Light Oil Research Articles

Oil price fluctuations and their relationship to government spending in Iraq for the period 2004-2022

The study aimed to know the fluctuations in global oil prices and their relationship to government spending in Iraq for the period 2004-2022, and to know their positive and negative effects and repercussions on the country’s general budget. The study was based on a set of hypotheses, the most important of which is: There is a positive correlation between fluctuations in global oil prices and government spending in Iraq. The descriptive analytical method was used in order to reach the results, the most important of which were the growth rates of total government spending, as they also varied greatly between rising at times and falling at other times throughout the study period. There is a complete direct relationship, which is demonstrated by the identical time path for the two series, which means that crude oil prices, whether average global prices, Basra Light oil prices, or others, are the influential and decisive factor in the volume of oil revenues.

Sustainable Liquid‐Organic‐Hydrogen‐Carrier‐Based Hydrogen‐Storage Technology Using Crude or Waste Feedstock/Hydrogen

For liquid organic hydrogen carrier (LOHC) technology to be competitive with other H2‐storage methods, it is crucial to reduce the cost of LOHC materials occupying the high proportion of the embodied energy required for system implementation. Promising approaches are to convert crude or waste feedstock into LOHC materials and to utilize crude hydrogen sources obtained from various routes. Thus, in this review, the state‐of‐the‐art advances in sustainable LOHC‐based hydrogen storage using crude or waste feedstock, associated with their conversion into LOHC materials, and coupling crude hydrogen with LOHC system to obtain high‐purity H2 without separation and purification are highlighted. Petroleum sources like light cycle oil and pyrolysis fuel oil are used after liquid–liquid extraction, combined distillation/hydroprocessing, and one‐pot hydrotreating–hydrocracking. In case of converting renewable resources (e.g., biomass and plastic waste), depolymerization followed by hydrodeoxygenation is an effective approach. To utilize crude hydrogen sources for hydrogen storage, catalysts should be designed and synthesized toward activating LOHC hydrogenation reaction at lower temperatures, along with high CO resistance. Consequently, this context provides guidance for the development of LOHC technology to accelerate its commercialization.

Controls on the stable Mo isotopic composition of inner-continental precipitation

The molybdenum (Mo) isotope budget of the surface environment has been well characterized in recent decades, facilitating accurate mass balance modeling of the ancient redox-driven Mo cycle. One yet unresolved component is the range of possible processes and sources that result in isotopically heavy river waters relative to continental sources. Following a recent hypothesis that isotopically heavy δ98Mo of precipitation may control the final δ98Mo of river water relative to its continental source bedrock, we investigated the δ98Mo composition of 19 snow samples from three locations in Central Europe: the Swiss Alps (“Alpine” samples) from the Hochalpine Forschungsstation Jungfraujoch (HFSJ) in both summer and winter, the Swiss Jura Mountains in winter and the French Vosges Mountains in winter. Stream waters from two snowmelt-fed streams were additionally collected from the Alpine site. Snow sample δ98Mo compositions were highly variable, ranging from −0.03 to +1.93 ‰, with no clear mixing trends indicating complex sources, source pathways, or post-depositional processing. Only the winter snow samples from the high-altitude HFSJ site had δ98Mo values consistently heavier than typical continental crust. The δ98Mo results were coupled with radiogenic Sr isotopic, major ion, and trace element compositions as tracers for three major sources of airborne ion inputs: sea salt, mineral dust, and anthropogenic aerosols. We found that the most likely source of Mo to precipitation in the lower elevation Vosges and Jura Mountains samples was isotopically light soil mineral dust, which reflected the underlying bedrock sources, with a likely additional anthropogenic component. The isotopically heavy winter snow samples at the elevated HFSJ site were attributed to a higher input of carbonate mineral dust from long-distance transport of carbonate-rich Saharan dust, which was overwritten in the summer by an influx of low elevation sources transported upwards during higher vertical thermal mixing. Finally, we concluded that precipitation has a negligible direct effect on the overall Mo content and isotopic composition of inner continental European streams and rivers relative to other sources, such as bedrock weathering. Future time-series studies may augment these conclusions to show possible heterogeneity of precipitation as well as the addition of sample sites closer to marine sources, where a larger flux of isotopically heavy marine aerosols to streams might be expected.

Integrated approach to determining the identity of the pollution of adjacent territories with oil products

The methodology of arranging laboratory studies of oil-contaminated soils, soils and bottom sediments to determine the source and composition of hydrocarbon contamination is described. The complex approach to laboratory analysis of samples of oil-contaminated soils, soils and bottom sediments is proposed, which allows a highly reliable identification of the potential source of contamination and/or making conclusions about the identity of the contamination of adjacent territories. The proposed complex of analytical methods includes infrared spectrometry, gas chromatography with mass-selective detection, thin-layer chromatography with flame ionization detection and elemental analysis (C, H, N, S, O). Application of the proposed integrated approach allows highly reliable determination of the nature of oil contamination of soils, estimation of the total gross content of oil products and their hydrocarbon composition, and identification of the potential source of pollution. Possible errors in the interpretation of the results of determining the identity of contamination of territories and the importance of using an integrated approach in drawing conclusions about the source (culprit) of pollution are shown using real soil samples taken from oil-contaminated objects and adjacent territories. The importance of taking into account the losses of volatile oil products at the stage of sample preparation for soil contamination with light oil fractions is demonstrated. The use of standard methods of sample preparation (drying of the samples under study) leads to errors in assessing the level of contamination of territories with volatile hydrocarbons and in the choice of methods of remediation of contaminated territories. To minimize losses of volatile hydrocarbons (petrol and naphtha fractions) at the stage of soil sampling and transportation the use of sorbent is proposed. Addition of a sorbent to the soil contaminated with oil products can reduce losses of volatile hydrocarbons by 15 – 20% in the analyzed samples. Application of the developed complex approach makes it possible to determine the features of the individual hydrocarbon composition, group and elemental composition of petroleum products and identify hydrocarbon indicators (markers) inherent only to a certain type of petroleum product.

Determination of Light and Condensate Oil Categories in a Complex Petroleum System by Fluorescence Parameters: A Case Study on the Northern Tazhong Uplift, Tarim Basin, China

Determination of Light and Condensate Oil Categories in a Complex Petroleum System by Fluorescence Parameters: A Case Study on the Northern Tazhong Uplift, Tarim Basin, China

EVALUATION OF MORPHOBIOLOGICAL AND PRODUCTIVE INDICATORS OF POTATO CULTIVARS (Solanum tuberosum l.) IN THE AREA OF MYZEQE, LUSHNJE

The potato is spread all over the world, being planted in plain, hilly, sub-mountain, and mountain areas. In Albania, 10,000 to 14,000 ha of early, medium, and late potatoes are planted. In recent years, the yield of potatoes in large-scale production has increased for two reasons: First, it is planted in more productive soils and under irrigated conditions, so there are improvements in cultivation. Secondly, new cultivars with higher biological productive capacity have been introduced into cultivation. The study of morphobiological and productive indicators of potato cultivars is ongoing to achieve high and sustainable yields. This also includes the study carried out in Zhama, Lushnje, in which eleven cultivars were included, specifically: La Perla, Valencia, Aleksjo, Gaya 1, Amora, Gaya 2, Juveli, Fidel, Solo, Zisi and Melene 2. The experiment was set up on light soils according to a randomized block design with eleven variants and four replications. Planting was done with the workforce in two days, on February 8 and 9, 2023. During the vegetation, ten plants for each variant and repetition were determined on which biometric and production measurements were made, such as Plant height, number of shoots per plant, production per plant, number of grains per plant, production in percentage by weight; up to 30 g, 31 - 80 g, 81 - 120 g and over 120 g. The data was processed to determine the best cultivar.

Roles of Catalysts and Feedstock in Optimizing the Performance of Heavy Fraction Conversion Processes: Fluid Catalytic Cracking and Ebullated Bed Vacuum Residue Hydrocracking

Petroleum refining has been, is still, and is expected to remain in the next decades the main source of energy required to drive transport for mankind. The demand for automotive and aviation fuels has urged refiners to search for ways to extract more light oil products per barrel of crude oil. The heavy oil conversion processes of ebullated bed vacuum residue hydrocracking (EBVRHC) and fluid catalytic cracking (FCC) can assist refiners in their aim to produce more transportation fuels and feeds for petrochemistry from a ton of petroleum. However, a good understanding of the roles of feed quality and catalyst characteristics is needed to optimize the performance of both heavy oil conversion processes. Three knowledge discovery database techniques—intercriteria and regression analyses, and artificial neural networks—were used to evaluate the performance of commercial FCC and EBVRHC in processing 19 different heavy oils. Seven diverse FCC catalysts were assessed using a cascade and parallel fresh catalyst addition system in an EBVRHC unit. It was found that the vacuum residue conversion in the EBVRHC depended on feed reactivity, which, calculated on the basis of pilot plant tests, varied by 16.4%; the content of vacuum residue (VR) in the mixed EBVRHC unit feed (each 10% fluctuation in VR content leads to an alteration in VR conversion of 1.6%); the reaction temperature (a 1 °C deviation in reaction temperature is associated with a 0.8% shift in VR conversion); and the liquid hourly space velocity (0.01 h-1 change of LHSV leads to 0.85% conversion alteration). The vacuum gas oil conversion in the FCC unit was determined to correlate with feed crackability, which, calculated on the basis of pilot plant tests, varied by 8.2%, and the catalyst ΔCoke (each 0.03% ΔCoke increase reduces FCC conversion by 1%), which was unveiled to depend on FCC feed density and equilibrium FCC micro-activity. The developed correlations can be used to optimize the performance of FCC and EBVRHC units by selecting the appropriate feed slate and catalyst.

RESPONSE SURFACE METHODOLOGY OPTIMIZATION AND UPGRADING OF AGBABU BITUMEN IN THE PRESENCE OF RICE HUSKS

With the current global trend in energy demand due to the increase in human population and technological inclination in carrying out day to day activities, the conventional crude oil is fast depleting and thus an alternative source of energy is needed for sustainability for the fuel/energy supply. Natural bitumen upgrading could serve as an alternative source for the future fuel supply but the process of upgrading the bitumen needs to be optimized to obtain the best conditions at which the bitumen upgrading process would effectively take place which brought about this study. In this study research work, optimization of Agbabu bitumen in the presence of rice husks using response surface methodology (RSM) was carried out to determine the optimal conditions at which the bitumen could be upgraded. Box-Behnken Designed experiment (BBD) was used as the template to design the experiment where the chosen variable factors were temperature, residence time and rice husks at a range or level of (300 – 350 oC), (30 – 180 min) and (0.6 – 1.0 wt.%) for each of the variable factor respectively and the chosen responses were viscosity, API gravity, residue yield and light oil yield. The Agbabu bitumen was characterized by viscosity at 70 oC to be 86.78 Pa.s, density at 60 oC to be 1.0153 Kg/L, H/C ratio 1.19:1 and API gravity of 7.87 o etc. The optimum conditions at which the Agbabu bitumen could be upgraded for maximum yield of light oil was found to be (temperature 345.716 oC, residence time 30.0 min, and rice husks 1.0 wt.%) at response value of viscosity 8.340 Pa.s, API gravity 24.520 o, residue yield 22.39 w/w% and light oil yield 50.064 w/w%. The light oil yield for the upgraded Agbabu bitumen at the optimum conditions had a desirability of 0.688989, amounting to 68.4% yield. The overall desirability for the whole upgrading process was 0.909415 at the optimum conditions. Thus, indicating an acceptable optimization and upgrading process for Agbabu bitumen.

Efficacy of Foldable Capsular Vitreous Body Implants Filled With Light or Heavy Silicone Oil in the Treatment of Silicone Oil-dependent Eyes.

The purpose of this study was to compare the clinical efficacy of foldable capsular vitreous body (FCVB) filled with either light or heavy silicone oil and the incidence of complications after their implantation for the treatment of severe ocular trauma and silicone oil-dependent eyes. FCVB filled with either light (n = 16) or heavy (n = 8) silicone oil was implanted in 24 patients. During the 12-month follow-up period, the intraocular pressure, final best-corrected visual acuity, retinal reattachment condition, position of the FCVB, and complications were assessed. All surgeries were performed without issue. There was no significant difference in preoperative and postoperative best-corrected visual acuity between the two groups. A significant improvement in the intraocular pressure was observed after surgery in both the light silicone oil (P = 0.029) and heavy silicone oil (P = 0.035) groups. None of the patients developed displacement or prolapse of the FCVB. The most common early and late postoperative complications were postoperative hemorrhage (33.3%) and corneal opacification (50%), respectively. FCVB filled with heavy silicone oil can be used as a supplemental therapy for patients who have lost the anterior segment of their eye, have lesions of the inferior retina, or cannot maintain the prone position for various reasons. Implantation of FCVB combined with heavy silicone oil compensates for the shortcomings of this with light silicone oil, providing patients with more personalized treatment.

Optimized interfacial tension and contact angle for spontaneous imbibition in low-permeable and oil-wet sandstone cores with light crude oil

Spontaneous imbibition is an important phenomenon of fluid transports in porous media, particularly in liquid environment with a certain range of interfacial tension and wettability. Meanwhile, the spontaneous imbibition could be enhanced with the additions of surfactants, through modifying the oil–water interfacial tension (IFT) and wettability. However, ultra-low IFT impairs the capillary pressure. Hence, appropriate ranges of the IFT and contact angle (CA), though lacking adequate investigations, are key to optimizing spontaneous imbibition. Here, a series of physical experiments were conducted to evaluate the spontaneous imbibition efficiency of surfactant solutions with wide-range IFTs (10−3–101 mN/m) in the porous media of permeability 11 mD, through designed interfacial property measurements with different surfactant concentrations. Besides, the inverse Bond number was employed to determine the optimized interfacial properties during the imbibition. Overall, the best imbibition-induced hydrocarbon recovery is reached at oil viscosity of 25.26 mPa·s, an IFT of 0.1–0.2 mN/m and a CA of 70–80°.

Eco-friendly bionic superwetting Janus membranes prepared from paper-based laser-induced graphene for photothermal anti-icing and on-demand oil–water separation

Laser-induced graphene (LIG) from carbon precursors is used in the manufacture of semiconductors, energy and biomedical devices. To expand its field of applications, there is a strong need to explore LIG conversion of eco-friendly precursors. An approach combining bionic structures and surface modification on paper-based LIG was investigated for producing asymmetric superwetting Janus membranes. Molecular dynamic simulation illustrates the paper-based LIG conversion mechanism. The Octadecanethiol-modified bionic crescent-shaped LIG surface exhibited superhydrophobic performance, the water contact angle (WCA) is 157° and the water sliding angle (WSA) is 3.5°. The plasma-modified LIG surface was superhydrophilic with the WCA of 0°. The Janus membranes were demonstrated for high-efficient separation of light oil–water and heavy oil–water mixtures. Furthermore, the superhydrophobic surface of the Janus membranes with excellent photothermal properties exhibited superior anti-icing capability. The proposed approach for fabrication of bionic Janus membranes would provide an eco-friendly solution to LIG applications.

Hydrophobic modification of biomass chitosan for treatment of oily wastewater and its demulsification mechanism

Traditional demulsifiers are commonly produced using raw materials like ethylene oxide and propylene oxide, which deplete significant petroleum resources and involve hazardous and complex manufacturing processes. In this investigation, a hydrophobically modified chitosan (HMC) was synthesized by grafting dodecyl diethanolamine onto natural chitosan to facilitate the separation of O/W emulsions. Characterization of HMC was conducted using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance hydrogen spectroscopy (1H NMR) and scanning electron microscopy (SEM). The demulsification efficacy of HMC was assessed through a bottle test in an O/W emulsion containing 0.2 % crude oil. Results showed that at a HMC dosage of 40 mg/L, the light transmission (WT) and oil removal efficiency (WR) of the resulted water phase were 93.4 ± 0.8 % and 99.8 ± 0.1 %, respectively. Furthermore, the competitive adsorption between natural surfactants and HMC at the interface was investigated using interfacial tension (IFT), three-phase contact angle (CA), droplet coalescence time (CTA), and interfacial film substitution. A potential demulsifying mechanism was also proposed, emphasizing HMC’s hydrophilic core and dispersed hydrophobic alkyl chains that enable rapid diffusion to the oil–water interface, replacing interfacial active components to induce demulsification by destabilizing the composite film. The advantages of HMC demulsifier over commercial demulsifiers lie in its superior environmental benefits, diverse range of sources, higher efficiency, and outstanding demulsification performance.

Bifunctional Janus Membranes for Multicomponent Contaminated Seawater Separation and Recovery.

Solar-driven interface desalination has emerged as a promising strategy to address the global freshwater shortage crisis. However, the separation and recovery of multicomponent oil-contaminated seawater remain a key challenge. This study reports a novel high-strength Janus photothermal membrane with a unique reverse wettability design. On one side, the membrane has hydrophilic and oleophobic properties, while on the other, it has hydrophobic and oleophilic characteristics. The Janus membrane demonstrates dual functionality: solar desalination and oil-water separation. This dual functionality enables efficient separation and recovery of four components from contaminated seawater: purified water, salt crystals, light oil, and heavy oil. As a result, the Janus membrane achieves an evaporation rate of 2.06 kg m-2 h-1 under 1.0 sun. The ion (Na+, K+, Ca2+, and Mg2+) removal rate approaches 100% with nearly complete recovery of salt crystals. Furthermore, various types of oils can be accurately separated, with separation efficiency approaching 100%. An integrated separation device successfully separates and recovers the four components. This research presents significant potential for efficient separation and recovery of complex components in oil-contaminated seawater.

Probing the Mechanism and Impact of Light Oil Oxidation on In Situ Hydrogen Production from Petroleum Reservoirs: A Combined SARA-Based Experimental and Numerical Investigation

Probing the Mechanism and Impact of Light Oil Oxidation on In Situ Hydrogen Production from Petroleum Reservoirs: A Combined SARA-Based Experimental and Numerical Investigation

Pigeonpea cyst nematode (Heteroderacajani Koshy) pathogenicity in black gram (Vigna mungo L.): Quantitative and qualitative yield losses, and bio- organic management

The pigeonpea cyst nematode (PCN) Heterodera cajani Koshy infects black gram (Vigna mungo L.), causing significant yield losses. However, there is a lack of systematic information on PCN pathogenicity, as well as quantitative and qualitative yield losses in black gram under various inoculum levels and soil conditions. Therefore, we have assessed the threshold inoculum level(s), estimated the yield and protein losses caused by PCN, and evaluated eco-friendly management option(s) with botanicals (neem cake, neem seed powder) and a microbial agent (Trichoderma harzianum). The results revealed a gradual and significant decline in crop growth parameters as the inoculum levels increased from 0 to 3000 juveniles (J2s)(2 kg soils). The severity of PCN infestation was notably higher in alluvial soils compared to lighter soils, exhibiting higher cyst counts (+63%) in plant roots. The threshold inoculum level(s) causing a 25% reduction in various agronomic parameters was significantly lower in alluvial soil(176–1262 J2s; mean = 921) compared to light soil (720–1444 J2s, mean = 1308), indicating that alluvial soil conditions favored increased PCN infestation over light soils, leading to more substantial growth inhibition. Strong positive correlations were found between initial inoculum levels and final populations of PCN. Inoculum levels ranging from 90 to 120 thousand J2s (representing 45–60 J2s per 100 cc soils) resulted in yield losses of 26–78% (p < 0.001). Additionally, there was a corresponding decrease in grain protein content by 9–22% (p < 0.01), subsequently reducing protein productivity by 11–83% (p < 0.001). In the PCN management experiment, among the different bio-organic components, neem cake at 1.0 t ha−1 exhibited the highest efficacy against PCN at crop harvest stage, leading to significant improvements in both dry shoot weight (4.3 g) and dry root weight (1.0 g)/plant compared to the inoculated check. Also, neem seed powder (at 0.1 t ha−1) and T. harzianum + farmyard manure (1 kg in 100 kg farmyard manure ha−1) showed increased effectiveness against the nematode. This study emphasizes the substantial influence of nematode infection on crop performance, particularly in alluvial soils, resulting in significant losses in both yield and protein content. Neem cake emerges as a promising eco-friendly management for managing the PCN in black gram.

Classical and reactive simulations of plastic co-pyrolysis: Effects of polystyrene and its fragments on product yields, aggregation, and reaction mechanisms

Mixtures of polyethylene (PE), polypropylene (PP), polystyrene (PS), and their fragments such as ethylbenzene (EB) and linear alpha olefin (LAO) are simulated at different ratios using classical and reactive force fields. Using all-atom models validated by calculating conformations and diffusivities of differently sized PE melts in agreement with experiments, simulations are performed at 450 or 513 K that mimics a low temperature under the thermal co-pyrolysis condition, showing that the decomposition of PE into LAO influences densities and diffusivities of PE, to an extent dependent on PE lengths. In PE/PP/PS simulations, PS polymers aggregate at PS concentrations of 20 wt% or higher, leading to the separation between PS and other polymers. With the inclusion of EB that are assumed to be decomposed from PS, polymers do not aggregate. To understand reaction mechanisms, reactive simulations of PE and PS are performed, showing more heavy oil and less gas products at higher PS concentrations, in agreement with experiments, because PS fragments such as benzene, EB, and methylbenzene bind to PE and end up in heavy or light oils. In particular, the transfer of H radicals between PE and PS not only prevents further decomposition of polymers but also yields free radicals of polymers that can expedite co-pyrolysis. These findings help explain experimental observations regarding the effect of PS on liquid and gas product yields and suggest the optimal PS concentration without aggregation under the thermal co-pyrolysis condition, interpreted by reaction mechanisms of the transfer of H radicals and benzene fragments.

A Comprehensive Approach to Modeling Air Injection-Based Enhanced Oil Recovery Processes

Summary Modeling of air-injection-based processes for enhanced oil recovery (EOR) is a challenging task, mostly due to the complexity of the chemical reactions taking place. Also, the applicability of currently available kinetic models is limited to the reservoir systems they were originally developed for. The objective of this study is to derive a general chemical reaction framework that could be used to develop a kinetic model for a variety of crude oils (i.e., light or heavy oils). The work is based on the modeling of high-pressure ramped temperature oxidation (HPRTO) experiments, and combustion tube (CT) tests, performed on two different oil systems: a volatile oil that is near critical at reservoir conditions (44 °API), and a bitumen sample (10 °API). The HPRTO test is a kinetic experiment that intends to mimic the flow conditions within the reservoir and allows the determination of kinetic parameters of the different reactions. On the other hand, the CT test is meant to provide quantitative information on the combustion performance that can be expected in the field. Therefore, a kinetic model was derived for each of the cases based on the history match of an HPRTO experiment. The resulting model was validated by history matching a CT test for each of the oils. An important feature of these experiments is that they were performed at representative reservoir pressure conditions. The modeling approach chosen is an extension of the methodology originally proposed by Belgrave et al. in 1993, which is arguably the most comprehensive kinetic model available in the air injection literature. However, their model was developed from experiments performed on Athabasca bitumen, and it fails to represent the high-pressure air injection process as it occurs in light oil reservoirs, which are typically encountered at higher pressure conditions. For example, Belgrave’s model is based on the deposition and combustion of semisolid residue commonly known as “coke,” which is rarely present during the combustion of light oils at high pressure. As in Belgrave’s model, this study also describes the original composition of the oil in terms of maltenes and asphaltenes. The main difference lies in the presence and importance of oxygen-induced cracking reactions, as well as the combustion of a liquid-vapor flammable hydrocarbon mixture that is generated by cracking and oxidation reactions, which take place in the gas phase. Also, a unique feature of these simulations is that, apart from history-matching traditional variables such as thermocouple temperatures, fluid recovery, and produced gas composition, they also capture changes in the physical properties of the produced oil, such as viscosity and density, as well as the amount of the residual phases in the post-test core. This enhancement to Belgrave’s reactions allows modeling the air injection process in cases where coke is not the main source of fuel, such as in high-pressure light oil reservoirs. This work changes a paradigm deeply rooted in the original in-situ combustion (ISC) theory, by deriving a general chemical reaction framework that is used to develop a kinetic model for two crude oils, which are at opposite ends of the density spectrum. This allows the consolidation of a new and comprehensive general theory for the description of the ISC process as applied to oil reservoirs. Moreover, as the pseudocomponents representing the fuel are not present in the original oil, the method is not limited to a fluid characterization in terms of maltenes and asphaltenes but could potentially be applied along with any type of characterization of the original oil.

Comparative Numerical Study on the Optimization of Double-Simultaneous Gas Injection Techniques for Enhanced Hydrogen Production from Depleted Light Oil Reservoirs

Comparative Numerical Study on the Optimization of Double-Simultaneous Gas Injection Techniques for Enhanced Hydrogen Production from Depleted Light Oil Reservoirs

Demulsification of water in crude oil emulsions via phosphonium-based ionic liquids: Statistical modeling and optimization

In the present study, the performance of two ionic liquids namely Tetrabutylphosphonium bromide (TBPB) and Tetraoctylphosphonium bromide (TOPB) as the demulsifying compounds are investigated in the demulsification operation of water in light and medium crude oil emulsions for the first time. The response surface methodology (RSM) is employed to evaluate the impact of temperature, pH, water content, demulsifier concentration, and settling time on the demulsification efficiencies of studied demulsifiers. In order to design the requisite experiments and optimize the effective factors on the water removal efficiency, the central composite design (CCD) is applied. To determine the optimal conditions of input parameters, four exact models are created by utilizing the responses of 184 experiments to predict the demulsification efficiencies of two demulsifiers for two types of crude oils based on statistical tests of different models using the analysis of variance (ANOVA). High R2 coefficient values imply that the developed models could reproduce the experimental results of the studied demulsifiers appropriately. At the optimal conditions, the water in light and medium crude oil emulsions are completely broken in the samples containing TOPB. Moreover, TBPB agent presents high and acceptable demulsification efficiencies for both types of crude oils at the optimal values of process parameters i.e. 98.078% and 96.025% for light and medium crude oil emulsions, respectively. The superior demulsification performance of TOPB with respect to TBPB can be ascribed to the longer alkyl chain length of TOPB.

Water-accommodated fractions of heavy and light oils impact DNA integrity, embryonic development, and immune system of Japanese medaka at early life stages.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants generally found in complex mixtures. PAHs are known to cause pleiotropic effects on living organisms, including developmental defects, mutagenicity, carcinogenicity and immunotoxicity, and endocrine disruptions. The main goal of this study is to evaluate the toxicity of water-accommodated fractions (WAFs) of oils in two life stages of the Japanese medaka, larvae and juveniles. The deleterious effects of an acute exposure of 48h to two WAFs from Arabian light crude oil (LO) and refined oil from Erika (HO) were analyzed in both stages. Relevant endpoints, including ethoxy resorufin-O-deethylase (EROD) activity, DNA damage (Comet assay), photomotor response, and sensitivity to nervous necrosis virus (NNV) infection, were investigated. Larvae exposed to both oil WAFs displayed a significant induction of EROD activity, DNA damage, and developmental anomalies, but no behavioral changes. Deleterious effects were significantly increased following exposure to 1 and 10μg/L of LO WAFs and 10μg/L of HO WAFs. Larval infection to NNV induced fish mortality and sharply reduced reaction to light stimulation. Co-exposure to WAFs and NNV increased the mortality rate, suggesting an impact of WAFs on fish defense capacities. WAF toxicity on juveniles was only observed following the NNV challenge, with a higher sensitivity to HO WAFs than to LO WAFs. This study highlighted that environmentally realistic exposure to oil WAFs containing different compositions and concentrations of oil generated high adverse effects, especially in the larval stage. This kind of multi-marker approach is particularly relevant to characterize the toxicity fingerprint of environmental mixtures of hydrocarbons and PAHs.