Pub Date : 2017-11-12DOI: 10.2298/HEMIND161018001Z
Aleksandar Zdravković, L. Nikolić, S. Ilić-Stojanović, V. Nikolić, S. Savić, A. Kapor
Hydrogels are synthesized by the method of radical polymerization of monomers: N -isopropylacrylamide (NIPAM) and acrylic acid (AA). Characterization of poly( N -isopropylacrylamide- co -acrylic acid) hydrogels, p(NIPAM/AA), has been performed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and by determination of the swelling behaviour in aqueous solutions at different temperatures (25, 31 and 37 °C) and pH values (2.2, 4.5, 6 and 6.8). After lyophilisation in the solution at pH 6 and temperature of 25 °C, p(NIPAM/AA) hydrogels have rapidly reached equilibrium degree of swelling, α e , in comparison to non-lyophilized samples. The mechanism of solvent transport within matrix in lyophilized samples corresponds to less Fickian diffusion, whereas Super case II diffusion is characteristic for non-lyophilized samples. p(NIPAM/AA) hydrogel with 1.5 mol% of ethylene glycol dimethacrylate (EGDM) at the temperature of 25 °C and pH 6.8, has reached the highest swelling equilibrium degree, α e = 259.8. The results of swelling studies have shown that p(NIPAM/AA) hydrogels can be classified as superabsorbent polymers (SAPs). For the evaluation of pH and temperature influences on synthesized hydrogels swelling, a full three-level experimental design has been used. Two-factor interaction model (2FI) is the most optimal model of a full three-level experimental design for representing the swelling equilibrium degree of p(NIPAM/AA) hydrogels as a function of investigated parameters, i.e., temperature and pH.
以N -异丙基丙烯酰胺(NIPAM)和丙烯酸(AA)为单体，采用自由基聚合法制备了水凝胶。采用傅里叶变换红外光谱(FTIR)、x射线衍射(XRD)以及在不同温度(25、31和37℃)和pH值(2.2、4.5、6和6.8)下水溶液中的溶胀行为对聚(N -异丙基-丙烯酰胺- co -丙烯酸)水凝胶p(NIPAM/AA)进行了表征。在pH为6，温度为25°C的溶液中冻干后，与未冻干的样品相比，p(NIPAM/AA)水凝胶迅速达到平衡膨胀度α e。在冻干样品中，溶剂在基质内的输运机制对应于较少的菲克扩散，而非冻干样品的超级案例II扩散是典型的。p(NIPAM/AA)水凝胶在25℃、pH 6.8条件下，加入1.5 mol%的乙二醇二甲基丙烯酸酯(EGDM)，膨胀平衡度达到最高，α e = 259.8。溶胀研究结果表明，p(NIPAM/AA)水凝胶可归类为高吸水性聚合物(sap)。为了评价pH和温度对合成水凝胶溶胀的影响，采用了完整的三水平实验设计。双因素相互作用模型(2FI)是完整三水平实验设计中表征p(NIPAM/AA)水凝胶溶胀平衡程度随实验参数(温度和pH)变化的最优模型。
{"title":"The evaluation of temperature and pH influences on equilibrium swelling of poly(n-isopropylacrylamide-co-acrylic acid) hydrogels","authors":"Aleksandar Zdravković, L. Nikolić, S. Ilić-Stojanović, V. Nikolić, S. Savić, A. Kapor","doi":"10.2298/HEMIND161018001Z","DOIUrl":"https://doi.org/10.2298/HEMIND161018001Z","url":null,"abstract":"Hydrogels are synthesized by the method of radical polymerization of monomers: N -isopropylacrylamide (NIPAM) and acrylic acid (AA). Characterization of poly( N -isopropylacrylamide- co -acrylic acid) hydrogels, p(NIPAM/AA), has been performed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and by determination of the swelling behaviour in aqueous solutions at different temperatures (25, 31 and 37 °C) and pH values (2.2, 4.5, 6 and 6.8). After lyophilisation in the solution at pH 6 and temperature of 25 °C, p(NIPAM/AA) hydrogels have rapidly reached equilibrium degree of swelling, α e , in comparison to non-lyophilized samples. The mechanism of solvent transport within matrix in lyophilized samples corresponds to less Fickian diffusion, whereas Super case II diffusion is characteristic for non-lyophilized samples. p(NIPAM/AA) hydrogel with 1.5 mol% of ethylene glycol dimethacrylate (EGDM) at the temperature of 25 °C and pH 6.8, has reached the highest swelling equilibrium degree, α e = 259.8. The results of swelling studies have shown that p(NIPAM/AA) hydrogels can be classified as superabsorbent polymers (SAPs). For the evaluation of pH and temperature influences on synthesized hydrogels swelling, a full three-level experimental design has been used. Two-factor interaction model (2FI) is the most optimal model of a full three-level experimental design for representing the swelling equilibrium degree of p(NIPAM/AA) hydrogels as a function of investigated parameters, i.e., temperature and pH.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"71 1","pages":"395-405"},"PeriodicalIF":0.9,"publicationDate":"2017-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42409543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-11-12DOI: 10.2298/HEMIND160715048R
B. Radosavljevic, S. Ilic, Z. Milojevic, C. Z. Bojovic, S. M. Marković
U ovom radu su prikazani rezultati modelovanja kinetike hidrodestilacije etarskog ulјa ploda kleke polinomno-logaritamskim modelom, dobijeni primenom nelinerane regresije. Za razliku od postojecih modela, gde je potrebno poznavanje ukupne kolicine etarskog ulјa koje se može izdvojiti iz bilјke () kako bi se odredili parametri modela, u nasem modelu je ta velicina sastavni deo nepoznatih parametara modela koji se određuju nelinearnom regresijom. Razvijeni model daje bolјe slaganje sa eksperimentalnim vrednostima u odnosu na postojece, opsteprihvacene kineticke modele ovog procesa, sto je dokazano upotrebom nekoliko razlicitih mera odstupanja izracunatih u odnosu na eksperimentalno dobijene rezultate.
{"title":"Modeling the kinetics of essential oil hydrodistillation from juniper berries (Juniperus communis L.) using non-linear regression","authors":"B. Radosavljevic, S. Ilic, Z. Milojevic, C. Z. Bojovic, S. M. Marković","doi":"10.2298/HEMIND160715048R","DOIUrl":"https://doi.org/10.2298/HEMIND160715048R","url":null,"abstract":"U ovom radu su prikazani rezultati modelovanja kinetike hidrodestilacije etarskog ulјa ploda kleke polinomno-logaritamskim modelom, dobijeni primenom nelinerane regresije. Za razliku od postojecih modela, gde je potrebno poznavanje ukupne kolicine etarskog ulјa koje se može izdvojiti iz bilјke () kako bi se odredili parametri modela, u nasem modelu je ta velicina sastavni deo nepoznatih parametara modela koji se određuju nelinearnom regresijom. Razvijeni model daje bolјe slaganje sa eksperimentalnim vrednostima u odnosu na postojece, opsteprihvacene kineticke modele ovog procesa, sto je dokazano upotrebom nekoliko razlicitih mera odstupanja izracunatih u odnosu na eksperimentalno dobijene rezultate.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"71 1","pages":"371-382"},"PeriodicalIF":0.9,"publicationDate":"2017-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45141803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-11-01DOI: 10.2298/HEMIND160525012K
M. Košutić, L. Pezo, J. Filipović, V. Filipović
This paper investigates the effects of simultaneous addition of sunflower (3, 6 or 9 g/100 g of sample) and dry residue of wild oregano (0.5 or 1 g/100 g of sample) on the essential amino acids pattern and antioxidant potential of flake products. The accepted experimental design plan was 3´4. Data point that Score and PDCAAS values in flake products increase with increasing share of sunflower. Maximum value of phenolic compounds and antioxidant activity were experienced of TPC 2.84 mg/g, DPPH 0.75 mg/ml, FRAP 1.57 mg/g with the product having maximum shares of sunflower and dry residue of wild oregano. Tukey’s HSD test showed statistically significant differences between most of the mean values of amino acids content and antioxidant activity in the observed corn flakes. The response surface method has been applied for evaluation of amino acid content and antioxidative potential of corn flakes. Sunflower in flake products positively contributed to the protein nutritive value and dry residues of wild oregano elevated antioxidant potential of flake products and also contributed to the food waste valorisation in the food industry. Corn flakes are new products with improved essential amino acid pattern, antioxidant activity and functional properties due to added dry residue of wild oregano and sunflower
{"title":"Improving the nutritive characteristics of corn flakes enriched with functional components","authors":"M. Košutić, L. Pezo, J. Filipović, V. Filipović","doi":"10.2298/HEMIND160525012K","DOIUrl":"https://doi.org/10.2298/HEMIND160525012K","url":null,"abstract":"This paper investigates the effects of simultaneous addition of sunflower (3, 6 or 9 g/100 g of sample) and dry residue of wild oregano (0.5 or 1 g/100 g of sample) on the essential amino acids pattern and antioxidant potential of flake products. The accepted experimental design plan was 3´4. Data point that Score and PDCAAS values in flake products increase with increasing share of sunflower. Maximum value of phenolic compounds and antioxidant activity were experienced of TPC 2.84 mg/g, DPPH 0.75 mg/ml, FRAP 1.57 mg/g with the product having maximum shares of sunflower and dry residue of wild oregano. Tukey’s HSD test showed statistically significant differences between most of the mean values of amino acids content and antioxidant activity in the observed corn flakes. The response surface method has been applied for evaluation of amino acid content and antioxidative potential of corn flakes. Sunflower in flake products positively contributed to the protein nutritive value and dry residues of wild oregano elevated antioxidant potential of flake products and also contributed to the food waste valorisation in the food industry. Corn flakes are new products with improved essential amino acid pattern, antioxidant activity and functional properties due to added dry residue of wild oregano and sunflower","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"71 1","pages":"495-502"},"PeriodicalIF":0.9,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42903932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-09-25DOI: 10.2298/HEMIND160118044B
Dubravka Bigović, T. Stevic, T. Janković, Nebojša Noveski, D. Radanović, D. Pljevljakušić, Z. Djuric̀
Dry flower heads of Helichrysum plicatum were characterized by HPLC-DAD and a detailed antimicrobial assay of its ethanol extract was performed. Identification of phenolic compounds indicated the presence of apigenin, naringenin and kaempferol as free aglycones, glycosides of apigenin, naringenin, quercetin and kaempferol as well as chlorogenic acid and chalcone derivate. Antimicrobial activity of the extract was evaluated against various bacteria and fungi as well as yeast Candida albicans using microdilution method. Gram-positive bacteria were more sensitive to the tested extract ( MIC values were to 0.02 mg/mL) than Gram-negative bacteria (the greatest MIC was 0.055 mg/mL). Regarding pathogenic fungi, our tests demonstrated that fungi were more sensitive to the tested extract than bacteria. The growth of the majority of the tested fungi was inhibited by concentration of 0.005 mg/mL. Moreover, the extract was significantly more active than commercial fungicide, fluconazole. The results of our tests indicate that the extract of H. plicatum has significant antimicrobial activity and may find application in the pharmaceutical and food industry and organic agriculture.
{"title":"Antimicrobial activity of Helichrysum plicatum DC.","authors":"Dubravka Bigović, T. Stevic, T. Janković, Nebojša Noveski, D. Radanović, D. Pljevljakušić, Z. Djuric̀","doi":"10.2298/HEMIND160118044B","DOIUrl":"https://doi.org/10.2298/HEMIND160118044B","url":null,"abstract":"Dry flower heads of Helichrysum plicatum were characterized by HPLC-DAD and a detailed antimicrobial assay of its ethanol extract was performed. Identification of phenolic compounds indicated the presence of apigenin, naringenin and kaempferol as free aglycones, glycosides of apigenin, naringenin, quercetin and kaempferol as well as chlorogenic acid and chalcone derivate. Antimicrobial activity of the extract was evaluated against various bacteria and fungi as well as yeast Candida albicans using microdilution method. Gram-positive bacteria were more sensitive to the tested extract ( MIC values were to 0.02 mg/mL) than Gram-negative bacteria (the greatest MIC was 0.055 mg/mL). Regarding pathogenic fungi, our tests demonstrated that fungi were more sensitive to the tested extract than bacteria. The growth of the majority of the tested fungi was inhibited by concentration of 0.005 mg/mL. Moreover, the extract was significantly more active than commercial fungicide, fluconazole. The results of our tests indicate that the extract of H. plicatum has significant antimicrobial activity and may find application in the pharmaceutical and food industry and organic agriculture.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"71 1","pages":"337-342"},"PeriodicalIF":0.9,"publicationDate":"2017-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44938315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-09-25DOI: 10.2298/HEMIND160522040P
M. Purenovic, S. M. Randjelovic, Z. M. Momcilovic, M. Purenovic, J. Stankovic, N. Andjelkovic
The physicochemical modification of peat through thermal and oxidation processes was carried out, in order to obtain new, inexpensive and active material for purification of different types of waters. During the modification, surface chemical compounds of Shilov type were formed. Batch adsorption properties and suitability of physicochemically modified peat (PCMP) for odor removal were tested in aqueous solutions of H 2 S and colloidal sulphur. Additionally, PCMP was tested in the removal of As(V) which is hazardous ingredient in contaminated waters. Possible mechanisms of pollutants binding include interactions, which lead to formation of adducts and clathrates. All these processes are elucidated in detail. The results showed that the obtained material can be used for the removal of sulphide, colloidal sulphur and As(V) from different types of waters.
{"title":"Physicochemically modified peat by thermal and oxidation processes as an active material for purification of wastewaters from certain hazardous pollutants","authors":"M. Purenovic, S. M. Randjelovic, Z. M. Momcilovic, M. Purenovic, J. Stankovic, N. Andjelkovic","doi":"10.2298/HEMIND160522040P","DOIUrl":"https://doi.org/10.2298/HEMIND160522040P","url":null,"abstract":"The physicochemical modification of peat through thermal and oxidation processes was carried out, in order to obtain new, inexpensive and active material for purification of different types of waters. During the modification, surface chemical compounds of Shilov type were formed. Batch adsorption properties and suitability of physicochemically modified peat (PCMP) for odor removal were tested in aqueous solutions of H 2 S and colloidal sulphur. Additionally, PCMP was tested in the removal of As(V) which is hazardous ingredient in contaminated waters. Possible mechanisms of pollutants binding include interactions, which lead to formation of adducts and clathrates. All these processes are elucidated in detail. The results showed that the obtained material can be used for the removal of sulphide, colloidal sulphur and As(V) from different types of waters.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"71 1","pages":"299-306"},"PeriodicalIF":0.9,"publicationDate":"2017-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42424005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-09-25DOI: 10.2298/HEMIND160627042G
I. Gligorijevic, Z. Zivkovic, V. Kovačević, P. Dimitrijevic, M. B. Pavkovic, M. Pavić, Z. Rodic
Mechanical properties of viscoelastic filled polymers strongly depend on temperature and strain rate and vary for several orders of magnitude. During service life, a viscoelastic body, especially carboxy-terminated polybutadiene (CTPB) composite solid rocket propellant grain, is subjected to many stress-inducing loads. Its structural integrity analysis (hereafter: “structural analysis”), unlike elastic bodies, is quite complex and sometimes impossible under the action of just a single load. An even greater problem occurs when multiple different types of loads act simultaneously. This study is based on a complete uniaxial mechanical characterization of a viscoelastic CTPB composite rocket propellant, made in MTI-Belgrade, whose results were used for the analysis of the propellant grain reliability. Through an example, this paper shows a behavior of the viscoelastic propellant grain when it is subjected to extremely different environmental loads at the same time. Similar explicit examples are difficult to found in the literature, except in the form of recommended principles for analysis. It is shown that the tensile strength under the action of fast load due to the pressure may be almost 20 times greater than the tensile strength under the slow temperature load. A probabilistic approach is presented in evaluation the reliability and service life. An example is shown for a rocket propellant grain as a viscoelastic body. The presented principles of the analysis can be applied to any arbitrary viscoelastic body in other areas.
{"title":"Analysis of viscoelastic behavior of a filled elastomer under action of different loads","authors":"I. Gligorijevic, Z. Zivkovic, V. Kovačević, P. Dimitrijevic, M. B. Pavkovic, M. Pavić, Z. Rodic","doi":"10.2298/HEMIND160627042G","DOIUrl":"https://doi.org/10.2298/HEMIND160627042G","url":null,"abstract":"Mechanical properties of viscoelastic filled polymers strongly depend on temperature and strain rate and vary for several orders of magnitude. During service life, a viscoelastic body, especially carboxy-terminated polybutadiene (CTPB) composite solid rocket propellant grain, is subjected to many stress-inducing loads. Its structural integrity analysis (hereafter: “structural analysis”), unlike elastic bodies, is quite complex and sometimes impossible under the action of just a single load. An even greater problem occurs when multiple different types of loads act simultaneously. This study is based on a complete uniaxial mechanical characterization of a viscoelastic CTPB composite rocket propellant, made in MTI-Belgrade, whose results were used for the analysis of the propellant grain reliability. Through an example, this paper shows a behavior of the viscoelastic propellant grain when it is subjected to extremely different environmental loads at the same time. Similar explicit examples are difficult to found in the literature, except in the form of recommended principles for analysis. It is shown that the tensile strength under the action of fast load due to the pressure may be almost 20 times greater than the tensile strength under the slow temperature load. A probabilistic approach is presented in evaluation the reliability and service life. An example is shown for a rocket propellant grain as a viscoelastic body. The presented principles of the analysis can be applied to any arbitrary viscoelastic body in other areas.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"71 1","pages":"307-317"},"PeriodicalIF":0.9,"publicationDate":"2017-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47213845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-09-25DOI: 10.2298/HEMIND160628041C
B. Catovic, Minela Šišić, Majda Srabovic, M. Huremović
Lignit je mrki ugalj koji u svom sastavu sadrži huminsku kiselinu. Izolacija huminskih kiselina je vrsena iz prethodno oksidovanog i osusenog lignita nakon cega je vrseno preciscavanje. Identifikacija tako dobivenih huminskih kiselina vrsena je FTIR spektroskopijom, a njena karakterizacija UV analizom gde je određivana opticka gustina izolovane huminske kiseline i izvrsena njena kompleksacija sa metalnim katjonima. Podaci dobiveni FTIR spektroskopskom analizom za izolovanu huminsku kiselinu ne pokazuju znacajnu strukturnu i hemijsku razliku u odnosu na spektar dobiven za standardnu huminsku kiselinu (Sigma–Aldrich). UV analizom je utvrđeno da izolovana i standardna huminska kiselina imaju E 4 /E 6 odnos u odgovarajucem opsegu od 3–5, sto indicira prisustvo veceg broja alifatskih struktura. Na osnovu stepena humifikacije utvrđeno je da izolovane huminske kiseline pripadaju tipu B dok standardne huminske kiseline pripadaju tipu A. Kompleksacija huminskih kiselina je vrsena rastvorima razlicitih koncentracija nitratnih soli metala i pri razlicitim pH vrednostima. Kolicina slobodnog metala merena je metodom ICP-OES. Podaci su analizirani i ANOVA statistickom metodom. Rezultati su pokazali da se povecanjem pH vrednosti smanjuje koncentracija metalnog jona adsorbovanog na huminsku kiselinu dok se povecanjem koncentracije metala i kolicine huminske kiseline ta moc povecava. Istraživanjem je utvrđen sledeci niz vezivanja metala za huminsku kiselinu Pb>Zn>Ni>Cu.
{"title":"Isolation of humic acid from oxidized lignite and complexation with metal cations","authors":"B. Catovic, Minela Šišić, Majda Srabovic, M. Huremović","doi":"10.2298/HEMIND160628041C","DOIUrl":"https://doi.org/10.2298/HEMIND160628041C","url":null,"abstract":"Lignit je mrki ugalj koji u svom sastavu sadrži huminsku kiselinu. Izolacija huminskih kiselina je vrsena iz prethodno oksidovanog i osusenog lignita nakon cega je vrseno preciscavanje. Identifikacija tako dobivenih huminskih kiselina vrsena je FTIR spektroskopijom, a njena karakterizacija UV analizom gde je određivana opticka gustina izolovane huminske kiseline i izvrsena njena kompleksacija sa metalnim katjonima. Podaci dobiveni FTIR spektroskopskom analizom za izolovanu huminsku kiselinu ne pokazuju znacajnu strukturnu i hemijsku razliku u odnosu na spektar dobiven za standardnu huminsku kiselinu (Sigma–Aldrich). UV analizom je utvrđeno da izolovana i standardna huminska kiselina imaju E 4 /E 6 odnos u odgovarajucem opsegu od 3–5, sto indicira prisustvo veceg broja alifatskih struktura. Na osnovu stepena humifikacije utvrđeno je da izolovane huminske kiseline pripadaju tipu B dok standardne huminske kiseline pripadaju tipu A. Kompleksacija huminskih kiselina je vrsena rastvorima razlicitih koncentracija nitratnih soli metala i pri razlicitim pH vrednostima. Kolicina slobodnog metala merena je metodom ICP-OES. Podaci su analizirani i ANOVA statistickom metodom. Rezultati su pokazali da se povecanjem pH vrednosti smanjuje koncentracija metalnog jona adsorbovanog na huminsku kiselinu dok se povecanjem koncentracije metala i kolicine huminske kiseline ta moc povecava. Istraživanjem je utvrđen sledeci niz vezivanja metala za huminsku kiselinu Pb>Zn>Ni>Cu.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"71 1","pages":"319-327"},"PeriodicalIF":0.9,"publicationDate":"2017-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43663671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-09-25DOI: 10.2298/HEMIND160421046M
G. M. Miljkovic, Z. Davidovic, S. Kralj, S. Šiler-Marinković, D. M. Rajilic-Stojanovic, I. S. Dimitrijević-Branković
The production of dextransucrase (DS) by Leuconostoc mesenteroides T3, novel isolate from water kefir grain, was studied and optimized. Bacterial supernatant reached activity of 3.1 U/ml when the culture was grown at 23 °C and under static culture condition using classical Tsuchiya medium for DS production. The increase of sucrose concentration to 7% led to an increase of DS activity by 52% compared to the control. Medium with 2% beef extract and 1% yeast extract resulted in 4.52 U/ml, which was 47% higher than in the control (with 2% yeast extract). Finally, the increase of K 2 HPO 4 concentration from 2 to 3% resulted in the increased enzyme activity by 28%. Enzyme purified by polyethylene glycol 400 fractionation displayed maximum activity at 30 °C and pH 5.4. Zymogram analysis confirmed the presence of DS of approximately 180 kDa. The addition of divalent cations Ca 2+ , Mg 2+ , Fe 2+ and Co 2+ led to a minor increase of DS activity, while the addition of Mn 2+ was the most prominent with 73% increase. These findings classify dextransucrase from Leuconostoc mesenteroides T3 as promising candidate for production of dextran, which has numerous applications in various industries.
{"title":"Characterization of dextransucrase from Leuconostoc mesenteroides T3, water kefir grains isolate","authors":"G. M. Miljkovic, Z. Davidovic, S. Kralj, S. Šiler-Marinković, D. M. Rajilic-Stojanovic, I. S. Dimitrijević-Branković","doi":"10.2298/HEMIND160421046M","DOIUrl":"https://doi.org/10.2298/HEMIND160421046M","url":null,"abstract":"The production of dextransucrase (DS) by Leuconostoc mesenteroides T3, novel isolate from water kefir grain, was studied and optimized. Bacterial supernatant reached activity of 3.1 U/ml when the culture was grown at 23 °C and under static culture condition using classical Tsuchiya medium for DS production. The increase of sucrose concentration to 7% led to an increase of DS activity by 52% compared to the control. Medium with 2% beef extract and 1% yeast extract resulted in 4.52 U/ml, which was 47% higher than in the control (with 2% yeast extract). Finally, the increase of K 2 HPO 4 concentration from 2 to 3% resulted in the increased enzyme activity by 28%. Enzyme purified by polyethylene glycol 400 fractionation displayed maximum activity at 30 °C and pH 5.4. Zymogram analysis confirmed the presence of DS of approximately 180 kDa. The addition of divalent cations Ca 2+ , Mg 2+ , Fe 2+ and Co 2+ led to a minor increase of DS activity, while the addition of Mn 2+ was the most prominent with 73% increase. These findings classify dextransucrase from Leuconostoc mesenteroides T3 as promising candidate for production of dextran, which has numerous applications in various industries.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"71 1","pages":"351-360"},"PeriodicalIF":0.9,"publicationDate":"2017-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45469734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-09-25DOI: 10.2298/HEMIND151110043A
A. Avdeenko, E. Belova, P. Dašić, S. Konovalova, L. Baklanova, S. Krstić, M. Milosavljević
Carotenoids are known for their lower environmental pollution, lower costs, shorter extraction time compared to regular extraction methods and higher extraction efficiency. Ultrasound has significant advantages in the extraction of a great number of biologically active compounds including carotenoids. Benefits of using ultrasound for extraction of various compounds are numerous and include effective mixing and micro-mixing, more efficient energy transfer, reduced thermal and concentration gradients, reduced temperature. The aim of this work was to investigate the influence of two-frequency ultrasound main parameters such as ultrasonic intensity, sonication time, and temperature. Application of two-frequency ultrasound (simultaneous influence of ultrasound with frequency of 20–46 kHz, intensity of 1.5–2.5 W/cm 2 and frequency of 1.0–2.0 MHz, intensity of 2.0–3.0 W/cm 2 ) raises the percentage of b -carotene extraction from biomass of the fungus Blakeslea trispora from 90–92% up to 98–99% in comparison with one frequency ultrasound. The recommended oil temperature for the extraction process is 35 °C, because lower temperature leads to reduction of percentage of β -carotene extraction, and higher temperature promotes unjustified increase of expenditure of energy.
{"title":"Efficient two-frequency ultrasound extraction of β-carotene from the fungus Blakeslea trispora","authors":"A. Avdeenko, E. Belova, P. Dašić, S. Konovalova, L. Baklanova, S. Krstić, M. Milosavljević","doi":"10.2298/HEMIND151110043A","DOIUrl":"https://doi.org/10.2298/HEMIND151110043A","url":null,"abstract":"Carotenoids are known for their lower environmental pollution, lower costs, shorter extraction time compared to regular extraction methods and higher extraction efficiency. Ultrasound has significant advantages in the extraction of a great number of biologically active compounds including carotenoids. Benefits of using ultrasound for extraction of various compounds are numerous and include effective mixing and micro-mixing, more efficient energy transfer, reduced thermal and concentration gradients, reduced temperature. The aim of this work was to investigate the influence of two-frequency ultrasound main parameters such as ultrasonic intensity, sonication time, and temperature. Application of two-frequency ultrasound (simultaneous influence of ultrasound with frequency of 20–46 kHz, intensity of 1.5–2.5 W/cm 2 and frequency of 1.0–2.0 MHz, intensity of 2.0–3.0 W/cm 2 ) raises the percentage of b -carotene extraction from biomass of the fungus Blakeslea trispora from 90–92% up to 98–99% in comparison with one frequency ultrasound. The recommended oil temperature for the extraction process is 35 °C, because lower temperature leads to reduction of percentage of β -carotene extraction, and higher temperature promotes unjustified increase of expenditure of energy.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"71 1","pages":"329-336"},"PeriodicalIF":0.9,"publicationDate":"2017-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41936091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-09-25DOI: 10.2298/HEMIND160620045A
R. M. Adzemovic, Z. A. Ivanovic-Sasic, D. Nikolic, J. Aleksic, R. Stevanović
{"title":"Redesigning current instruments as a precondition for a more effective environmental protection","authors":"R. M. Adzemovic, Z. A. Ivanovic-Sasic, D. Nikolic, J. Aleksic, R. Stevanović","doi":"10.2298/HEMIND160620045A","DOIUrl":"https://doi.org/10.2298/HEMIND160620045A","url":null,"abstract":"","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"71 1","pages":"343-350"},"PeriodicalIF":0.9,"publicationDate":"2017-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49524590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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