhanced remediation of hydrocarbons contaminated groundwater

Kinetics and physicochemical studies of surfactant enhanced remediation of hydrocarbons contaminated groundwater were investigated for efficiency and effectiveness. 10% pollution was simulated in the laboratory by contaminating groundwater samples with crude oil, automatic gasoline oil (diesel) and domestic purpose kerosene (DPK) in replicates of five. Physicochemical properties of the hydrocarbons contaminated groundwater samples and a control sample were investigated before and after treatments. Total petroleum (TPH) hydrocarbon as target contaminant was monitored periodically to assess the extent of the remediation process. TPH was determined by molecular spectrophotometry technique. Other physicochemical parameters such as pH, turbidity, alkalinity, dissolved oygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), condutiivity, ammonia, nitrate, phosphate, salinity, total dissolved solids (TDS), total suspended solids (TSS) and total solids (TS) were obtained using standard methods while heavy metals levels were determined by atomic absorption spectrophotometry. Different kinetics models were tested to determine the appropriate kinetics model. The pseudo-first order kinetics is established with rate constant as 1.80 × 10⁴; 1.78 × 10⁴; 1.53 × 10⁴ mg^?1 L h^?1 for crude oil, diesel and kerosene respectively at 30 °C. At the end of the remediation after 6 h there was 89.11%; 93.21%; 87.76% reduction in TPH as crude oil, diesel and kerosene for the treated samples in that order. The application of surfactant enhanced remediation using sodium dodecyl sulphate is found be very efficient, effective and rapid in reducing total petroleum hydrocarbon as crude oil, kerosene and diesel as target contaminants. There is the need for post-treatments after remediation for most of the physicochemical parameters are impaired and do not meet the Guideline and Standards for Environmental Pollution Control in Nigeria set by Federal Ministry of Environment and World Health Organization for drinking water and agricultural uses in order to make them fit for these purposes.     

聚烯烃催化剂硅胶载体的制备和表征

采用并流共沉淀法制备了适用于聚烯烃催化剂的硅胶载体,为减少颗粒的聚集,在制备过程中添加一种表面活性剂。利用透射电子显微镜(TEM)、比表面积测定(BET)和X射线粉末衍射(XRD)法对制备的硅胶载体进行了表征;考察了在制备硅胶载体过程中原料硅酸钠溶液的浓度、溶液pH以及焙烧温度对产物硅胶载体的物理性能的影响。实验结果表明,硅酸钠溶液的浓度影响硅胶的初始粒子的大小,溶液pH直接影响硅酸钠的水解速率,焙烧温度影响硅胶的孔结构和比表面积。当硅酸钠溶液的浓度为0．2mol／L、溶液pH为8-9、反应温度为70℃、焙烧温度为700℃时,硅胶载体的BET比表面积为242．22m2／g、最可几孔径为16．45 nm、堆密度为0．492 1g/mL,与进口硅胶(Silica Gel 955)的物理性能相近。     

土壤中分段石油烃热脱附行为研究

采用管式炉模拟土壤中石油烃热脱附过程,考察了加热温度、保持时间以及负压条件对土壤中分段石油烃热脱附过程的影响,为实际石油烃污染土壤修复工作提供理论依据。结果表明：提高加热温度、延长保持时间以及提供负压条件均对提高土壤中总石油烃去除率产生积极作用;常压下,在250℃保持2 h与300℃保持1 h的条件下,土壤中总石油烃去除率均达到97%以上,总石油烃残留量低于GB 36600—2018《土壤环境质量建设用地土壤污染风险管控标准》中第一类用地风险筛选值;当温度为150℃时,土壤中C₁₀～C₁₆,C₁₇～C₂₈,C₂₉～C₄₀段石油烃组分在1 h内的去除率均低于40%;当温度高于250℃时,土壤中C₁₀～C₁₆和C₁₇～C₂₈段的石油烃组分可被快速有效去除;C₂₉～C₄₀段石油烃组分受加热温度和保持时间变化影响明显,因此提高重质石油...     

用中和烃氧化产物制备高界面活性的驱油剂

为了用C_(22)和C_(26)直链和环烷烃的石油馏分油作原料制备适用于强化采油的活性剂,先将原料汽相氧化,再用碱液中和氧化产物。用红外光谱研究了氧化产物和中和产物的组成,发现前者含有羧酸,后者含有羧酸盐。得到的羧酸盐活性剂用于模拟油[由38.8%(体积)的异丙苯和61.2%(体积)的正癸烷组成],使油水间达到低于10~(-2)mN/cm的超低界面张力。实验表明,用氢氧化钠进行中和,比用其他的碱性物质(如硅酸钠、三聚磷酸钠、碳酸钠)更易得到界面活性高的活性剂溶液;当硅酸钠或三聚磷酸钠协同氢氧化钠一起与氧化产物反应时,所得活性剂的界面张力对电解质浓度的敏感程度比仅用氢氧化钠作处理剂时低,中和时的碱量会影响所得活性剂体系的界面张力。对于活性剂浓度不同的体系,若pH值相同则最佳含盐量也相同;若pH值高,则最佳含盐量低。当活性剂体系含有1000ppm的氯化钙时,仍具有良好的界面活性。在驱油试验中,浓度为1%的1个孔隙体积的活性剂溶液可采出42%的二次残油。     

不同铁基催化剂活化过硫酸钠修复石油污染土壤

目的 在活化过硫酸钠(Na₂S₂O₈)体系处理石油污染土壤中,采用不同形态的铁基材料作为催化剂,进行石油烃的去除研究。方法 通过室内模拟实验,比较了3种铁基催化剂(柠檬酸亚铁、零价铁、四氧化三铁)活化Na₂S₂O₈处理石油污染土壤,探究了氧化剂的持续性、污染物去除的有效性、可溶性碳氮含量和pH值的变化。结果 外加零价铁显著促进了石油污染土壤中总石油烃(TPH)的去除,反应10天后TPH去除率为53.39%,比对照组高出15.3%;外加铁基催化剂对溶解性有机碳和总氮含量的影响较大,后续若采用微生物手段联合修复,需要外加营养物质以调节至微生物生长适宜的碳氮磷比。结论 加入零价铁能够增加Na₂S₂O₈有效利用率,进而提高对TPH去除的持续性和有效性。研究结果对采用更多类别的铁基材料活化过硫酸钠技术处理有机污染土壤具有一定的参考价值。     

Assessment of In Situ Bioremediation of Oil Contaminated Soil and Groundwater in a Petroleum Refinery: A Laboratory Soil Column Study

Precipitation and seasonal water level fluctuations mostly add to the problem of soil and groundwater contamination and lead to pollution of capillary fringe layer and exacerbation of groundwater contamination. At the Tehran Oil Refining Company (TORC), with critical problem of soil and groundwater pollution, finding a suitable remediation method has been a big concern. As bioremediation is one of the most economically and technically attractive decontamination methods, it was chosen for preliminary study to solve this problem. For simulation of the region, soil column treatment method by using oil habituated indigenous microorganisms of the area was selected. The main purpose was assessing the suitability of bioremediation method in the target area for treatment of capillary fringe layer. Two columns (one as treatment column and the other as a control) were designed and the variation of different parameters including dissolved oxygen (DO), pH, the number of viable and active microorganisms (CFU/mL), and biodegradation rate during 30 working days were recorded. The experiments showed that a major part of degrading microorganisms were facultative anaerobic. pH was not an inhibiting factor and the number of active microorganisms was increasing during aeration time. The results of solvent extraction method also revealed that during 30 days, about 6% of total petroleum hydrocarbon in columns was biologically degraded. Finally, it was disclosed that bioremediation method could be effective in solving the area's pollution problem. However, new studies should be conducted to optimize the biodegradation rate and extrapolate from the laboratory scale results to the field ones.     

固定化微生物对石油污染土壤生物学特性的影响

在固定化微生物对石油污染土壤修复35d的过程中,考察了土壤脱氢酶、过氧化氢酶、多酚氧化酶、脲酶活性及细菌数量几种生物学特性的变化规律,进一步分析其石油烃降解率变化与酶活性、细菌数量之间的相关性,并以添加游离菌、秸秆及土著菌的土壤对照。结果表明,固定化微生物修复石油污染土壤的各个阶段,细菌数量、酶活性均高于对照组,石油烃降解效果最好,降解率高达40.8%;土壤的脲酶活性与其石油烃降解率的相关性最显著,相关性系数为0.994,可以作为固定化微生物降解石油污染土壤效果的指标。     

Geochemical evidences of trace metal anomalies for finding hydrocarbon microseepage in the petroliferous regions of the Tatipaka and Pasarlapudi areas of Krishna Godavari Basin, India

The long-term seepage of hydrocarbons, either as macroseepage or microseepage, can set up near-surface oxidation reduction zones that favor the development of a diverse array of chemical and mineralogical changes. The bacterial oxidation of light hydrocarbons can directly or indirectly bring about significant changes in the values of pH and Eh of the surrounding environment, thereby also changing the stability fields of the different mineral species present in that environment. The paper reports the role of hydrocarbon microseepage in surface alterations of trace metal concentrations. In this study trace metal alterations were mapped that appear to be associated with hydrocarbon microseepages in the oil/ gas fields. A total of 50 soil samples were collected near oil and gas fields of the Tatipaka and Pasarlapudi areas of the Krishna Godavari Basin, Andhra Pradesh. The soil samples were collected from a depth of 2-2.5 m. The paper reports the chemical alterations associated with trace metals in soils that are related to hydrocarbon microseepages above some of the major oil and gas fields of this petroliferous region. Trace metals, such as scandium (Sc), vanadium (V), chromium (Cr), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), barium (Ba) and strontium (Sr), in soil samples were analyzed using inductively coupled plasmamass spectrometry (ICP-MS). The concentrations of Sc (8 to 40 mg/kg), V (197 to 489 mg/kg), Cr (106 to 287 mg/kg), Co (31 to 52 mg/kg), Ni (65 to 110 mg/kg), Cu (88 to 131 mg/kg), Zn (88 to 471 mg/kg), Ba (263 to 3,091 mg/kg) and Sr (119 to 218 mg/kg) were obtained. It was observed that the concentrations of trace elements were tremendously increased when they were compared with their normal concentrations in soils. The analysis of adsorbed soil gas showed the presence of high concentrations of ΣC 2+ (C 2 H 6 , C 3 H 8 and n-C 4 H 10 ) ranging from 7 to 222 μg/kg respectively. Integrated studies of trace elements over adsorbed light gaseous hydrocarbons (ΣC 2+ ) anomalies showed good correlation with the existing oil and gas wells. The carbon isotopic composition of δ 13 C 1 of the samples ranges between -36.6‰ to -22.7‰ (Pee Dee Belemnite) values indicate thermogenic origin, which presents convincing evidence that the adsorbed soil gases collected from these sediments are of catagenetic origin. The increase in the concentrations of trace metals near oil/gas producing areas, suggests a soil chemical change to a reducing environment, presumably due to the influence of hydrocarbon microseepage, which could be applied with other geoscientific data to identify areas of future hydrocarbon exploration in frontier areas.     

Optimization for microbial degradation of petroleum hydrocarbon (TPH) by Enterobacter sp. S-1 using response surface methodology

In this research, the response surface method designed by Box-Behnken was used to study the effect of temperature, pH value and TPH concentration on the biodegradation of Enterobacter sp. S-1contaminated soil. The value of determination coefficient (R²=0.9565) by analysis of variance (ANOVA) indicated a satisfactory agreement between the quadratic model and the experimental data. It was found that TPH degradation rate was more significantly affected (P?<?0.0006) by temperature compared with other two parameters. In the temperature of 30?°C, pH value of 7.14 and TPH concentration was 4.83?g/L, the best degradation rate was 81.63%.     

Optimization,kinetics, physicochemical and ecotoxicity studies of Fenton oxidative remediation of hydrocarbons contaminated groundwater

Fenton oxidation remediation of hydrocarbons contaminated groundwater was investigated for efficiency and effectiveness. 10% pollution was simulated in the laboratory by contaminating groundwater samples with diesel and domestic purpose kerosene (DPK) in two different experimental set ups. Optimum conditions of concentrations of the treatment solutions and pH were established: 300 mg/L (FeSO₄), 150,000 mg/L (H₂O₂) and pH = 3 for the kerosene contaminant; 100 mg/L (FeSO₄), 300,000 mg/L (H₂O₂) and pH = 3 for the diesel contaminant. The results from kinetics study show that the remediation process is pseudo-first order reaction with a rate constant of 8.07 × 10⁴ mgL^?1hr^?1 and 3.13 × 10⁴ mgL^?1hr^?1 for the diesel and kerosene contaminants in that order with 95.32% and 79.25% reduction in chemical oxygen demand (COD) for diesel and kerosene contaminated samples at the end of the remediation process respectively indicated that remediation have occurred significantly. Percent reduction in Total Petroleum Hydrocarbon (TPH) as kerosene was 89.84% and that of the diesel contaminant as 91.87% after 6 hours of remediation. The general pollution index (GPI) for the hydrocarbons contaminated samples was in the range of 6.70–7.52 against the background value of 4.39 for the control groundwater sample. After treatment the GPI had dropped to 4.13–4.43 which depicts remarkable remediation although the samples remained impaired. Therefore there is the need of post-treatments to make the groundwater fit for domestic and agricultural uses. The application of the Fenton oxidative process is found to be very efficient, effective and rapid in reducing total petroleum hydrocarbon as kerosene and diesel as target contaminants.     

硅酸盐钻井液的抑制性及其影响因素的研究

硅酸盐钻井液具有良好的井壁稳定作用，且无毒、无荧光、成本低，被认为是具有发展前景的水基钻井液之一。着重研究和探讨了硅酸盐的抑制能力、影响因素及稳定井壁的机理。研究表明，硅酸盐具有较强的抑制能力，抑制效果明显地优于KCl、CaCl2等无机盐类；硅酸盐的模数、加量和钻井液的PH值是影响硅酸盐抑制能力的主要因素；钻井液中硅酸钠的模数为2．8～3．0，加量为3％～4％，且钻井液的pH值维持在11以上时，硅酸钠的抑制效果更好；硅酸盐能与无机盐和聚醇类产生协同作用，从而提高硅酸盐的抑制能力。硅酸盐稳定井壁的机理：硅酸盐与地层矿物反应生成沉淀封堵地层微小裂缝和孔隙，改善和提高了泥页岩的半透膜效率；抑制粘土水化膨胀和分散；降低地层孔隙中压力传递速度；与地层中粘土矿物发生反应。     

秸秆载体腐解对微生物修复石油污染的影响

以一种农作物秸秆(简称MG)为载体,采用高效石油烃降解菌群制备固定化微生物,在花盆中模拟石油污染土壤的原位修复。在污染土壤中分别加入秸秆（MG）、游离菌、秸秆（MG）+游离菌、秸秆（MG）固定化微生物,并以只含土著菌的土壤样品为对照,定期测定不同修复方式下土样中石油烃、腐殖质、胡敏酸含量和微生物数量,考察微生物对石油污染土壤的修复作用及MG腐解对修复的影响。结果表明,随着修复的进行, MG在土壤中逐渐腐解,土壤中腐殖质和胡敏酸质量分数明显增高,加入固定化微生物的土样中腐殖质和胡敏酸质量分数增长率最高,分别增加了4458%和3927%;加入固定化微生物的土样修复35 d的石油烃降解率最高,达到4178%,且微生物数量最多,其次为添加MG+游离菌的土样,石油烃降解率为 3175%,均高于只含游离菌土样的石油烃降解率2783%。载体MG腐解产生的腐殖质和胡敏酸对石油污染土壤的修复起到了明显的促进作用。     

Inactivation of Bacillus subtilis spores by pulsed electric fields (PEF) in combination with thermal energy – I. Influence of process- and product parameters

In addition to inactivation of vegetative microorganisms, PEF can be used to inactivate bacterial endospores when combined with thermal energy. In the first part of this study, the impact of the product parameters pH value (4 and 7), sugar level (5 and 10%) and conductivity (4 and 15 mS/cm) as well as the process parameters specific energy (up to 350 kJ/kg), electric field strength (6–11 kV/cm) and inlet temperature (56, 70 and 80 °C) on the inactivation of Bacillus subtilis spores were analyzed.The results of spore inactivation by PEF at different inlet temperatures indicated less energy requirements for sufficient inactivation at higher inlet temperatures. Comparing the inactivation at different pH values, the inactivation at acid pH value required less energy than at neutral pH value. A 1.6 log reduction using 167 kJ/kg was detected in Ringer solution at pH 4 compared to 0.6 log in neutral medium at an energy of 165 kJ/kg (inlet temperature of 80 °C and 9 kV/cm as electric field strength). Under the same process conditions (9 kV/cm and 80 °C inlet temperature), the addition of 10% sugar permitted to reduce the energy from 178 to 146 kJ/kg, require to reach a 3 log cycles inactivation of B. subtilis spores. The results showed a successful inactivation of B. subtilis spores by PEF in combination with thermal energy and represent therefore a promising process for spore inactivation with reduced heat load.     

SDBS残留对微生物修复石油污染土壤的影响

为探究表面活性剂清洗对微生物修复石油污染土壤的影响,模拟实际石油污染土壤微生物修复,考察不同十二烷基苯磺酸钠(SDBS)添加量的土壤修复过程中总石油烃降解率的变化情况,探究了SDBS对微生物修复石油污染土壤效果的影响;比较了不同微生物法修复石油污染土壤的实验方案,确定了最佳微生物修复方式。结果表明：少量的SDBS残留对后续微生物修复有促进作用,但SDBS残留质量分数大于1 mg/g时,则不宜于石油污染土壤的生物修复;土著菌+秸秆固定化微生物和土著菌+游离高效降解菌+秸秆2种修复方式,启动快,降解率的增速大,修复效率高,可以实现石油污染土壤快速和持续修复。     

Enhanced removal of Escherichia coli O157:H7 and Listeria innocua from fresh lettuce leaves using surfactants during simulated washing

Removal of foodborne bacterial pathogens from fresh produce during washing and sanitation process can significantly improve inactivation of the bacteria. Currently, produce wash systems mainly rely on mechanical forces to aid in removal of bacteria attached to the produce surface during washing and sanitation. This study evaluates the potential of surfactants to enhance removal of pathogens from the surface of fresh produce. Influence of three types of commercial food-grade surfactants, including Tween-20, sodium dodecyl sulfate (SDS), and lauric arginate (LAE), on the mechanical removal of pathogenic bacteria and viruses from fresh lettuce leaves in the presence of soil was evaluated. The addition of surfactants did not increase the removal of T7 phages from lettuce leaf surface (P > 0.05). The improvement of bacterial removal by addition of surfactants to wash water is corresponding to the decrease of the contact angle between wash water and leaf surface. The most effective Escherichia coli O157:H7-lux removal was obtained by washing with 0.1% LAE, followed by 0.1% Tween-20, then 0.1% SDS. The most enhanced detachment of Listeria innocua was achieved by 0.1% LAE, followed by 0.1% SDS, then 0.1% Tween-20. The presence of soil resulted in an increased resistance of bacterial cells to the washing process. There was no significant difference in the cell persistence on the lettuce surface within the extended incubation period (P > 0.05). The evaluation of lettuce quality indicated that the introduction of surfactants during the washing procedure may affect the firmness of leaves, but the color and electrolyte leakage rate were not affected by the exposure to wash water with surfactants (P > 0.05). Overall, these results suggest the potential of food grade surfactants to enhance the removal of bacteria particularly foodborne pathogens from the surface of fresh produce.     

Improving the antimicrobial activity of d-limonene using a novel organogel-based nanoemulsion

The purpose of this research was to develop a novel antimicrobial delivery system by encapsulating d-limonene into an organogel-based nanoemulsion and investigating its antimicrobial activity. The d-limonene organogel-based nanoemulsion was prepared by high pressure homogenization method. The surfactant concentration had a major impact on the droplets' formation and distribution. At the optimal condition (10% w/w Tween 80, 100 Mpa, and 10 Cycles) the smallest droplet size (d ≈ 36 nm) could be obtained, which has shown a narrow structure and good stability. Results from the antimicrobial activity have shown the encapsulation of d-limonene (4% w/w) into the organogel-based nanoemulsion contributed to the increase of its antimicrobial activity. In addition, the mechanism of d-limonene organogel-based nanoemulsion against the tested microorganisms was studied by the electronic microscope observation and the cell constituent release. This research would have an important implication for the design of more efficient antimicrobial systems for food preservation and production.     

Effects of oil types and pH on carcinogenic polycyclic aromatic hydrocarbons (PAHs) in grilled chicken

The effects of oil types and the pH of marinade were investigated on the formation of carcinogenic polycyclic aromatic hydrocarbons (EPA priority 16 PAHs) in grilled chicken. The formation of PAHs in grilled chicken breast with different marinades after charcoal-grilling for 3 min/side was evaluated using high performance liquid chromatography with a photodiode array detector (HPLC-DAD). Compared with the control marinade treatment (without vegetable oil), the addition of commercial palm oil and sunflower oil that contained significantly different amounts of polyunsaturated and saturated fatty acids led to a significant (p < 0.05) increase in the PAH levels in grilled chicken from 190.1 μg/kg to 457.6 μg/kg and 376.6 μg/kg, respectively and there was only a slight difference between both oil marinade treatments due to the presence of antioxidant compounds in the commercial vegetable oils. The pH values of the marinade treatments for both acidic and alkali marinades using citric acid and sodium bicarbonate, respectively, produced the highest pH value (7.51, alkali marinade) which resulted in a major increase of more than 70% in the PAH levels in grilled chicken. The results of this study suggested that the addition of oil and/or alkali ingredients in the marinade could be important in increasing the levels of PAHs in grilled meat products.     

利用磷肥副产含氟硅胶制δ型层状结晶二硅酸钠

磷肥副产含氟硅胶经氨洗、水洗至中性后，与片状烧碱反应，制得模数为2．0的水玻璃，然后加3％的KCI作晶型转化剂，经煅烧制备δ型层状结晶二硅酸钠。实验得出制取中间产物水玻璃的最佳工艺条件是：反应温度720-800℃、反应时间40min；水玻璃煅烧制d型层状结晶二硅酸钠的最佳工艺条件是：煅烧保温温度600℃、保温时间30．50min。在最佳条件下，可得到钙离子交换量大于4A沸石的优质δ型层状结晶二硅酸钠。     

Biochemical characteristics of dry-cured lacón (a Spanish traditional meat product) throughout the manufacture, and sensorial properties of the final product. Effect of some additives

The gross composition, the main physicochemical parameters, the proteolytic changes and the characteristics of the fat throughout the manufacture process, and the sensorial characteristics of the final product, were studied in dry-cured lacón, a traditional dry-salted and ripened meat product made in the north-west of Spain from the fore leg of the pig following a similar technological process to that of dry-cured ham. The effect of the use of additives (glucose, sodium nitrite, sodium nitrate, sodium ascorbate and sodium citrate) was also studied.In comparison with other dry-cured meat products made from whole meat pieces, dry-cured lacón is characterised by the low moisture contents, the high pH values, and the low transformation of the pigments. The proteolytic and lipolytic processes throughout the manufacture of this product were not intense. Except for the total carbohydrate and nitrate contents, and the percentage of transformation of the pigments, which were significantly (P < 0.05) higher in the batches processed with additives, the use of additives did not influence the biochemical modifications that occur throughout the manufacture process of the dry-cured lacón. Regarding the sensorial characteristics, the use of additives seems to improve the colour and the odour of the final product.     

某石油化工厂区有机污染物的表征 Ⅰ．土壤

采用网格法布点,并参照美国EPA的采样和分析方法,调查了某润滑油添加剂厂区不同深度土壤中总石油烃（TPH）,挥发性有机物（VOC）及半挥发性有机物（SVOC）的分布特征,以作为开展风险评价和采取补救措施的依据。结果表明,该厂区的有机污染是局部的和有特征性的,土壤污染带主要位于2m以上渗透性良好的人工填土层,污染物主要来自各类储罐的泄漏和污水隔油池的渗漏,柴油范围有有机物（DRO）及润滑油范围的有机物（ORO）的含量超过10g/kg的区域分别占厂区,面积的2．0％和1．5％,98．4％,的目标VOC及96．2％的目标SVOC检出率不足255,92．1％点位的总VOC低于100/,89．4％点位的总SVOC低于50mg/kg;检出[浓度较高的目标VOC和目标SVOC分别是苯系物,多环芳烃,苯酚类及邻苯二甲酸酯类化合物,除一个点位的一个深度土样苯并（a)芘超过HJ／T25－1999土壤基准直接接触1．4倍外,其它均不超标;推测定性VOC或SVOC的估算浓度高于目标VOC或SVOC的检出浓度。