ASTM Standard Method Research Articles

Transesterification and Hydrotreating Reactions of Rice Bran Oil for Bio-Hydrogenated Diesel Production

Two different methods of production of bio-hydrogenated diesel (BHD), simply called green diesel from rice bran oil (RBO), were performed. In the first route, a direct hydrotreating reaction of RBO to BHD catalysed by Pd/Al2O3 was performed in a high-pressure batch reactor. Operating conditions were investigated as follows: catalyst loading (0.5 to 1.5% wt.), temperature (325 to 400 °C), initial hydrogen (H2) pressure (40 to 60 bar) and reaction time (30 to 90 min). The optimal condition was obtained at 1% wt catalyst loading, 350 °C, 40 bar H2 pressure and 60 min. Yields of crude/refined biofuels and BHD achieved were approximately 98%, 81.71% and 73.71%, respectively. In another route, transesterification together with hydrotreating reactions of rice bran methyl ester (RBME) to BHD was performed using the optimal conditions obtained from the first route. The amount of 98% crude biofuel was obtained and was equivalent to production yields of refined biofuel (85.71%) and BHD (68.51%). Furthermore, physical and chemical properties of both RBO/RBME green diesel were also considered following ASTM standard methods. In summary, both catalytic reactions were achieved in the range of a low-speed industrial diesel and were further recommended for BHD or green diesel production from RBO.

Mathematical Analysis on Matlab Environment for Experimental Study of the Thermal Properties of Epoxy Reinforced Composite

Over the years, before the invention of software, some experiments especially direct base experiments had minimum limits to conduct compared to now, due to some possible issues surrounding the process, such as high cost, hazard, and time waste, even some experiments are impossible to run due to complex data involved, which then gave rise to the invention of software that aims in making some of these experiments flexible and safe. This research involved thermal experimentation, mathematical analyses in a MATLAB environment, and data comparison of the experiment and mathematical analysis results of an epoxy-reinforced composite. Five samples were developed (E, S1, S2, S3, and S4) using epoxy reinforced with coconut shell fiber, silicon carbide (SiC), and aluminum oxide (Al2O3) in different proportions and compositions, applying hand-layup and compression molding. Thermal conductivity, diffusivity, degradation, and specific heat capacity tests were conducted using suitable apparatus and ASTM standard methods. The results indicated the minimum thermal properties of polymer material seen in sample ‘E’, due to no reinforced composite. Polymer material in sample E was improved in sample S1, where coconut shell fiber as municipal solid waste was used as reinforcement, possessing satisfactory thermal strength. Natural synthetic fibers (Al2O3 and SiC) used in this research indicated maximum thermal strength seen from samples S2 - S4, due to ceramic properties and close bond microstructural formation of synthetic fibers. 2020 Commercial License Model (CLM) MATLAB software was used to develop mathematical analyses from the experimental data, which when compared, the mathematical analysis results indicated 95% confident bounds on the root mean square error (RMSE) result having the same graphical trend as the experimental result.

Novel hybrid materials based on mesoporous Gamma-Alumina@ Riboflavin@ vanadium for biodiesel production

In the present study, Mesoporous Gamma-Alumina@ Riboflavin@ Vanadium heterogeneous nanocatalyst was successfully synthesized and applied to generate biodiesel from oleic acid using an esterification process. In this sense, the catalyst surface was characterized using XRD, FTIR, TGA, BET, SEM, X-ray mapping, EDX, and ICP analyses. The BMA (Boehmite-based Mesoporous Alumina) materials exhibited high activity for the esterification of oleic acid. Moreover, the catalyst can be simply recovered and efficiently reutilized several times without significant loss in its activity. Furthermore, the obtained results show that the BMA materials can be used for appropriate and rapid biodiesel production. The physicochemical properties of biodiesel such as flash point, cloud point, Ash content, and kinematic viscosity were examined on the biodiesel to the standard ASTM methods. Significantly, the resulting biodiesel is pure, which illustrates excellent physical and chemical properties meeting international standards.

Laboratory testing of dispersant effectiveness at high pressures

AbstractOil spills remain a serious environmental problem, and can have significant economic and ecological consequences. Despite the advantages, accidental deep‐sea oil releases during offshore exploration or production activities are of particular concern as the potential for such incidents increases significantly as we move to deeper waters. Dispersants are important mitigation tools as they have the capability to disperse the oil into a cloud of tiny oil droplets that can be readily degraded by hydrocarbon degraders if suitable environmental conditions prevail. In the case of an offshore incident, the dispersant is injected near the point of crude oil release so that dispersion is more effective. Given that our experience with subsea dispersant use is limited, the effect of pressure on the effectiveness of the dispersant has not been established, and hence, the composition and amount of dispersant to be injected has not been optimized. For typical surface oil spills, dispersant effectiveness is experimentally measured under laboratory conditions by the US‐Environmental Protection Agency (EPA) baffled flask test, which was later adapted as ASTM standard method F3251. Despite its extended use, this test cannot be used for testing dispersants at elevated pressures. In order to see whether pressure affects dispersant effectiveness, we developed a simple laboratory test protocol using a high‐pressure reactor (HPR). In addition, the effectiveness of five commercially available dispersants (COREXIT™ EC9500A, COREXIT™ EC9500B and COREXIT™ EC9527A, Marichem™, and Oiler 60) applied to a dead light crude oil has been determined at various pressures for the first time, and these values have been related to the standard baffled flask test (BFT) at atmospheric pressure. It is shown that pressure increase adversely affects dispersant effectiveness; however, the effect varies from a few percent to nearly a 50% decrease for a pressure increase of 100 bar depending on the particular dispersant used.

Fabrication of cardanol (a phenolic lipid) based polyamine coatings for anti-corrosive applications

Inhibition of corrosive ions is an important parameter for industrial steel application. The present study deals with the synthesis of polyamine (PA) resin-based coatings from cardanol (Col) with three different ratios (PA1-PA3). Fourier Transform Infra-Red (FTIR) and Nuclear Magnetic Resonance (NMR; 1H &13C) spectroscopy were used to characterize the presence of functional group and structural elucidation of resin, respectively. Physico-mechanical testing of PA coatings was performed by standard ASTM methods to check their mechanical durability. PA1 coatings seemed to have the best physico-mechanical properties and are considered to be the optimum composition for the preparation of durable coatings. Thermal analysis was performed using thermogravimetric analysis (TGA) which revealed that these coatings were stable up to 520 °C. Contact angle values (117°) suggested that these PA1 coating has self-cleaning ability and less wettability. Corrosion inhibition efficiency of these coatings was examined through electrochemical impedance spectroscopy (EIS) investigations. The superior corrosion inhibition properties of PA1 (one-component) coatings were compared with reported Col-based epoxy (two-component) coatings. Such one-component coatings can be used in place of epoxy coatings that could eliminate the usage of two-component coatings resulting in less consumption of energy, time, and material. Moreover, this work supports an approach for the synthesis of green polymeric coating using economic precursor in absence of expensive catalysts/solvents. PA coating have high efficiency towards corrosion resistance, thus, could effectively be used in the field of corrosion protection in near future.

Improved impurity determination of pure organic substances by differential scanning calorimetry with a dynamic method.

Differential scanning calorimetry can be used to measure the impurity contents of pure organic substances on the principle of freezing-point depression. Impurity determination by differential scanning calorimetry with a dynamic method, which has the advantages of speediness and convenience, remains to be explored. Here, a series of acetanilide and dibenzothiophene samples with various purities was prepared through zone melting, and the samples were then analyzed by gas chromatography-mass spectrometry. A modified dynamic method, including encapsulating the analyte in a volatile pan through cold welding, remelting the analyte with a low heating rate, calculating the melted fraction considering the area of the tailing under the heat-flow curve, and reducing the error from solid-solution formation, is proposed. Encapsulating with a volatile pan using a proper torque gave an accurate result. Remelting gave a lower impurity content and a more narrow and sooth peak of heat-flow compared with the first melting. The impurity-content results calculated by the modified method were usually higher than those calculated by the ASTM standard method. For acetanilide and dibenzothiophene with impurity contents of less than 0.30%, the modified dynamic method showed good accuracy. The proposed method is applicable to determination of reference materials of organic substances with high purity owing to its accuracy and convenience.

Synthesis of Biodiesel from Ricinus communis L. Seed Oil, a Promising Non-Edible Feedstock Using Calcium Oxide Nanoparticles as a Catalyst

This work aimed to synthesize biodiesel from Ricinus communis L., using calcium oxide (CaO) nanoparticles as a catalyst. The CaO nanoparticles were examined by scanning electron microscopy (SEM) and X-Ray Diffraction (XRD). The physico-chemical properties of biodiesel were studied through H and C-NMR, GC-MS, FT-IR, and fuel properties were studied according to ASTM and EN standard methods. The oil content of the feedstock was 53.7% with a free fatty acid (FFA) content of 0.89 mg KOH/g. The suitable condition for the optimum yield (89%) of biodiesel was 1:15 of oil to methanol using 20 mg of catalyst at a temperature of 60 °C for 80 to 100 min of reaction time. The H and C-NMR confirm the biodiesel synthesis by showing important peaks at 3.661, 2.015–2.788, 24.83–34.16 and 174.26 and 130.15 ppm. Similarly, GC-MS spectroscopy confirmed 18 different types of fatty acid methyl esters (FAME) in the biodiesel sample. FT-IR spectroscopy confirmed the synthesis of biodiesel by showing characteristic peaks of biodiesel formation in the range of 1725–1750 cm−1 and 1000–1300 cm−1. The fuel properties were compared with the international ASTM and EN standards. The physico-chemical properties confirm that RCB is both an engine and environmentally friendly fuel.

Biodiesel Production from Waste Frying Oil using Catalysts Derived from Waste Materials

Domestic resources such as vegetable oil, animal fats, tallows, and waste frying oil are common raw materials for making biodiesel. In contrast to ordinary diesel, biodiesel helps to reduce CO2 emissions. This study aimed to produce biodiesel using waste frying oil in the presence of suitable solid waste-derived heterogeneous catalysts. Firstly, CaO/K2O catalyst was synthesised using eggshells and banana peels. Then, the pre-prepared catalyst (CaO/K2O) modified with ZnO was utilized for biodiesel production. The prepared catalyst and biodiesel were characterized using X-ray diffraction (XRD) and FTIR spectroscopy. The AOAC and ASTM standard methods were employed to analyze the physicochemical properties of oils and biodiesel. The catalytic efficiency of CaO/K2O and CaO/K2O-ZnO tested for the transesterification of purified oil to biodiesel at the catalyst weight (1-7 %wt), temperature (60-80°C), and methanol to oil ratios ranging from 3:1 to 12:1. The highest biodiesel yield (92%) obtained when 5 %wt CaO/K2O catalyst used. However, a 95% yield resulted when using a 3 %wt CaO/K2O-ZnO catalyst load in 2 h with a methanol to oil (v/v) ratio of 9:1 at 65°C. The study revealed that waste frying oil is a good source of biodiesel which could replace nonrenewable energy in the future. The catalysts made from solid waste could also replace an expensive chemical catalyst.

Experimental Investigation in Compression Ratio on Performance, Combustion and Emission of VCR Engine using Pyrolysis-oil Produced from Waste Plastic Materials

The generation of waste plastic is one of the major concerns for the scientific community due to its non biodegradable nature. Plastic has been primarily used in different packaging sectors across the globe and polyolefins are primarily used for this purpose to mitigate the demand. However, the lower recycling rate of waste plastics creates several long-term issues in the ecosystem. Therefore, reducing the waste plastic and producing some valuable chemicals is one of the ideal directions to overcome this issue.In this study, we have reported the production of liquid fuels from waste plastics material through thermo-chemical conversion and analyzed for engine performance, combustion, and emission characteristics in compression ignition (CI) engine. The liquid product (or pyro-oil) was characterized by different ASTM standard methods to evaluate the fuel properties. Finally, fuel was used at 10 and 20% blending with commercial diesel to analysis the engine performance, combustion and emission at varying brake mean effective pressure and compression ratio. The results revealed that blending of PO reduces brake specific fuel consumption (BSFC) to achieve the same power. Comparing with commercial diesel, the blended fuels showed better brake power, brake thermal efficiency, mechanical efficiency, cylinder pressure, net heat release rate, and exhaust gas emission. An enhancement in BTE and ME with increasing in BMEP was observed and varies in the range of ∼ 0–34% and ∼ 0–95%, respectively. The blending of PO significantly reduces the emissions of CO, CO2, NOx and un-burnt hydrocarbon as well as improved the O2 emission. Reduced CO emission means a better lifestyle as the health risks factor is also reduced because inhalation of CO can form carboxyhemoglobin (COHb or HbCO) by dissolving in hemoglobin and restrict the oxygen circulation from lungs to the tissues that causes several health issues including death of a person.

Comparative study of biodiesel production from different waste oil sources for optimum operation conditions and better engine performance

Biodiesel from waste sources can be considered as the cheapest and most viable fuel alternative to depleting mineral diesel. In this work, biodiesel has been produced from different sources of waste oil; grilled chicken waste oil (GCWO) which is animal based source and waste cooking oil (WCO) which is vegetable based using transesterification method. The impact of different variables such as temperature, transesterification time, and amount of catalyst on the conversion and yield of biodiesel were investigated. Produced biodiesel was characterizes using ASTM standard methods for biodiesel property testing to determine the fuel properties including; kinematic viscosity, specific gravity, flash point, pour point, cloud point and acid number. Engine test has been conducted at increasing speed and constant load to evaluate the engine performance using the produced fuel. The results obtained indicate that the yield and conversion of bio-diesel from grilled chicken waste oil are greater than waste cooking oil. Both produced biodiesel fuel properties are within the standard biodiesel fuel specifications ASTM D6751. The maximum conversion and yield of biodiesel obtained by 97.76% and 94.4% suing GWCO and WCO respectively at optimum operating variables of 600C temperature, 3 h reaction time, and 0.4 wt% potassium hydroxide. Engine test results show similar trends for both biodiesels compared to diesel in term of engine brake power (BP) and brake specific fuel consumption (BSFC) with increasing engine speed. The maximum reduction in BP is found to be about 19% at 2400 rpm and a maximum increase in BSFC of 17% is obtained at 1800 rpm engine speed with both biodiesels compared to diesel fuel. Accordingly, though both biodiesels show comparable engine performance, GWCO presents higher biodiesel yield.

Physicochemical Characteristics Study of Oil Extracted from Almond Seed

The physicochemical properties of the extracted oil from almond seed were investigated. Physical properties such as cloud point, pour point, fire point, smoke point, specific gravity, refractive index, and viscosity; and the chemical properties such as acid value, free fatty acid, saponification value, iodine value, ester value, and peroxide value were investigated for both raw almond oil and transesterified almond oil. The various properties were investigated using ASTM standard methods and calculations. Results obtained for physical properties: cloud point, pour point, fire point, smoke point, specific gravity, refractive index, and kinematic viscosity were 〖-3〗^o C, 〖-9〗^o C, 〖220〗^o C, 〖130〗^o C, 0.928, 1.462, 21.84 〖mm〗^2/sec respectively for the transesterified almond oil. Result obtained for the chemical properties of the transesterified almond oil: acid value, free fatty acid, saponification value, iodine value 〖mgI〗_2/g, and ester value, values were determined to be: 2.05, 1.03, 79.71, 34.33, and 77.66. It was concluded that transesterified Almond oil have a great potential for use as fuel alternative and substitute for internal combustion engine with its high purity, low corrosion ability and ease of ignition.

Influences of Biopetrol-Ethanol Fuel on Performance and Emission in Internal Combustion Engine

The purpose of this study is to experimentally investigate the engine performance and pollutant emission of a commercial SI engine using ethanol–gasoline blended fuels with various blended rates (0%, 5%, 10%, 20%, and 30%). Fuel properties of ethanol–gasoline blended fuels were first examined by the standard ASTM methods. Results showed that by increasing the ethanol content, the heating value of the blended fuels is decreased, while the octane number of the blended fuels increases. It was also found that with the increment of ethanol content, the Reid vapor pressure of the blended fuels initially increases to a maximum at 10% ethanol addition, and then decreases. Results of the engine test indicated that using ethanol–gasoline blended fuels, torque output and fuel consumption of the engine slightly increase; CO and HC emissions decrease dramatically as a result of the leaning effect caused by the ethanol addition; and CO2 emission increases because of the improved combustion. Finally, it was noted that NOx emission depends on the engine operating condition rather than the ethanol content.

Investigation of biodiesel production parameters by transesterification of watermelon waste oil using definitive screening design and produced biodiesel characterization

In the present work, biodiesel was produced from watermelon waste oil by the transesterification process. A definitive screening design was used to investigate the effect of transesterification parameters such as catalyst concentration (4−10%), methanol-to-oil ratio (2−10mol/mol)and reaction temperature (46-60°C). The quadratic regression analysis was used to predict the yield of biodiesel. It is found that the optimum catalyst concentration, methanol-to-oil molar ratio and reaction temperature are 5.51%, 5.77:1 and 60°C, respectively, resulting in a 96.763% yield of methyl esters, which is in excellent confirmation with the predicted value. According to the results, all variables had a significant effect on the yield of biodiesel. The physicochemical property of the extracted watermelon waste oil and produced biodiesel using optimum process parameters was analyzed. The results revealed that the extracted oil and produced biodiesel met the requirements of ASTM and EN14214 (European committee for standardization) standard methods. Oleic acid and Linoleic acid were detected to be the dominant unsaturated fatty acids; while palmitic acid was found to be the highest amount of saturated fatty acid. It can be concluded that a definitive screening design for optimization of transesterification reaction parameters is an effective way to boost the yield of biodiesel. In addition, this method significantly reduces the number of experiments, which is important for a limited amount of raw materials. In general, the finding of this work proposes that the watermelon waste oils seem to be a potential and alternative feedstock for the production of biodiesel from waste materials.

Synthesis of 2-Hydroxyethyl Esters from Castor Oil as Lubrication Bio-Additive Candidates for Low-Sulfur Fossil Diesel

The present work aims to study the synthesis of 2-hydroxyethyl esters from castor oil and its lubrication properties, promising as a lubrication bio-additive in low sulfur diesel fuel. This compound has been successfully synthesized from castor oil and ethylene glycol. The oil to ethylene glycol molar ratio was adjusted to 1:10, and the catalyst loading was used at 9% mole oil. Then, the mixture was refluxed for 5 h. The product components were characterized using GC-MS. The standard ASTM method was used to study the kinematic viscosity and lubrication. The product was dominated by 2-hydroxyethyl esters (94.16%), di-ester (1.12%), and cyclic ester (1.92%). The analysis of friction coefficient and wear scar diameter (WSD) using High-Frequency Reciprocating Rig (HFRR) shows the coefficient of friction and WSD of the product better than reference diesel fuel. From the results of this study, the 2-hydroxyethyl ester of castor oil, especially 2-hydroxyethyl ricinoleate, is the main responsible for the lubricating properties. Thus, 2-hydroxyethyl esters of castor oil can be proposed as an alternative bio-additive to improve the lubrication of low-sulfur fossil diesel fuels.

Field Study and Chemical Analysis of Plant Waste in the Fez-Meknes Region, Morocco

Throughout the entire world, the biomass plant remains an important source of renewable energy. However, in Morocco, the energy recovery of this biomass is little or badly exploited compared to other solar, hydraulic, and wind resources. The aim of this study is to know the extent to which Moroccan companies are involved in the valorization of green waste and to identify among the latter those that have great energy and industrial value. The field investigation was carried out with the use of a questionnaire to different sectors of activity. The chemical analyses of the waste samples were carried out by different methods: Van Soest to investigate the fiber content, dinitrosalicylic acid and phenol-sulfuric acid to determine sugars, while the Folin–Ciocalteu method was employed for the determination of phenolic compounds. These are the ASTM standard methods to determine elemental, proximate composition, and calorific value (CV). The results of this survey showed that solid vegetable waste is diverse and represents 68.4% of the total green waste, of which 98% is not treated. Moreover, the chemical analysis displayed that forestry waste (FW), extracted parts wastes (EPW), and unused parts wastes (UPW) of medicinal and aromatic plants have high contents of cellulose (respectively 34.75, 48.44, and 54.19%) and hemicelluloses (28.44, 27.19 and 28.50%) and containing low amounts of lignin and phenolic compounds compared to olive waste (OW), olive pomace (OP), and household waste (HW). Almost all biomass wastes, except HW, have a low moisture (<12%), ash content less than 5.1%, a significant percentage of C and H, and CV between 14.5 and 21.6 MJ/Kg. The PCA analysis showed a discrepancy in terms of components between the set formed by FW, UPW, and EPW with other solid waste. In conclusion, FW, UPW, and EPW, specially can be potentially energetic biomass and valorized together in the form of a mixture.

Combustion Characteristics of Briquette Fuel Produced from Biomass Residues and Binding Materials

Proper management and effective conversion of biomass residues for biofuel production are crucial to reduce deforestation due to the cutting of trees for cooking and heating as a primary source of fuel and improving energy utilization of households. Thus, this study is aimed at investigating the effects of biomass residues of the coffee husk (CH), sawdust (SD), khat waste (KW), and dry grass (DG) and binding materials prepared from the waste paper pulp (PP) and clay soil (CS) under a low-pressure piston press densification machine. The biomass waste and binders were combined in a 3 : 1 ratio of CH : PP, CH : CS, SD : PP, SD : CS, KW : PP, KW : CS, DG : PP, and DG : CS. The briquettes were produced using a manually operated closed-end piston press machine compacted at an average pressure of 2 MPa. Briquette proximate and ultimate analysis of moisture content, volatile matter, fixed carbon, and ash content was determined using standard ASTM methods, while the calorific value was determined using a bomb calorimeter and data analysis was carried out using the R-program. Results revealed that the briquette produced from biomass residues has a mean value of fixed carbon and calorific value that ranged from38.62±1.53to41.75±2.14and3979.21±232.05 cal/g to4577.34±397.11 cal/g, respectively. Generally, briquettes produced from saw dust residue and the paper pulp binder had better quality of fuel and this could be used as an alternative source of energy and proper waste management option.

Natural Antioxidant Extracted Waste Cooking Oil as Sustainable Biolubricant Formulation in Tribological and Rheological Applications.

Developing eco-friendly formulations using waste cooking oil as renewable biomass is of great interest and commercial importance in the fuels and lubricant industry. This manuscript reports novel study on preparing a biolubricant formulations as WCO-1, WCO-2 and WCO-3 by blending the curcumin extracted soybean waste cooking oil in three different compositions viz 10%, 20%, 30% v/v with the mineral base oil N-150. Curcumin was extracted as a natural antioxidant in 0.5 wt% waste cooking oil to inhibit thermal oxidation. This study comprises a detailed analysis in terms of tribological, rheological and thermophysical characteristics such as viscosity, viscosity index, pour point and flash point parameters of the biolubricant by standard ASTM methods. Further, tribological and rheological analysis was done by the four-ball wear tester and Anton Paar, MCR-72, respectively. The thermophysical evaluation of WCO formulated biolubricant has shown excellent properties. The viscosity index of the formulated biolubricant increases with an increase in the concentration of waste cooking oil. In contrast, the pour point has also been depressing at lower temperature conditions. Thus, WCO based biolubricant was found to be more effective at extreme temperature conditions than the mineral base oil (N-150). Rheological studies have indicated the non-Newtonian behaviour of the biolubricant with an increase in shear rate. Whereas, tribological analysis demonstrates that wear scar diameter has significantly reduced from 0.685 to 0.573 mm, and the coefficient of friction decreased from 0.117 to 0.080 with respect to the mineral base oil. Thus, a straightforward green approach has been discovered by directly utilizing waste cooking oil for biolubricant formulation.Graphical abstract

ENGINEERING APPLICATIONS OF CHEMICALLY ACTIVATED CARBON COMPOSITES FROM AGROWASTES OF PALM KERNEL AND COCONUT SHELLS

Epoxy/activated carbon composites of particle sizes (60, 105, 150μm) and reinforcement weight percentages of (2, 4, 6 and 8) have been developed and evaluated for engineering applications. The physicomechanical properties were determined according to ASTM standard methods. Density decreased with an increase in reinforcement weight percentage. 2% weight increment of the particle sizes of the chemically activated carbon fillers yielded tensile and flexural strengths higher than that of the selected commercial brake pads (CB1) and (CB2), with the tensile strength of 4.84 and 6.58MPa, the flexural strength of 12.84 and 21.61MPa respectively while the hardness results compared well with the commercial brake pads samples. In general, from the standpoint of its tensile strength, %elongation at break, flexural strength, and hardness properties, these new formulations can find applications in aerospace and automobile industries where lightweight, high strength materials are sought after, hence a potential organic friction lining precursor for brake pad manufacture.

Comparative Effect of Different Plasticizers on Barrier, Mechanical, Optical, and Sorption Properties of Hydroxypropyl Methylcellulose (HPMC)–Based Edible Film

Identifying ideal plasticizer is pivotal to develop a biopolymer-based edible films for food packaging. The effect of different plasticizers (glycerol, polyethylene glycol, sorbitol) on the mechanical, water vapor barrier, optical, and moisture sorption properties of hydroxypropyl methylcellulose (HPMC) -based flexible films was examined in this study. Mechanical properties and water vapor permeability (WVP) of films were determined using standard ASTM methods. Moisture sorption isotherm (MSI) for different HPMC films were obtained thermogravemitically and seven sorption models were fitted to experimental sorption data through nonlinear regression using curve fitting tool in MATLAB R2015b and goodness of fit of these models was compared based on Akaike information criterion (AIC). GAB model was used to determine the monolayer moisture content and heat of sorption of different films. Plasticizing efficacy of different plasticizers was significantly different for HPMC film in studied concentration range. Water vapor permeability (WVP) for native HPMC film was 0.451 g mm/kPa m2 h, which further increased to 0.972, 0.890, and 0.615 g mm/kPa m2 h when 25% (w/w of HPMC) glycerol, PEG, and sorbitol were added as plasticizers, respectively. GAB model showed an increase in monolayer moisture (M0) content with increasing plasticizer concentration and the highest M0 value was observed for glycerol-plasticized film. Added plasticizers were found to be effective in providing desirable flexibility in terms of elongation to HPMC film which is beneficial for coating and shrink wrap packaging application but adversely affect the tensile strength and transparency of film. Henderson and Oswin models were selected as the best fit model to the experimental sorption data based on AIC values. The findings from the current study would serve in selection of suitable plasticizer for HPMC-based film/coating in food packaging applications.

Molecular characterization of aromatics in petroleum fractions by combining silica sulfuric acid sulfonation with electrospray ionization high-resolution mass spectrometry

Aromatic hydrocarbons are one of the main components of petroleum and its fractions. However, the characterization of its molecular composition is still a technical challenge for mass spectrometry because of the lack of ionization methods, especially for quantitative analysis. This study presents a novel approach for the molecular characterization of aromatics in petroleum fractions. Aromatic hydrocarbons were converted into their corresponding sulfonates and then analyzed by negative-ion electrospray ionization mass spectrometry. The method showed good selectivity and sensitivity for aromatic hydrocarbons. More importantly, no significant discrimination was found on monoaromatic compouds compared with atmospheric pressure photoionization, which has been considered the most suitable technique for aromatic hydrocarbon analysis. The method was used to characterize two vacuum gas oil samples, and the result was verified by the hydrocarbon group composition obtained by the ASTM standard method. The method enables a semiquantitative anlaysis for molecular characterization of aromatic compounds in heavy petroleum fractions. In addition, this method can be used to distinguish monoaromatic steranes from alkyl naphthalenes which have the same molecular composition.