In this paper, the extraction of phenolics from sage (Salvia Officinalis L.) which was grown in t... more In this paper, the extraction of phenolics from sage (Salvia Officinalis L.) which was grown in the plantations of MP Ljekobilje Trebinje, was carried out by maceration at different extraction time periods (30, 60, 90 , 120, 150 and 180 min), using different organic solvents (40%, 50% and 60% ethanol, 40%, 50% and 60% methanol) and water. The influence of each solvent on the extraction of total phenolics, flavonoids and antioxidative activity of obtained extracts was evaluated. The effect of solid-to-solvent ratio (1:7, 1:10 and 1:15) on the extraction yield of total phenolics was investigated. The influence of different extraction temperatures (room temperature, 30, 40, 50 and 60 ºC) on the content of total phenolics and flavonoids and antioxidative activity of the extract was also investigated. The content of total phenolics and flavonoids in the obtained sage extracts was determined spectrophotometrically. The radical scavenging capacity was determined by the DPPH method, wherein the extract concentration required to neutralize 50% of the initial DPPH radical concentration was also determined. The aqueous solutions of ethanol gave the highest yield of the extract, ie. the highest content of total phenolics and flavonoids in extracts obtained at room temperature and optimal extraction time of 60 minutes. Increasing the time of extraction has increased the content of the total phenolics and flavonoids in extracts, while the excessive time and temperature of the extraction had a negative effect on total phenolics, flavonoids and antioxidative activity of sage extracts.
International Journal of Innovative Research in Science, Engineering and Technology, 2014
In this paper supercritical fluid extraction with carbon dioxide at different pressure was invest... more In this paper supercritical fluid extraction with carbon dioxide at different pressure was investigated and the total yield of the extract was measured. With increasing pressure from 80 to 300 bar extraction yield was increasing. It was due to the fact that supercritical carbon dioxide density increases by increasing pressures. Qualitative and quantitative analyses obtained extracts and essential oils obtained from these extracts were done using GC/MS and GC/FID analyses. Also, investigation of the extraction kinetics in the function of pressure (80, 100 and 200 bar), where every point of kinetic curve with new sample of drug in extractor was obtained is performed. The highest extract yield was obtained at pressure 200bar (4.17g/100g drug). At the end of the extraction process, CO 2extract has been removed, and content of residual essential oil in the drug was determined. Essential oil content in drug after supercritical extraction was the highest at pressure 80 bar.
The used arable land covering in Croatia 882752 ha and in Bosnia and Herzegovina (B&H) 447181 ha ... more The used arable land covering in Croatia 882752 ha and in Bosnia and Herzegovina (B&H) 447181 ha or 15.60% (Croatia) and 8.75% (B&H) of the state territory. Main field crops are maize for grain (302266 ha and 189 557 ha and winter wheat (168433 ha and 57480 ha). Annual yields of wheat in the mentioned period were from 4.00 to 5.50 t/ha (Croatia) and from 2.63 to 3.80 t/ha (B&H). Global warming and increasingly experiencing with extreme weather conditions around the globe affecting often adversely on field crop yields. Annual temperature over Europe increased between 0.1 and 0.4% /decade. In our study, average air temperature in 2008-2012 (October-June) were higher from average (19611990) for 0.9 oC (Osijek), 1.5 oC (Zagreb), 0.8 oC (Tuzla) and 1.2 oC (Banja Luka). As both in Croatia and B&H are dominant less permeable soils, the low yields of wheat in the growing season 2009/2010 (4.04 t/ha in Croatia and 2.67 t/ha in B&H: average of the remaining four years 5.30 t/ha and 3.74 t/ha,...
The samples of stinging nettle were collected during June in the Tuzla region. Aqueous extracts w... more The samples of stinging nettle were collected during June in the Tuzla region. Aqueous extracts were prepared from fresh and dried leaves in order to determinate and compare content of bioactive components and antioxidant potential. Conventional soxhlet, ultrasound assisted extraction and traditional maceration extraction were used as extraction methods. Quantitative determination of phenols and flavonoids was carried out using spectrophotometric methods. Antioxidant activity of nettle aqueous extracts was determined using ferric reducing antioxidant power and DPPH free radical scavenging activity. Extracts obtained by Soxhlet extraction showed the highest total phenolic and flavonoid content and expected the highest antioxidant capacity, while extracts obtained by maceration gave the lowest results.
International Journal of Thermophysics, Jan 7, 2019
A new method for deriving accurate thermodynamic properties of gases and vapors (the compression ... more A new method for deriving accurate thermodynamic properties of gases and vapors (the compression factor and heat capacities) from the speed of sound is recommended. A set of PDEs connecting speed of sound with other thermodynamic properties is solved as a nonlinear least squares problem, using a modified Levenberg-Marquardt algorithm. In supercritical domain, boundary values of compression factor are imposed along two isotherms (one slightly above T c and another several times T c) and two isochores (one at zero density and another slightly above ρ c). In subcritical domain, the upper isochore is replaced by the saturation line, the lower isotherm is slightly above the triple point, and the upper isotherm is slightly below the critical point. Initial values of compression factor inside the domains are obtained from the boundary values by a cubic spline interpolation with respect to density. All the partial derivation with respect to density and temperature, as well as speed of sound interpolation with respect to pressure, is also conducted by a cubic spline. The method is tested with Ar, CH 4 and CO 2. The average absolute deviation of compression factor and heat capacities is better than 0.002 % and 0.1 %, respectively.
Two different methods for deriving the density and isobaric heat capacity of liquids in the subcr... more Two different methods for deriving the density and isobaric heat capacity of liquids in the subcritical pressure range, from the speed of sound, are recommended. In each method, corresponding set of differential equations relating these properties is solved as the initial boundary value problem (IBVP). The initial values are specified at the lowest pressure of the range and the boundary values along the saturation line. In the first method, numerical integration is performed along the paths connecting the Chebyshev points of the second kind between the minimum and maximum temperature at each pressure. In the second method, numerical integration is performed along the isotherms distributed in the same way, with the temperature range being extended to the saturation line after each integration step. The methods are tested with the following substances: Ar, N 2 , CO 2 , and CH 4. The results obtained for the density and isobaric heat capacity have the average absolute deviation from the reference data of 0.0005% and 0.0219%, respectively. These results served as the initial values for deriving the same properties in the transcritical pressure range up to the pressure approximately twice as large as the critical pressure. The results obtained in this pressure range have respective deviations of 0.0019% and 0.1303%.
Wastewaters from the galvanization process contain high concentrations of heavy metals representi... more Wastewaters from the galvanization process contain high concentrations of heavy metals representing a great danger to human health as well as to the environment. Heavy metals in the galvanization process are used in the coating process, whereby the coatings of certain metals are formed. The treatment of wastewaters generated by the galvanization process can be conducted by a number of methods, however, today more research is being done on processes which are efficient, economical and cost-effective, but environmentally acceptable. One of those techniques is adsorption. The adsorption process of Cd 2+ , Ni 2+ and Cr 2+ ions from galvanization water using brewer's grain as the adsorbent, at different pH values and adsorbent granulation of 0.5 mm is analyzed in this paper. The percentage of moisture and ash was determined, and the FTIR analysis was performed confirming the presence of certain functional groups. Based on the obtained values, it has been shown that the brewer's grain can be successfully used as a natural adsorbent to remove Cd 2+ , Ni 2+ and Cr 2+ ions from galvanization waters, and also that high level of efficiency is obtained at all analyzed pH values. The analysis has also shown that the affinity of adsorbents to Cd 2+ , Ni 2+ and Cr 2+ ions is in correlation with physical and chemical properties, but that the best removal efficiency is achieved at the pH 4 value.
Journal of engineering & processing management, Dec 31, 2014
Vapneni mulj koji nastaje u industrijskim procesima mekšanja vode predstavlja značajno okolinsko ... more Vapneni mulj koji nastaje u industrijskim procesima mekšanja vode predstavlja značajno okolinsko i ekonomsko opterećenje, obzirom na sve strožije domaće i međunarodne propise koji se odnose na upravljanje otpadnim tokovima. Visok sadržaj kalcijum karbonata u navedenom materijalu otvara mogućnost njegove primjene u procesima neutralizacije kiselih otpadnih voda. U ovom radu vršeno je istraživanje karakteristika procesa neutralizacije kiselosti vode u uslovima različitih početnih pH vrijednosti i režima strujanja, primjenom vapnenih muljeva koji su generisani tretmanom slanih i slatkih voda. Rezultati istraživanja pokazali su da početna pH vrijednost vode, i prisustvo NaCl imaju značajan uticaj na topivost kalcijum karbonata u procesu neutralizacije, dok je ispitivani režim strujanja (brzina mešanja magnetne mešalice) imao neznatan uticaj.
Lecture notes in networks and systems, May 11, 2018
The production of high quality plant extracts is the basis for the production of herbal preparati... more The production of high quality plant extracts is the basis for the production of herbal preparations and the isolation of bioactive ingredients. Recently, there is a tendency of replacing synthetic antioxidants, due to their toxic and potentially cancerous effects, with natural antioxidants. For this reason, it is necessary to intensify research of antioxidative and biological effects of plant extracts, as well as the influence of the process conditions of extraction on the mentioned effects and the yield of extraction. In this paper, the antioxidative activity of sage extract was tested, depending on the concentration of methanol as a solvent in the process of maceration with occasional mixing. Total phenolic and flavonoid content in obtained sage extracts was determined spectrophotometrically. The radical scavenging capacity was determined by the DPPH method, where the extract concentration required for the neutralization of 50% of the initial concentration of the DPPH radical was also determined.
ABSTRACT: The hydroxide precipitation method, using NaOH as a precipitant agent, was conducted to... more ABSTRACT: The hydroxide precipitation method, using NaOH as a precipitant agent, was conducted to treat synthetic monocomponent and two-component water solutions of Pb<sup>2+</sup> and Zn<sup>2+</sup> with initial concentrations of 50 and 500 mg/l of each metal. The effect of pH and initial concentration of lead and zinc ions on their removal were investigated. The precipitation experiments were carried out by batch method that involves the mixing of NaOH with solutions containing metal ions to occur nucleation, solid growth and subsequent separation of precipitates from solution by filtration. The results showed that the removal efficiency was increased by increasing of pH and initial concentration of metal ions in their water solutions. Hydroxide precipitation method using NaOH is an efficient technique for the removal of lead and zinc ions from their monocomponent and two-component water solutions of different concentrations, with maximum removal efficienc...
In this paper, supercritical extraction of hyssop (Hyssopus officinalis L.) is performed by using... more In this paper, supercritical extraction of hyssop (Hyssopus officinalis L.) is performed by using carbon dioxide as extractant. Effect of pressure (80, 100 and 150 bar) on the yield of total extract at a temperature 313 K, flow 0.00323 kg/min and the average diameter of particles 0.49 mm is investigated. For modeling of extraction system hyssop – supercritical CO2, Naik's model is applied, where in the total yield of extract is determined. On the basis of the value of the correlation coefficient |r| (0.976 – 0.992), it was concluded that a very strong correlation was obtained between reciprocal values of the total extract yield and extraction time (1/y i 1/t), so it can be concluded that Naik's model can succesfully be applied for determining yield of total extract.
The consequence of drastic reduction in fossil fuel reserves has forced the scientific community ... more The consequence of drastic reduction in fossil fuel reserves has forced the scientific community to find and develop new ways to exploit renewable resources and optimize the process of polymer materials production. The aim is to obtain applicable polymer whose complete life cycle is set in ecological framework. Poly(lactide) (PLA) meets these requirements as biodegradable polyester whose monomer is derived from the plant feedstock containing carbohydrates. PLA could be prepared using the different synthesis routes, but from the point of energy saving, as well as environmental protection, the microwave synthesis of PLA is the best solution. In this work, poly(L-lactide) were synthesized in microwave reactor. Reaction time was varied, while the other parameters of the synthesis were constant. The structures of obtained polymers were confirmed by Fourier – transform infrared spectroscopy (FT-IR). For determination of molar masses of poly(L-lactide) samples, the gel permeation chromatog...
4 ABSTRACT: The Hyssop officinalis L. was extracted using supercritical carbon - dioxide (SFE - C... more 4 ABSTRACT: The Hyssop officinalis L. was extracted using supercritical carbon - dioxide (SFE - CO2) as extractant. Extraction was carried out in the two steps: the first one being carried out at 100 bar and 40oC in time 4 h for the mean particle size 0.49 mm (extract A), and the second was the extraction of the hyssop sample at same conditions (pressure, temperature and time) for the mean particle size 0.13 mm (extract B). The supercritical fluid extraction (SFE) with carbon dioxide was carried out using a laboratory scale high pressure extraction plant - HPEP (Nova Swiss, Effretikon, Switzerland). Separator conditions were 15 bar and 25 oC. Extraction kinetics of the system hyssop - SFE - CO2 was investigation. Mathematical modeling using Modified Reverchon - Sesti Osseo equation has been performed on Hyssop officinalis L. With modified equation fitted results was well.
In this paper an investigation was done on the extraction of sage (Salvia officinalis L.) using s... more In this paper an investigation was done on the extraction of sage (Salvia officinalis L.) using supercritical carbon dioxide at different extraction temperatures (313, 323 and 333 K). For the qualitative and quantitative analysis of the obtained extracts methods GC-FID and GC-MS were applied. Qualitative and quantitative composition of the obtained CO2 extracts and essential oils isolated from CO2 extracts at different temperatures of extraction was also determined. The extraction system was modeled by using the modified equation Reverchon - Sesti Osseo, whereby the effect of temperature on the yield of the extract was studied. Based on the results of modeling the overall yield of the extract depending on the temperature, it is concluded that a given model approximates the experimental results very well in all cases.
Bentonites are aluminosilicate minerals which, due to their porosity, layered structure and compo... more Bentonites are aluminosilicate minerals which, due to their porosity, layered structure and composition have a wide application. Structural and textural characteristics of bentonite may be improved by different modification procedures. The aim of this study was to investigate compositional, structural and textural characteristics of domestic bentonite in place Gerzovo, before and after the activation with sulfuric acid. These characteristics were investigated by analytical methods, X-ray diffraction (XRD) and the method of low-temperature nitrogen adsorption (BET). Characteristics of acid-activated bentonite were compared with the characteristics of commercial active clay. The obtained results showed that the activation of bentonite with sulfuric acid leads to a significant improvement in structural and textural characteristics. Using these results it can be assumed that this bentonite will have good adsorption characteristics and can serve as an alternative in comparison with impor...
New Technologies, Development and Application II, 2019
Chemical precipitation is the most widely used method for heavy metal removal from water, and its... more Chemical precipitation is the most widely used method for heavy metal removal from water, and its effectiveness depends on several factors such as the type and initial concentration of heavy metals present in water, the precipitating agent used and the pH of the solution. In this paper an experiment of chemical precipitation and removal of Pb(II) and Zn(II) from their monocomponent and two-component aqueous solutions was carried out in a laboratory by batch process, using sodium carbonate as precipitating agent. The influence of initial concentrations of Pb(II) and Zn(II) and pH values of their aqueous solutions on the efficiency of precipitation and removal of lead and zinc ions was examined. By increasing the pH of the aqueous solutions, a higher efficiencies of chemical precipitation and removal of Pb(II) and Zn(II) were obtained, with higher removal efficiencies being achieved for the lead. The efficiency of removal of heavy metals was higher in solutions that had higher initial...
GLASNIK HEMIČARA, TEHNOLOGA I EKOLOGA REPUBLIKE SRPSKE, 2018
Superkritični fluidi imaju veoma široku mogućnost primene u raznim oblastima. Koriste se u energe... more Superkritični fluidi imaju veoma široku mogućnost primene u raznim oblastima. Koriste se u energetskim procesima, kao reakcioni rastvarači, promotori prenosa mase i toplote, separacioni agensi i radni fluidi u procesima sa biogorivom. Iako je ugljen-dioksid još uvek jedan od najčešće korišćenih superkritičnih fluida, propan i fluorovano-hlorovani fluidi se takođe koriste. Postoje brojni slučajevi gde su se kao superkritični fluidi koristili metanol, smeša metanola i sirćetne kiseline, metil – acetat, dimetilkarbonat. Procesi dekofeinizacije čaja i kafe, ekstrakcije hmelja i uklanjanja pesticida iz pirinča primenom superkritičnih fluida zastupljeni su već duže vremena na industrijskom nivou. Glavni cilj primene superkritičnih fluida je još uvek ekstrakcija prirodnih proizvoda radi dobijanja sastojaka hrane, nutraceutikalija i fitofarmaceutikalija. Superkritični procesi su ispitivani i radi dekontaminacije zemljišta, uklanjanja zaostalih rastvarača iz farmaceutskih proizvoda, ekstrakc...
Biosensors are nowadays a powerful alternative to conventional analytical techniques for controll... more Biosensors are nowadays a powerful alternative to conventional analytical techniques for controlling the quality of not only natural water but also process water used by the food industry during the production process, as well as wastewater prior to release into natural watercourses. The goal is to provide the required quality and safety of water from the standpoint of heavy metal contamination. The basic and most important characteristics of biosensors are high sensitivity, short response time, specificity, and relatively low production cost. Biosensors can detect the presence and measure the content of various toxic substances (pesticides, heavy metals, etc.) not only in water but also in food. Detection of contaminants, primarily heavy metals in water used in food production processes, is a potential area of biosensor application in the food industry. Biosensors can be adapted for direct and continuous (online) monitoring by measuring certain analytes that can affect the quality and safety of water. This chapter will give an overview of the development and application of biosensors in order to control the quality and safety of water from the standpoint of the presence of heavy metals.
In this paper, the influence of MgO and CaO content on the quality of technical ceramics (which o... more In this paper, the influence of MgO and CaO content on the quality of technical ceramics (which originally represents the Al<sub>2</sub>O<sub>3</sub> - SiO<sub>2</sub> - CaO - MgO system) has been investigated. Therefore, quality tests were performed on samples where the contents of CaO and MgO were taken as variable values. Based on the obtained test results and their analysis, certain characteristics of ceramics are defined with the different percentages of individual oxides content in 98.2 - 99% Al<sub>2</sub>O<sub>3</sub>.
In this paper, the extraction of phenolics from sage (Salvia Officinalis L.) which was grown in t... more In this paper, the extraction of phenolics from sage (Salvia Officinalis L.) which was grown in the plantations of MP Ljekobilje Trebinje, was carried out by maceration at different extraction time periods (30, 60, 90 , 120, 150 and 180 min), using different organic solvents (40%, 50% and 60% ethanol, 40%, 50% and 60% methanol) and water. The influence of each solvent on the extraction of total phenolics, flavonoids and antioxidative activity of obtained extracts was evaluated. The effect of solid-to-solvent ratio (1:7, 1:10 and 1:15) on the extraction yield of total phenolics was investigated. The influence of different extraction temperatures (room temperature, 30, 40, 50 and 60 ºC) on the content of total phenolics and flavonoids and antioxidative activity of the extract was also investigated. The content of total phenolics and flavonoids in the obtained sage extracts was determined spectrophotometrically. The radical scavenging capacity was determined by the DPPH method, wherein the extract concentration required to neutralize 50% of the initial DPPH radical concentration was also determined. The aqueous solutions of ethanol gave the highest yield of the extract, ie. the highest content of total phenolics and flavonoids in extracts obtained at room temperature and optimal extraction time of 60 minutes. Increasing the time of extraction has increased the content of the total phenolics and flavonoids in extracts, while the excessive time and temperature of the extraction had a negative effect on total phenolics, flavonoids and antioxidative activity of sage extracts.
International Journal of Innovative Research in Science, Engineering and Technology, 2014
In this paper supercritical fluid extraction with carbon dioxide at different pressure was invest... more In this paper supercritical fluid extraction with carbon dioxide at different pressure was investigated and the total yield of the extract was measured. With increasing pressure from 80 to 300 bar extraction yield was increasing. It was due to the fact that supercritical carbon dioxide density increases by increasing pressures. Qualitative and quantitative analyses obtained extracts and essential oils obtained from these extracts were done using GC/MS and GC/FID analyses. Also, investigation of the extraction kinetics in the function of pressure (80, 100 and 200 bar), where every point of kinetic curve with new sample of drug in extractor was obtained is performed. The highest extract yield was obtained at pressure 200bar (4.17g/100g drug). At the end of the extraction process, CO 2extract has been removed, and content of residual essential oil in the drug was determined. Essential oil content in drug after supercritical extraction was the highest at pressure 80 bar.
The used arable land covering in Croatia 882752 ha and in Bosnia and Herzegovina (B&H) 447181 ha ... more The used arable land covering in Croatia 882752 ha and in Bosnia and Herzegovina (B&H) 447181 ha or 15.60% (Croatia) and 8.75% (B&H) of the state territory. Main field crops are maize for grain (302266 ha and 189 557 ha and winter wheat (168433 ha and 57480 ha). Annual yields of wheat in the mentioned period were from 4.00 to 5.50 t/ha (Croatia) and from 2.63 to 3.80 t/ha (B&H). Global warming and increasingly experiencing with extreme weather conditions around the globe affecting often adversely on field crop yields. Annual temperature over Europe increased between 0.1 and 0.4% /decade. In our study, average air temperature in 2008-2012 (October-June) were higher from average (19611990) for 0.9 oC (Osijek), 1.5 oC (Zagreb), 0.8 oC (Tuzla) and 1.2 oC (Banja Luka). As both in Croatia and B&H are dominant less permeable soils, the low yields of wheat in the growing season 2009/2010 (4.04 t/ha in Croatia and 2.67 t/ha in B&H: average of the remaining four years 5.30 t/ha and 3.74 t/ha,...
The samples of stinging nettle were collected during June in the Tuzla region. Aqueous extracts w... more The samples of stinging nettle were collected during June in the Tuzla region. Aqueous extracts were prepared from fresh and dried leaves in order to determinate and compare content of bioactive components and antioxidant potential. Conventional soxhlet, ultrasound assisted extraction and traditional maceration extraction were used as extraction methods. Quantitative determination of phenols and flavonoids was carried out using spectrophotometric methods. Antioxidant activity of nettle aqueous extracts was determined using ferric reducing antioxidant power and DPPH free radical scavenging activity. Extracts obtained by Soxhlet extraction showed the highest total phenolic and flavonoid content and expected the highest antioxidant capacity, while extracts obtained by maceration gave the lowest results.
International Journal of Thermophysics, Jan 7, 2019
A new method for deriving accurate thermodynamic properties of gases and vapors (the compression ... more A new method for deriving accurate thermodynamic properties of gases and vapors (the compression factor and heat capacities) from the speed of sound is recommended. A set of PDEs connecting speed of sound with other thermodynamic properties is solved as a nonlinear least squares problem, using a modified Levenberg-Marquardt algorithm. In supercritical domain, boundary values of compression factor are imposed along two isotherms (one slightly above T c and another several times T c) and two isochores (one at zero density and another slightly above ρ c). In subcritical domain, the upper isochore is replaced by the saturation line, the lower isotherm is slightly above the triple point, and the upper isotherm is slightly below the critical point. Initial values of compression factor inside the domains are obtained from the boundary values by a cubic spline interpolation with respect to density. All the partial derivation with respect to density and temperature, as well as speed of sound interpolation with respect to pressure, is also conducted by a cubic spline. The method is tested with Ar, CH 4 and CO 2. The average absolute deviation of compression factor and heat capacities is better than 0.002 % and 0.1 %, respectively.
Two different methods for deriving the density and isobaric heat capacity of liquids in the subcr... more Two different methods for deriving the density and isobaric heat capacity of liquids in the subcritical pressure range, from the speed of sound, are recommended. In each method, corresponding set of differential equations relating these properties is solved as the initial boundary value problem (IBVP). The initial values are specified at the lowest pressure of the range and the boundary values along the saturation line. In the first method, numerical integration is performed along the paths connecting the Chebyshev points of the second kind between the minimum and maximum temperature at each pressure. In the second method, numerical integration is performed along the isotherms distributed in the same way, with the temperature range being extended to the saturation line after each integration step. The methods are tested with the following substances: Ar, N 2 , CO 2 , and CH 4. The results obtained for the density and isobaric heat capacity have the average absolute deviation from the reference data of 0.0005% and 0.0219%, respectively. These results served as the initial values for deriving the same properties in the transcritical pressure range up to the pressure approximately twice as large as the critical pressure. The results obtained in this pressure range have respective deviations of 0.0019% and 0.1303%.
Wastewaters from the galvanization process contain high concentrations of heavy metals representi... more Wastewaters from the galvanization process contain high concentrations of heavy metals representing a great danger to human health as well as to the environment. Heavy metals in the galvanization process are used in the coating process, whereby the coatings of certain metals are formed. The treatment of wastewaters generated by the galvanization process can be conducted by a number of methods, however, today more research is being done on processes which are efficient, economical and cost-effective, but environmentally acceptable. One of those techniques is adsorption. The adsorption process of Cd 2+ , Ni 2+ and Cr 2+ ions from galvanization water using brewer's grain as the adsorbent, at different pH values and adsorbent granulation of 0.5 mm is analyzed in this paper. The percentage of moisture and ash was determined, and the FTIR analysis was performed confirming the presence of certain functional groups. Based on the obtained values, it has been shown that the brewer's grain can be successfully used as a natural adsorbent to remove Cd 2+ , Ni 2+ and Cr 2+ ions from galvanization waters, and also that high level of efficiency is obtained at all analyzed pH values. The analysis has also shown that the affinity of adsorbents to Cd 2+ , Ni 2+ and Cr 2+ ions is in correlation with physical and chemical properties, but that the best removal efficiency is achieved at the pH 4 value.
Journal of engineering & processing management, Dec 31, 2014
Vapneni mulj koji nastaje u industrijskim procesima mekšanja vode predstavlja značajno okolinsko ... more Vapneni mulj koji nastaje u industrijskim procesima mekšanja vode predstavlja značajno okolinsko i ekonomsko opterećenje, obzirom na sve strožije domaće i međunarodne propise koji se odnose na upravljanje otpadnim tokovima. Visok sadržaj kalcijum karbonata u navedenom materijalu otvara mogućnost njegove primjene u procesima neutralizacije kiselih otpadnih voda. U ovom radu vršeno je istraživanje karakteristika procesa neutralizacije kiselosti vode u uslovima različitih početnih pH vrijednosti i režima strujanja, primjenom vapnenih muljeva koji su generisani tretmanom slanih i slatkih voda. Rezultati istraživanja pokazali su da početna pH vrijednost vode, i prisustvo NaCl imaju značajan uticaj na topivost kalcijum karbonata u procesu neutralizacije, dok je ispitivani režim strujanja (brzina mešanja magnetne mešalice) imao neznatan uticaj.
Lecture notes in networks and systems, May 11, 2018
The production of high quality plant extracts is the basis for the production of herbal preparati... more The production of high quality plant extracts is the basis for the production of herbal preparations and the isolation of bioactive ingredients. Recently, there is a tendency of replacing synthetic antioxidants, due to their toxic and potentially cancerous effects, with natural antioxidants. For this reason, it is necessary to intensify research of antioxidative and biological effects of plant extracts, as well as the influence of the process conditions of extraction on the mentioned effects and the yield of extraction. In this paper, the antioxidative activity of sage extract was tested, depending on the concentration of methanol as a solvent in the process of maceration with occasional mixing. Total phenolic and flavonoid content in obtained sage extracts was determined spectrophotometrically. The radical scavenging capacity was determined by the DPPH method, where the extract concentration required for the neutralization of 50% of the initial concentration of the DPPH radical was also determined.
ABSTRACT: The hydroxide precipitation method, using NaOH as a precipitant agent, was conducted to... more ABSTRACT: The hydroxide precipitation method, using NaOH as a precipitant agent, was conducted to treat synthetic monocomponent and two-component water solutions of Pb<sup>2+</sup> and Zn<sup>2+</sup> with initial concentrations of 50 and 500 mg/l of each metal. The effect of pH and initial concentration of lead and zinc ions on their removal were investigated. The precipitation experiments were carried out by batch method that involves the mixing of NaOH with solutions containing metal ions to occur nucleation, solid growth and subsequent separation of precipitates from solution by filtration. The results showed that the removal efficiency was increased by increasing of pH and initial concentration of metal ions in their water solutions. Hydroxide precipitation method using NaOH is an efficient technique for the removal of lead and zinc ions from their monocomponent and two-component water solutions of different concentrations, with maximum removal efficienc...
In this paper, supercritical extraction of hyssop (Hyssopus officinalis L.) is performed by using... more In this paper, supercritical extraction of hyssop (Hyssopus officinalis L.) is performed by using carbon dioxide as extractant. Effect of pressure (80, 100 and 150 bar) on the yield of total extract at a temperature 313 K, flow 0.00323 kg/min and the average diameter of particles 0.49 mm is investigated. For modeling of extraction system hyssop – supercritical CO2, Naik's model is applied, where in the total yield of extract is determined. On the basis of the value of the correlation coefficient |r| (0.976 – 0.992), it was concluded that a very strong correlation was obtained between reciprocal values of the total extract yield and extraction time (1/y i 1/t), so it can be concluded that Naik's model can succesfully be applied for determining yield of total extract.
The consequence of drastic reduction in fossil fuel reserves has forced the scientific community ... more The consequence of drastic reduction in fossil fuel reserves has forced the scientific community to find and develop new ways to exploit renewable resources and optimize the process of polymer materials production. The aim is to obtain applicable polymer whose complete life cycle is set in ecological framework. Poly(lactide) (PLA) meets these requirements as biodegradable polyester whose monomer is derived from the plant feedstock containing carbohydrates. PLA could be prepared using the different synthesis routes, but from the point of energy saving, as well as environmental protection, the microwave synthesis of PLA is the best solution. In this work, poly(L-lactide) were synthesized in microwave reactor. Reaction time was varied, while the other parameters of the synthesis were constant. The structures of obtained polymers were confirmed by Fourier – transform infrared spectroscopy (FT-IR). For determination of molar masses of poly(L-lactide) samples, the gel permeation chromatog...
4 ABSTRACT: The Hyssop officinalis L. was extracted using supercritical carbon - dioxide (SFE - C... more 4 ABSTRACT: The Hyssop officinalis L. was extracted using supercritical carbon - dioxide (SFE - CO2) as extractant. Extraction was carried out in the two steps: the first one being carried out at 100 bar and 40oC in time 4 h for the mean particle size 0.49 mm (extract A), and the second was the extraction of the hyssop sample at same conditions (pressure, temperature and time) for the mean particle size 0.13 mm (extract B). The supercritical fluid extraction (SFE) with carbon dioxide was carried out using a laboratory scale high pressure extraction plant - HPEP (Nova Swiss, Effretikon, Switzerland). Separator conditions were 15 bar and 25 oC. Extraction kinetics of the system hyssop - SFE - CO2 was investigation. Mathematical modeling using Modified Reverchon - Sesti Osseo equation has been performed on Hyssop officinalis L. With modified equation fitted results was well.
In this paper an investigation was done on the extraction of sage (Salvia officinalis L.) using s... more In this paper an investigation was done on the extraction of sage (Salvia officinalis L.) using supercritical carbon dioxide at different extraction temperatures (313, 323 and 333 K). For the qualitative and quantitative analysis of the obtained extracts methods GC-FID and GC-MS were applied. Qualitative and quantitative composition of the obtained CO2 extracts and essential oils isolated from CO2 extracts at different temperatures of extraction was also determined. The extraction system was modeled by using the modified equation Reverchon - Sesti Osseo, whereby the effect of temperature on the yield of the extract was studied. Based on the results of modeling the overall yield of the extract depending on the temperature, it is concluded that a given model approximates the experimental results very well in all cases.
Bentonites are aluminosilicate minerals which, due to their porosity, layered structure and compo... more Bentonites are aluminosilicate minerals which, due to their porosity, layered structure and composition have a wide application. Structural and textural characteristics of bentonite may be improved by different modification procedures. The aim of this study was to investigate compositional, structural and textural characteristics of domestic bentonite in place Gerzovo, before and after the activation with sulfuric acid. These characteristics were investigated by analytical methods, X-ray diffraction (XRD) and the method of low-temperature nitrogen adsorption (BET). Characteristics of acid-activated bentonite were compared with the characteristics of commercial active clay. The obtained results showed that the activation of bentonite with sulfuric acid leads to a significant improvement in structural and textural characteristics. Using these results it can be assumed that this bentonite will have good adsorption characteristics and can serve as an alternative in comparison with impor...
New Technologies, Development and Application II, 2019
Chemical precipitation is the most widely used method for heavy metal removal from water, and its... more Chemical precipitation is the most widely used method for heavy metal removal from water, and its effectiveness depends on several factors such as the type and initial concentration of heavy metals present in water, the precipitating agent used and the pH of the solution. In this paper an experiment of chemical precipitation and removal of Pb(II) and Zn(II) from their monocomponent and two-component aqueous solutions was carried out in a laboratory by batch process, using sodium carbonate as precipitating agent. The influence of initial concentrations of Pb(II) and Zn(II) and pH values of their aqueous solutions on the efficiency of precipitation and removal of lead and zinc ions was examined. By increasing the pH of the aqueous solutions, a higher efficiencies of chemical precipitation and removal of Pb(II) and Zn(II) were obtained, with higher removal efficiencies being achieved for the lead. The efficiency of removal of heavy metals was higher in solutions that had higher initial...
GLASNIK HEMIČARA, TEHNOLOGA I EKOLOGA REPUBLIKE SRPSKE, 2018
Superkritični fluidi imaju veoma široku mogućnost primene u raznim oblastima. Koriste se u energe... more Superkritični fluidi imaju veoma široku mogućnost primene u raznim oblastima. Koriste se u energetskim procesima, kao reakcioni rastvarači, promotori prenosa mase i toplote, separacioni agensi i radni fluidi u procesima sa biogorivom. Iako je ugljen-dioksid još uvek jedan od najčešće korišćenih superkritičnih fluida, propan i fluorovano-hlorovani fluidi se takođe koriste. Postoje brojni slučajevi gde su se kao superkritični fluidi koristili metanol, smeša metanola i sirćetne kiseline, metil – acetat, dimetilkarbonat. Procesi dekofeinizacije čaja i kafe, ekstrakcije hmelja i uklanjanja pesticida iz pirinča primenom superkritičnih fluida zastupljeni su već duže vremena na industrijskom nivou. Glavni cilj primene superkritičnih fluida je još uvek ekstrakcija prirodnih proizvoda radi dobijanja sastojaka hrane, nutraceutikalija i fitofarmaceutikalija. Superkritični procesi su ispitivani i radi dekontaminacije zemljišta, uklanjanja zaostalih rastvarača iz farmaceutskih proizvoda, ekstrakc...
Biosensors are nowadays a powerful alternative to conventional analytical techniques for controll... more Biosensors are nowadays a powerful alternative to conventional analytical techniques for controlling the quality of not only natural water but also process water used by the food industry during the production process, as well as wastewater prior to release into natural watercourses. The goal is to provide the required quality and safety of water from the standpoint of heavy metal contamination. The basic and most important characteristics of biosensors are high sensitivity, short response time, specificity, and relatively low production cost. Biosensors can detect the presence and measure the content of various toxic substances (pesticides, heavy metals, etc.) not only in water but also in food. Detection of contaminants, primarily heavy metals in water used in food production processes, is a potential area of biosensor application in the food industry. Biosensors can be adapted for direct and continuous (online) monitoring by measuring certain analytes that can affect the quality and safety of water. This chapter will give an overview of the development and application of biosensors in order to control the quality and safety of water from the standpoint of the presence of heavy metals.
In this paper, the influence of MgO and CaO content on the quality of technical ceramics (which o... more In this paper, the influence of MgO and CaO content on the quality of technical ceramics (which originally represents the Al<sub>2</sub>O<sub>3</sub> - SiO<sub>2</sub> - CaO - MgO system) has been investigated. Therefore, quality tests were performed on samples where the contents of CaO and MgO were taken as variable values. Based on the obtained test results and their analysis, certain characteristics of ceramics are defined with the different percentages of individual oxides content in 98.2 - 99% Al<sub>2</sub>O<sub>3</sub>.
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