High Molecular Weight Components Research Articles

Ultrasonic-microwave-assisted extraction for enhancing antioxidant activity of Dictyophora indusiata polysaccharides: The difference mechanisms between single and combined assisted extraction

The purpose of this study is to investigate the effects of different extraction methods (hot water-assisted extraction (HWE), microwave-assisted extraction (MAE), ultrasonic-assisted extraction (UAE), and ultrasonic-microwave- assisted extraction (UAME)) on the yield, chemical structures and antioxidant activity of Dictyophora indusiata polysaccharides (DPs). The research results showed that UMAE treatment had greater degree of damage to the cell wall of DPs and better comprehensive antioxidant capacity. Different extraction methods had no obvious effect on the types of glycosidic bonds and sugar rings, similar chemical composition and monosaccharide composition, with different absolute molecular weight (Mw) and molecular conformation. In particular, DPs for UMAE method had the highest polysaccharides yield, which was related to the conformational stretching and degradation avoidance of DPs in the higher molecular weight components under the simultaneous action of microwave and ultrasonic. These findings suggest that the UMAE technology has good potential for modification and application of DPs in the functional food industry.

Investigating centrifugal filtration of serum-based FTIR spectroscopy for the stratification of brain tumours.

Discrimination of brain cancer versus non-cancer patients using serum-based attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy diagnostics was first developed by Hands et al with a reported sensitivity of 92.8% and specificity of 91.5%. Cameron et al. then went on to stratifying between specific brain tumour types: glioblastoma multiforme (GBM) vs. primary cerebral lymphoma with a sensitivity of 90.1% and specificity of 86.3%. Expanding on these studies, 30 GBM, 30 lymphoma and 30 non-cancer patients were selected to investigate the influence on test performance by focusing on specific molecular weight regions of the patient serum. Membrane filters with molecular weight cut offs of 100 kDa, 50 kDa, 30 kDa, 10 kDa and 3 kDa were purchased in order to remove the most abundant high molecular weight components. Three groups were classified using both partial least squares-discriminate analysis (PLS-DA) and random forest (RF) machine learning algorithms; GBM versus non-cancer, lymphoma versus non-cancer and GBM versus lymphoma. For all groups, once the serum was filtered the sensitivity, specificity and overall balanced accuracies decreased. This illustrates that the high molecular weight components are required for discrimination between cancer and non-cancer as well as between tumour types. From a clinical application point of view, this is preferable as less sample preparation is required.

A dialysis medium refreshment cell culture set-up for an osteoblast-osteoclast coculture.

Culture medium exchange leads to loss of valuable auto- and paracrine factors produced by the cells. However, frequent renewal of culture medium is necessary for nutrient supply and to prevent waste product accumulation. Thus it remains the gold standard in cell culture applications. The use of dialysis as a medium refreshment method could provide a solution as low molecular weight molecules such as nutrients and waste products could easily be exchanged, while high molecular weight components such as growth factors, used in cell interactions, could be maintained in the cell culture compartment. This study investigates a dialysis culture approach for an in vitro bone remodeling model. In this model, both the differentiation of human mesenchymal stromal cells (MSCs) into osteoblasts and monocytes (MCs) into osteoclasts is studied. A custom-made simple dialysis culture system with a commercially available cellulose dialysis insert was developed. The data reported here revealed increased osteoblastic and osteoclastic activity in the dialysis groups compared to the standard nondialysis groups, mainly shown by significantly higher alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) activity, respectively. This simple culture system has the potential to create a more efficient microenvironment allowing for cell interactions via secreted factors in mono- and cocultures and could be applied for many other tissues.

Recent advances in permeable polymersomes: fabrication, responsiveness, and applications.

Polymersomes are vesicular nanostructures enclosed by a bilayer-membrane self-assembled from amphiphilic block copolymers, which exhibit higher stability compared with their biological analogues (e.g. liposomes). Due to their versatility, polymersomes have found various applications in different research fields such as drug delivery, nanomedicine, biological nanoreactors, and artificial cells. However, polymersomes prepared with high molecular weight components typically display low permeability to molecules and ions. It hence remains a major challenge to balance the opposing features of robustness and permeability of polymersomes. In this review, we focus on the design and strategies for fabricating permeable polymersomes, including polymersomes with intrinsic permeability, the formation of nanopores in the membrane bilayers by protein insertion, and the construction of stimuli-responsive polymersomes. Then, we highlight the applications of permeable polymersomes in the fields of biomimetic nanoreactors, artificial cells and organelles, and nanomedicine, to underline the challenges in the development of polymersomes as soft matter with biomedical utilities.

Natural organic matter source, concentration, and pH influences the toxicity of zinc to a freshwater microalga

Zinc is a contaminant of concern in aquatic environments and is a known toxicant to many aquatic organisms. Dissolved organic matter (DOM) is a toxicity modifying factor for zinc and is an important water chemistry parameter. This study investigated the influence of DOM concentration, source, and water pH on the chronic toxicity of zinc to a freshwater microalga, Chlorella sp. The influence of DOM on zinc toxicity was dependent on both concentration and source. In the absence of DOM, the 72-h EC50 was 112 μg Zn.L−1. In the presence of a DOM high in fulvic-like components, zinc toxicity was either slightly decreased (<4-fold increase in EC10s across 15 mg C.L−1 range) or unchanged (minimal difference in EC50s). In the presence of a DOM high in humic-like (aromatic and high molecular weight) components, zinc toxicity was slightly decreased at the EC10 level and strongly increased at the EC50 level. The influence of pH on zinc toxicity was dependent on the source of DOM present in the water. In the presence of DOM high in humic-like components pH did not influence toxicity. In the presence of DOM high in fulvic-like components, pH had a significant effect on EC50 values. Labile zinc (measured by diffusive gradients in thin-films) followed linear relationships with dissolved zinc but could not explain the changes in observed toxicity, with similar DGT-labile zinc relationships shown for the two DOMs despite each DOM influencing toxicity differently. This indicates changes in toxicity may be unrelated to changes in zinc lability. The results suggest that increased toxicity of zinc in the presence of DOM may be due to direct uptake of Zn-DOM complexes. This study highlights the importance of considering DOM source and characteristics when incorporating DOM into water quality guidelines through bioavailability models.

The effect of polyvinylpyrrolidone addition on microstructure, surface aspects, the glass transition temperature and structural strength of honey and coconut sugar powders

Deep knowledge of the microstructure and physicochemical properties of polymeric food systems, such as honey powders (HP) and coconut sugars (CS), has practical importance for industry and end users. This study investigated the effect of polyvinylpyrrolidone (PVP) addition on microstructure, roughness, glass transition, α-relaxation temperatures and structural strength (S) of anhydrous complex carbohydrates mixtures. The addition of PVP slightly increased the glass transition and α-relaxation temperature for HP and CS systems as high molecular weight components. Systems with PVP addition showed “stronger” behaviour according to the S approach. Polarized light, scanning electron and atomic force microscopies showed slight differences in transparency and shapes between controls and systems with PVP addition. Surface morphological changes and roughness were investigated in this study to provide insight into HP and CS particles’ structural changes. Moreover, S-involved structural diagrams were built to determine S parameters for controlling the structural transformation of HP and CS systems with and without PVP addition. The results obtained in this work provide new information on polymer-carbohydrate interactions in complex food systems and structural transformations during their production and storage.

EFFECT OF Fe2O3 AND Al2O3 NANOPARTICLES ON THE ANTIOXIDANT ENZYMES IN SEEDLINGS OF TRITICUM AESTIVUM L.

During their lifetime, plants are constantly exposed to varied environmental factors, which leads to an enhancement in the generation of reactive oxygen species (ROS), and the antioxidant system (AOS) that controls the level of ROS and protects the plant cells. The latest study considered the changes in the activity of several high molecular weight components of the AOS—ascorbate peroxidase (APO), catalase (CAT), and polyphenol oxidase (POL)—in two-week old seedlings of soft wheat (Triticum aestivum L.) cultivars under the influence of different (trivalent ferric oxide and aluminum oxide nanoparticles [NPs]). The study observed the activity of investigated enzymes under the influence of several NPs depends on varietal characteristics in wheat seedlings. In the tested wheat cultivars’ seedlings, ferric oxide NPs led to a sharp increase in activity of APO in the cultivars Dagdash and Gobustan. However, in the seedlings of cultivars, Sheki-1 and Mirbashir-128, a decline in the enzyme activity was observed. Concerning the influence of aluminum oxide NPs, the study affirmed that increasing the concentration of NPs leads to increase in the enzyme activity, in addition to the activity of APO. The results concluded that each plant genotype has its mechanisms for removing the harmful effects of aluminum oxide NPs, which include antioxidant enzymes. Thus, the latest findings can help serve as a basis for the wheat cultivars selection with more resistance to abiotic stress conditions.

Large-scale study on groundwater dissolved organic matter reveals a strong heterogeneity and a complex microbial footprint

Dissolved organic matter (DOM) in terrestrial groundwater is generally low in concentration compared to inland surface waters. However, the overall amount of groundwater DOM is huge, as there is 100 times more fresh groundwater than fresh surface water. To date, research on groundwater DOM has merely focused on specific threats to humans such as e.g. DOM and heavy metal complexations and DOM from hydrocarbon contamination. A comprehensive, large-scale study of groundwater is still missing. Here, we examine DOM properties in a large-scale approach with regards to surface characteristics such as land use and altitude, aquifer characteristics as well as microbial features. We analyzed 1600 water samples from 100 groundwater bodies all over Austria with regards to their DOM quantity, quality and bacterial abundance (BA). DOM quality was evaluated with self-organizing maps on fluorescence excitation-emission-matrices (EEMs) combined with Ward clustering and subsequent parallel factor analysis to describe DOM properties of each cluster. We evaluated how these clusters differed among each other, based on DOC and nitrate concentrations, BA and selected environmental characteristics. Our results show that fluorescence components in groundwater resemble components found in other groundwater studies, in studies from forest streams, the dark ocean, agricultural catchments and wastewater treatment plants. The latter fluorescence components were associated with a cluster that is characterized by agricultural and urban land use, as well as by high nitrate concentrations. Clusters with an increased abundance of high-molecular weight and humic components, commonly associated with vascular plant and soil origin, correlated with a higher bacterial abundance. This observation provides evidence that elevated numbers of suspended bacteria mainly originate from the surface. Our study shows that DOM fluorescence can be a fast monitoring tool to identify aquifers under anthropogenic stress and delineate sensitive recharge areas with high surface-groundwater interaction.

Effect of corona discharge treatment on the polyethersulfone microfiltration membrane surfaces to reduce fouling phenomenon during tomato juice clarification

Tomato juice with high molecular weight components (high foulants) creates a turbid appearance as well as high fouling and a substantial flux decline in membrane applications. For this purpose, the surface modification of polyethersulfone (PES) microfiltration (MF) membranes was investigated by corona discharge to improve fouling propensities for clarifying tomato juice. The results revealed that corona discharge changed the surface hydrophilicity, morphology, and antifouling performance of the membranes. However, it has not made any substantial changes to mechanical properties. The hydrophilicity of the modified membranes with the reduction of contact angle (CA) from 53° to 10°, increased. Accordingly, the tomato juice flux of the modified membranes increased from 11 to 26 kg m−2 h−1 (∼2.4 times). Moreover, the reduction of the cake resistance as the main fouling mechanism (1.81 × 1012 m−1) was 1.4 times, and the enhancement of the flux recovery ratio (27%) was 2 times higher than of the neat PES membrane.

Insights into the properties of surface waters and their associated nanofiltration membrane fouling: The importance of biopolymers and high molecular weight humics

Nanofiltration (NF) membrane fouling by surface waters is still an unclear and unpredictable topic due to the heterogeneity and variability of natural organic matter (NOM) in waters. The objective of this study was to identify the key water quality parameter/s responsible for NF membrane fouling. Six representative surface waters were systematically investigated in terms of the water quality characteristics and their fouling potential on a polyamide NF membrane. The results showed that these waters exhibited significant discrepancies in DOC, Ca2+, composition, and chemical characteristics of NOM. Removal performance and membrane fouling analysis indicated a preferential rejection of hydrophobic over hydrophilic NOM, and the hydrophobicity of NOM was positively correlated with reversible fouling. The biopolymer content exhibited a strong positive correlation to the total membrane fouling and irreversible fouling, indicating that it could be used as a surrogate of NF fouling behaviors by surface waters. Ca2+ and humic substances contents could not explain the membrane fouling due to their insignificant correlation with membrane fouling. However, the proportion of high molecular weight component in humic substances (%-HMW) exhibited a negative correlation with the total membrane fouling and irreversible fouling, suggesting that the HMW component has a positive effect on NF membrane fouling prevention. A reasonable explanation is that the HMW component is preferentially deposited on the membrane surface, forming a ‘controlling layer’ that prevents low MW organics from entering and blocking the membrane pores.

A functional-group-based approach to modeling real-fuel combustion chemistry – III: Application to biodiesels

Real biodiesel fuels are mixtures comprising many high molecular weight components, making it a challenge to predict their combustion chemistry with detailed kinetic models. Our group previously proposed a functional-group approach (FGMech) to model the combustion chemistry of real gasoline and jet fuels; this approach has now been extended to model real biodiesel combustion and mixtures with petroleum fuels. As in our previous work, a decoupling philosophy is adopted for construction of the model. A lumped reaction mechanism describes the (oxidative) pyrolysis of fuels, while a detailed base chemistry model represents the oxidation of key pyrolysis intermediates. However, due to the presence of the ester group, several oxygenated species are identified as additional primary products and incorporated into the lumped reaction steps. In addition to the lumped reactions initiated by unimolecular decomposition and H-atom abstraction reactions, a lumped H-atom addition-elimination reaction is also incorporated as a new reaction class to account for the presence of double bonds. Stoichiometric parameters are obtained based on a multiple linear regression (MLR) model, which establishes relationships between the fuel's functional group distributions and the stoichiometric parameters of the lumped reactions. Global rate constants are developed from consistent rate rules obtained from pure fuels. New pyrolysis experimental data for methyl pentanoate/methyl nonanoate and methyl heptanoate/n-heptane mixtures (50%/50% in mol) are obtained in a jet-stirred reactor at atmospheric pressure. In general, kinetic models developed using the FGMech approach can reasonably reproduce all the validation targets obtained in this work, as well as those in the literature, confirming that functional-group-modeling is a promising approach to simulate combustion behavior of diesel/biodiesel surrogate fuels and real biodiesels.

Molecular weight distribution effects of polyacrylamide flocculants on clay aggregate formation

This article investigates the effect of polyacrylamide dispersity (broad and narrow molecular weight distributions) on their flocculation performance in a system of kaolinite clay suspended in water. A series of uniform chain length (dispersity, Đ = 1.04 – 1.35) polyacrylamide flocculants were synthesized using reversible addition-fragmentation chain-transfer polymerization. These uniform polyacrylamides were used individually, as low dispersity flocculants, and in blends, as high dispersity flocculants. Flocculation of the kaolinite suspension was monitored using a focused beam reflectance measurement system where the chord-length distribution of the clay aggregates could be recorded in real-time. Polyacrylamide flocculants with lower dispersities made larger clay aggregates than those with lower dispersities at equal doses. In the polymer blends, the fraction of the high molecular weight component was the best indicator of aggregate size formation; the low molecular weight fraction influenced less the final aggregate size. These findings suggest that polymers with narrow molecular weight distributions can be used in lower dosages than standard high dispersity flocculants with a similar concentration of high molecular weight polymer chains.

Fabrication and characterization of a cannabidiol-loaded emulsion stabilized by a whey protein-maltodextrin conjugate and rosmarinic acid complex

A cannabidiol (CBD)-loaded oil-in-water emulsion stabilized by a whey protein (WP)-maltodextrin (MD) conjugate and rosmarinic acid (RA) complex was fabricated, and its stability characteristics were investigated under various environmental conditions. The WP-MD conjugates were formed via dry-heating. The interaction between WP and MD was assessed by browning intensity, reduced amount of free amino groups, the formation of high molecular weight components in sodium dodecyl sulfate-PAGE, and changes in secondary structure of whey proteins. The WP-MD-RA noncovalent complex was prepared and confirmed by fluorescence quenching and Fourier-transform infrared spectroscopy spectra. Emulsions stabilized by WP, WP-MD, and WP-RA were used as references to evaluate the effect of WP-MD-RA as a novel emulsifier. Results showed that WP-MD-RA was an effective emulsifier to produce fine droplets for a CBD-loaded emulsion and remarkably improved the pH and salt stabilities of emulsions in comparison with WP. An emulsion prepared with WP-MD-RA showed the highest protection of CBD against UV and heat-induced degradation among all emulsions. The ternary complex kept emulsions in small particle size during storage at 4°C. Data from the current study may offer useful information for designing emulsion-based delivery systems which can protect active substance against environmental stresses.

Rheological behavior of crude oil and its dependence on the composition and chemical structure of oil components

In this article on the example of two crude oil with the same content of resins, asphaltene, and solid paraffin, it is shown that they have different rheological behavior at low shear rates. The chemical composition of crude oil's high molecular weight components (asphaltene and solid paraffin) was studied by EPR, IR spectroscopy, and chromatography. It is shown that their composition does not differ significantly. It was revealed that the reason for the different rheological behavior of the crude oils is the content of saturated and aromatic hydrocarbons. When the content of mono- and bi-aromatic hydrocarbons in crude oil increases, the degree of its non-Newton behavior increases. It is due to the formation of a coagulation structure in it. The data obtained have to take into account to predict crude oil viscosity when technologies for oil recovery and transportation developed.

Photocatalysis-enhanced coagulation for removal of intracellular organic matter from Microcystis aeruginosa: Efficiency and mechanism

• Optimized photocatalysis with coagulation for IOM removal from algae. • Photocatalysis is complementary with coagulation for IOM fractionations removal. • Bi 2 O 3 -TiO 2 /PAC composite adsorbing IOM as flocculation core to assist coagulation. • Control of co-existence of algal pollution by combined process is observed. Photocatalysis is an efficient advanced oxidation process that provides a promising alternative for pollution control during algal blooms in lakes or water reservoirs. Previous research has mainly focused on the destruction of algal cells by photocatalysis, whereas the release and control of concomitant secretions specially intracellular organic matter (IOM) is undervalued. Herein, we studied the removal efficiency and mechanism of algal IOM extracted from Microcystis aeruginosa during stationary phase by the combined process of pre-photocatalysis with a novel composite of Bi 2 O 3 -TiO 2 /PAC (Bi-doped TiO 2 nano-composites supported by powdered activated carbon) followed by enhanced coagulation with aluminum sulfate (AS) coagulant. Optimized photocatalysis and coagulation combined treatment (PC) was indicated to enhance IOM removal with 64%, 92% and 100% for DOC, absorbance at 254 nm (UV 254 ) and the optical density at 680 nm (OD 680 ) respectively. Pre-photocatalysis reduced the required AS coagulant dose and weakened the effect of solution pH. Photocatalysis was more inclined to remove humic substances and building blocks than high-molecular weight components, while coagulation alone displayed preference for high-molecular weight biopolymers and protein-like substance. Pre-photocatalysis was complementary with subsequent coagulation for efficient removal of protein-like substances and fractionation with medium molecular weight of 0.5–1 kDa. The produced flocs revealed that the Bi 2 O 3 -TiO 2 /PAC adsorbing IOM acted as a flocculation core to improve coagulation performance. Besides, the combined PC process was proved to perform well to co-existing algal pollution without damaging cells integrity and enhanced algal cells removal from 26% by coagulation alone to 61%. Therefore, this combined treatment was an effective method for the removal of IOM of Microcystis aeruginosa and control cyanobacteria bloom.

Natural organic matter removal by electrospun nanofiber membranes coated with heated aluminum oxide particles

The removal of natural organic matter (NOM) from water was studied using polyacrylonitrile (PAN) electrospun nanofibrous membrane (ENM) coated with HAOPs (heated aluminum oxide particles). The removal efficiencies of virgin PAN and HAOP-coated PAN were examined and the suitability of PAN as a support material for HAOPs was studied.The membranes were characterized with Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscope and energy dispersive X-ray spectrometer (SEM-EDS) as well as X-ray photoelectron spectroscopy (XPS). Several analytical techniques were applied to both the feed and the permeate to assess the effectiveness of NOM removal.In filtration of lake water, HAOPs efficiency in NOM removal was 56% measured by UV254 absorbance, but when it comes to virgin PAN membrane the removal efficiency was only 13%. In case of filtration of NOM's high molecular weight component, such as humic acid (HA), the rejection rate of HA was maintained above 97% of aromatic compounds of NOM, and above 43% of total organic carbon (TOC).Additionally, HA adsorption by HAOPs were fitted to isotherm models such as Langmuir and Freundlich models. The results showed that Langmuir model could fit the data better than Freundlich model. The kinetics of HA adsorption by HAOPs were also fitted to the pseudo-first order and pseudo-second order and for the initial HA concentration of 19.9 mg/L the pseudo-first order equation fitted the experimental data better with correlation coefficient of R2 = 0.8336.The results demonstrate that PAN ENM filtration has the potential to be employed as a pretreatment in water treatment and HAOP-coated PAN ENM can significantly enhance the removal of NOM.

Transformation of asphaltenes of vacuum residues in thermal and thermocatalytic processes

The work deals with the study of high molecular weight components of oils, namely with asphaltenes. The relevance of research aimed at studying the structural changes and thermal properties of asphaltenes under the conditions of heavy residual feedstock processing increases every year. It has been shown that the addition of NiCr-WC promotes the retardation of gas formation and an increase in the destruction of resins and asphaltenes of the vacuum residue.The average diameter of the aromatic layers (L a) increases from 8.10 to 10.58 Å in the cluster and decreases the number of aromatic layers in a cluster (M) and the average height of a cluster of aromatic layers (L c) from 7.58 to 5.09 and 26.70 to 18.34 Å respectively in the series ‘initial asphaltenes – asphaltenes after thermal processing – asphaltenes after thermocatalytic processing. Based on differential scanning calorimetry in the temperature range 400–700 °C, the destruction of asphaltenes is accompanied not only by the formation of low molecular weight hydrocarbon structures but the intensive removal of heteroatoms (S and N).

Different mechanisms driving the preferential adsorption of dissolved organic matter by goethite and montmorillonite

Molecular fractionation of dissolved organic matter (DOM) at the mineral-water interface governs its role in biogeochemical processes in both terrestrial and aquatic environments. However, adsorptive fractionation of DOM onto phyllosilicates lacks molecular-scale investigation. Moreover, the mechanisms driving DOM adsorptive fractionation onto typical mineral surface remains unknown. Using ultra-high resolution mass spectrometry, traditional spectroscopic method, and different background electrolytes (CaCl2, NaCl and NaCl-NaH2PO4), we investigated the molecular fractionation of DOM by typical phyllosilicate (montmorillonite) and iron oxyhydroxide (goethite) and provided direct and quantitative evidence for the specific driving mechanisms for the adsorptive fractionation. Montmorillonite selectively adsorbed the comparatively low molecular weight (MW) and high O/C constituents having aliphatic moieties (mainly protein- and carbohydrate-like species) or one benzene ring as first identified using a new aromaticity equivalent. This structural preference was more remarkable in the adsorption system with large contribution of “Ca2+ bridging” reaction (45.6–76.0%). By contrast, goethite preferentially stabilized the constituents with high MW components containing aromatics with ≥3 condensed benzene rings and high O/C, which was notable in the system where “ligand exchange” mechanism predominated (55.5–71.4%). For both montmorillonite and goethite, non-selective adsorption of DOM was detected when van der Waals dominated. These findings would advance the mechanistic understanding of biogeochemical processes of DOM in the environments.

Simulated in vitro digestion of α-lactalbumin modified by phosphorylation: Detection of digestive products and allergenicity

The effects of phosphorylation on the allergenicity of bovine α-lactalbumin (BLA) and digestive products were studied in vitro digestion. Two components with different molecular weight and conformation were obtained from natural and phosphorylated BLA. In vivo and in vitro assessment of allergenicity showed that phosphorylation prior to digestion significantly decreased the IgE/IgG binding capacity and allergic response in KU812 cells, and reduced the levels of IgG, IgE, IL-4 and histamine, with an increase in IFN-γ levels in mouse serum, depending on the changes in BLA structures, producing numerous small peptides. There were four phosphorylated sites (S22, T29, S47 and S70) in the high molecular weight components of phosphorylated BLA after digestion. These phosphorylated sites could mask the linear epitopes of digestive products, resulting in reduced allergic activity. Phosphorylation prior to digestion of dairy products can reduce the risk of anaphylaxis in patients with milk allergy to some extent.

NiO based catalysts obtained “in-situ” for heavy crude oil upgrading: effect of NiO precursor on the catalytic cracking products composition

Heavy and super-heavy oils are characterized by a high content of resins and asphaltenes, which complicate the transportation and refining of oil and lead to an increase in the cost of refinery products. Currently, of particular interest are catalysts that are formed directly under the conditions of the process from precursors, which are various salts. In this work influence of NiO precursor on the heavy oil catalytic cracking products composition. The upgrading in all experiments was carried out at a temperature 450 °C for 80 min. The optimal catalyst content calculated to the NiO in experiments 2 and 3 was 0.5 wt. % of the feedstock weight. The ratio salt:ethanol in experiment 3 was 1:1 wt. The products of catalytic cracking were analyzed by SARA, GC, XRD and FT-IR spectrometry. The dissolution of Ni(NO3)2•6H2O in ethanol results in a decrease in the content of high molecular weight components and an increase in the yield of the fraction boiling up to 360 °C. A decrease of sulfur content in the course of heavy oil cracking is caused by both interactions of NiO formed over cracking with S-containing compounds of feedstock leading to formation of Ni9S8 and Ni0.96S and sulfur removal in form of gas.