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Search Results: 1 - 10 of 149841 matches for " ??iban Marina B. "
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Effect of different conditions on Cu(II) and Cr(VI) biosorption by dried waste tea fungal biomass
Razmovski Radojka N.,??iban Marina B.
Acta Periodica Technologica , 2007, DOI: 10.2298/apt0738149r
Abstract: Some industrial wastewaters contain high quantities of non-toxic salts besides heavy metal ions. The presence of salt ions leads to a high ionic strength of water, which may significantly affect the performance of the biosorption process, so that the effect of salts on the biosorption of heavy metal ions should be investigated. In this study the effect of different salts concentrations (0.1; 0.5 and 1 mol L-1) and dosage of tea fungal biomass (0.15; 0.25 and 0.5 g L-1) dried at different temperatures: 20°C, 70°C, 80°C, 105°C and 125°C on Cu(II) and Cr(VI) biosorption was studied in a batch system. Biosorption at an ionic strength of 0.1 mol L-1 of all salts investigated had a decreasing effect on Cu(II) and Cr(VI) removal. It was observed that (NH4)2SO4 at the concentrations of 0.5 mol L-1 and 1 mol L-1 was more efficient than other salts for metal ions removal. In case of Cr(VI) the most efficient removal was obtained for the water with K2SO4 at a concentration of 0.5 mol L-1. The lowest biosorbent dosage (0.15 g L-1 tea fungal biomass dried at 20°C in the case of Cu(II) biosorption and at 80°C in the case of Cr(VI) biosorption) resulted in the highest metal uptake of 38 mg g-1 in case of Cu(II) and 33 mg g-1 in case of Cr(VI).
The kinetics of chromium(VI) adsorption from water on some natural materials
??iban Marina B.,Kla?nja Mile T.
Acta Periodica Technologica , 2002, DOI: 10.2298/apt0233101s
Abstract: This paper is concerned with the kinetics of chromium(VI) adsorption by wood sawdust, pulp, and Kraft lignin. In our previous works we determined adsorption efficiency of these adsorbents. In this paper we focused our attention on the influence of contact time on chromium(VI) adsorption from water by the same adsorbents. The analytical data were approached from the following kinetic models: First-order kinetic model, Parabolic diffusion model, Elovich model, and Modified Freundlich model. Elovich model was shown to be the best fit for the description of chromium(VI) adsorption. It was found that adsorption was the fastest on pulp and slowest on Kraft lignin.
Treatment of sugar beet thick juice spent wash by chemical and natural coagulants
??iban Marina B.,Kla?nja Mile T.,Antov Mirjana G.
Acta Periodica Technologica , 2009, DOI: 10.2298/apt0940177s
Abstract: The possibility of treatment of wastewater from bioethanol production by aluminium sulfate and natural coagulant extracted from common bean seed was studied. The highest coagulation activity at pH 6.5 is reached with analum dose of 1 g/l, but only a little lower coagulation activities were obtained by the dose of 0.05 and 0.10 g/l, which is more favorable for economic and environmental reasons. When natural coagulant from common bean was applied the highest coagulation activity, 14.3%, at pH 6.5 is reached with a dose of 0.5 ml/l. However, when common bean natural coagulant was used simultaneously with alum, the highest turbidity removal resulting in 24% coagulation activity was achieved and this was more efficient than when alum or natural coagulant were used.
Biosorption of copper(II) and chromium(VI) by modified tea fungus
??iban Marina B.,Prodanovi? Jelena M.,Razmovski Radojka N.
Acta Periodica Technologica , 2012, DOI: 10.2298/apt1243335s
Abstract: The tea fungus was found to have good adsorption capacities for heavy metal ions. In this work it was treated with HCl or NaOH at 20°C or 100°C, with the aim to improve its adsorption ability. The sorption of Cu(II) and Cr(VI) ions from aqueous solutions by raw and treated tea fungus was investigated in the batch mode. The largest quantity of adsorbed Cu(II), of about 55 mg/g, was achieved by tea fungus modified with NaOH at 100°C. For Cr(VI), the largest quantity of adsorbed anions, of about 58 mg/g, was achieved by the adsorbent modified with NaOH at 20°C. It was shown that acid modification of tea fungus biomass was not effective. [Projekat Ministarstva nauke Republike Srbije, br. III 43005 i br. TR 31002]
The impact of calculation on the value of thermodynamic parameters of copper adsorption on poplar sawdust
Brdar Mirjana M.,??iban Marina B.,Taka?i Aleksandar A.
Acta Periodica Technologica , 2011, DOI: 10.2298/apt1142167b
Abstract: The adsorption of Cu(II) onto poplar sawdust as an adsorbent is analyzed. The experimental data were fitted by the Langmuir isotherm using four linearized forms at the isotherm along with the original one. The least squares regression method was applied. Using the obtained Langmuir constants by each at methods, the enthalpy, entropy and Gibbs free energy at adsoption were calculated. A comparison of the used linear and non-linear regression methods in view at the goodness of the fit is presented. The coefficient of correlation was adopted as a criterionn to select the best method. The impact of the choice at regression model on the resulting estimates of the thermodynamic parameters is discussed. The best fit of the experimental data is obtained by the nonlinear regression. Thus, it is recommended to use the Langmuir parameters calculated by the nonlinear regression for estimating the thermodynamic parameters of adsorptin. The differences in the values obtained by different models are not so large to change the basic conclusion that the adsorption of copper ions on poplar sawdust is a spontaneous endothermic process i.e. that tested adsorbent has an affinity for copper ions.
Investigation of coagulation activity of natural coagulants from seeds of different leguminose species
??iban Marina B.,Kla?nja Mile T.,Stojimirovi? Jelena Lj.
Acta Periodica Technologica , 2005, DOI: 10.2298/apt0536081s
Abstract: The ability of seeds of plants: Phaseolus vulgaris, Robinia pseudoacacia Ceratonia siliqua and Amorpha fruticosa, to act as natural coagulants was tested using synthetic turbid water. This water was prepared by adding kaolin into tap water, just before the test. Active components were extracted from ground seeds with distilled water. The coagulation ability of this extract was assessed by the use of standard jar test measurements in water with various initial turbidity. Investigation of these natural coagulants was confirmed their positive coagulation activity. Of all plants that have been examined, the seed extract from Ceratonia siliqua appeared to be one of the most effective coagulants for water treatment. A dose of 20 mg/l of this coagulant resulted in 100% coagulation activity for clarification of water with 17.5 NTU initial turbidity.
Extraction and partial purification of coagulation active components from common bean seed
??iban Marina B.,Antov Mirjana G.,Kla?nja Mile T.
Acta Periodica Technologica , 2006, DOI: 10.2298/apt0637037s
Abstract: An active coagulation component was extracted from common bean seed by NaCl solution and the obtained crude extract was partially purified through a sequence of steps that included precipitation of protein by ammonium sulphate, desalting by dialysis and anion exchange. A turbid water was treated by protein fractions obtained in the anion- exchange elution process by stepwise increase in NaCl concentration. The jar tests were conducted at various dosages of eluates. Different mode of relation between coagulation activity and applied coagulant dose for each protein fraction indicated the existence of different mechanisms of coagulation/flocculation, depending of characteristics of different proteins in the fractions.
Isotherms for the adsorption of Cu(II) onto lignin: Comparison of linear and non-linear methods
Brdar Mirjana M.,Taka?i Aleksandar A.,??iban Marina B.,Raki? Du?an Z.
Hemijska Industrija , 2012, DOI: 10.2298/hemind111114003b
Abstract: Equilibrium studies were carried out for the adsorption of Cu(II) onto Kraft lignin as an adsorbent. The experimental data were fitted to the Freundlich, Langmuir and Redlich-Peterson isotherms by linear and non-linear method. Comparison of linear and non-linear regression method was given in selecting the optimum isotherm for the experimental data. The coefficient of correlation r2 and Chi-square test χ2 was used to select the best linear theoretical isotherm. The best linear model is Redlich-Peterson isotherm model, where r2=0,985 and χ2=0,02. In order to predict the error ERRSQ, HYBRD, MPSD, ARE and EABS were used. Moreover, by minimizing these error functions the optimal values of parameters and also the optimum isotherm was found. The Redlich-Peterson isotherm was found to be the best representative for adsorption of Cu(II) on the adsorbent in the cases when ERRSQ, HYBRD, MPSD functions were used. There coefficients of determination are 0.986, 0.985, 0.984, respectively and Chi-square is 0.02 in all cases. Freundlich isotherms which were obtained by minimization of the ERRSQ, HYBRD, MPSD, ARE and EABS function showed very good agreement with experimental data. In all cases the coefficients of determination are greater than 0.91. Besides, it was observed that non-linear isotherm models were better for representation of equilibrium data than linearized models.
Investigation of isolation conditions and ion-exchange purification of protein coagulation components from common bean seed
Antov Mirjana G.,??iban Marina B.,Adamovi? Slavica R.,Kla?nja Mile T.
Acta Periodica Technologica , 2007, DOI: 10.2298/apt0738003a
Abstract: Investigation of an extraction procedure of protein coagulants from common bean seed regarding concentration of NaCl and pH was performed. High values of protein concentration and coagulation activity in crude extract (9.19 g/l and 23.9%, respectively) were obtained when the extraction was performed using 0.5 mol/l NaCl and water as solvent, which represents an advantage for economic and environmental reasons. Crude extract of common bean seed was purified by precipitation at two different percentages of (NH4)2SO4 saturation, followed by batch ion-exchange chromatography. The highest obtained coagulation activity, 45%, was determined in fraction that was eluated at 1.75 mol/l NaCl from resin loaded with proteins precipitated upon 80-100% (NH4)2SO4 saturation. High values of coagulation activity showed by some eluates suggest their application as natural coagulant for water purification. .
Analysis of pretreatments of sugar beet shreds for bioethanol production in respect of cellulose hydrolysis and waste flows
Iveti? Darjana ?.,Vasi? Vesna M.,??iban Marina B.,Antov Mirjana G.
Acta Periodica Technologica , 2011, DOI: 10.2298/apt1142223i
Abstract: This paper analyzes some chemical pretreatments of sugar beet shreds concerning generated waste flows and yield of reducing sugars obtained by enzymatic hydrolysis of pretreated material. Waste flows produced in pretreatments of sugar beet shreds originated from pectin and lignin removal from raw material. Suitability of substrates prepared in single and two-step pretreatment procedure for enzymatic hydrolysis was determined based on the yield of reducing sugars released by cellulase action on them, while different possibilities of processing of wastewaters were discussed based on the characteristic of waste flows.
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