Analysis of the Photo Conversion of Asphaltenes Using Laser Desorption Ionization Mass Spectrometry: Fragmentation, Ring Fusion, and Fullerene Formation

The conversion or photo conversion of asphaltenes to polycyclic aromatic hydrocarbons (PAH’s) promoted by a laser source is analyzed using both experimental and theoretical methods. We propose that during measurements performed at an intermediate laser power, fragmentation to afford PAH’s and ring fusion to yield fused PAH’s (FPAH’s) may occur either within molecular clusters (resin case) or within molecular aggregates (asphaltene case) which are vaporized or sublimed after ionization by the laser source. These events change the initial molecular mass distribution (MMD) of the sample to a continuous statistical MMD that can be fitted to a log-normal distribution. At a high laser power, the experimental MMD is converted to a sequence of Cn bands (n is an even number) which are separated by a 24-amu, the characteristic of a mixture of fullerene compounds

Ethyl biodiesels derived from non-edible oils within the biorefinery concept - Pilot scale production & engine emissions

Procedures and operating conditions optimized in laboratory scale for the production of ethyl biodiesels from non-edible vegetable oils (NEVOs) were successfully transferred at pilot scale, with implementation of separation and purification stages. The three NEVOs candidates are Balanites aegyptiaca (BA), Azadirachta indica (AI), and Jatropha curcas (JC), converted into BAEEs, AIEEs and JCEEs respectively via homogeneous catalysis. Quality specifications of the produced biofuels were used to explain pollutant emissions and engine performance observed via a power generator. Under the same conditions, blends of petrodiesel with crude BA or JC oil (50 wt.%) were also investigated. The selected overall methodology “feedstock-conversion-engine” led to the proposal of a sustainable alternative fuel. The candidate NEVO is BA oil to which the proposed alkali route should lead to a low cost biodiesel production process thanks to easy operating conditions, associated with a two-stage procedure (glycerol recycling) and a dry-purification method (rice husk ashes). Glycerol addition should be carried out at ambient temperature to play positively at phenomena occurring in the reacting medium (chemical kinetics, chemical equilibrium, phase equilibrium). Tests on power generator demonstrated that BAEEs led to cleaner combustion than petrodiesel, particularly for the most harmful emissions (light carbonyls and ultrafine particulate matter)

Impact of oil on bacterial community structure in bioturbated sediments

Oil spills threaten coastlines where biological processes supply essential ecosystem services. Therefore, it is crucial to understand how oil influences the microbial communities in sediments that play key roles in ecosystem functioning. Ecosystems such as sediments are characterized by intensive bioturbation due to burrowing macrofauna that may modify the microbial metabolisms. It is thus essential to consider the bioturbation when determining the impact of oil on microbial communities. In this study, an experimental laboratory device maintaining pristine collected mudflat sediments in microcosms closer to true environmental conditions - with tidal cycles and natural seawater - was used to simulate an oil spill under bioturbation conditions. Different conditions were applied to the microcosms including an addition of: standardized oil (Blend Arabian Light crude oil, 25.6 mg.g21 wet sediment), the common burrowing organism Hediste (Nereis) diversicolor and both the oil and H. diversicolor. The addition of H. diversicolor and its associated bioturbation did not affect the removal of petroleum hydrocarbons. After 270 days, 60% of hydrocarbons had been removed in all microcosms irrespective of the H. diversicolor addition. However, 16S-rRNA gene and 16S-cDNA T-RFLP and RT-PCR-amplicon libraries analysis showed an effect of the condition on the bacterial community structure, composition, and dynamics, supported by PerMANOVA analysis. The 16S-cDNA libraries from microcosms where H. diversicolor was added (oiled and un-oiled) showed a marked dominance of sequences related to Gammaproteobacteria. However, in the oiled-library sequences associated to Deltaproteobacteria and Bacteroidetes were also highly represented. The 16S-cDNA libraries from oiled-microcosms (with and without H. diversicolor addition) revealed two distinct microbial communities characterized by different phylotypes associated to known hydrocarbonoclastic bacteria and dominated by Gammaproteobacteria and Deltaproteobacteria. In the oiled-microcosms, the addition of H. diversicolor reduced the phylotype-richness, sequences associated to Actinobacteria, Firmicutes and Plantomycetes were not detected. These observations highlight the influence of the bioturbation on the bacterial community structure without affecting the biodegradation capacities

Fractionation and Characterization of Petroleum Asphaltene: Focus on Metalopetroleomics

Asphaltenes, as the heaviest and most polar fraction of petroleum, have been characterized by various analytical techniques. A variety of fractionation methods have been carried out to separate asphaltenes into multiple subfractions for further investigation, and some of them have important reference significance. The goal of the current review article is to offer insight into the multitudinous analytical techniques and fractionation methods of asphaltene analysis, following an introduction with regard to the morphologies of metals and heteroatoms in asphaltenes, as well their functions on asphaltene aggregation. Learned lessons and suggestions on possible future work conclude the present review article

Biogenic RH-SiO 2 Nanoparticles for Vanadium Removal from Asphaltenes via GPC-ICP MS and spICP MS Analysis

Based on significant evidence, asphaltenes are found in crude oil and can form stably dispersed nanoaggregates in solution, which can be directly adsorbed onto surfaces by different interactions. These nanoaggregates contain mainly vanadium and nickel compounds, which are effectively adsorbed or occluded in their structure in the form of metal porphyrins. In this study, SiO2 nanoparticles produced from rice husks (RH-SiO2 NPs) were used as adsorbents for asphaltene. Adsorption experiments with asphaltene solutions from Cerro Negro crude oil were conducted, and the vanadium concentrations in the solution and in the material adsorbed were determined. Based on high-resolution analysis techniques, such as gel permeation chromatography with inductively coupled plasma-mass spectrometry (GPC-ICPMS) and single-particle inductively coupled plasma-mass spectrometry (spICP MS), vanadyl compounds associated with asphaltene aggregates were found to be mostly adsorbed on the nanoparticles, with preference in the pores. The analysis of the remnant solution after adsorption using a gel permeation chromatography system with inductively coupled plasma-mass spectrometry showed profiles corresponding to different molar mass ranges, with a decrease in the zone corresponding to larger-molecular-weight aggregates rich in vanadium compounds. The analysis of the solid material before and after adsorption was performed using spICP MS. The results showed that the size and composition of the RH-SiO2 NPs could be accurately determined using this technique; after adsorption, the signals corresponding to vanadium were detected in the nanoparticles with dimensions smaller than the actual nanoparticles. A comparison of the size distributions of nanoparticles and the vanadium signal from the material adsorbed onto nanoparticles indicated that vanadium compounds associated with aggregates were adsorbed and migrated to the pores of the nanoparticles. When simultaneous aggregation is present, the adsorption processes are complex, and the possibility of multilayer adsorption or aggregate adsorption mechanisms is difficult to discern. Using very high-resolution analysis techniques, such as GPC-ICPMS and spICP MS, we acquired reliable evidence that the vanadyl compounds associated with asphaltene aggregates were mostly adsorbed and certified that vanadium in high proportion was strongly adsorbed on the nanoparticles. These results have an important impact on the determination of asphaltene aggregate adsorption mechanisms and facilitate practical applications using nanoparticles to concentrate and separate vanadium compounds from crud

Spéciation du mercure et de l'arsenic dans les condensats de gaz.

Ce mémoire se propose de développer une méthode d'analyse fiable permettant de réaliser la spéciation de composés organo-mercuriques et organo-arséniés dans des produits pétroliers (condensats de gaz et coupes de condensats). Ces composés présents dans certains condensats de gaz posent de nombreux problèmes dans l'industrie pétrolière lors de l'exploitation ou du raffinage (empoisonnement des catalyseurs, oxydation des échangeurs de chaleur en aluminium, problèmes environnementaux) et leurs remédiations dépend des espèces en présence. Afin de réaliser cette spéciation, une technique de couplage entre une méthode de séparation (la chromatographie en phase gazeuse) et un détecteur spécifique et robuste (l'ICP MS) a été mise au point et utilisée. Cette technique a permis de mettre en évidence et de quantifier le mercure métallique (Hgʿ) et le Hg2+ comme étant les espèces du mercure majoritairement présentes ainsi que de nombreuses espèces volatiles de l'arsenic (Et3As, Et3AsS, Ph3As).The PhD presents the development of the analytical method for the speciation of organic mercury and organic arsenic compounds in petroleum products (gas condensates and condensate fraction). These compounds present in some gas condensates can cause major problems in petroleum industry during production or refinery treatment processes (catalyst poisoning, corrosion of aluminium in steam cracker cold boxes, environmental pollution). The understanding of speciation of these elements is required to predict and improve the efficiency of mercury and arsenic removal technologies. The coupling between a separation method (gas chromatography) and a specific, sensitive and powerful detector (ICP MS) was optimized. The analyses of gas condensates by this hyphenated technique show that metallic mercury and Hg2+ are the main species present. The investigation of speciation of arsenic species by this coupling shows a number of volatile arsenic species (Et3As, Et3AsS, Ph3As)PAU-BU Sciences (644452103) / SudocSudocFranceF

Study of the Size Distribution of Sulfur, Vanadium, and Nickel Compounds in Four Crude Oils and Their Distillation Cuts by Gel Permeation Chromatography Inductively Coupled Plasma High-Resolution Mass Spectrometry

International audienceThe size distribution of sulfur, vanadium, and nickel was determined for four crude oils and their distillation cuts using gel permeation chromatography (GPC) coupled to inductively coupled plasma high-resolution mass spectrometry (ICP HR MS). The results show a trimodal distribution of vanadium and nickel compounds in the crude oils, the atmospheric residues, and the vacuum residues and, for sulfur compounds, either a mono- or bimodal distribution depending upon the distillation cut considered. A correlation exists between the sulfur fraction retention times and the temperature cuts of the distillation for a temperature below 560 degrees C and also between the viscosity of the crude oils and the proportion of trapped sulfur compounds in a higher boiling temperature fraction. The thermic treatment applied for the distillation increases the aggregation of low- and medium-molecular-weight compounds of vanadium and nickel into higher molecular weight aggregates between the crude oil on the one hand and the atmospheric residue and vacuum residue on the other hand, especially when the crude oil has a high total sulfur content

Sampling and analysis of trace metal elements in natural gas by high pressure bubbling sampler and ICP-MS analysis

COMInternational audienc