Технолошки факултет [Научни радови] / Faculty of Technology [Scientific papers]

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Absorption Features of Symmetric Molecular Nanofilms
(American Scientific Publishers, 2013) Šetrajčić, J. P.; Markoski, B.; Rodić, D.; Pelemiš, S. S.; Vučenović, S. M.; Škipina, B.; Mirjanić, D. Lj.
Electronic components are used today in extreme physical conditions and in that sense, ultrathin dielectric crystalline films could be used as surface layers for electronic component protection. Calculating dynamical permittivity by the single-pole Green’s functions it was shown that the threshold of light absorption can be moved along frequencies, changing the film thickness and the intensity of boundary perturbations. We study the basic micro and macroscopic physical characteristics of symmetric ultrathin molecular crystalline films and one can see that essential optical properties of these systems arise with perturbation conditions, which appear at their surface layers. Depending on the values of the parameters of surface interactions, certain energy levels can lie outside the energy band of the ideal crystal, so there appear the surface localized states of excitons. Characteristic resonant peaks appear in the dependence of dielectric permittivity and absorption index (extinction coefficient) of ultrathin film on frequency of external electro-magnetic field.
Adaption and application of the Green function method to research on molecular ultrathin film optical properties
(IOP Publishing, 2009) Setrajčić, Jovan P; Ilić, Dušan I.; Markoski, Branko; Setrajčić, Ana J.; Vučenović, Siniša M; Mirjanić, Dragoljub Lj.; Škipina, Blanka; Pelemiš, Svetlana
Interest in the study of the exciton subsystem in crystalline structures (in this case nanostructures, i.e. thin films) occurred because dielectric, optical, photoelectric and other properties of materials can be explained by means of it. The basic question to be solved concerning theoretical research into the spatially strongly bounded structures is the inability to apply the standard mathematical tools: differential equations and Fourier analysis. In this paper, it is shown how the Green function method can also be efficiently applied to crystalline samples so constrained that quantum size effects play a significant role on them. For the purpose of exemplification of this method’s application, we shall consider a molecular crystal of simple cubic structure: spatially unbounded (bulk) and strongly bounded alongside one direction (ultrathin film).
Altered diversity of bacterial communities in two Drosophila species under laboratory conditions and lead exposure
(2021) Beribaka, Mirjana B.; Dimkić, Ivica Z.; Jelić, Mihailo Đ.; Stanković, Slaviša M.; Pržulj, Novo M.; Anđelković, Marko Lj.; Stamenković-Radak, Marina M.
The composition of microbiota affects different traits of Drosophila throughout its life cycle and represents an important part of the adaptive response to environmental changes, such as increased levels of accumulated heavy metals in their habitats. We investigated the effects of lead added to the feeding substrate on the microbiota diversity in the fruit flies, Drosophila melanogaster and Drosophila subobscura. We compared the bacterial diversity of wild-caught flies and their progeny reared under standard laboratory conditions. We analyzed the shifts in bacterial diversity in the experimental groups of flies reared for 13 generations on standard and lead(II) acetate (Pb(CH3COO)2), Pb acetate-saturated substrates. Identification of the main bacterial genera was performed by next-generation sequencing (NGS) of the V3-V4 variable regions of the 16S rRNA gene. Results indicate significant species-specific differences in bacterial composition between natural and laboratory populations, and between the substrates. Diversity increased in both species under prolonged exposure to lead-polluted substrate, suggesting a potential adaptive response to an environmental stress.
ANALIZA KRISTALIZACIJE NATRIJUM HLORIDA IZ RASTVORA U VAKUUM KRISTALIZERU SA RECIRKULACIJOM SUSPENZIJE
(Association of the Chemical Engineers of Serbia, 2009) JOTANOVIĆ, MILOVAN B.; SULJKANOVIĆ, MIDHAT S.
U ovom radu je izvedena analiza kristalizacije NaCl iz vodenih rastvora u vakuum kristalizerima sa recirkulacijom suspenzije. Vakuum kristalizer kao objekat projektovanja prikazan je kao skup osnovnih aparativno-procesnih jedinica. Aparativno-procesna jedinica je krupni sastavni dio aparata u kojoj se odvija niz fizičko-hemijskih pojava koje zajedno čine jedinični proces kristalizacije. Analizom teorijskih postavki, literaturnih podataka i rezultata istraživanja opisana je svaka aparativno-procesna jedinica odgovarajućim sistemom matematičkih funkcija. Ovaj rad je doprinos stvaranju jedinstvene metodologije projektovanja vakuum kristalizera.
Analysis of Pungency Sensation Effects from an Oral Processing, Sensorial and Emotions Detection Perspective—Case Study with Grilled Pork Meat
(MDPI, 2021) Djekic, Ilija; Ilić, Jovan; Chen, Jianshe; Djekic, Rastko; Sołowiej, Bartosz G.; Vujadinović, Dragan; Tomasevic, Igor
Pungency is an interesting sensory stimulus analyzed from different perspectives, in particular the underpinning mechanisms of its sensation and perception. In this study, grilled pork meat coated with three types of hot sauces were investigated regarding its main food oral processing characteristics and evaluated using time-intensity and temporal dominance of pungency sensations methods analyzing the pungency descriptors and intensities. Besides these methods, facial expressions obtained from video capturing were subject to emotion detection. Mastication parameters showed a slight, but not statistically significant, trend of an increased number of chews and consumption time associated with pungency intensity, while saliva incorporation indicated an increasing trend depending on the pungency intensity, especially after 25 strokes and before swallowing. Both time intensity and temporal dominance of pungency sensations showed that the complexity of understanding these sensations is in relation to intensity and type. Finally, the use of emotion detection software in analyzing the faces of panelists during mastication confirmed the increase in non-neutral emotions associated with the increase in pungency intensity.
Application of Biopolymers in the Food Industry.
(Springer, 2017) Grujic, Radoslav; Vukic, Milan; Gojkovic, Vesna
Plastic materials obtained from oil are used in the food industry. These polymers are cheap and available. They have good mechanical properties, good barriers for oxygen and vaporizable aromatic substances, and they can be hot welded. However, the main disadvantage is that biopolymers are not biodegradable, and certainly not environmentally friendly. That is the reason why the application of plastic materials must be limited and gradually replaced by materials that cause fewer ecological problems. Edible and biodegradable natural polymeric materials are one of the alternatives for food usage. These are made from polysaccharides, lipids, and proteins. Their application saves money that would otherwise need to be spent on environmental protection. Biodegradable natural polymeric materials can be used as edible films and coatings, packaging materials, carriers of antimicrobial and antioxidative materials, etc. Nanocomposites will be applied for food packaging in the future. Nanoscale research, including detection of a pathogen, active packaging, antimicrobial packaging, and the formation of barriers, will improve food packaging. It may be possible to use particles that are not organic to introduce diverse components such as colors and odors. They also may be used as tanks for the controlled release of drugs or fungicides.
Application of Edible Films and Coatings in Food Production
(Springer, 2017) Vukić, Milan; Grujić, Slavica; Odzaković, Božana
Today, edible films and coatings can be used for a variety of purposes related to food products, singly or in conjunction with other compounds. There are many variations of edible film and coating, and all can be summarized in the following sentence. Edible films and coatings are thin protective, edible and biodegradable layers deposited on or wrapped around a food’s surface. Numerous usages of such films and coatings have been investigated, with reasonable success, one of which is active food packaging. Edible films and coatings are designed by blending edible raw materials with food grade additives. Biopolymers are naturally occurring polymers that are most important for the creation of edible films and coatings, including proteins, polysaccharides and lipids. In proper application, edible films and coatings make it possible to improve the physical characteristics of food products and enhance the distinctive tactile and visual attributes of their surfaces. In other words, edible films and coatings can aid in the function of active substance conveyance for such factors as antioxidants, antimicrobials, colors, and flavors. Protection of food products from oxidation, moisture absorption/desorption, microbial growth, and other chemical reactions is of the greatest importance. Through all these properties, edible films and coatings prolong the quality of food products and improve food safety.
Application of solvent retention capacity tests for prediction of rheological parameters of wheat flour mill streams
(Association of Chemical Engineers of Serbia, 2020) Vukić, Milan S.; Janić Hajnal, Elizabet P.; Mastilović, Jasna S.; Vujadinović, Dragan P.; Ivanović, Marko M.; Šoronja-Simović, Dragana M.
This paper presents relationship between the rheological properties of dough and individual polymer swelling properties in wheat flour mill streams. The swelling properties were measured by applying the Solvent Retention Capacities (SRC) tests. Significant correlation coefficients were determined for certain rheological parameters. In an effort to extract additional insights from the properties measured, a multivariate analysis was used to develop relationships between the studied parameters. To determine relevant relationships among the parameters, the data exploration step by the Principal Component Analysis was performed. Then, multivariate Partial Least Squares Regression (PLSR) models were developed, to predict certain empirical rheology parameters based on the SRC parameters. The processing of experimental data indicated the possibility of using SRC parameters for predicting rheological properties in conjunction with a suitable mathematical model. The presented approach may be useful for rapid prediction of wheat flour mill streams characteristics and for optimization of the end-flour performances.
Association of Dietary Patterns with MRI Markers of Hepatic Inflammation and Fibrosis in the MAST4HEALTH Study
(MDPI, 2022) Amanatidou, Athina I.; Kaliora, Andriana C.; Amerikanou, Charalampia; Stojanoski, Stefan; Milosevic, Natasa; Vezou, Chara; Beribaka, Mirjana; Banerjee, Rajarshi; Kalafati, Ioanna-Panagiota; Smyrnioudis, Ilias; Kurth, Mary Jo; Kannt, Aimo; Francino, M. Pilar; Visvikis-Siest, Sophie; Deloukas, Panos; Llorens, Carlos; Marascio, Fernando; Milic, Natasa; Medic-Stojanoska, Milica; Gastaldelli, Amalia; Trivella, Maria Giovanna; Dedoussis, George V.
Whereas the etiology of non-alcoholic fatty liver disease (NAFLD) is complex, the role of nutrition as a causing and preventive factor is not fully explored. The aim of this study is to associate dietary patterns with magnetic resonance imaging (MRI) parameters in a European population (Greece, Italy, and Serbia) affected by NAFLD. For the first time, iron corrected T1 (cT1), proton density fat fraction (PDFF), and the liver inflammation fibrosis score (LIF) were examined in relation to diet. A total of 97 obese patients with NAFLD from the MAST4HEALTH study were included in the analysis. A validated semi-quantitative food frequency questionnaire (FFQ) was used to assess the quality of diet and food combinations. Other variables investigated include anthropometric measurements, total type 2 diabetes risk, physical activity level (PAL), and smoking status. Principal component analysis (PCA) was performed to identify dietary patterns. Six dietary patterns were identified, namely “High-Sugar”, “Prudent”, “Western”, “High-Fat and Salt”, “Plant-Based”, and “Low-Fat Dairy and Poultry”. The “Western” pattern was positively associated with cT1 in the unadjusted model (beta: 0.020, p-Value: 0.025) and even after adjusting for age, sex, body mass index (BMI), PAL, smoking, the center of the study, and the other five dietary patterns (beta: 0.024, p-Value: 0.020). On the contrary, compared with low-intake patients, those with medium intake of the “Low-Fat Dairy and Poultry” pattern were associated with lower values of cT1, PDFF, and LIF. However, patients with a “Low-Fat Dairy and Poultry” dietary pattern were negatively associated with MRI parameters (cT1: beta: 􀀀0.052, p-Value: 0.046, PDFF: beta: 􀀀0.448, p-Value: 0.030, LIF: beta: 􀀀0.408, p-Value: 0.025). Our findings indicate several associations between MRI parameters and dietary patterns in NAFLD patients, highlighting the importance of diet in NAFLD.
ATMOSPHERIC COLD PLASMA TECHNOLOGY FOR MEAT INDUSTRY: A BIBLIOMETRIC REVIEW
(V.M Gorbatov Federal Research Center for Food Systems of de Russian Academy of Sciences, 2022) Vukić, Milan; Vujadinović, Dragan; Smiljanić, Milenko; Gojković-Cvjetković, Vesna
Atmospheric cold plasma is an innovative, non-thermal technology. It has shown promising results for a broad range of food processing applications. On the basis of those facts, it has prompted growing attention in the scientific community. This paper reviews the literature generation trends surrounding the atmospheric cold plasma technology. A bibliometric analysis was carried out to objectively and analytically uncover the knowledge development in the atmospheric cold plasma technology within the context of meat processing. The research began with querying the Dimensions database for scientific articles published over the past two decades. A total of 105 papers were published during this period. The articles were examined according to several bibliometric metrics such as the year of publication, countries, institutions, sources, authors, and keywords frequency. The results of the bibliometric analysis revealed that researchers are very interested in studying the interface of the atmospheric cold plasma technology and meat processing. In the last couple of years, the number of publications on the topic has been growing. This is the first bibliometric investigation of the atmospheric cold plasma technology in the context of meat processing. To the authors’ best knowledge, no similar analysis has been performed before. This paper provides researchers with a better understanding of topic developments. A better understanding can aid future research by closing present knowledge gaps. Hence, the paper provides the continuation of up-to-date technological discussions among researchers.
Biodegradable Polymers Based on Proteins and Carbohydrates
(Springer, 2017) Vasiljevic, Ljubica; Pavlović, Stefan
Biodegradable polymers have become an import focus of interest in recent years. They include polymers manufactured from feedstocks originating either from non-renewable petroleum resources or from renewable biological resources. This review presents a general overview of biodegradable polymers, with a special emphasis on the polymers based on proteins and carbohydrates. Most biodegradable polymers (e.g., starch, chitin, cellulose, collagen and other polypeptides) have been synthesised or are formed in the natural environment during the growth cycles of organisms. These complex forms of carbohydrate consisting of glycosidic bonds are usually one of the major constituents of animal and vegetable exoskeletons (cellulose, carrageenan, chitin). Scientists have already identified certain microorganisms and enzymes that can degrade such polymers. Certain polymers draw attention to their biodegradability property. Bacteria, plants and animals produce this type of polymer, which presents the possibility for very momentous renewable resources. Some of the main plant proteins that can be used as potential sources are soy protein, corn protein (zein) and wheat proteins (gluten). Casein, collagen protein or gelatin, and keratin are important animal proteins. Environmental effects and chemical structure are the main factors upon which biodegradability depends. Another feature that depends on these factors is mechanical behaviour. Some other factors that impact mechanical behaviour are: processing parameters, storage, etc.
Biopolymers as Food Packaging Materials
(Springer, 2017) Grujić, Radoslav; Vujadinović, Dragan; Savanović, Danica
This review examines the recent trends, current technology and future challenges in applications of biopolymers as food packaging materials, together with potential solutions, as well as discussing the major safety concerns regarding food packaging materials produced from sustainable and renewable resources. As food contact materials, biopolymers are increasingly being utilized as alternatives to conventional plastics obtained from oil derivatives. This review covers most of the available polymers, focusing on the general principles of their production, properties, and analysis of the possibilities for potential use in food packaging. The use of biopolymers brings new opportunities, not only from the point of replacing conventional polymers and other materials that are widely used in food packaging (glass, paper, metals, etc.), but also in the way it opens up a whole new level of properties and characteristics. Bio-based resources are the base source for production of biopolymers in food application, while in practice, bioresource content may be different. Biopolymers can be produced by microorganisms through fermentative processes of different bioresources [e.g., polyhydroxyalkanoates (PHAs)] and biomass may be produced directly from different kind of plant (starch, cellulose, etc.). In the context of growing environmental and safety concerns, biopolymers have gained increased attention, related to concerns about conventional plastics traditionally produced from fossil fuel.
Ceria Particles as Efficient Dopant in the Electrodeposition of Zn-Co-CeO2 Composite Coatings with Enhanced Corrosion Resistance: The Effect of Current Density and Particle Concentration
(MDPI, 2021) Riđošić, Marija; Bučko, Mihael; Salicio-Paz, Asier; García-Lecina, Eva; Živkovic, Ljiljana S.; Bajat, Jelena B.
Novel Zn-Co-CeO2 protective composite coatings were deposited successfully from chloride plating solutions. Two different types of ceria sources were used and compared: commercial ceria powder and home-made ceria sol. Electrodeposition was performed by a direct current in the range of 1–8 A dm􀀀2. Two different agitation modes were used and compared, magnetic stirring and ultrasound-assisted stirring (US). The influence of magnetic stirring on the stability of the related plating baths was evaluated via a dynamic scattering method. The results pointed to better stability of the prepared ceria sol. The morphology of the composite coatings was examined by scanning electron microscopy (SEM), and particle content was determined by energy-dispersive X-ray spectroscopy (EDS). The results showed that the increase in the deposition current density was not beneficial to the coating morphology and particle content. The corrosion behavior of the Zn-Co-CeO2 composite coatings was analyzed and compared by electrochemical impedance spectroscopy and polarization resistance. The ultrasound-assisted electrodeposition at small current densities was favorable for obtaining composite coatings with enhanced corrosion stability. The protection was more effective when US was applied and, additionally, upon utilization of ceria sol as a particle source, which was revealed by higher polarization resistance and greater low-frequency impedance modulus values for sol-derived composite coatings deposited under ultrasound.
Changes in Optical Properties of Molecular Nanostructures
(Polish Academy of Sciences, 2010) Vucenovic, S. M.; Šetrajcic, J. P.; Markoski, B.; Mirjanic, D. Lj.; Pelemiš, S.; Škipina, B.
This paper represents an overview about exciton systems in the molecular nanostructures (ultra thin films and superlattices) and their implications on optical properties, primarily on absorption coefficient, which is given in the form of dielectric permittivity. With utilization of Green’s function method, we have calculated dispersion law, spectral weight of exciton states and dielectric permittivity for every type of nanostructures. All obtained results are compared with optical properties in bulk crystals. Dielectric permittivity in all types of nanostructures shows very narrow and discrete dependence of external electromagnetic field frequency, which is a consequence of the expressed quantum effects, very thin thickness in these structures (or at least one dimension confinement) and boundary conditions.
CHROMATOGRAPHIC SEPARATION OF GLUTENIN WITH HIGH MOLECULAR WEIGHT FROM WHEAT FLOUR
(KEY, 2020) Gojković Cvjetković, Vesna; Grujić, Radoslav; Marjanović-Balaban, Željka
Glutenins with high molecular weight (HMW glutenins) are one of the glutenin's fractions. They play a key role in the formation of the gluten elasticity property and contribute to the formation of large glutenin polymers. The aim of this study was to investigate the effect of solvent type and column temperature on the chromatographic separation of HMW glutenins from wheat flour. For HMW glutenins extraction, 50% (v/v) ethanol, 1-propanol and isopropanol was used to which Tris-HCl (0.05 mol/L, Ph = 7.5), urea (2 mol/L) and dithioerythritol (1%) were added. The high performance liquid chromatography (HPLC) method (HPLC Agilent Technologies 1260 Infinity, Zorbax 300SB-C3 column) was used for protein separation at a column temperature 40, 45 and 50 0C. Absorbance measurements were performed at 210 nm and 280 nm. The effect of the solvents tested on the separation of HMW glutenins was shown by determining the number of observed peaks (proteins) on the chromatogram and calculating the relative concentration of HMW in the total number of glutenins from wheat flour (RC). After the extraction of glutenin proteins with 50% (v/v) ethanol, the highest number of proteins at 210 nm was observed when the column temperature was 45 0C and 50 0C (Xsr = 6.17 and RC1 = 17.76% and RC2 = 27.07%) and the lowest number at a column temperature of 40 0C (Xsr = 4, RC = 13.43%). By extraction with 50% (v/v) 1-propanol, the highest number of proteins was observed at column temperatures of 40 0C and 45 0C (Xsr = 5.17 and RC1 = 28.22% and RC2 = 31.70%, respectively) and the lowest number at 50 0C (Xsr = 4.67, RC = 34.68%) and by extraction with 50% (v/v) isopropanol the highest number of proteins was observed at a column temperature of 50 0C (Xsr = 7.17, RC = 23.61%) and the lowest number at 45 0C (Xsr = 5.83, RC = 10.67%). After the extraction of glutenin proteins with 50% (v/v) ethanol and detection at a wavelength of 280 nm, the highest number of proteins was observed at a column temperature of 45 0C (Xsr = 8.33, RC = 36.49%), and the lowest at 40 0C (Xsr = 5.50, RC = 32.57%). In the case of protein extraction with 50% (v/v) 1-propanol, the highest number of HMW glutenins was observed at 40 0C (Xsr = 7.83, RC = 61.62%) and the lowest at 50 0C (Xsr = 4.67, RC = 39.18%). When extraction was performed with 50% (v/v) isopropanol, the highest number of proteins was observed at a column temperature of 45 °C (Xsr = 7.33, RC = 21.66%), and the lowest number at a column temperature of 40 0C and 50 0C (Xsr = 7.00, RC1 = 28.64%, RC2 = 34.22%). Based on the obtained results it can be seen that the highest number of proteins was observed with 50% (v/v) ethanol (Xsr = 8.33)
Color change of orange and carrot juice blend treated by non-thermal atmospheric plasma
(Wiley, 2017) Vukić, Milan; Vujadinović, Dragan; Ivanović, Marko; Gojković, Vesna; Grujić, Radoslav
Dielectric barrier discharge (DBD) atmospheric plasma treatment is an innovative non-thermal food processing technology. There is an abundant body of research on the effectiveness in inactivation of foodborne pathogens on fresh fruit and vegetable produce with atmospheric air DBD plasma. However, studies that disclose plasma interactions with fruit or vegetable juices are scarce in number to the knowledge of the author. Color changes of orange and carrot juice blend due to atmospheric air DBD plasma treatment have been examined to estimate the extent of juice changes after treatments at varying durations of 5 s,15 s, and 30 s. Results indicate potentiality of cloud loss reduction, while treatments can cause minor degradation of color attributes. However, browning of treated samples was not observed. The influence of this new non-thermal treatment on measured properties of orange and carrot juice blend shows promising results which need to be further confirmed and established.
COMPARISON OF METHODS FOR DETERMINING THE FALSIFICATION OF MILK
(KEY, 2017) Vujadinović, Dragan; Beribaka, Mirjana; Vukić, Milan; Marjanović-Balaban, Željka
Falsification of milk creates many difficulties in the dairy industry. Diluting milk with water can cause changes in the chemical composition, nutritional, hygienic and technological quality of milk. The aim of this study was to evaluate the possibility of applying the standard method for milk analysis for determining the presence of added water in sterilized milk products. Samples were prepared by diluting the milk with distilled water in the range from 5 to 50%, with a gradient of 5% and monitoring the impact of water on the relevant physical and chemical indicators of milk. Standard methods for milk analysis were performed, such as: determination of fat content, density, viscosity, acidity and sensory evaluation. Analysis of milk samples prepared with the proper dilution has shown that the average value of the freezing point of the milk samples ranged from -0.484 0C to -0.25 0C. Determination of the fat content showed that the fat content was constantly decreasing, from 3% (5% H2O) to 1.48% (50% H2O). With the increased proportion of water in milk, the density and viscosity were reduced, and pH value was slightly increased. Sensory evaluation was only partially accurate. In addition to cryoscopy, as a reliable method for determining the presence of added water in milk, some other methods have also proven to be reliable, such as: determination of fat content, density, viscosity and acidity.
Comparison of the Bacterial Inactivation Efficiency ofWater Activated by a Plasma Jet Source and a Pin-to-Pin Electrode Configuration Source
(MDPI, 2023) Čobanović, Radovan; Maletić, Dejan; Kocić-Tanackov, Sunčica; Čabarkapa, Ivana; Kokić, Bojana; Kojić, Predrag; Milošević, Slobodan; Stulić, Višnja; Vukušić Pavičić, Tomislava; Vukić, Milan
In this comparative study, the bacterial inactivation efficiency of plasma-activated water (PAW) generated by two distinct plasma reactors, one utilizing a nitrogen plasma jet electrode and the other a hybrid argon plasma reactor, was explored. The present study involved the assessment of antimicrobial activity against suspensions of three Gram-positive and three Gram-negative bacterial strains in their planktonic cell state. Bacterial suspensions were introduced into PAW five days after generation. Subsequently, the viability of the bacteria was assessed at various time intervals, specifically at 0.5, 1, 3, 5, 10, and 24 h, in order to evaluate the effect of inactivation. Structural changes in bacteria after PAW treatment were assessed using a scanning electron microscope (SEM). The physicochemical properties of PAW, including pH, conductivity, and concentrations of H2O2, NO2 -, and NO3 - during aging were measured. The present study demonstrated the effective inactivation of the tested bacterial strains by PAW. Gram-positive bacteria displayed greater resistance compared to Gram-negative species, with the lowest reductions in bacterial counts observed for B. cereus, and the highest for Escherichia coli O157:H7. Morphological damage was evident across all bacterial species examined. Physicochemical measurements showed slow decay of the reactive species in the aging process. This study illustrated the potential utility of PAW as an alternative disinfectant.
Decolorization of reactive violet 5 dye in textile wastewater by electrocoagulation
(International Association of Physical Chemists, Croatia, 2016) Malinovic, Borislav N.; Pavlovic, Miomir G.
The textile dyeing industry consumes large quantities of water and produces large volumes of wastewater from different steps in the dyeing and finishing processes. Wastewater from printing and dyeing units is often rich in color, containing residues of reactive dyes and chemicals, such as complex components. This study investigates the decolorization of synthetic dye wastewater containing textile dye Reactive Violet 5 (RV5) by electrocoagulation. A laboratory batch reactor was used to investigate the effect of various operating parameters using aluminium (Al), iron (Fe) and stainless steel (SS) anode. The effect of dye concentration, current density, supporting electrolyte, sup-porting electrolyte concentration, electrolysis duration, and material of anode of the systems were evaluated. Color removal efficiency was 22, 91.5 and 99.8 % in 15 minutes using Al, Fe and SS anode, respectively (j = 10 mA/cm2, cNaCl = 0.171 M).
Determination of silicon dioxide content in bauxite: comparing the ICP-OES method with the UV-VIS method
(Platform and Workflow by OJS/PKP, 2022) Ostojić, Gordana S.; Lazić, Dragica Z.; Zeljković, Saša M.
In this paper, the ICP-OES method (induced coupled plasma optical emission spectrometry) was used to determine the content of silicon dioxide in bauxite, as an important impurity that affects the quality and application of bauxite in alumina production by the Bayer process. Twenty bauxite samples from seven different deposits were analysed. The results were compared with the reference spectrophotometric UV-VIS method. The mean relative difference between the silicon dioxide content determined by the ICP-OES method and the reference method is found to be 4.88 %. Statistical tests were used to assess the comparability of the two methods, followed by a scatter plot, the Bland Altman, Passing-Bablok, and the "Mountain" plot. Graphical comparisons generally do not show statistically significant differences between methods. The accuracy and precision of the ICP-OES method were verified by using the standard reference material SRM NIST 697, Dominican Bauxite. Recovery and repeatability values, expressed as relative standard deviation (RSD), are within the acceptance criteria. Based on the t-test, there is a statistically significant difference between the mean value of ICP-OES measurements and the certified value of silicon dioxide, which can be attributed to the effect of systematic error of ICP-OES analysis.

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