Diesel Adsorption Research Articles

Tuning electron configuration of metal sites for the diesel adsorptive desulfurization over ion-exchanged zeolite Y

In diesel adsorption desulfurization, the coordination bonding between the adsorbent and sulfur compounds is interfered by aromatic compounds in diesel. Transition metal cation exchanged zeolites Y has exhibits exceptional anti-interference performance. In this work, the influence of electron configuration on coordination bonding is explored, specifically between the adsorbent and substrate, using both experimental and DFT theoretical methods. Initially, NiY, CuY and ZnY were synthesized and evaluated for their desulfurization performance in model solution (sulfur content: 25 ppmw dibenzothiophene [DBT]) with two toluene concentrations (1 w% and 3 w%). It is found that CuY showed the highest performance with retention rate at 70.2 %. Subsequently, DFT calculations revealed the binding energy between Cu(II) and DBT was −2.71 eV, higher than Ni(II) and Zn(II), and that between Cu(II) and toluene was −1.75 eV, lower than Ni(II) and Zn(II), indicating that the highest binding energy difference was responsible for the best adsorption capability. Apart from these, wave function analysis show the electron configuration between Cu(II) and DBT had the highest binding energy difference. Finally, the impact of electron configuration on adsorption performance is further investigated by modulating the electron configuration of Ni(II) to enhance/suppress its adsorption capability. According to the findings of this study, tuning the electron configuration is an effective strategy to develop materials in adsorptive desulfurization particularly for extra low sulfur content.

The impact of metal ions on flotation of coal gasification fine slag: an experimental study

ABSTRACT This study investigates the flotation performance of coal gasification fine slag in the presence of metal ions with different valences. The impact of metal ions on the surface topography, wettability, zeta potential, functional group, and particle size distribution of coal gasification fine slag were analyzed. The results demonstrated that K+, Ca2+, Mg2+, and Al3+ all have a positive effect on flotation, with Al3+ being particularly effective. At a concentration of 0.2 mol/L, Al3+ increased the recovery of combustible matter in coal gasification fine slag from 66.70% to 91.05% compared to deionized water. Metal ions reduce the absolute value of the gasification fine slag potential, compress its double layer while increasing its surface hydrophobicity. Higher ion concentration leads to a closer-to-zero potential and increased hydrophobicity. Additionally, Al3+ promote diesel adsorption onto coal gasification fine slag. This work explains the effects of metal ions on coal gasification fine slag flotation.

Reuse of polymeric waste for the treatment of marine water polluted by diesel

Accidental diesel spills can occur in marine environments such as harbors, leading to adverse effects on the environmental compartment and humans. This study proposes the surgical mask as an affordable and sustainable adsorbent for the remediation of diesel–contaminated seawater to cope with the polymeric waste generated monthly in hospital facilities. This approach can also be helpful considering a possible future pandemic, alleviating the pressure on the waste management system by avoiding improper mask incineration and landfilling, as instead occurred during the previous COVID–19. Batch adsorption–desorption experiments revealed a complete diesel removal from seawater after 120 min with the intact laceless mask, which showed an adsorption capacity of up to 3.43 g/g. The adsorption curve was better predicted via Weber and Morris's kinetic (R2 = 0.876) and, in general, with Temkin isotherm (R2 = 0.965–0.996) probably due to the occurrence of chemisorption with intraparticle diffusion as one of the rates–determining steps. A hysteresis index of 0.23–0.36 was obtained from the desorption isotherms, suggesting that diesel adsorption onto surgical masks was faster than the desorption mechanism. Also, the effect of pH, ionic strength and temperature on diesel adsorption was examined. The results from the reusability tests indicated that the surgical mask can be regenerated for 5 consecutive cycles while decreasing the adsorption capacity by only approximately 11%.

Study on the intermediate products of Fischer Tropsch synthesis as a collector for coal flotation: Molecular dynamics and experimental studies

As a general coal flotation collector, diesel is often used in the industrial production process, and diesel is not renewable and belongs to the hazardous reagents, so there is an urgent need to find a new type of flotation collector to replace diesel. In this paper, three intermediate products produced by Fischer-Tropsch synthesis technology were used as collector. And five emulsifiers, Span80, Tween80, sodium dodecyl sulfate, betaine, and hexadecyl trimethyl ammonium bromide were used to emulsify 3# synthetic oils to produce emulsion with good stability. The flotation performance of three synthetic oil products as well as emulsified collectors were investigated, and the adsorption capacity of 2# and 3# synthetic oils on the coal surface was studied by molecular dynamics simulation. The results showed that the flotation results of synthetic oil were better than those of diesel, with collector 1# having the best flotation results. The oil in water (O/W) emulsion formulated with Tween80 had the best properties, and remained unstratified in half a month, and there were a large number of 0.1–1 μm oil droplet in the emulsion. Moreover, the emulsified collector of Tween80 with oil-water ratio of 4:6 showed excellent flotation performance, which was nearly 1.5 % higher than that of diesel. The molecular dynamics results are consistent with the synthetic oil flotation results at high concentration dosages, where 3# oil showed better adsorption behavior on the coal surface than 2# oil, but was slightly inferior to diesel adsorption. Therefore, the synthetic oil can be completely used as a substitute for diesel, and the emulsion with oil-water ratio of 4:6 formulated with Tween80 has excellent flotation performance and greatly saves the actual consumption of synthetic oil, which has very high economic and environmental value.

Spent coffee ground torrefaction for waste remediation and valorization

Spent coffee grounds (SCGs) are a noticeable waste that may cause environmental pollution problems if not treated appropriately. Torrefaction is a promising low-temperature carbonization technique to achieve waste remediation, recovery, and circular bioeconomy efficiently. This study aims to maximize lipids retained in thermally degraded SCGs, thereby upgrading their fuel quality to implement resource sustainability and availability. This work also analyzes the lipid contribution to biochar's calorific value under various carbonization temperatures and times. Torrefaction can retain 11-15 wt% lipids from SCG, but the lipid content decreases when the pyrolysis temperature is higher than 300 °C. Extracted lipid content consisting of fatty acids echoed the results of diesel adsorption capacity. The lipid content in the biochar from SCG torrefied at 300 °C for 30 min is 11.00 wt%, and its HHV is 28.16 MJ kg−1. In this biochar, lipids contribute about 14.84% of the calorific value, and the other carbonized solid contributes 85.16%. On account of the higher lipid content in the biochar, it has the highest diesel adsorption amount per unit mass, with a value of 1.66 g g−1. This value accounts for a 22.1% improvement compared to its untorrefied SCG. Accordingly, torrefaction can sufficiently remediate SCG-derived environmental pollution. The produced biochar can become a spilled oil adsorbent. Furthermore, oil-adsorbed biochar (oilchar) is a potential solid fuel. In summary, SCG torrefaction can simultaneously achieve pollution remediation, waste valorization, resource sustainability, and circular bioeconomy.

Flotation specificity of coal gasification fine slag based on release analysis

Coal gasification fine slag is a solid waste of difficult-to-separate nature . In this study, the residual carbon was enriched from fine slag by conventional flotation. The optimal flotation results in the concentrates yield of 59.01%, the concentrates ash content of 37.64%, and the flotation perfect index of 41.12%, respectively. Under the identical conditions, step release flotation exhibits abnormal results, i.e., the lowest ash content is concentrates 3 (C 3 ) corresponding to 29.21%. The particle distribution analysis of concentrates 1 (C 1 ) to concentrates 5 (C 5 ) and tailings (T) shows that particles of the highest carbon content transfer to C 3 , while dominated by ash are enriched in T. Additionally , the particle structure characteristics (with SEM , BET surface area, BJH pore volume/average pore width, FHH fractal characteristics) demonstrate that the particles differ in pore's volume, average width, and interior smoothness. This concludes that it is the larger pore volume, the wider average pore width, and the smoother pore interior that contributes to the greater amount of diesel adsorption and therefore easier release of carbon-content particles in flotation. Such regularities of particle transfer in flotation and release mechanism manifest the flotation specificities of gasification fine slag, which may provide a scientific reference for effectively enriching residual carbon in coal gasification fine slag. • Conventional flotation upgrades coal gasification fine slag with η as 41.12%. • Concentrates 3 (C 3 ) abnormally contains the lowest ash content of 29.21%. • Analysis of particle distribution reveals regularities of particle transfer. • Particle structure study learned the release mechanisms of particles. • Flotation specificities of coal gasification fine slag were clarified.

Production and characteristic features of lignin-PVA aerogels for oil spillage applications

Cleaning of oil contaminated water channels is of an absolute significance for aquatic habitats, oceanography and in environmental protection. Aerogels are envisaged suitable materials for such applications due to their interesting properties. Polypropylene is widely used material for such applications but being not biodegradable and non-renewable needs to be replaced with other economical, non-toxic and biodegrade materials. In this work, lignin a renewable material, was chosen as blend material with a non-toxic and environmental friendly polyvinyl alcohol (PVA) matrix for the fabrication of lignin polyvinyl alcohol (LP) aerogels. These materials show promising features in terms of high porosity (95.25%), low density (0.033), considerable surface area (BET) (7.20 m2/g) along with an adequate surface morphology. The water contents additionally played a positive role in increasing the surface area (7.20 m2/g) with water addition. The aerogels after coating with Tetraethyl Orthosilicate were applied to study the diesel adsorption test showed an uptake of 10.10 g/g of diesel. Moreover, these aerogels showed a good durability during their reusability of even up to 4 cycles. It can be anticipated that lignin/PVA aerogels can be employed for oil spillage applications keeping in view their non-toxic behaviour.

Characteristics and oil sorption effectiveness of areca nut husk

Oil spill accident occur due to human carelessness and error during oil transportation, storage, and production of the hydrocarbon. Effect of oil spill can be either short or long term. It is not only affecting the environment but also marine life, economy, and social. Thus, effective recovery and control method must be carefully implemented to minimise the effect. There are various studies and technologies to mitigate the oil spill incident but mostly the techniques are very expensive, difficult and use of non-environmental friendly material. Hence, this study is conducted to study areca nut husk as a potential oil adsorbent for oil spill recovery. The characteristics of areca nut husk include morphological structures and chemical composition. The areca nut husk oil sorption effectiveness and capacity also been investigated. Areca nut husk were tested for both heavy crude oil and diesel adsorption. The result shows that the efficiency of oil sorption of areca nut husk toward heavy crude oil is 14.8% and it can be an alternative sorbent material to the current modern material. Meanwhile, the areca nut husk is not recommended to be used for diesel absorption activity for its low effectiveness (i.e., 2.04%) showed in this study.

Spent coffee grounds biochar from torrefaction as a potential adsorbent for spilled diesel oil recovery and as an alternative fuel

A new approach using torrefied spent coffee grounds (TSCG) as a bioadsorbent is presented for marine oil spill recovery. The adsorbent after diesel adsorption is referred to as “oilchar”. The torrefaction of spent coffee grounds (SCG) is performed at 200, 250, and 300 °C where the solid yields are 95%, 80%, and 62%, respectively. The specific surface area, hydrophobicity, thermal stability, diesel adsorption capacity of SCG increases with increasing torrefaction temperature. SCG torrefied at 300 °C (300-TSCG) can intensify its specific surface area, contact angle, crystallinity, diesel adsorption capacity by factors of 7.6 folds, 10.3%, 35%, and 1.47 times, respectively. The diesel adsorption capacity of 300-TSCG is 1.36 times that of commercial activated carbon. The higher heating value of 300-TSCG is 30.32 MJ kg−1, accounting for a 45.1% improvement compared with that of untorrefied SCG. After adsorbing diesel, the HHV of the oilchar from 300-TSCG is 1.23 times that of SCG-oilchar, while the ignition temperature of 300-TSCG decreases from 301 to 157 °C. Overall, TSCG is a promising material to adsorb spilled diesel oil for environmental protection, and the resultant oilchar is a potential alternative fuel for thermal power plants and steel mills, thereby achieving waste reuse and circular economy.

Synthesis and characterisation of an ultra-light, hydrophobic and flame-retardant robust lignin-carbon foam for oil-water separation

The lignin extracted from Arecanut husk (Areca catechu) was used as an additive in lignin-carbon foam synthesis to enhance oil uptake in oil-water separation. The lignin yield from the arecanut husk increased as the husk fibre size reduced. The extracted lignin and lignin-carbon foam were characterised for morphology, structural, compositional and thermal degradation properties. The synthesised lignin-carbon foam appears to be ultralight (density = 0.0294 g/cm3), excellent hydrophobic (water contact angle was 124°), mesoporous (3D cell-like structure), fire-retardant and thermally stable. The foam showed an excellent sorption capacity for different oils, and the highest sorption was observed for diesel oil (7842.71 mg/g). The optimisation of contact time (30 min), lignin-carbon foam dosage (0.5 g), and initial oil concentration (30 g/L) were done for the diesel oil sorption. The isotherm study and kinetic model evaluation were done for the diesel adsorption on the lignin-carbon foam. The Temkin model was found the best fit for the adsorption isotherm. The adsorption kinetics of the lignin-carbon foam for diesel oil was best described by pseudo-second-order kinetics. The thermodynamic parameters showed that the adsorption was endothermic and spontaneous (standard enthalpy change, ΔH° = +4926.46 J/mol and standard entropy change, ΔS° = 25.249 J/mol/K). The proposed mechanism depicts that the adsorption primarily influenced hydrogen bonding (H-bonding) and n-π interactions. The enduring adsorption of oil into the lignin-carbon foam within few seconds shows the material oleophilicity and confirms their application prospect in oil spill cleanup.

Systematic adsorption process of petroleum hydrocarbon by immobilised petroleum-degradation bacteria system in degradation pathways

In order to effectively control petroleum hydrocarbon pollution by immobilisation technology, it is necessary to understanding the degradation pathways of petroleum hydrocarbon in immobilised petroleum-degradation bacteria system. However, the adsorption in degradation process is rarely studied. In this study, adsorption process of petroleum hydrocarbon was synergistically studied by means of the surface properties, adsorption thermodynamics and molecular simulation. The results indicate that the immobilised petroleum-degradation bacteria have many holes for the bacteria to adsorb. The diesel adsorption by immobilised petroleum-degradation bacteria is a spontaneous, entropy-increasing and endothermic process. Diesel is first adsorbed to the surface of immobilised petroleum-degradation bacteria through hydrogen bonding, and then is biodegraded. This study provided substantial knowledge of immobilised technology in controlling petroleum hydrocarbon pollution.

Facile Preparation of a Porous Biochar Derived from Waste Crab Shell with High Removal Performance for Diesel

In this study, a porous biochar material derived from waste crab shell was prepared by one-step hydrothermal carbonization and acetic acid activation method at 180°C, which was characterized by SEM, BET, XRD and FTIR. The results show that the as-prepared crab shell biochar (CSB) exhibits a fluffy irregular layered structure with abundant pores and oxygen-containing functional groups, which can facilitate the adsorption of diesel using CSB. In addition, batch adsorption experiments had been performed, effects of initial diesel concentration, adsorption time, adsorbent dosage and pH on the diesel adsorption using CSB were analyzed, which could be observed that CSB has high removal efficiency for diesel, and the maximum removal rate is up to 80.1%. The adsorption isotherms and kinetic studies were also investigated to determine the adsorption mechanism of diesel using CSB, the results show that the Langmuir model and the pseudo-second-order model are more suitable for describing the adsorption of diesel using CSB, indicating that the adsorption of diesel oil by CSB is monolayer chemical adsorption. This study will provide a theoretical basis for the high-value utilization of waste crab shell, which has a great potential in the treatment of oil spill.

Bottom-up and up-down strategy to obtain the highly porous polystyrene foam for oily water remediation

Bottom-up and up-down strategy were adopted simultaneously to fabricate the interconnected porous polystyrene monolith based on the high internal phase emulsions (HIPEs) technique. Interface-initiated polymerization strategy of the HIPEs combined with porogen toluene molecule offered an attractive route to fabricate the ultra-light polystyrene foam. High porosity and extra-light density endowed the polystyrene foam with outstanding oil adsorption performance towards a wide range of oil/organic solvents and diesel adsorption capacity exceeded 75.1 g/g. For recyclability, the oil adsorbed in the monolithic polystyrene foam was recovered just by means of centrifugation and the deoiling rate was over 90%. Even after ten cycles of adsorption-centrifugation, the material showed little decline in the adsorption capacity. Oleophilicity, hydrophobicity, permeable pore structure, ultra-low density, excellent oil adsorption performance and recyclability, all these features help the polystyrene foam find great application in the field of oil–water separation.

Chemical and physical modification of low rank coal floatability by a compound collector

Effective collectors are essential for improving coal floatability. In this investigation, contact angle, X-ray photoelectron spectroscopy (XPS), optical micrograph, field emission scanning electron microscope (FE-SEM), and flotation tests were used to characterize chemical and physical modification of low rank coal floatability by a compound collector consisting of coal tar and diesel. XPS showed that the C-C/C-H content on coal surface after compound collector adsorption was higher than that on coal surface after diesel adsorption. Optical microscope image results showed that compound collector produced more flocs than diesel, which increased flotation efficiency. Contact angle results showed compound collector enhanced coal surface hydrophobicity more significantly than diesel. FE-SEM images illustrated that coal surface after compound collector adsorption was rougher than that after diesel adsorption, which accelerated the rupture of liquid film between coal particle and bubble. Therefore, coal floatability after compound collector adsorption was much better than that after diesel adsorption.

Development of a new compound based on low-density polyethylene degraded with zeolite waste for the removal of diesel from water

A new adsorbent composite has been developed based on low-density polyethylene and zeolite. This material was used to remove diesel as pollutant in an aqueous system. In the synthesis of the composite and diesel removal were combined these effects: capacity of the zeolite to degrade polyethylene, partial filling of the zeolite with the polyethylene degradation products, favorable thermodynamic interactions between composite-diesel and porosity of the composite (imbibition effect). The term composite is used in the sense that partially degraded-polyethylene oligomers (waxes) are introduced into the zeolite pores in intergranular positions, insuring a good cohesion of waxes and zeolite. The material was synthetized easily by mixing low-density polyethylene and zeolite (1:1) and degraded at 200 °C at three different times: 2, 4 and 6 h. Several techniques as Differential Scanning Calorimeter, Thermogravimetric analysis, Size Exclusion Chromatography and X-Ray Diffraction are combined to study the steps of synthesis and the mechanism of diesel adsorption. The molecular weight obtained at different degradation time varied between 8470 and 99,100, while the molecular weight of the original LDPE was 136,300 g/mol. Diesel removal capacity was determined by TGA through the difference of weight loss at diesel evaporation temperatures (115–275 °C). All the prepared materials presented buoyancy in water and swelling of diesel. Highlighting among them the material prepared at 2 h with a weight loss of 39%, meanwhile the materials prepared for 4 and 6 h presented a weight loss of 29% and 23% respectively, that corresponded to the diesel removed from the water.

Systematic degradation mechanism and pathways analysis of the immobilized bacteria: Permeability and biodegradation, kinetic and molecular simulation

In order to effectively improve the degradation rate of diesel, a systematic analysis of the degradation mechanism used by immobilized bacteria is necessary. In the present study, diesel degradation mechanisms were assessed by analyzing permeability, biodegradation, adsorption kinetics, and molecular simulation. We found that bacteria immobilized on cinnamon shells and peanut shells degraded relatively high amounts of diesel (69.94% and 64.41%, respectively). The primary degradation pathways used by immobilized bacteria included surface adsorption, internal uptake, and biodegradation. Surface adsorption was dominant in the early stage of degradation, whereas biodegradation was dominant in later stages. The diesel adsorption rate of the immobilized bacteria was in agreement with the pseudo second-order kinetic model. The immobilized bacteria and diesel interacted through hydrogen bonds.

Interaction characteristics between diesel and coal with different hydrophilicity: Kinetic and force effects

Collector adhesion and spreading on the surface of coal plays a critical role in increasing the floatability and flotation efficiency of coal. In this work, the interaction characteristics, including kinetic and force effects, between the collector and coal surface with different hydrophilicity was comprehensively investigated using collector adsorption tests, induction time measurements, the atomic force microscope (AFM) colloidal probe technique, and molecular dynamics simulation (MDS). The results showed that the process of diesel adsorption on the coal surface conformed to the pseudo first-order kinetic model. As coal hydrophilicity increased, the maximum capacity exhibited a non-linear exponential decrease while the rate exhibited a linear decrease, in accordance with the induction time of coal particle-oil bubble. Force effects results showed that the adhesion force and acting distance between model diesel and coal decreased as coal hydrophilicity increased. MDS results further showed that hydrocarbon collectors were adsorbed on the hydrophobic sites of coal, but not on the hydrophilic sites. Therefore, the number of hydrophobic sites for non-polar diesel adsorption and the adhesion force between diesel and coal particles decrease as hydrophilicity increases, which in turn causes a reduction in the collector adsorption rate and maximum adsorption capacity. Furthermore, flotation tests were conducted to validate the kinetic and force effects and to indicate that both the combustible matter recovery and clean coal ash content of coal samples significantly decrease from 98.49% to 58.44% and from 3.02% to 2.65%, respectively, with increasing coal hydrophilicity.

Diesel Adsorption to Polyvinyl Chloride and Iron During Contaminated Water Flow and Flushing Tests.

This paper presents an experimental and theoretical study of aqueous diesel contamination and decontamination of a polyvinyl chloride (PVC) surface and an iron (Fe) surface. A test apparatus designed for the purpose of studying adsorption of diesel from a flowing dilute diesel/water mixture was used to measure the mass of diesel adsorbed per unit surface area (the excess surface density) and the bulk concentration of the diesel in the flow using a fluorescence based measurement technique. Both bulk composition and the excess surface density measurements were achieved via a traverse of the fluorescent measurement probe perpendicular to the test surface. The diesel adsorption to each test surface was examined for three different Reynolds numbers between zero and 7000. Measurements for a given condition were made over a period of approximately 200 h for a diesel mass fraction of approximately 0.15 % in tap water. For a Reynolds number of approximately 7000, the largest excess layer thickness was approximately 4.4 μm, which was measured on a PVC surface. Averaging over all contaminating flow rates and exposure times, the excess layer thickness on the PVC surface was approximately 2.0 μm. Reynolds number had little or no effect on the accumulation of diesel on an iron surface, which was approximately 0.71 μm. The adsorbed diesel on the PVC and iron surfaces was removed by flushing with tap water. Models to predict excess layer thickness during flushing and contamination were developed. The models predict flushing times to within 7 h and predict the influence of pipe surface on contamination level.

Novel floating photocatalysts based on polyurethane composite foams modified with silver/titanium dioxide/graphene ternary nanoparticles for the visible‐light‐mediated remediation of diesel‐polluted surface water

ABSTRACTPhotocatalyst loading on a floating substitute is accepted as a promising method for the remediation of diesel‐polluted surface water. Therefore, novel photocatalysts based on polyurethane foams modified with silver/titanium dioxide/graphene ternary nanoparticles (PU–Ag/P25/G) were synthesized and investigated. Scanning electron microscopy, energy‐dispersive X‐ray spectrometry, X‐ray diffraction, Fourier transform infrared spectroscopy, and UV–visible spectroscopy showed the coexistence of Ag, Degussa P25 (P25), and graphene and the nanoscale dispersion of nanoparticles in the matrix and on the surface of the polyurethane (PU) foam. The diesel adsorption capacity of the photocatalyst reached 96 g/g. The maximum diesel degradation was found to be 76% in a period of 16 h. Compared with polyurethane‐foam‐supported P25/graphene (PU–P25/G) and polyurethane‐foam‐supported P25 (PU–P25), all of the adsorption isotherm and degradation kinetics followed the order PU–Ag/P25/G > PU–P25/G > PU–P25 > PU; this was due to the loading of different nanoparticles. Moreover, the degradation efficiency was reduced only 5% after five consecutive reactions; this showed good stability and reusability of the photocatalyst for surface water restoration. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43400.

Role of Sophorolipid Biosurfactant in Degradation of Diesel Oil by Candida tropicalis

ABSTRACT The yeast Candida tropicalis, isolated from petroleum-contaminated soil in India, was found to be the potent producer of biosurfactant in mineral salt media containing diesel oil as the carbon source and found to be an efficient degrader of diesel oil (98%) over a period of 10 days. The crude biosurfactant decreased the surface tension of cell-free broth, 78 to 30 mN/m, with a large oil displacement area and highly positive drop collapse test. The crude biosurfactant was purified using silica gel column chromatography followed by dialysis. With the use of Fourier transform infrared (FT-IR) spectroscopy, in combination with gas chromatography–mass spectrometry (GC-MS) analysis, chemical structures of the purified biosurfactant was identified as sophorolipid species. Involvement of biosurfactant in physiological mechanism of diesel adsorption on yeast cell surface was characterized based on zeta potential. When diesel oil was emulsified with biosurfactant, the surface charge of the diesel was modified, resulting in more adsorption of diesel on yeast cell surface. Biosurfactant production by yeast species was monitored using scanning electron microscopy (SEM) analysis and found that yeast species could form thick mat of mucilaginous biosurfactant that could interconnect the individual cells. Uptake of diesel oil by C. tropicalis was elucidated through transmission electron microscopy (TEM) analysis. Interestingly, it was observed that internalization of diesel oil droplet was taking place, suggesting a mechanism similar in appearance to active pinocytosis.