Diesel Oil Fractions Research Articles

Modified Polymetallic Zeolite-Based Catalysts for Hydroprocessing Diesel Oil Fraction and Tetradecane

Modified Polymetallic Zeolite-Based Catalysts for Hydroprocessing Diesel Oil Fraction and Tetradecane

Short-term study of biological degradation of diesel oil by bacteria isolated from petroleum-contaminated soil

The use of fossil fuels leads to environmental contamination during their extraction, processing and distribution. Microbial biodegradation provides a sustainable method for cleaning contaminated areas which follows the principles of sustainability. This paper presents the dynamics of biodegradation of hydrocarbon fractions of diesel oil, using Planomicrobium sp. and Rhodococcus sp. isolated from petroleum-contaminated sites. GC–MS analysis was employed to analyse abundances of the specific compounds such as n-alkanes, isoprenoids, sesquitepranes, hopanes, steranes and aromatic compounds (naphthalene and its methylated homologues, phenanthrene and anthracene and their methylated homologues, and dibenzothiophene and its methylated homologues). The obtained results showed that after 30 days of biodegradation of diesel, a significant degradation was achieved, with almost complete degradation of n-alkanes and a decrease in the amount of sesquiterapanes. Rhodococcus sp. had a higher efficiency in degradation of n-alkanes, while Planomicrobium sp. had a higher efficiency in the degradation of branched hydrocarbons. Both strains showed high activity in the biodegradation of sesquitepranes and demonstrate ability to degrade methylated phenanthrenes. Additionally, dimethyl-dibenzothiophenes were almost completely degraded and removed from the system. This study presents the first comprehensive report on the GC–MS analysis of the diesel biodegradation pattern of the Planomicrobium sp., compared with the well-established Rhodococcus sp.

Efficient Removal of Water Soluble Fraction of Diesel Oil by Biochar Sorption Supported by Microbiological Degradation

The contamination of the water bodies by diesel oil (DO) and its water-soluble fraction (WSF) represents one of the most challenging tasks in the management of polluted water streams. This paper contains data related to the synthesis and characteristics of the plum stone biochar material (PmS-B), which was made from waste plum stones (PmS), along with its possible application in the sorption of the WSF of DO from contaminated water. Techniques applied in sample characterisation and comparisons were: Elemental Organic Analysis (EOA), Scanning Electron Microscopy−Energy Dispersive X-ray Spectroscopy (SEM-EDX), Fourier Transform Infrared Spectroscopy (FTIR), pH (pHsus) and point of zero charge (pHpzc). In order to increase the overall efficiency of the removal process, sorption and bioremediation were subsequently combined. Firstly, PmS-B was used as a sorbent of WSF, and then the remaining solution was additionally treated with a specific consortium of microorganisms. After the first treatment phase, the initial concentration of diesel WSF was reduced by more than 90%, where most of the aromatic components of DO were removed by sorption. The sorption equilibrium results were best fitted by the Sips isotherm model, where the maximum sorption capacity was found to be 40.72 mg/g. The rest of the hydrocarbon components that remained in the solution were further subjected to the biodegradation process by a consortium of microorganisms. Microbial degradation lasted 19 days and reduced the total diesel WSF concentration to 0.46 mg/L. In order to confirm the non-toxicity of the water sample after this two-stage treatment, eco-toxicity tests based on a microbial biosensor (Aliivibrio fischeri) were applied, confirming the high efficiency of the proposed method.

The green tide causative-species Ulva prolifera responding to exposure to oil and dispersant

In order to study the role of oil spills in the occurrence of green tide in the Yellow Sea, the physiological characteristics and photosynthetic activities of green tide causative-species Ulva prolifera was monitored under different conditions including two oil water-accommodated fractions (WAFs) of diesel oil and crude oil, dispersed water-accommodated fractions (DWAFs) and dispersant GM-2. The results showed that, the physiological parameters of U. prolifera including the growth, pigment, carbohydrate and protein contents decreased with the increased diesel oil WAF (WAFDO) concentration, while crude oil WAF (WAFCO) showed low concentration induction and high concentration inhibition effect. In addition, with the increase of WAFs concentration, two antioxidant activities were activated. However, compared with WAFDO alone and WAFCO alone, the mixture of oil and dispersant enhanced the toxicity on the above physiological characteristics of U. prolifera. On the other hand, the photosynthetic efficiency of U. prolifera showed a similar trend. Two WAFs showed significant concentration effects on the chlorophyll-a fluorescence transients and JIP-test. The addition of dispersant further blocked the electron flow beyond QA and from plastoquinone (PQ) to PSI acceptor side, damaged the active OEC centers at the PSII donor side, suppressed the pool size and the reduction rate of PSI acceptor side, and reduced the energy transfer efficiency between PSII functional units. These results implied that the crude oil spills may induce the formation of U. prolifera green tide, and the oil dispersant GM-2 used after the oil spills is unlikely to further stimulate the scale of bloom, while the diesel oil spills is always not conducive to the outbreak of green tide of U. prolifera.

Aquathermolysis of Heavy Crude Oil: Comparison Study of the Performance of Ni(CH3COO)2 and Zn(CH3COO)2 Water-Soluble Catalysts

Aquathermolysis is one of the crucial processes being considered to successfully upgrade and irreversibly reduce the high viscosity of heavy crude oil during steam enhanced oil recovery technologies. The aquathermolysis of heavy oil can be promoted by transition metal-based catalysts. In this study, the catalytic performance of two water-soluble catalysts Ni(CH3COO)2 and Zn(CH3COO)2 on the aquathermolytic upgrading of heavy oil at 300 °C for 24 h was investigated in a high pressure–high temperature (HP-HT) batch reactor. The comparison study showed that nickel acetate is more effective than zinc acetate in terms of viscosity reduction at 20 °C (58% versus 48%). The viscosity alteration can be mainly explained by the changes in the group composition, where the content of resins and asphaltenes in the upgraded heavy crude oil sample in the presence of nickel catalyst was reduced by 44% and 13%, respectively. Moreover, the nickel acetate-assisted aquathermolysis of heavy oil contributed to the increase in the yield of gasoline and diesel oil fractions by 33% and 29%, respectively. The activity of the compared metal acetates in hydrogenation of the crude oil was judged by the results of the atomic H/C ratio. The atomic H/C ratio of crude oil upgraded in the presence of Ni(CH3COO)2 was significantly increased from 1.52 to 2.02. In addition, the catalyst contributed to the desulfurization of crude oil, reducing the content of sulfur in crude oil from 5.55 wt% to 4.51 wt% The destructive hydrogenation of resins and asphaltenes was supported by the results of gas chromatography-mass spectroscopy (GC-MS) and Fourier-transform infrared (FT-IR) spectroscopy analysis methods. The obtained experimental results showed that using water-soluble catalysts is effective in promoting the aquathermolytic reactions of heavy oil and has a great potential for industrial-scale applications.

Effects of the water-soluble fraction of diesel oil on the sera biochemical indicators, histological changes, and immune responses of black rockfish Sebastes schlegelii

In order to understand the physiological and immune responses of Sebastes schlegelii to the water-soluble fraction of diesel oil (WSD), S. schlegelii were used as the experimental objects to study the effect of WSD on the sera biochemical indicators, histological changes, and immune responses. Significant differences in sera biochemical indicators were observed in S. schlegelii after WSD exposure. The alkaline phosphatase (ALP), glucose (GLU), and globulin (GLB) were reduced by 3.51-fold, 3.12- fold, and 1.58-fold, respectively; however, K+ was increased by 3.55-fold. The results of HE staining showed that interstitial congestion was observed in the liver; the secondary lamellae deformity and hyperplasia, epithelial lifting, the primary lamellae hyperplasia, and aneurism were observed in the gill. Epidermis thickness increased, and epidermal hyperplasia in the skin was shown. The length of the secondary lamellae shortened significantly after WSD exposure. The results of AB-PAS staining showed that three different types of mucous cells were observed in the gill, and a significant increase in the number of all three types of mucous cells was observed after WSD exposure (P < 0.05). In addition, the results of the relative mRNA expressions in the liver of eleven immune-related genes showed that the relative expression levels of IL-1β, IL-8, TNF receptor, BAFF, C1s, C1r, and MyD88 in the WSD group were substantially higher than those in the LPS group (P < 0.05), and the relative expression of caspase 10 was significantly lower than that in the LPS group (P < 0.05). At the same time, no significant differences were observed in the relative expression levels of IL-1, TNFα, and C1inh between the two groups (P > 0.05). This study was expected to provide essential data for health assessments of S. schlegelii and establish the foundation for the immune-related researches of S. schlegelii after WSD exposure.

Characterization Studies for Derived Biodiesel from the Fluid Catalytic Cracking (FCC) of Waste Cooking Oil through a Fixed Fluidized Bed (FFB)

Biodiesel production through transesterification or catalytic hydrogenation using vegetable oil is a sustainable method, but it has the downsides of by-product generation and a higher cost. Therefore, in this study, waste cooking oil was selected as a raw material, and fluidized catalytic cracking was carried out on the catalyst (LDO-75) through a fixed-fluidized-bed (FFB) reactor. The effects of the reaction temperature, catalyst–oil ratio and weight hourly space velocity (WHSV) on the yield of pyrolysis gas, gasoline, diesel and heavy oil fractions were studied. The composition of the pyrolysis gas was determined by gas chromatography (GC), the composition of the gasoline fraction was analyzed by gas chromatography-mass spectrometry (GC-MS), and the characteristics of the diesel and heavy oil fractions were determined by nuclear magnetic resonance (NMR). The results show that light olefins are the main products of pyrolysis gases, and the liquid products are mainly composed of aromatic compounds. In addition, the catalytic cracking process of waste cooking oil fluid is proposed, indicating that the process of the catalytic cracking of waste cooking oil fluid includes deoxygenation, oligoaromatization and hydrodeoxygenation. The results of this study will provide a basis for the high value-added utilization of waste cooking oil.

Activity features of catalysts for thermocatalytic hydrogenation processing of polymer waste

The aim of this study was to obtain new catalysts for the processing of carbon-containing polymer waste based on polyethylene and polypropylene, represented mostly by lids from beverages bottled in plastic containers, which accumulate in huge quantities in landfills, by the method of thermocatalytic hydrogenation into liquid fuels and other products. The process was carried out in the presence of fuel oil as a binder, a source of hydrogen and additional hydrocarbons. Thus, two tasks can be solved simultaneously: recycling the polymer waste and obtaining the alternative raw materials from the polymer waste in order to save resources and improve the environmental situation in general. New catalysts based on activated zeolite modified with Mo(VI) and W(VI) salts of various concentrations for the thermocatalytic hydrogenation processing of waste plastics into motor fuels were synthesized. The composition, structure, morphology and adsorption properties of the catalysts were determined by different physicochemical methods. The suitability of the obtained catalysts for use in the thermocatalytic hydrogenation processing of plastic waste into fuels was determined. The catalysts were tested during the processing of a mixture of polyethylene-polypropylene: a paste-forming agent (fuel oil) at T=450 °C and a pressure of 0.6 MPa. The individual and group composition of gasoline, diesel and gas oil fractions was determined by chromatography coupled with mass spectrometry. The maximum yield of the gasoline fraction (16.9 wt.%) and diesel fraction (39.31 wt.%) was obtained on a 2%W(VI)/diatomite catalyst.

Zbor sastava kolektora i temperaturnih uslova za separaciju dijamanata procesom flotiranja

Quantitative and qualitative regularities of a collector low and high molecular weight fractions distribution between solid and liquid phases in foam separation process were determined with the use of extraction-spectrophotometrical technique. The feasibility of producing a collector with optimal ratio of fractions of light distillates, hydrocarbon oils, resin, and asphaltenes by mixing M-40 fuel oil with diesel fuel oil in specified ratios was substantiated. It was shown that applying compound collectors with M-40 fuel oil weight percentage of 60-70 enabled increasing diamond recovery by 2.7-3.5%. Similar increase was also achieved when using F-5 bunker fuel oil diluted by 10-18% with diesel oil fraction. The optimal temperature of 24 °C for initial ore feed conditioning with flotation agents and foam separation providing maximum diamond recovery into concentrate and high selectivity was determined. The proposed collectors and temperature conditions enabled increasing diamond recovery.

Hydrodesulfurization of 4,6-Dimethyldibenzothiophene and the Diesel Oil Fraction on NiMo Catalysts Supported over Proton-Exchanged AlMCM-41 and TiMCM-41 Extrudates

NiMo catalysts supported on mesoporous MCM-41 type materials shaped with binder were tested for activity in the hydrodesulfurization of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and the diesel fuel fraction (0.92 wt% of sulfur). The aim of the investigation was to evaluate the effect of ion exchange with protons of Al- or Ti-substituted MCM-41 mesoporous supports. The subjected catalytic systems were NiMo/HAlMCM-41 and NiMo/HTiMCM-41, and for comparison purposes NiMo/AlMCM-41 and NiMo/TiMCM-41. The samples were characterized by N2 sorption (at 77 K), XRD, TEM, XPS, SEM and Py–IR. It was found that the functionalization of AlMCM-41 and TiMCM-41 with protons increased the conversion of 4,6-DMDBT and the pseudo-first-order rate constant. Correspondingly, 4,6-DMDBT HDS reactions over the NiMo/HTiMCM-41 catalyst proceeded to a similar extent via hydrogenation and direct desulfurization, whereas over the NiMo/HAlMCM-41 they proceeded mainly via direct desulfurization. Furthermore, the ion-exchanged catalysts displayed two-fold higher efficiency in direct desulfurization than their non-modified counterparts. The NiMo/HTiMCM-41 catalyst exhibited the highest catalytic efficiency in the HDS of 4,6-DMDBT and the diesel oil fraction. The high activity of the NiMo/HTiMCM-41 catalyst is mainly attributed to its appropriate acidity, as well as the metal–support interaction providing both the high dispersion of the active phase and the desirable multilayered stacking morphology of the active phase slabs.

The effect of thermal aging on the composition of pyrolysis oil fuel derived from typical waste plastics

This study reveals the influence of thermal aging on the pyrolysis oil fuel components of typical waste plastics, including polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC). Plastic samples were continuously heated in an aging oven at 100 °C to simulate thermal aging. The pyrolysis volatile compositions of fresh and aged plastic samples were comparatively studied by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) at 500 °C. The volatile composition analysis results showed that thermal aging changes the pyrolysis oil composition, and the influence strongly depends on the type of plastic. For PE and PP, which underwent random scission after thermal aging treatment, the influence of thermal aging on the heavy oil fraction was more obvious than that on the light oil and diesel oil fractions. For PVC samples, the thermal aging process caused structural defects and turned the color of the PVC light yellow. After 128-h thermal aging, the maximum weight loss rate decreased by 35.8%, and the fraction of C5-C9 components and aromatics first increased and then decreased. The maximum values were 80.21 ± 1.62% and 73.69 ± 0.73%, and the minimum values were 65.58 ± 2.63% and 63.98 ± 0.39%, respectively.

HYDROPROCESSING OF PETROLEUM FRACTIONS OVER MODIFIED ALUMINIUM OXIDE CATALYSTS

The hydro processing of gasoline and diesel oil fractions over aluminum-nickel-molybdenum catalysts modified by additives HY, ZSM-5, phosphorus and rare earth elements were studied. At the hydro processing of straight-run gasoline over NiO-MoO3- Ce2О3-Р2О5–ZSM(30%)-Al2O3 the content of isoalkanes increases in comparison with the initial from 26.3 to 35.7- 38.3% at 320-400оС. The octane number of refined gasoline at 400оС is 83.7 (RON) and 69.7 (MON). The sulfur content decreases from 0.037% (initial gasoline) to 0.0022%. At hydro processing of straight-run gasoline over NiO-MoO3-La2О3-Р2О5-ZSM-Al2O3 in the range of 320–400 oC the content of isoalkanes is 30.7- 44.3%. The octane number of refined gasoline at 400oC is maximum and is equal to 91.8 (RON) and 72.4 (MON). Under these conditions the sulfur content decreases from 0.0092% to 0.0028%. The optimal conditions for the hydro processing of straight-run gasoline were revealed: T=400˚С, V=2 h-1, Р = 4.0MPa. The catalyst NiO-MoO3-La2О3-Р2О5-ZSM-HY-Al2O3 has the highest hydro desulfurizing activity, the residual sulfur content at 400oС is 0.0012%. The catalyst NiO-MoO3-La2О3-Р2О5-ZSM-Al2O3 has the highest hydro desulfurizing activity. At hydro processing of straight-run diesel fraction on this catalyst under optimal conditions the sulfur content decreases from 0.6400 % to 0.0740 % and during hydro processing of a straight-run diesel fraction with a higher sulfur content 0.8042% - up to 0.053%, which, apparently, is associated with the presence in the feedstock of various types of organosulfur compounds. The lowest pour point and cloud point under optimal conditions reaches minus 39.6oС and minus 30.5oС respectively. Thus, developed modified zeolite-containing catalysts for the hydro processing of gasoline and diesel fractions carry out hydro processing, hydro isomerization and hydrogenation in one stage. The developed catalysts make possible to obtain high-octane low-sulfur gasoline and low-solidification low-sulfur diesel fuel.

Formation and use of anaerobic consortia for the biotransformation of sulfur-containing extracts from pre-oxidized crude oil and oil fractions

A new solution for fossil raw materials desulfurization based on a hybrid chemical-biocatalytic scheme with biogas and sulfide production is proposed.·H2O2, formic acid and Na2MoO4 were used for petroleum or oil fractions pre-oxidation. Ethanol or dimethylformamide was used as extractant to remove sulfur-contained compounds from pre-oxidized straight-run diesel oil fraction, non-hydro treated vacuum gas oil, gas condensate or crude oil. Compositions of cells (anaerobic sludge, Desulfovibrio vulgaris, Clostridium acetobutilycum, Rhodococcus ruber, Rhodococcus erythropolis) were specially developed, immobilized in poly(vinyl alcohol) cryogel and used for methanogenic treatment of sulfur-containing extracts, diluted with phosphate buffer (pH 7.2) and hydrolysates of renewable raw materials. The sulfur coming into the reactor with the extracts was 100% converted to inorganic sulfide or cell biomass. The ratio of methane in the biogas was 68–76%. Bioluminescent express-methods were used to control the possible toxicity of media and metabolic activity of cells used as biocatalysts.

HYDROTREATING AND HYDROISOMERIZATION OF OIL FRACTIONS ON MODIFIED ALUMINUM-COBALTMOLYBDENUM CATALYSTS

In this work we are given results and research of hydro refining of gasoline and diesel oil fractions on alumina catalysts CoO-MoO3-La2О3-Р2О5-ZSM-Al2O3, CoO-MoO3-Ce2О3-Р2О5-ZSM-HY-Al2O3, CoO-MoO3-La2О3-Р2О5- AAC-ZSM -Al2O3. The catalysts were prepared by impregnating a mixture of aluminum hydroxide and zeolites ZSM-5, HY with aqueous solutions of salts Co, Mo, La and phosphoric acid. Large-scale laboratory tests of the synthesized catalysts were carried out in the process of hydro processing of various types of gasoline and diesel fractions. At hydro treating of straight-run gasoline over CoO-MoO3-La2О3-Р2О5-ZSM-Al2O3 shows that in the temperature range 320 - 350оС the maximum amount of isoalkanes is formed 33.4-40.4%. The octane number of refined gasoline increases in comparison with the initial one from 78.9 to 89.3 (RON) and from 60.9 to 73.4 (MON). The sulfur content of catalysate with increasing temperature up to 400оС decreased to 0.0012 %. At hydro processing of catalytic cracking gasoline on CoO-MoO3-La2О3-Р2О5-ZSM-Al2O3 the octane number of refined gasoline is slightly reduced. The sulfur content of catalysate with increasing temperature up to 400оС decreased from initial with from 0.0134 to 0 0014 %. It was found that the lowest pour point and cloud point of hydro-refined diesel fuel is observed on the catalyst CoO-MoO3-La2O3-P2O5-ZSM-Al2O3. After hydro treating on this catalyst the pour point and cloud point are equal to minus 52.7oC and minus 40.8oC accordingly. This same catalyst has the highest hydro desulfurization activity: the sulfur content decreases from 0.5600% to 0.104%. Thus, the developed modified zeolite-containing catalysts CoO-MoO3-La2О3-P2O5-ZSM-Al2O3, CoO-MoO3-Се2О3-P2O5-ZSM-HY-Al2O3, CoO-MoO3-La2О3-P2O5-AAC-ZSM-Al2O3, exhibiting high activity at hydro treating of gasoline and diesel fractions and is able in one stage deep hydro treating, hydro isomerization and hydrocracking which allows to obtain low-sulfur, high-octane gasoline and low-sulfur and low solidifying diesel fuel which is important for operation of vehicles in winter conditions.

Sublethal effects of the Water -Soluble Fractions of Virgin Diesel Oil on some Physiological Parameters of Clarias Gariepinus Juveniles.

This study was undertaken to evaluate the sublethal effects of the water-soluble fractions of virgin diesel oil on some physiological parameters of C. gariepinus juveniles. The mean weight of C.gariepinus Juveniles weight of 1.61±1.86g, total length of 9.5±10.5cm and standard length of 11.0±12.5cm were exposed to sublethal concentrations of 0.58 ml/L, 0.29 ml/L, 0.14 ml/L, 0.07 ml/L, 0.04 ml/L and control 0.00 ml/L. There were significant differences at (P&lt;0.05) on the different levels of sublethal concentrations. The tissues include; gills, liver and intestine. The alterations considered include; the gills; inflammation, hyperplasia, fusion, lamella aneurism, epithelial lifting, abrasion and necrosis, in the liver, there was lesions, and inflammation, and also alterations of the intestine were mainly sloughing of the intestinal villi and intestinal mucosa. It was concluded that contamination of water-soluble fractions of virgin diesel oil in any water body or aquatic environment can induce several histopathological alterations in the tissues of Clarias gariepinus juvenile.

ГИДРОПЕРЕРАБОТКА ДИЗЕЛЬНЫХ ФРАКЦИЙ НА МОДИФИЦИРОВАННОМ АЛЮМОНИКЕЛЬМОЛИБДЕНОВОМ КАТАЛИЗАТОРЕ КГО – 12

The paper presents the results of the study of hydrotreatment of hexane, decane and diesel oil fractions on a new aluminum oxide zeolite-containing catalyst KGO – 12, modified with metals with variable valence, phosphorus and lanthanum additives. The hydrotreatment process was studied in a high-pressure flow unit with a stationary catalyst bed at temperatures of 320 – 400° C, a pressure of 4.0 MPa, and a volumetric feed rate of 2 h-1. After hydrotreating the diesel fraction of oil on the KGO – 12 catalyst at 400° C, the sulfur content in the catalysate decreases from 0.141 to 0.0092%, and the solidification temperature decreases from minus 27 to minus 57° C. The study of the process of hydrotreatment of the n-alcanes diesel fraction on the KGO – 12 catalyst showed that hydrotreatment, hydroisomerization and hydrocracking reactions occur simultaneously. It is established that the developed KGO – 12 catalyst has a high activity in the process of hydrotreating the diesel fraction of oil and makes it possible to obtain low-setting low-sulfur diesel fuel.

Diesel Fraction Hydrotreating in the Presence of Nickel–Tungsten Sulfide Catalyst Particles In Situ Synthesized in Pores of Aromatic Polymers

A catalyst based on mixed nickel and tungsten sulfides has been synthesized by the decomposition of the thiosalt [N(n-Bu)4]2[Ni(WS4)2] in pores of a polymer matrix, namely, mesoporous aromatic framework PAF-FC-1. The catalyst has been tested in diesel oil fraction hydrotreating at a hydrogen pressure of 5 MPa and a temperature of 380°C. Reaction products have been analyzed by two-dimensional gas chromatography using a time-of-flight mass detector and a flame ionization detector. It has been shown that the use of the synthesized catalyst provides a decrease in the content of bi- and polycyclic hydrocarbons and a significant decrease in the sulfur compound concentration in oil fractions.

Morphological and histopathological changes in seahorse (Hippocampus reidi) gills after exposure to the water-accommodated fraction of diesel oil

Industrial activities and urbanization are the main sources of pollutants in estuarine environments. Diesel, which is widely used in urban and port activities, is an important source of hydrocarbons in the aquatic environment, and its water-accommodated fraction (WAF) is toxic to the local biota. This study was performed to analyze the effects of diesel oil WAF on fish. Specifically, we characterized the gill morphology of the seahorse Hippocampus reidi and analyzed the histopathological changes in the gills after exposure to 50% diesel oil WAF. Acute (12, 24, 48, and 96 h) and subchronic (168 and 336 h) toxicity tests were performed. Furthermore, a recovery protocol was conducted: after exposure to 50% WAF for 168 h, the fish were transferred and kept in seawater without contaminants for 336 h, for a total experimental period of 504 h. The seahorse branchial apparatus was found to be tufted with short filaments; the apical surfaces of the pavement cells in the filament and lamellar epithelia formed “crests” and had microridges. Mitochondria-rich cells were distributed exclusively in the lamellar epithelium, while mucous cells were distributed in the filament epithelium. All pathologies observed after acute and subchronic exposure featured progressive time-dependent alterations of lamellar structure that might disrupt gill physiological and metabolic functions. During the recovery period, the gill alterations were gradually repaired.

Hydrotreating of gasoline and diesel oil fractions over modified alumina/zeolite catalysts

This paper deals with hydrotreating of straight-run gasoline (SRG) and diesel oil fractions (DOF) over new Ni (Co) containing alumina/zeolite catalysts, modified by transition metals (W and Mo) with the addition of P and Ce elements. In hydrotreating of the DOF, the CoO-WO3-CAR catalyst has the highest hydrodesulphurization activity that reaches 97.2% at 400 °C, P = 4MPa and V = 2h−1. Moreover, increasing of pressure until 5 MPa leads to reducing of the sulfur content up to 0.0007%. The greatest decrease in the pour (−58.9 °C) and the cloud (−56.7 °C) points during the hydrotreating of the DOF is observed using the NiO-MoO3-CAR catalyst. The octane number of SRG after hydrotreating over the NiO-MoO3-CAR catalyst rises up to 88.6. Obtained results clearly show that using synthesized catalysts, motor fuel with Euro-5 standard could be obtained.

Prospects of photocatalysis in diesel fraction purification

The photocatalysis process is widely used for removal of toxic chemical compounds from water and air. Oxides, sulfides of semiconductor materials are used as catalysts in photochemical processes, one of which is titanium dioxide. The manufacturing of an effective catalyst – nanotubes of titanium dioxide and the study of its physicochemical characteristics are considered in this paper. The behavior of titanium dioxide with various structures in the course of removing sulfur-containing organic compounds from diesel oil fractions is investigated. It is found out that titanium dioxide nanotubes (NT) are the most efficient catalysts for the photooxidation. Photocatalytic treatment of diesel fractions allows efficient and simple purification of oil products from unwanted components.