RESUMO
This study reports a simple and convenient analytical method for the simultaneous determination of biodiesel and vegetable oils or used cooking oils in petrodiesel and green diesel (hydrotreated vegetable oils or paraffinic diesel). The approach is based on normal-phase high-performance liquid chromatography with refractive index detection. It employed silica stationary phase, n-hexane mobile phase with isopropanol modifier to achieve optimum separation between hydrocarbons (petrodiesel or green diesel), fatty acid methyl esters (biodiesel) and triglycerides (vegetable oils and used cooking oil). In addition to determining vegetable oils or used cooking oils as adulterants in diesel, this method is also proposed as a better alternative to the standard method ASTM D7371, which is currently recommended for determining fatty acid methyl esters in petrodiesel. The method development involved screening of various stationary and mobile phases, with and without modifiers, to achieve acceptable chromatographic resolutions between analytes. Under the optimized method conditions, silica column, and n-hexane containing 0.6% isopropanol as the mobile phase provided the best results. The real-world scenario was simulated for the method validation carried out by fortifying Jatropha seed oil, soybean oil, and used cooking oil in the biodiesel blended petrodiesel and green diesel. Measurement of all analytes was accompanied by high precision, low limit of detection/quantification and linear response range of 0.05 to 50% for biodiesel, and 0.05 to 30% for vegetable oils. The proposed method is simple, fast (runtime 7 min), and does not require sample pre-treatment and backflushing.
Assuntos
Biocombustíveis/análise , Cromatografia Líquida de Alta Pressão/métodos , Óleos de Plantas/análise , Gasolina/análise , Hidrocarbonetos/análise , Hidrocarbonetos/isolamento & purificação , Óleos de Plantas/química , Óleo de Soja/análise , Triglicerídeos/isolamento & purificaçãoRESUMO
Effective targeted delivery of nanoparticle agents may enhance the remediation of soils and site characterization efforts. Nanoparticles coated with Pluronic, an amphiphilic block co-polymer, demonstrated targeted binding behaviour toward light non-aqueous phase liquids such as heavy crude oil. Various factors including coating concentration, oil concentration, oil type, temperature, and pH were assessed to determine their effect on nanoparticle binding to heavy crude oil-impacted sandy aquifer material. Nanoparticle binding was increased by decreasing the coating concentration, increasing oil concentration, using heavier oil types, and increasing temperature, while pH over the range of 5-9 was found to have no effect. Nanoparticle transport and binding in columns packed with clean and oily porous media demonstrated the ability for efficient nanoparticle targeted binding. For the conditions explored, the attachment rate coefficient in columns packed with clean sand was 2.10 ± 0.66 × 10-4 s-1; however, for columns packed with oil-impacted sand a minimum attachment rate coefficient of 8.86 ± 0.43 × 10-4 s-1 was estimated. The higher attachment rate for the oil-impacted sand system indicates that nanoparticles may preferentially accumulate to oil-impacted zones present at heterogeneous impacted sites. Simulations were used to demonstrate this hypothesis using the set of parameters generated in this effort. This work contributes to our understanding of the application conditions that are required for efficient targeted binding of nanoparticles to crude-oil impacted porous media.
Assuntos
Compostos Férricos/química , Hidrocarbonetos/química , Nanopartículas/química , Petróleo , Poluentes do Solo/química , Água Subterrânea/química , Hidrocarbonetos/isolamento & purificação , Poloxâmero/química , Porosidade , Dióxido de Silício/química , Poluentes do Solo/isolamento & purificaçãoRESUMO
The present study describes the production of biosurfactant from isolate B. licheniformis Ali5. Seven different, previously-reported minimal media were screened for biosurfactant production, and two selected media were further optimized for carbon source. Further, various fermentation conditions such as (pH 2-12, temperature 20-50 °C, agitation speed 100-300 rpm, NaCl (0-30 g·L-1) were investigated. The partially purified biosurfactant was characterized by Fourier transform infrared spectroscopy (FTIR) and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MS) and found a lipopeptide mixture, similar to lichenysin-A. Biosurfactant reduced surface tension from 72.0 to 26.21 ± 0.3 and interfacial tension by 0.26 ± 0.1 mN.m-1 respectively, biosurfactant yield under optimized conditions was 1 g·L-1, with critical micelle concentration (CMC) of 21 mg·L-1 with high emulsification activity of (E24) 66.4 ± 1.4% against crude oil. Biosurfactant was found to be stable over extreme conditions. It also altered the wettability of hydrophobic surface by changing the contact angle from 49.76° to 16.97°. Biosurfactant efficiently removed (70-79%) motor oil from sand, with an efficiency of more than 2 fold as compared without biosurfactant (36-38%). It gave 32% additional oil recovery over residual oil saturation upon application to a sand-packed column. These results are indicative of potential application of biosurfactant in wettability alteration and ex-situ microbial enhanced oil recovery.
Assuntos
Bacillus licheniformis/química , Poluição Ambiental/análise , Petróleo/análise , Areia/química , Tensoativos/química , Bacillus licheniformis/crescimento & desenvolvimento , Carbono/análise , Emulsões/química , Hidrocarbonetos/isolamento & purificação , Concentração de Íons de Hidrogênio , Micelas , Filogenia , Salinidade , Espectroscopia de Infravermelho com Transformada de Fourier , Tensão Superficial , Temperatura , MolhabilidadeRESUMO
The main petroleum product transported through pipelines in Canada is diluted bitumen (dilbit), a semiliquid form of heavy crude oil mixed with natural gas condensates to facilitate transport. The weathering, fate, behavior, and environmental effects of dilbit are crucial to consider when responding to a spill; however, few environmental studies on dilbit have been completed. We report on 11-d-long experimental spills of dilbit (Cold Lake Winter Blend) in outdoor microcosms meant to simulate a low-energy aquatic system containing natural lake water and sediments treated with low (1:8000 oil:water) and high (1:800 oil:water) volumes of dilbit. In the first 24 h of the experiment, volatile hydrocarbons quickly evaporated from the dilbit, resulting in increased dilbit density and viscosity. These changes in dilbit's physical and chemical properties ultimately led to its submergence after 8 d. We also detected rapid accumulation of polycyclic aromatic compounds in the water column of the treated microcosms following the spills. The present study provides new information on the environmental fate and behavior of dilbit in a freshwater environment that will be critical to environmental risk assessments of proposed pipeline projects. In particular, the study demonstrates the propensity for dilbit to sink under ambient environmental conditions in freshwaters typical of many boreal lakes. Environ Toxicol Chem 2019;38:2621-2628. © 2019 SETAC.
Assuntos
Hidrocarbonetos/química , Lagos/química , Poluentes Químicos da Água/química , Canadá , Hidrocarbonetos/isolamento & purificação , Petróleo/análise , Poluição por Petróleo/análise , Poluentes Químicos da Água/isolamento & purificação , Tempo (Meteorologia)RESUMO
A bench-scale apparatus was used for the low-temperature thermal desorption (LTTD) treatment of oil-based drill cuttings (OBDCs). The effects of treatment temperature, treatment duration, sand/OBDCs mixing ratio, and initial oil content on the LTTD treatment performance were investigated. It was found that the petroleum hydrocarbons (PHCs) were barely left in the high-oil-content drill cuttings after LTTD (at 300⯰C for 20â¯min), and thus the overall soil health was improved. The desorption kinetics models of PHCs under various conditions were established, and it was found that the LTTD of OBDCs followed nonlinear least-squares exponential kinetics (adjusted R2â¯>â¯0.9). The energy consumption models of LTTD treatment under different temperatures were also developed. The modeling results are of practical guiding significance and useful for designing effective LTTD treatment systems of OBDCs.
Assuntos
Recuperação e Remediação Ambiental/métodos , Hidrocarbonetos/isolamento & purificação , Modelos Teóricos , Petróleo , Adsorção , Temperatura Baixa , Cinética , Poluentes do Solo/análise , TemperaturaRESUMO
Beetles in the genus Sphenophorus Schönherr, or billbugs, potentially utilize both volatile and non-volatile behavior-modifying chemical signals. These insects are widely distributed across North America, often occurring in multi-species assemblages in grasses. However, details about their host- and mate-finding behavior are poorly understood. This study tested the hypothesis that volatile organic compounds from host-plants and conspecifics direct the dispersal behavior of hunting billbug S. venatus Say. Further, we characterized the cuticular hydrocarbon profiles of two widespread pest species, S. venatus and bluegrass billbug S. parvulus Gyllenhaal, to assess the potential role of contact pheromones in mate-recognition. In Y-tube olfactometer bioassays, S. venatus males were attracted to a combination of conspecifics and Cynodon dactylon host-plant material, as well as C. dactylon plant material alone. S. venatus females were attracted to a combination of male conspecifics and host-plants but were also attracted to male conspecifics alone. Field evaluation of a putative male-produced aggregation pheromone, 2-methyl-4-octanol, identified from two congeners, S. levis Vaurie and S. incurrens Gyllenhaal, did not support the hypothesis that S. venatus and S. parvulus were also attracted to this compound. Gas chromatography-mass spectrometry analysis of S. venatus and S. parvulus whole-body cuticular extracts indicated a series of hydrocarbons with qualitative and quantitative interspecific variation in addition to intraspecific quantitative variation between males and females. This study provides the first evidence that S. venatus orients toward host- and insect-derived volatile organic compounds and substantiates the presence of species-specific cuticular hydrocarbons that could serve as contact pheromones for sympatric Sphenophorus species.
Assuntos
Besouros/fisiologia , Plantas/química , Comportamento Sexual Animal/fisiologia , Compostos Orgânicos Voláteis/análise , Animais , Fracionamento Químico , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Hidrocarbonetos/análise , Hidrocarbonetos/isolamento & purificação , Masculino , Extratos Vegetais/química , Plantas/metabolismo , Plantas/parasitologia , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/isolamento & purificaçãoRESUMO
Remediation of water bodies from petroleum hydrocarbons is of the utmost importance due to health risks related to the high toxicity, mutagenicity and carcinogenicity of the hydrocarbons components that may enter into the food chain. Though several methods were proposed to face up this challenge, they are generally not easily feasible at a contaminated site and quite costly. Here we propose a green, cost-effective technology based on hydrophobized Spanish Broom (SB) cellulose fiber. The natural cellulose fiber was extracted by alkaline digestion of the raw vegetable. The hydrophilic cellulose surface was transformed into a hydrophobic one by the reaction with 4,4'-diphenylmethane diisocyanate (MDI) forming a very stable urethane linkage with the hydroxyl groups of cellulose emerging from the fibers surface. Chemical functionalization was performed with a novel solvent-free technology based on a home-made still reactor were the fiber was kept under vortex stirring and the MDI reactant then spread onto the fiber surface by nebulizing it in form of micrometer-sized droplets. The functionalized fiber, characterized by means of WCA measurements, XPS and ATR-FTIR spectroscopy, shows fast adsorption kinetics adsorption capacity as high as 220â¯mg/g, among the highest ever reported so far in the literature for cellulosic materials.
Assuntos
Celulose/química , Recuperação e Remediação Ambiental/métodos , Hidrocarbonetos/isolamento & purificação , Interações Hidrofóbicas e Hidrofílicas , Adsorção , Cinética , Petróleo , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/isolamento & purificaçãoRESUMO
This study evaluated the use of commercial rhamnolipid biosurfactant supplementation in the phytoremediation of a soil via sunflower (Helianthus annuus L.) cultivation. The soil, obtained from an industrial area, was co-contaminated with heavy metals and petroleum hydrocarbons. The remediation tests were monitored for 90 days. The best results for removal of contaminants were obtained from the tests in which the sunflower plants were cultivated in soil with 4 mg kg-1 of the rhamnolipid. Under these conditions, reductions of 58% and 48% were obtained in the total petroleum hydrocarbon (TPH) and polycyclic aromatic hydrocarbon (PAH) concentrations, respectively; reductions in the concentrations of the following metals were also achieved: Ni (41%), Cr (30%), Pb (29%), and Zn (20%). The PCR-DGGE analysis of soil samples collected before and after the treatments verified that the plant cultivation and biosurfactants supplementation had little effect on the structure of the dominant bacterial community in the soil. The results indicated that sunflower cultivation with the addition of a biosurfactant is a viable and efficient technology to treat soils co-contaminated with heavy metals and petroleum hydrocarbons.
Assuntos
Misturas Complexas/isolamento & purificação , Helianthus/química , Resíduos Industriais , Indústria de Petróleo e Gás , Poluentes do Solo/isolamento & purificação , Solo/química , Tensoativos/química , Biodegradação Ambiental , Misturas Complexas/química , Humanos , Hidrocarbonetos/análise , Hidrocarbonetos/isolamento & purificação , Metais Pesados/análise , Metais Pesados/isolamento & purificação , Petróleo/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Poluentes do Solo/análiseRESUMO
Solid-phase microextraction fibers coated with polydimethylsiloxane (PDMS) provide a convenient passive sampling format to characterize bioavailability of petroleum substances. Hydrocarbons absorb onto PDMS in proportion to both freely dissolved concentrations and partitioning properties of the individual constituents, which parallels the mechanistic basis used to predict aquatic toxicity in the PETROTOX model. When deployed in a non-depletive manner, combining SPME with thermal desorption and quantification using gas chromatography-flame ionization creates a biomimetic extraction (BE) procedure that has the potential to simplify aquatic hazard assessments of petroleum substances since the total moles of all hydrocarbons sorbed to the fiber can be related to toxic thresholds in target lipid of aquatic organisms. The objective of this work is to describe the technical basis for applying BE measurements to predict toxicity of petroleum substances. Critical BE-based PDMS concentrations corresponding to adverse effects were empirically derived from toxicity tests on different petroleum substances with multiple test species. The resulting species sensitivity distribution (SSD) of PDMS effect concentrations was then compared and found consistent with the previously reported target lipid-based SSD. Further, BE data collected on samples of aqueous media dosed with a wide range of petroleum substances were highly correlated to predicted toxic units derived using the PETROTOX model. These findings provide justification for applying BE in environmental hazard and risk evaluations of petroleum substances and related mixtures.
Assuntos
Biomimética/métodos , Petróleo/toxicidade , Microextração em Fase Sólida/métodos , Disponibilidade Biológica , Cromatografia Gasosa , Dimetilpolisiloxanos/química , Hidrocarbonetos/química , Hidrocarbonetos/isolamento & purificação , Petróleo/análise , Poluentes da Água/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidadeRESUMO
Contamination in coastal aquifer plains is of great concern in many countries given that non-aqueous phase liquids (NAPLs) have polluted numerous sites through accidental oil spills or improper disposal. We have developed a method to remove pollutants such as NAPLs from sandy sediment samples collected from the Mandol area of Gomso Bay in western South Korea. The sediments were collected from around the diffuser in a two-dimensional (2D) acrylic reaction apparatus, and these contained a total petroleum hydrocarbon (TPH) concentration of 89.3 ppm (mg/kg media). The maximum perchloroethylene (PCE) concentration was 398.51 ppm in the unsaturated zone and 0.77 ppm in the saturated zone. Volatile organic compounds (VOCs) were detected between 20 and 44 hour. However, non-volatile contaminants remained in the sediments after treatment. In situ air sparging (IAS) combined with soil vapor extraction (SVE), transformation from sorbed and nonaqueous phases to the vapor phase, is incomplete when treatment is performed using a pervasive air flow for sediments such as the sand of Mandol. During air transformation, the groundwater flow conditions increased the rate of contaminant removal. Although pilot-scale testing in the field site was fluctuated due to the heterogeneous of sediments condition, this 2D study found that the proposed method can alter the measurable geophysical properties of NAPLs. These findings demonstrate that IAS combined with SVE in the saturated zone is an effective technology for aquifer remediation high applicability of sandy coastal sediments contaminated by NAPLs.
Assuntos
Recuperação e Remediação Ambiental/métodos , Sedimentos Geológicos/química , Água Subterrânea/química , Hidrocarbonetos/isolamento & purificação , Poluição por Petróleo , Solo/química , Compostos Orgânicos Voláteis/isolamento & purificação , Poluição Ambiental , Gases/isolamento & purificação , Humanos , Petróleo/toxicidade , República da Coreia , Poluentes do Solo/isolamento & purificação , Extração em Fase Sólida/métodos , Eliminação de Resíduos Líquidos/métodosRESUMO
A reliance on diesel generated power and a history of imperfect fuel management have created a legacy of petroleum hydrocarbon contamination at subantarctic Macquarie Island. Increasing environmental awareness and advances in contaminant characterisation and remediation technology have fostered an impetus to reduce the environmental risk associated with legacy sites. A funnel and gate permeable bio-reactive barrier (PRB) was installed in 2014 to address the migration of Special Antarctic Blend diesel from a spill that occurred in 2002, as well as older spills and residual contaminants in the soil at the Main Power House. The PRB gate comprised of granular activated carbon and natural clinoptilolite zeolite. Petroleum hydrocarbons migrating in the soil water were successfully captured on the reactive materials, with concentrations at the outflow of the barrier recorded as being below reporting limits. The nutrient and iron concentrations delivered to the barrier demonstrated high temporal variability with significant iron precipitation observed across the bed. The surface of the granular activated carbon was largely free from cell attachment while natural zeolite demonstrated patchy biofilm formation after 15 months following PRB installation. This study illustrates the importance of informed material selection at field scale to ensure that adsorption and biodegradation processes are utilised to manage the environmental risk associated with petroleum hydrocarbon spills. This study reports the first installation of a permeable bio-reactive barrier in the subantarctic.
Assuntos
Poluentes Ambientais/química , Poluentes Ambientais/isolamento & purificação , Hidrocarbonetos/química , Hidrocarbonetos/isolamento & purificação , Ilhas , Petróleo/análise , Adsorção , Regiões Antárticas , Biodegradação Ambiental , Carvão Vegetal/química , Poluentes Ambientais/metabolismo , Hidrocarbonetos/metabolismo , Permeabilidade , Zeolitas/químicaRESUMO
Bioaugmented compost was created by inoculating petroleum-degrading bacteria into mature compost. The petroleum hydrocarbon degradation efficiencies were investigated by applying this enhanced compost to petroleum-contaminated soil under low temperatures. The results showed that the degrading bacteria can be enriched in the mature compost. After 30 d of remediation, the removal efficiency of TPH, alkanes, and PAHs in the soil was 27.0%, 19.6%, and 10.0%, compared to natural attenuation (CK), which was 4.5%, 9.5%, and 2.3%, respectively. In response to remediation, the relative abundance of Proteobacteria and Actinobacteria phyla decreased from 53.4% and 25.9% to 48.9% and 14.1%, respectively, and Bacteroidetes phylum increased from 5.0% to 24.5%. At the genus level, the relative abundance of Acinetobacter and Pseudomonas increased from 0.02% and 3.4% to 15.2% and 4.6%, respectively. The results indicated that the bioaugmented compost may efficiently facilitate and speed up the bioremediation of petroleum-contaminated soil under low-temperature conditions. Soil microbial diversity and structure of microbial communities are sensitive to the remediation.
Assuntos
Biodegradação Ambiental , Compostagem , Petróleo , Microbiologia do Solo , Poluentes do Solo/isolamento & purificação , Bactérias/classificação , Bactérias/metabolismo , Hidrocarbonetos/isolamento & purificação , SoloRESUMO
Adding clay to marine oil pollution represents a promising approach to enhance bacterial hydrocarbon degradation in nutrient poor waters. In this study, three types of regionally available clays (Ca-bentonite, Fuller's Earth and kaolin) were tested to stimulate the biodegradation of source and weathered oil collected from the Deepwater Horizon spill. The weathered oil showed little biodegradation prior to experimentation and was extensively degraded by bacteria in the laboratory in a similar way as the alkane-rich source oil. For both oils, the addition of natural clay-flakes showed minor enhancement of oil biodegradation compared to the non-clay bearing control, but the clay-oil films did limit evaporation. Only alkanes of a molecular weight (MW) > 420 showed significant reduction by enhanced biodegradation following natural clay treatment. In contrast, all fertilized clay flakes showed major bacterial degradation of the oil, with a 6-10 times reduction in alkane content, and an up to 8 fold increase in the rate of O2 consumption. Compared to the control, such treatment showed particular reduction of longer chained alkanes (MW > 226). The application of natural and fertilized clay flakes also showed selective reduction of PAHs, mainly in the MW range of 200-300, but without significant change in the toxicity indices measured. These results imply that a large variety of clays may be used to boost oil biodegradation by aiding attachment of fertilizing nutrients to the oil.
Assuntos
Silicatos de Alumínio/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/metabolismo , Hidrocarbonetos/metabolismo , Poluição por Petróleo , Biodegradação Ambiental/efeitos dos fármacos , Argila , Golfo do México , Hidrocarbonetos/isolamento & purificação , Petróleo/análise , Poluição por Petróleo/análise , Tempo (Meteorologia)RESUMO
Remediation of soils contaminated with petroleum is a challenging task. Four different bioremediation strategies, including natural attenuation, biochar amendment, phytoremediation with ryegrass, and a combination of biochar and ryegrass, were investigated with greenhouse pot experiments over a 90-day period. The results showed that planting ryegrass in soil can significantly improve the removal rate of total petroleum hydrocarbons (TPHs) and the number of microorganisms. Within TPHs, the removal rate of total n-alkanes (45.83 %) was higher than that of polycyclic aromatic hydrocarbons (30.34 %). The amendment of biochar did not result in significant improvement of TPH removal. In contrast, it showed a clear negative impact on the growth of ryegrass and the removal of TPHs by ryegrass. The removal rate of TPHs was significantly lower after the amendment of biochar. The results indicated that planting ryegrass is an effective remediation strategy, while the amendment of biochar may not be suitable for the phytoremediation of soil contaminated with petroleum hydrocarbons.
Assuntos
Carvão Vegetal/metabolismo , Hidrocarbonetos/isolamento & purificação , Petróleo/análise , Solo/química , Biodegradação Ambiental , Hidrocarbonetos/metabolismo , Petróleo/metabolismoRESUMO
In this study, we performed a greenhouse pot-culture experiment to investigate the potential of a wild ornamental plant Iris pseudacorus L. in remediating petroleum contaminated soils from the Dagang Oilfield in Tianjin, China. The results suggested that Iris pseudacorus L. had great resistance to ≤ 40,000 mg · kg(⻹ of total petroleum hydrocarbons (TPHs). The removal rate of TPHs with concentrations of 10,000 mg · kg⻹, 20,000 mg · kg⻹ and 40,000 mg · kg⻹ in soils by Iris pseudacorus L. was 42.1%, 33.1% 31.2%, respectively, much higher than those in the corresponding controls (31.8%, 21.3% 11.9%, respectively) (P < 0.05). The root specific surface area of Iris pseudacorus L. was determined by the root scanner. The results suggested that TPHs with concentrations of 10,000 mg · kg⻹, 20,000 mg · kg⻹ and 40,000 mg · kg⻹ in soils increased the root specific surface area comparing with the controls. Additionally, the metabolic analysis showed that root metabolism changed to different degrees under the stress of TPHs, and the levels or species of metabolites had a significant change (P < 0.001). Furthermore, the results showed that 5 of 11 metabolites (VIP value > 1.2) with the root specific surface area from the PLS-DA model analysis, including ethanedioic acid, lactic acid, 2-butenedioic acid, phosphate and propanedioic acid, were positively correlated with the root specific surface area, but the others, gluconic acid, uridine, butanoic acid, maltose, 9,12-octadecadienoic acid, phenylalanine, were negatively correlated with it. In conclusion, using Iris pseudacorus L. to remediate petroleum contaminated soils is feasible, and the metabolic analysis in roots is useful to better understand the metabolic response of plants exposure to petroleum contaminated soils, and then reveals its remediated mechanisms.
Assuntos
Hidrocarbonetos/isolamento & purificação , Gênero Iris/metabolismo , Petróleo , Raízes de Plantas/metabolismo , Poluentes do Solo/isolamento & purificação , Biodegradação Ambiental , China , Solo/química , Microbiologia do SoloRESUMO
To explore the potential of Pseudomonas aeruginosa NY3 for the treatment of highly concentrated crude oil-contaminated water, the immobilization of strain NY3 on the surface of polyurethane foam (PUF), the conditions for using these biofilms and the possibility of recovering the used biofilms were studied. The results demonstrated that the biofilm formation process for strain NY3 was quick and easy. Under optimum conditions, the biomass immobilized on the PUF surface could reach 488.32 mg dry cell/g dry PUF. The results demonstrated that when the degradation time was 12 h, the average oil removal rate in 2 g crude oil/L contaminated water was approximately 90% for 40d. Meanwhile, the biofilms could be recovered for reuse. The recovery ability and the high and steady oil removal rate facilitated the application of the biofilms for the removal of concentrated oil from wastewater.
Assuntos
Biofilmes , Hidrocarbonetos/isolamento & purificação , Petróleo , Pseudomonas aeruginosa/metabolismo , Águas Residuárias/química , Biodegradação Ambiental , Células Imobilizadas , Meios de Cultura/química , Concentração de Íons de Hidrogênio , Poliuretanos/química , Águas Residuárias/microbiologiaRESUMO
Asparagus suaveolens is a medicinal plant used in Lesotho and South Africa to treat epilepsy and gonorrhea. The current investigation identifies the compound responsible for the antiepileptic and antimicrobial properties as palmitone which showed antigonorrhea activities against WHO 2008 Neisseria gonorrhea F and 0 strains more than the standard used, gentamicin. These results support the traditional use of A. suaveolens for treatment of gonorrhea and epilepsy since palmitone is known as an anticonvulsant agent. This is the first study indicating the presence of palmitone in the Asparagus genus and demonstrates the in vitro antigonorrhea activity of palmitone.
Assuntos
Antibacterianos/farmacologia , Asparagus/química , Hidrocarbonetos/farmacologia , Cetonas/farmacologia , Neisseria gonorrhoeae/efeitos dos fármacos , Componentes Aéreos da Planta/química , Antibacterianos/isolamento & purificação , Anticonvulsivantes/isolamento & purificação , Anticonvulsivantes/farmacologia , Hidrocarbonetos/isolamento & purificação , Cetonas/isolamento & purificação , Testes de Sensibilidade Microbiana , Extratos Vegetais/química , Plantas Medicinais/química , África do SulRESUMO
Self-sustaining treatment for active remediation (STAR) is an emerging, smoldering-based technology for nonaqueous-phase liquid (NAPL) remediation. This work presents the first in situ field evaluation of STAR. Pilot field tests were performed at 3.0 m (shallow test) and 7.9 m (deep test) below ground surface within distinct lithological units contaminated with coal tar at a former industrial facility. Self-sustained smoldering (i.e., after the in-well ignition heater was terminated) was demonstrated below the water table for the first time. The outward propagation of a NAPL smoldering front was mapped, and the NAPL destruction rate was quantified in real time. A total of 3700 kg of coal tar over 12 days in the shallow test and 860 kg over 11 days in the deep test was destroyed; less than 2% of total mass removed was volatilized. Self-sustaining propagation was relatively uniform radially outward in the deep test, achieving a radius of influence of 3.7 m; strong permeability contrasts and installed barriers influenced the front propagation geometry in the shallow test. Reductions in soil hydrocarbon concentrations of 99.3% and 97.3% were achieved in the shallow and deep tests, respectively. Overall, this provides the first field evaluation of STAR and demonstrates that it is effective in situ and under a variety of conditions and provides the information necessary for designing the full-scale site treatment.
Assuntos
Alcatrão/química , Poluição Ambiental/análise , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/análise , Carvão Mineral , Hidrocarbonetos/isolamento & purificação , Peso Molecular , Petróleo/análise , Projetos Piloto , Solo , Temperatura , VolatilizaçãoRESUMO
Compact filter systems, which are installed to significantly reduce the load of pollutants from road runoff, are very promising treatments for urban runoff. The objective of this research was to evaluate the effectiveness of activated carbon, activated lignite, zero valent iron, exfoliated graphite, amorphous ferric hydroxide, and activated alumina at removing petrol hydrocarbons from synthetic road runoff. Therefore, the kinetics and the equilibrium adsorption of petrol hydrocarbons onto these adsorbents were investigated using column adsorption experiments at levels ranging from 100 to 42 g L(-1). Of the tested adsorbents, exfoliated graphite is the most effective with a maximum adsorption capacity for petrol hydrocarbons of 3,850 mg g(-1). The experimental equilibrium data are fitted to the Freundlich and Langmuir models.
Assuntos
Filtração , Hidrocarbonetos/isolamento & purificação , Poluição por Petróleo/prevenção & controle , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Óxido de Alumínio/química , Carvão Vegetal/química , Compostos Férricos/química , Ferro/química , CinéticaRESUMO
The present study focuses on the comparison of two materials, compost from municipal solid waste and natural zeolite for the simultaneous removal of petroleum hydrocarbons (benzene, toluene, ethylbenzene, xylenes - BTEX) and toxic metals from groundwater. First, batch experiments were conducted to identify the optimal removal conditions. All of the kinetic experiments were fitted to the pseudo-second-order kinetic model; equilibrium was reached within approximately 8 h for the zeolite and 12 h for the compost. An increase in the adsorbent dose and the pH value as well as a decrease in the initial concentration enhanced the pollutants' removal. The removal selectivity of both materials with slight differences follows the order Cd > Zn & toluene > ethylbenzene > m- & p-xylene > o-xylene > benzene. According, to the results derived from the continuous flow experiments the maximum adsorption capacity of the compost (90%) referred to Cd (0.88 mmol/g) whereas the minimum refers to benzene (65%) with a capacity up to 0.065 mmol/g. Zeolite had lower efficiencies for the studied pollutants with a higher performance corresponding to Cd (0.26 mmol/g), whereas the minimum zeolite capacity (63%) corresponds to toluene (0.045 mmol/g). Thus, this paper provides evidence that compost, a low cost material produced from waste, is capable for the simultaneous removal of both organic and inorganic pollutants from wastewater, and its performance is superior to zeolite.