Diesel In Water Research Articles

Diesel removal in non-aqueous phase by fibres from Calotropis procera: kinetic, isothermal and sorption potential evaluation

ABSTRACT Calotropis procera fibres have been proposed for free-phase diesel removal in case of spillage into groundwater. For this, characterizations were carried out using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FEG-SEM), wettability and contact angle measurements. Sorption oil capacity, kinetic, isothermal and recycling behaviour were evaluated. For initial optimization of the oil sorption capacity, an experimental design (DOE) was applied, with the optimized condition being 60 g L−1 of diesel in water and 0.01 g of fibre. Then, the results clearly indicated that the fibres have a hydrophobic and oleophilic character, quickly reaching more than 71.43 g g−1 of diesel sorption, according to the adjustment (R² > 0.99) of the pseudo-second order and Langmuir models, governed by absorption mechanisms. It should also be noted that at the end of 8 reuse cycles, the fibre presented a total accumulated sorption capacity of about 252.6 g g−1 of diesel. Furthermore, a laboratory-scale experiment was carried out to remove diesel from groundwater in gas station areas, the fibre removed 98.55% to 99.97% of removal efficiencies were achieved of the free phase over time. Therefore, the material demonstrates excellent characteristics for removing diesel spills in groundwater due to its fast, high and stable removal capacity.

Combined effects of diesel and air exposure on oxidative stress parameters of mussels Perna perna (Mytilidae, Bivalvia)

This study aimed to assess the combined effect of hypoxia and exposure to diesel on biochemical parameters of Perna perna mussels. Mussels previously kept for 48 h in clean seawater were submitted to hypoxia for 24 h followed by reoxygenation in clean seawater for 48 h. The same procedure was done but using seawater containing 0.01 mL/L of diesel, before and after hypoxia. Antioxidant enzymes as well as levels of glutathione and lipid peroxidation were measured in gills and digestive glands. The neutral red retention time assay was also evaluated in hemocytes. Results showed that cycles of air exposure and reoxygenation caused oxidative stress and antioxidant modulation in both the gills and digestive glands. The presence of diesel in water triggered additional modulation of antioxidants under hypoxia and reoxygenation stress, apparently enhancing the capacity of mussels to avoid lipid peroxidation.

Selective adsorption and efficient degradation of oil pollution by microorganisms immobilized natural biomass aerogels with aligned channels

Efficient elimination of organic pollution from wastewater is of great importance for sustainable human development. In this paper, natural biomass of lotus root (LR) and sorghum straw (SS), which showed aligned structure after treatment, was used to prepare efficient, low-cost, selective adsorption and self-floating microbial immobilization materials by hydrophobic modification assembly for the efficient degradation of diesel. By immobilizing microorganisms in aligned structured lotus flower (ALR) and sorghum straw (ASS) aerogels, hydrophobically modifying the aerogel surfaces with SiO2/PDMS, and assembling them with polyurethane foam to form hydrophobically immobilized microbial bilayer structured self-floating composites (SA6-ALR4@SiO2/PDMS and SA6-ASS4@SiO2/PDMS), diesel in water can be selectively adsorbed for biodegradation. The kinetic and thermodynamic parameters of diesel degradation process were investigated by treating oily wastewater and the effect of different carriers on microbial tolerance under different factors (temperature, pH, degradation substrate concentration, salinity) was examined. The results showed that the different carriers were effective in the degradation of diesel. However, the rich vertical aligned channels and excellent self-floating characteristics of SA6-ALR4@SiO2/PDMS accelerated the mass transfer rate between microorganisms and pollutants, achieving a high degradation rate of 96.25% for diesel in 276 h, which was better than that of 33.06% for free microorganisms under the same conditions. The degradation of oily wastewater by immobilized microorganisms follows first order kinetics. Moreover, this degradation process is spontaneous and the ΔG value is less than 0 at different temperatures. Compared with the existing methods using natural biomass to treat oily wastewater or applying only free microorganisms for biodegradation to remove oily wastewater, these methods have the disadvantages of poor selective adsorption, easy settling and low efficiency. It has greater advantages and application potential in on-site oil spill accident treatment, and opens up an effective green channel for the purification of oily wastewater.

Phytotoxicity of Salvinia molesta in Diesel Exposure

Phytoremediation is one of the methods to remove various types of pollutants from water and soil using plants. Salvinia molesta, an aquatic plant, is chosen in this study to determine its ability to degrade diesel as the pollutant in synthetic wastewater with different diesel concentrations (0, 8,700, 17,400, and 26,100 mg/L) for 14 days. Total petroleum hydrocarbon (TPH) has been used as an indicator to represent diesel concentration variation in wastewater. Degradation of TPH was 85.1% for diesel concentration of 8,700 mg/L, compared with only 53.9% in the corresponding control without plant. While, acute toxicity on S. molesta exposed in diesel concentrations of 17,400 and 26,100 mg/L was observed and eventually had caused the plants to die after 14 days of exposure. Additionally, throughout the phytotoxicity test, the biomass of S. molesta was found to fluctuate confirming inhibition on plant to survive with diesel contaminated water compared with the corresponding control without contaminant. Based on the results obtained it is suggested to decrease diesel concentration less than 8,700 mg/L in future study due to insolubility of diesel in water and the toxicity to the aquatic plants

Post-Impact Characteristics of a Diesel-in-Water Emulsion Droplet on a Flat Surface Below the Leidenfrost Temperature

Droplet impingement on solid surfaces takes place in a variety of industrial and environmental applications. However, there are still some areas that are not fully comprehended; emulsion droplet impact on a heated surface is one of these areas that require further comprehension. Hence, the present work represents an experimental exploration for spread characteristics of diesel-in-water (DW) emulsion droplet impacting a heated flat plate. Three different emulsions in which water concentration is set to 10%, 20%, and 30% of the overall emulsion content by volume have been tested in addition to the neat diesel. The temperature of the flat plate is varied over the range 20, 40, 60, and 80ºC respectively. Magnified high speed direct imaging and shadowgraphy have been used simultaneously for tracking droplet spread over the heated surface post impact. Droplet spread rate, maximum diameter, rebound height and velocity represent the main evaluated parameters. The results show that the maximum spread diameter is proportional while spread rate is inversely proportional to the increase in plate temperature for all diesel concentrations including the neat diesel. Whereas, droplet rebound height and velocity are found to be more responsive to the variation in diesel concentration than the variation in plate temperature, so they are both minimum in the case of neat diesel and are increasing by the decrease of diesel concentration in the emulsions.

Injectable cationic traps and sticky bacterial emulsifiers: A safe alliance during diesel bioremediation

This study proposes injectable polymeric filters to prevent diesel migration during its bioremediation. Pseudomonas aeruginosa (Gram negative bacterium) was isolated from forest soil and used to biodegrade diesel. P. aeruginosa produced biosurfactants that emulsified diesel in water while degrading it, by decreasing the interfacial tension and forming skins around diesel droplets. In lab experiments, emulsified diesel droplets could migrate through model soil columns (sand and limestone) saturated with water (to mimic aquifers). These results indicate that clean aquifers downstream of diesel spills are at risk of becoming contaminated during diesel bioremediation by P. aeruginosa. Injectable filters were developed to mitigate this risk. Injectable filters were obtained by injecting into model soils aqueous solutions of quaternized hydroxyethylcellulose (HEC+, with a positive electrostatic charge). HEC + adsorbed onto model soils, yielding positively charged surfaces. Diesel droplets stabilized by P. aeruginosa had a negative electrostatic charge (as demonstrated through zeta potential measurements) and adhered onto HEC + coated soil, likely due to attractive electrostatic forces. As a result, diesel droplet mobility through soil columns decreased. Our proof of concept indicates that injectable HEC + filters can protect clean regions of aquifers during the bioremediation of diesel spills by P. aeruginosa.

Triazole Linked N-Acetylglucosamine Based Gelators for Crude Oil Separation and Dye Removal.

Marine oil-spills have a long-lasting impact on the environment; therefore, it is a major concern in the scientific community to find a solution for remediation. Recently, phase selective organo-gelators emerged as potential materials for removal of oil from water through selective gelation. Herein, we report synthesis of a series of C-6 triazole linked N-acetylglucosamine derivatives, among which three have shown excellent selective gelation of organic solvents, diesel, petrol, and crude oils in water and seawater. We have studied phase selective gelation against different API grade crude oils (from light to heavy), and the gelation was achieved using nontoxic carrier solvent at room temperature in less than 15 min, and gelators were found useful for recovering crude oils. Critical gel concentration (CGC) of crude oil gelators was found to be 2.3-12% (w/v). The variable temperature NMR and FTIR experiments reveal that intermolecular hydrogen bonding was responsible for gel formation. Furthermore, a gelator was utilized for selective dye removal from water.

Phytotoxicity testing of diesel-contaminated water using Petunia grandiflora Juss. Mix F1 and Marigold-Nemo Mix (Tagetes patula L.).

Tagetes patula (marigold) and Petunia grandiflora (petunia) have been shown to exhibit potential in phytoremediation of environmental pollutants including heavy metals and textile dyes. To investigate their phytoremediation potential of diesel, it was necessary to evaluate diesel phytotoxicity of these two ornamental plants. Marigold and petunia seeds were incubated, for 10 and 15days, respectively, in deionised water contaminated with 0 to 4%, v/v, diesel in Petri dishes in a growth room with continuous lighting at 25°C. It was found that as far as seed germination was concerned, petunia was less sensitive than marigold to 4% diesel in water. In contrast, petunia exhibited poorer seedling root growth than marigold in the presence of diesel contamination. This finding of differential sensitivity of these two ornamental plants to diesel-contaminated water during germination and seedling growth has not been reported before. Therefore, the implications of phytotoxicity evaluation and comparison between different species or genotypes of plants at both seed germination and postgermination seedling growth should both be taken into consideration in screening tolerant plants for phytoremediation.

Ethylene Separation via Hydrate Formation in W/O Emulsions

An hybrid absorption-hydration method was adopted to recover C2H4 from C2H4/CH4 binary gas mixtures and the hydrate formation conditions of C2H4/CH4 mixtures was studied experimentally in diesel in water (w/o) emulsions. Span 20 at a concentration of 1.0 wt% in the aqueous phase was added to form water in diesel emulsions before hydrate formation and then hydrate in diesel slurry was separated after hydrate formation. The influences of initial gas-liquid volume ratio (53–142), pressure (3.4–5.4 MPa), temperature (274.15–278.15 K), water cuts (10–30 vol%), and the mole fraction of C2H4 in feed gas (13.19–80.44 mol%) upon the C2H4 separation efficiency were systematically investigated. The experimental results show that ethylene can be enriched in hydrate slurry phase with high separation factor (S) and recovery ratio (R). Most hydrate formation finished in 20 min, after that, the hydrate formation rate became very slow. The conclusion is useful for determining the suitable operation conditions when adopting an absorption-hydration method to separate C2H4/CH4.

The relationship between the stability of emulsified diesel and flotation of graphite

The emulsified diesel is a good collector of non-metallic minerals, such as coal and graphite, but it suffers from easily stratification which may lead to the change of graphite flotation. This paper reports research on the relationship between the stability of emulsified diesel and graphite flotation. The results shows that the proper Hydrophile Lipophilic Balance (HLB) value (13–14) and co-emulsifier (hexyl alcohol) can improve the stability of emulsified diesel and increase the recovery of graphite. Better dispersion state of diesel in water and smaller oil droplets could be formed when the stability of emulsified increases, which leads to enhancement of graphite recovery. Besides, the tests of the real ore proved that emulsified diesel is better collector than common diesel.

Phytotoxicity test of Scirpus grossus on diesel-contaminated water using a subsurface flow system

A phytotoxicity experiment with diesel as a model hydrocarbon pollutant at different concentrations (0, 8700, 17,400 and 26,100mg/L) was performed on the emergent wetland bulrush of Scirpus grossus in a subsurface flow system (SSF). After 72 days of exposure, maximum removal occurred at the diesel concentration of 17,400mg/L at 91.5%; in the corresponding control without plants, the removal was only 54.1%. Furthermore, the removal efficiency of hydrocarbons from sand was determined to be in the range of 67.2–69.9% for all treatments. According to the plant growth parameters, it was shown that S. grossus could effectively promote the degradation of total petroleum hydrocarbons (TPH) when the concentration of diesel in water was up to17,400mg/L. The population of living microorganisms in the planted aquariums could also adapt to ≤17,400mg/L diesel contaminated water. This study showed that S. grossus and rhizobacteria in a subsurface flow system has potential in reclaiming hydrocarbon-contaminated water.

Integral Approach for Improving the Degradation of Recalcitrant Petrohydrocarbons in a Fixed-Film Reactor

The degradation of diesel and phenanthrene in waste water was studied in a column combining a submerged trickling-flow with a fixed-film at a determined biofilm thickness with recirculation. Degradation efficiencies were found to be high with the production of a biofilm thickness of 789 μm structured in a package material with proper adsorption and physicochemical properties necessary to reach a stable state condition for the degradation of recalcitrant components in 78% at a retention time of 3 h. Improved degradation rates were reached with a biofilm built from an adapted inoculum that showed the presence of Pseudomonas sp., Klebsiella sp. Enterobacter in a concentration of 6.45 × 109 CFU mL−1. Moreover, the biodegradation rate of the inoculumn was quantified. The diesel kinetic experimental data were well described by Gompertz model which provides a specific grow rate (Kb) of 0.76 ± 0.36 h−1 and a correlation of R 2 = 0.93. The integral approach study of the variables of a complex degradation process lead to improve the complete operation of the reactor in comparison with other more specific component-based approaches.

Simple, rapid detection of biodiesel in diesel and oil in water for the nuclear industry

Simple, rapid detection of biodiesel in diesel and oil in water for the nuclear industry

Mutagenic Screening of Crude Oil Fractions Using Modified Ames Test and Allium cepa (Linn) Assay

Problem statement: Crude oil which may be broadly characterized as paraffinic or naphthenic is a complex mixture of alkanes, cycloalkanes and aromatic hydrocarbons. About 500,000 workers are employed in crude oil exploration and production worldwide. There have been reports of occupational exposure during drilling, pumping and transportation of crude oil, including maintenance of equipment used for these processes. Thus, skin tumors have been reported in mice after repeated application of the east Wilmington crude oil to their skin. Approach: It may thus be necessary to investigate the mutagenic potentials of crude oil fractions using a modified Ames test and internationally accepted Allium cepa (Linn) assay. The Allium cepa assay was done to determine the mean root length, mitotic index and chromosomal aberrations of the onions root grown in various concentrations of 5, 10 and 15% v/v crude oil, petrol, kerosene, engine oil and diesel in water. The modified Ames test which is a modification of the standard Ames test was done using E. coli (0157: H7) that has the phenotypic characteristics of glucose and lactose fermentation, motile, urease negative, indole positive and citrate negative. Thus the alteration in normal biochemical characteristics was determined by inoculating the revertant strains produced by the organism after incubating with the crude oil fractions into the specified media to re-determine their biochemical characteristics. Results: The results obtained from the Allium cepa assay showed increasing root growth inhibition with increased concentration and decreasing mitotic index with increased concentration. Stickiness, Vagrant, Bridges and fragments, Bi-nuclei, C-mitosis, multi polar anaphase and anaphase with laggards chromosomal aberration were observed. The modified Ames test showed a remarkable alteration in the biochemical characteristics of E. coli (0157: H7) by petrol and engine oil indicating mutagenicity. Conclusion: The results of the Ames test showed petrol and engine oil to demonstrate mutagenicity in bacteria, while, the Allium cepa assay showed mitodepressive effects of crude oil, petrol, engine oil, diesel and kerosene.

Utilization of Solar Energy and Atmospheric Oxygen in the Photodregradation of Diesel in Water by Cu/TiO2 Catalysts

AbstractPhotocatalytic destruction of the water soluble diesel fraction (WSF) was performed using Cu/TiO2 catalysts. Inexpensive and clean solar light and atmospheric oxygen were used as the energy source and oxidant, respectively. We investigated the effect of Cu species on the formation of a doping energy level between the conduction and valence band in TiO2. Photocatalytic reactions were investigated by monitoring the evolution of WSF as a function oftime of solar irradiation by UV-vis and FTIR spectroscopic techniques. The photocatalytic process in the presence of 5%Cu/TiO2 catalyst, is shown to be quantitatively efficient in the destruction of the water-soluble diesel fraction. The total destruction of water-soluble compounds originating from diesel residues indicates that photocatalysis can be employed for WSF treatment.

Biological treatment of mineral oil in a salty environment

Mineral oil may be spilled into the marine or coastal environment through the discharges of ballast and bilge water, dry docking activities and tanker and non-tanker accidents to contaminate both of the seawater and coastline, especially in harbors. The unsuitable storage and disposal of wasted mineral oil may also contaminate saltified soil or brackish groundwater that have been polluted by salty wastes or intruded by seawater in coastal areas. In order to clean those contaminated sites, the mineral oil must be removed from the salty environment. In this study, a lab-scale aerobic biofilter-biotrickling tower system packed with particulate plastic media (1.5 cm, hexagon in shape) was used to treat the salty artificial wastewater polluted by mineral oil (diesel fuel) mixed with chemical dispersant (CPC OD-10) and inorganic nutrients. The volatile organic compounds (VOCs) escaped from the biofilter due to aeration was then treated by the biotrickling tower of the treatment system. According to the experimental results, the optimal removal efficiencies of the emulsified diesel in this salty water was found to be 95% controlled under concentrations as high as 1000 mg TOC/L of diesel in the influent and volumetric loading rate of 1.5 kg TOC/m3-day. The biodegradation rate constant (k) was measured to be 0.169 hr–1 for a first-order reaction assumed. As to the removal efficiency for VOCs, a low percentage of 68.2% was measured due to short hydraulic retention time (10 seconds) applied to the tower. However, only a small fraction (7.9%) of total amounts of diesel was measured as VOCs. The chemical dispersant used in this study was biodegradable, which could be used as a surfactant to emulsify the mineral oil into seawater for biological treatment. Due to short HRT applied to this aerobic biofilter-biotrickling tower treatment system, both the surface area and reactor volume required to build this treatment equipment are thus decreased to make it more easily set up in a mobile ship or truck. Thus, we may treat the mineral oil in marine or any other salty environment more conveniently.

Analysis of oil in water at the low ppm level using direct supercritical fluid extraction coupled on-line with infrared spectroscopy

The continued development of direct aqueous SFE instrumentation has enabled the on-line SFE-FTIR analysis of automobile diesel in water at the low ppm level. The integrated system requires minimum sample handling stages with analysis of a 500 ml water sample being completed within 15 min. Diesel-spiked water samples provide a linear response for absorbance values measured at 2932 cm–1 (νasymmetric CH3), through the range 17.2–137.6 ppm. Method accuracy for determining spiked diesel concentrations within this range was greater than 85% with RSD 3–8.6% (n = 4 for each set of spiked calibration standards). The technique allows analyses to be performed with samples containing high levels of particulates and is also suitable for the determination of volatile aromatics and hydrocarbons. The detection limits for benzene and n-decane are 17.6 and 4 ppm, respectively.