Volatile Oxidation Research Articles

Short communication: The effect of liquid storage on the flavor of whey protein concentrate

Unit operations in dried dairy ingredient manufacture significantly influence sensory properties and, consequently, their use and consumer acceptance in a variety of ingredient applications. In whey protein concentrate (WPC) manufacture, liquid can be stored as whey or WPC before spray drying. The objective of this study was to determine the effect of storage, composition, and bleaching on the flavor of spray-dried WPC80. Liquid whey was manufactured and subjected to the following treatments: bleached or unbleached and liquid whey or liquid WPC storage. The experiment was replicated 3 times and included a no-storage control. All liquid storage was performed at 4°C for 24h. Flavor of the final spray-dried WPC80 was evaluated by a trained panel and volatile compound analyses. Storage of liquids increased cardboard flavor, decreased sweet aromatic flavor, and resulted in increased volatile lipid oxidation products. Bleaching altered the effect of liquid storage. Storage of unbleached liquid whey decreased sweet aromatic flavor and increased cardboard flavor and volatile lipid oxidation products compared with liquid WPC80 and no storage. In contrast, storage of bleached liquid WPC decreased sweet aromatic flavor and increased cardboard flavor and associated volatile lipid oxidation products compared with bleached liquid whey or no storage. These results confirm that liquid storage increases off-flavors in spray-dried protein but to a variable degree, depending on whether bleaching has been applied. If liquid storage is necessary, bleached WPC80 should be stored as liquid whey and unbleached WPC80 should be stored as liquid WPC to mitigate off-flavors.

Effect of dietary soybean oil and antioxidants on fatty acids and volatile compounds of tail subcutaneous and perirenal fat tissues in fattening lambs.

BackgroundFat is the primary source of the volatiles that determine the characteristic flavors of animal products. Because unsaturated fatty acids (UFAs) contribute to changes in flavor as a result of the oxidation process, a feeding trial was performed to investigate the effects of dietary soybean oil or antioxidants on the fatty acid and volatile profiles of the tail subcutaneous (SF) and perirenal fat tissues (PF) of fattening lambs. Thirty-six Huzhou lambs were assigned to four dietary treatments in a randomized block design. The lambs’ diets were supplemented with soybean oil (0 or 3 % of DM) or antioxidants (0 or 0.025 % of DM).ResultsNeither soybean oil nor antioxidant supplementation had an effect on lamb growth (P > 0.05). In regard to tail SF, soybean oil supplementation increased the 18:2n6t (P < 0.05) and the total amount of volatile acids, whereas antioxidant supplementation increased the content of C18:2n6c and C18:3n3 (P < 0.05) but had no effect on the volatiles profile. In regard to PF, dietary soybean oil supplementation increased the C18:0 content (P < 0.01); decreased the C18:1 (P = 0.01), C22:1 n9 (P < 0.01) and total UFA (P = 0.03) contents; and tended to decrease the E-2-octenal (P = 0.08), E, E-2, 4-decadienal (P = 0.10), 2-undecenal (P = 0.14) and ethyl 9-decenoate (P = 0.10) contents. Antioxidant supplementation did not affect either the fatty acid content or the volatiles profile in the PF.ConclusionsTail SF and PF responded to dietary soybean oil and antioxidant supplementation in different ways. For SF, both soybean oil and antioxidant supplementation increased the levels of unsaturated fatty acids but triggered only a slight change in volatiles. For PF, soybean oil supplementation decreased the levels of unsaturated fatty acids and oxidative volatiles, but supplementation with antioxidants had little effect on PF fatty acids and the volatiles profile.

Non-thermal plasma as preparative technique to evaluate olive oil adulteration

In recent years adulteration of pure extra virgin olive oil (EVOO) with other types of vegetable oils has become an important issue. In this study, non-thermal plasma (NTP) is investigated as an innovative preparative analytical technique enabling classification of adulterated olive oil from an ascertained authentic batch of olive oil in a more sensitive manner. Non-thermal plasma discharges are a source of highly oxidative species such as singlet oxygen, and atomic oxygen. It was assumed that NTP-induced oxidation triggers unique lipid oxidation mechanisms depending on the specific composition of the oil matrix and minor constituents. In this work EVOO samples were adulterated with sunflower oil (1–3%) and submitted to NTP treatment. Results showed that while untreated samples could not be classified from the authentic olive oil reference, NTP treatments of 60min (Ar/O2 0.1%) on the oil batches resulted in the formation of a unique set of secondary volatile lipid oxidation products enabling classification of adulterated oil samples.

Effects of Solution Depletion and Segregation Oxidation on Morphology of Modified 310 Austenitic Stainless Steel

The oxidation morphologies of modified 310 steel exposed in 900 and 1100 °C air were investigated. A double layer morphology consisting of a (Cr, Mn)-rich outer layer and a fine Cr-rich inner layer was formed at 900 °C. It was related to the breakaway oxidation induced by the Cr-depletion and the Mn-segregation in inner layer. Some Cr-rich oxides with amorphous state were formed along grain boundaries. And some new finer oxide grains, voids and Cr-rich precipitates were observed in spallation areas at 1100 °C. Correspondingly, the oxidation kinetic curve dropped with the spallation of scale and increased with the formation of some new oxide grains. It was caused by segregation of Cr and the transformation of oxides from Cr2 O3 to the volatile oxides at elevated temperature. XRD analysis showed that the precipitates were mainly composed of CrO3. Segregation and depletion for solutions were also discussed by oxidation diffusion mechanisms.

Production, composition, and oxidative stability of milk highly enriched in polyunsaturated fatty acids from dairy cows fed alfalfa protein concentrate or supplemental vitamin E

Given its elevated content of carotenoids, alfalfa protein concentrates (APC) have the potential to prevent oxidation of milk enriched in polyunsaturated fatty acids. The effects of feeding APC or supplemental vitamin E on production, composition, and oxidative stability of milk enriched in polyunsaturated fatty acids were evaluated using 6 lactating Holstein cows (224±18d in milk) in a replicated 3×3 Latin square (21-d periods, 14d for adaptation). Treatment diets contained (dry matter basis) (1) 9% soybean meal (control, CTL); (2) 9% soybean meal + 300 IU of vitamin E/kg (VitE treatment); or (3) 9% APC (APC treatment). Cows received a continuous abomasal infusion of 450g/d of linseed oil. As a result, milk fat content of cis-9,cis-12 18:2 increased from 1.08±0.13 to 3.9±0.40% (mean ± SD), whereas cis-9,cis-12,cis-15 18:3 increased from 0.40±0.04 to 14.27±1.81% during the experimental period compared with the pretrial period. Milk yield tended to be higher for APC (14.7kg/d) compared with CTL (13.4kg/d), and was greater than that for VitE (13.0kg/d). Protein yield was higher in cows fed APC (518g/d) compared with VitE (445g/d) but was not different from that in cows fed CTL (483g/d). These effects resulted in improved milk N efficiency in cows fed APC (26.1% of N intake secreted in milk) compared with CTL (23.0%) and VitE (22.9%). Feeding APC increased milk fat content of lutein (252μg/g) compared with CTL (204μg/g) and VitE (190μg/g). Milk fat content of vitamin E was higher for APC (34.5μg/g) compared with CTL (19.0μg/g) and tended to be lower than that with VitE (44.9μg/g). Redox potential of fresh milk from cows fed APC (152mV) was similar to that of VitE (144mV), but lower than that of CTL (189mV). Treatments had no effect on fresh milk contents of dissolved oxygen (8.1±1.5mg/L), and conjugated diene hydroperoxides (2.7±0.5mmol/L). The concentrations of volatile lipid oxidation products (propanal, hexanal, hept-cis-4-enal, 1-octen-3-one) tended to be decreased by APC relative to CTL, whereas similar values were observed for VitE, except for hexanal, which was reduced by 40% in VitE. In conclusion, feeding APC to lactating dairy cows could serve as a source of dietary protein that improves dietary N utilization efficiency, and also as a preharvest technology to increase natural antioxidant levels in milk to limit oxidation.

MoSi2 Oxidation in 670–1498 K Water Vapor

Molybdenum disilicide (MoSi2) has well documented oxidation resistance at high temperature (T &gt; 1273 K) in dry O2 containing atmospheres due to the formation of a passive SiO2 surface layer. However, its behavior under atmospheres where water vapor is the dominant species has received far less attention. Oxidation testing of MoSi2 was performed at temperatures ranging from 670–1498 K in both 75% water vapor and synthetic air (Ar‐O2, 80%–20%) containing atmospheres. Here the thermogravimetric and microscopy data describing these phenomena are presented. Over the temperature range investigated, MoSi2 displays more mass gain in water vapor than in air. The oxidation kinetics observed in water vapor differ from that of the air samples. Two volatile oxides, MoO2(OH)2 and Si(OH)4, are thought to be the species responsible for the varied kinetics, at 670–877 K and at 1498 K, respectively. Increased oxidation (140–300 mg/cm2) was observed from 980–1084 K in water vapor, where passivation is observed in air.

Spruce galactoglucomannans inhibit lipid oxidation in rapeseed oil-in-water emulsions

Oil-in-water (O/W) emulsions are functional and highly significant systems in industrial settings. Their large interfacial area makes them prone to deterioration, including the oxidation of polyunsaturated lipids. Spruce galactoglucomannans (GGM), which are wood biomacromolecules that are abundantly available from emerging forestry biorefineries, were characterized as novel, bio-based, sustainable stabilizers against lipid oxidation in rapeseed O/W emulsions. The formation of hydroperoxides, volatile oxidation products, and polymerized lipids were followed in emulsions during an accelerated storage test at 40 °C for two weeks. The free and bound phenolic residues associated with plant polysaccharides were quantified to explain the differences in the oxidation pathways of emulsions stabilized with GGM and their carboxymethyl derivatives (CMGGM) in comparison to the “golden standard” food stabilizer, gum arabic (GA), and a promising alternative, corn fiber gum (CFG). GGM and CMGGM efficiently inhibited and altered the pathways of lipid oxidation of rapeseed oil. GGM showed an exceptional capacity to inhibit lipid oxidation and act as a multifunctional stabilizer, enhancing both the physical and oxidative sility of emulsions.

SOA formation from the photooxidation of &amp;lt;i&amp;gt;α&amp;lt;/i&amp;gt;-pinene: systematic exploration of the simulation of chamber data

Abstract. Chemical mechanisms play an important role in simulating the atmospheric chemistry of volatile organic compound oxidation. Comparison of mechanism simulations with laboratory chamber data tests our level of understanding of the prevailing chemistry as well as the dynamic processes occurring in the chamber itself. α-Pinene photooxidation is a well-studied system experimentally, for which detailed chemical mechanisms have been formulated. Here, we present the results of simulating low-NO α-pinene photooxidation experiments conducted in the Caltech chamber with the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) under varying concentrations of seed particles and OH levels. Unexpectedly, experiments conducted at low and high OH levels yield the same secondary organic aerosol (SOA) growth, whereas GECKO-A predicts greater SOA growth under high OH levels. SOA formation in the chamber is a result of a competition among the rates of gas-phase oxidation to low-volatility products, wall deposition of these products, and condensation into the aerosol phase. Various processes – such as photolysis of condensed-phase products, particle-phase dimerization, and peroxy radical autoxidation – are explored to rationalize the observations. In order to explain the observed similar SOA growth at different OH levels, we conclude that vapor wall loss in the Caltech chamber is likely of order 10−5 s−1, consistent with previous experimental measurements in that chamber. We find that GECKO-A tends to overpredict the contribution to SOA of later-generation oxidation products under high-OH conditions. Moreover, we propose that autoxidation may alternatively resolve some or all of the measurement–model discrepancy, but this hypothesis cannot be confirmed until more explicit mechanisms are established for α-pinene autoxidation. The key role of the interplay among oxidation rate, product volatility, and vapor–wall deposition in chamber experiments is illustrated.

Cellular combustion and delay periods of ignition of a nearly stoichiometric H2–air mixture over a platinum surface

Cellular combustion regime of a 40% H2–air mixture in the presence of Pt wire at 270–350 °C was observed for the first time. The regime is caused by the catalytic action of Pt-containing particles formed by the decomposition of volatile platinum oxide in a gas phase.

Co-pelletization of sewage sludge and biomass: Thermogravimetric analysis and ash deposits

In this study, the combustion behaviors of sludge–biomass mixed pellets with different sludge ratios in air atmosphere were investigated by thermogravimetric analysis. The pellets consisted of sludge and Chinese fir or rice straw with sludge ratios of 0%, 25%, 50%, 75% and 100%, respectively. The thermogravimetric data were applied for kinetic analysis using the Coats and Redfern (CR) equation. Results showed that there were four main stages such as dehydration, volatile oxidation, char burning and burnout during thermal decomposition of pellets. The reactivities of sludge–biomass pellets were improved by the increment of the mixing ratio of biomass. In addition, the potential slagging behaviors of the resultant ashes were evaluated by X-ray fluorescence (XRF). The suitable sludge to biomass ratio should consider the combustion properties and ash slagging deposition of pellets. It is inappropriate for the production of sludge–straw pellet in the present state due to the high ash slagging potential.

A low-order coupled chemistry meteorology model for testing online and offline data assimilation schemes: L95-GRS (v1.0)

Abstract. Bocquet and Sakov (2013) introduced a low-order model based on the coupling of the chaotic Lorenz-95 (L95) model, which simulates winds along a mid-latitude circle, with the transport of a tracer species advected by this zonal wind field. This model, named L95-T, can serve as a playground for testing data assimilation schemes with an online model. Here, the tracer part of the model is extended to a reduced photochemistry module. This coupled chemistry meteorology model (CCMM), the L95-GRS (generic reaction set) model, mimics continental and transcontinental transport and the photochemistry of ozone, volatile organic compounds and nitrogen oxides. Its numerical implementation is described. The model is shown to reproduce the major physical and chemical processes being considered. L95-T and L95-GRS are specifically designed and useful for testing advanced data assimilation schemes, such as the iterative ensemble Kalman smoother (IEnKS), which combines the best of ensemble and variational methods. These models provide useful insights prior to the implementation of data assimilation methods into larger models. We illustrate their use with data assimilation schemes on preliminary yet instructive numerical experiments. In particular, online and offline data assimilation strategies can be conveniently tested and discussed with this low-order CCMM. The impact of observed chemical species concentrations on the wind field estimate can be quantitatively assessed. The impacts of the wind chaotic dynamics and of the chemical species non-chaotic but highly nonlinear dynamics on the data assimilation strategies are illustrated.

Cladding oxidation during air ingress. Part II: Synthesis of modelling results

Air ingress is a potential risk in some low probable situations of severe accidents in a nuclear power plant. Air is a highly oxidizing atmosphere that can lead to an enhanced Zr-based cladding oxidation and core degradation affecting the release of fission products. This is particularly true speaking about ruthenium release, due to its high radiotoxicity and its ability to form highly volatile oxides in a significant manner in presence of air. The oxygen affinity is decreasing from the Zircaloy cladding, fuel and ruthenium inclusions. It is consequently of great need to understand the phenomena governing cladding oxidation by air as a prerequisite for the source term issues in such scenarios. In the past years, many works have been done on cladding oxidation by air under severe accident conditions.This paper with in addition the paper “Cladding oxidation during air ingress – Part I: Synthesis of experimental results” of this journal issue aim at assessing the state of the art on this phenomenon.In this paper, the modelling of air ingress phenomena in the main severe accident codes (ASTEC, ATHLET-CD, MAAP, MELCOR, RELAP/SCDAPSIM, SOCRAT) is described in details, as well as the validation against the integral experiments QUENCH-10, QUENCH-16 and PARAMETER-SF4. A full review of cladding oxidation by air is thus established.

Haemoglobin-Mediated Lipid Oxidation in Washed Chicken Mince

Background/Objectives: Loss in quality of chicken meat caused by lipid oxidation mediated by haemoglobin can lead to the rejection. The study aimed to study lipid oxidation and colour of washed chicken as affected by different haemoglobins. Methods/Statistical Analysis: Different forms of haemoglobin from chicken blood including Oxyhaemoglobin (OxyHb) and Methaemoglobin (MetHb) were prepared and added into washed chicken mince to obtain the final concentration of 8 μmole Hb/kg washed mince. Lipid oxidation products, volatile compounds and color in chicken mince samples were monitored during 8 days of the refrigerated storage. Findings: Washed chicken mince added with oxyHb and metHb contained the higher Peroxide Value (PV) and Thiobarbituric Acid-Reactive Substances (TBARS), compared with the control (P<0.05). Oxy-form was more pro-oxidative than met-form as evidenced by the higher PV and TBARS (P<0.05). Volatile lipid oxidation compounds, especially hexanal, were formed at higher rate in the sample added with oxyHb, compared with the control and that added with MetHb. At day 0 of storage, the sample added with oxyHb showed the higher a*-value but lower L* and b* value when compared with the control sample. The decrease in a* value was more pronounced in the sample containing oxyHb at day 8 of refrigerated storage. Thus, lipid oxidation and colour of chicken mince were more likely governed by the form of haemoglobin. Applications/Improvements: Bleeding should be carried out effectively during slaughtering process to prevent the lipid oxidation and discoloration of chicken meat.

Hydrogen measurement during steam oxidation using coupled thermogravimetric analysis and quadrupole mass spectrometry

An analytical technique is presented with the goal of measuring reaction kinetics during steam oxidation reactions for three cases in which obtaining kinetics information often requires a prohibitive amount of time and cost. The technique presented relies on coupling thermogravimetric analysis (TGA) with a quantitative hydrogen measurement technique using quadrupole mass spectrometry (QMS). The first case considered is in differentiating between the kinetics of steam oxidation reactions and those for simultaneously reacting gaseous impurities such as nitrogen or oxygen. The second case allows one to independently measure the kinetics of oxide and hydride formation for systems in which both of these reactions are known to take place during steam oxidation. The third case deals with measuring the kinetics of formation for competing volatile and non-volatile oxides during certain steam oxidation reactions. In order to meet the requirements of the coupled technique, a methodology is presented which attempts to provide quantitative measurement of hydrogen generation using QMS in the presence of an interfering fragmentation species, namely water vapor. This is achieved such that all calibrations and corrections are performed during the TGA baseline and steam oxidation programs, making system operation virtually identical to standard TGA. Benchmarking results showed a relative error in hydrogen measurement of 5.7–8.4% following the application of a correction factor. Finally, suggestions are made for possible improvements to the presented technique so that it may be better applied to the three cases presented.

Cladding oxidation during air ingress. Part I: Experiments on air ingress

Air ingress is a potential risk in some low probable situations of severe accidents in a nuclear power plant. Air is a highly oxidizing atmosphere that can lead to an enhanced Zr-based cladding oxidation and core degradation affecting the release of fission products. This is particularly true speaking about ruthenium release, due to its high radiotoxicity and its ability to form highly volatile oxides in a significant manner in presence of air. The oxygen affinity is decreasing from the Zircaloy cladding, fuel and ruthenium inclusions. It is consequently of great need to understand the phenomena governing cladding oxidation by air as a prerequisite for the source term issues in such scenarios. In the past years, many works have been done on cladding oxidation by air under severe accident conditions.This paper with in addition the paper “Part II: Synthesis of modeling results” of this journal issue aim at assessing the state of the art on this phenomenon.In this paper (Part I), the phenomenological approach is based on the analysis of experiments at different scales as separate-effect tests and integral tests like CODEX-AIT (low degree of pre-oxidation, high air flow rate), QUENCH-10 (high degree of pre-oxidation, moderate air flow rate, quench initiation at high temperature), PARAMETER-SF4 (moderate degree of pre-oxidation, low air flow rate, quench initiation at high temperature) and QUENCH-16 (moderate pre-oxidation, very low air flow rate, quench initiation at moderate temperature). The following phenomena will be described: formation of a porous nitride–oxide layer, subsequent steam penetration through this porous layer during reflood, accompanied by nitride re-oxidation and intensive cladding oxidation.

Interaction of ruthenium tetroxide with surfaces of nuclear reactor containment building

During a severe nuclear accident, different fission products will be released from the nuclear fuel and some of them may eventually reach the containment building. Ruthenium is considered to be an important fission product due to the possible formation of volatile oxides. Radiotoxicity and chemical toxicity of the volatile ruthenium compounds present a considerable hazard during a severe nuclear accident.In this work, experiments regarding behavior of ruthenium tetroxide in the reactor containment were performed. The interactions of ruthenium tetroxide (RuO4) with zinc, copper, aluminum and epoxy paint in dry and humid atmosphere were examined. SEM/EDX (scanning electron microscope/energy-dispersive X-ray spectroscopy), XPS (X-ray photoelectron spectroscopy) and EXAFS (extended X-ray absorption fine structure) techniques were used to identify the chemical composition of the deposits formed after the interaction of RuO4 with the different materials. Additionally, distribution of ruthenium between different metals was examined.Interaction of RuO4 with the studied samples led to formation of dark, ruthenium-rich deposits. Examination of these deposits showed different chemical speciation of ruthenium on the surface when compared to the deeper layers of deposits. Interaction of RuO4 with zinc, copper and aluminum resulted to different amounts of the deposited ruthenium on the metals.

A method for assessing the volatility of oxides in high-temperature high-velocity water vapor

A steam-jet furnace was utilized to assess the volatility of SiO2, TiO2 and Y2O3 in a simulated turbine engine environment. Specimens were exposed in the steam-jet furnace at 1atm H2O, steam temperatures of 1240–1300°C, and gas velocities of 165–177m/s. The jet of steam impinged on the specimen under study leading to surface recession via the formation of volatile hydroxide species. Linear volatilization kinetics were observed for SiO2. The measured recession rate of SiO2 was in reasonable agreement with the calculated recession rate based on assessed thermodynamic data for Si(OH)4 (g). The measured recession rate of TiO2 in this study was considerably higher than the recession rate based on measured thermodynamic data for TiO(OH)2 (g) and lower than prior experimental results. The measured recession rate of Y2O3 was in fair agreement with the calculated recession rate using estimated thermodynamic data for Y(OH)3 (g) formation and was significantly lower than prior experimental results.

Oxidation Stability of Rapeseed Biodiesel/Petroleum Diesel Blends

The effects of fuels, including contaminants such as fuel oxidation products, on vehicle fuel system materials are important for vehicle durability and operation. Fuel oxidation is accelerated at the elevated temperatures and pressures of vehicle fuel systems. An extended time-course study of the oxidation of a biodiesel fuel blend consisting of 30% (v/v) rapeseed methyl ester in petroleum diesel (B30) was conducted at 70 and 90 °C with three aeration rates. Oxidation rates increased with increasing temperature as indicated by decreases in induction period (Rancimat), concentrations of unsaturated fatty acid methyl esters, and the time required to form hydroperoxides and acids. Peroxide values (PVs) rose to peak values in the range of 250–400 mequiv of O2/kg at 90 °C and 375–450 mequiv of O2/kg at 70 °C and then declined. Total acid number (TAN) increased rapidly as peroxides were formed after which the rate of TAN increase slowed, reaching values of up to 32 mg of KOH/g at 90 °C and 20 mg of KOH/g at 70 °C. The timing and maximum values of PV and TAN were somewhat dependent on aeration rate. Fuel mass decreased initially due to fuel volatilization, then increased as oxygen was incorporated, and then decreased reflecting volatilization of fuel and volatile oxidation products. Peroxide concentration showed a peak that coincided with the most rapid rate of oxygen incorporation, acid formation, and polyunsaturated FAME degradation. Net oxygen incorporation exhibited a plateau at approximately 5–6 wt % O above the 3.5 wt % O initially present in the FAMEs. This exceeds (by approximately 50%) the amount needed for incorporation of a single oxygen atom at every carbon atom allylic to carbon–carbon double bonds in the FAMEs that were oxidized.

Volatile Oxidation Compounds and Stability of Safflower, Sesame and Canola Cold-Pressed Oils as Affected by Thermal and Microwave Treatments.

The goal of this study was to investigate the effect of heating and microwave treatment on the levels of volatile oxidation products and the stability of safflower (Carthamus tinctorius L.), sesame (Sesamum indicum) and canola (Brassica napus L.) cold-pressed oils. Cold-pressed oils were subjected to conventional heating (oven test) using air-forced oven at 60°C and microwave heating for 2 and 4 min. The changes in conjugated diene (CD) and conjugated triene (CT) values were monitored during treatments. As expected, heating generates an increase in CD and CT values. The volatile compounds in treated oils were determined using solid phase micro-extraction-gas chromatography/mass spectrometry (SPME-GC/MS). The obtained GC/MS data were used to characterize volatile compounds of cold-pressed oils during heating and microeave treatments. Under oven conditions, 2-heptenal and 2,4-heptadienal isomers were identified as major components in canola oil, while hexanal and 2-heptenal were found in high levels in safflower and sesame oils. Among volatiles, p-cymene was the dominant compound found in microwave-treated canola oil. In addition, hexanal and 2-hexenal were found at high amounts upon microwave treatment especially after 4 min of application.

An Assessment of Pollution with Volatile Organic Compounds in the Electric Arc Furnaces

The steelmaking in the electric arc furnace is in the category of the industrial processes with high degree of pollution because in the air environmental factor are transferred the following pollutant substances: volatile organic compounds (VOCs), particulate matter, carbon oxides, sulphur oxides, nitrogen oxides, dioxins and furans. The aim of this paper is to assess the volatile organic compounds (VOCs) emissions from steelmaking in the electric arc furnaces, in order to improve the industrial gaseous emissions management. The experimental researches were carried out on two electric arc furnaces with alkaline lining. The measurement of volatile organic compounds emissions was performed using a Mini Rae Plus Classic device. After evaluating the level of emissions, during the melting stage of charge, it results that the VOCs concentrations from electric arc furnaces depend on the degree of contamination of the charge with organic matter, paints and plastics. The reduction of volatile organic compounds emissions to the steelmaking in the electric arc furnaces may be accomplished by charge component selection and by the use of raw materials with a degree of contamination as low as possible.