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    Adsorption of levulinic acid from aqueous solution by Amberlite XAD-4
    (Elsevier Science Bv, 2017) Datta, Dipaloy; Uslu, Hasan
    Levulinic acid (LA) from aqueous solutions was removed by using commercial adsorbent Amberlite XAD-4 (XAD-4). The equilibrium and kinetic studies were performed to investigate the effect of adsorbent amount (1 g to 3.5 g at 298 K, 308 K and 318 K), initial acid concentration (2 g.L-1 to 4 g.L-1 at 298 K, 308 K and 318 K), and contact time (t, 10 min to 90 min at 298 K) on the capability of XAD-4. The uptake capability and removal efficiency of XAD-4 for the adsorption of LA was observed to increase by increasing amount of adsorbent. In the equilibrium experiments of LA adsorption, adsorption capacity value was increased to 26.85 mg.g(-1) from 10 mg.g(-1) at 298 K with an increase in the amount of XAD-4. In the kinetic studies, the equilibrium time of 70 min was obtained. Also equilibrium study was performed at three different temperatures, 298, 308 and 318 K. The maximum removal was obtained at 298 K. Thermodynamic model parameters such as Delta G degrees, Delta H degrees and Delta S degrees are estimated at three different LA concentration (2 g.L-1, 3 g.L-1 and 4 g.L-1). Different isotherm and kinetic models were applied to estimate the equilibrium and kinetic parameters. (C) 2017 Elsevier B.V. All rights reserved.
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    Adsorption Studies of Lactic Acid by Polymeric Adsorbent Amberlite XAD-7: Equilibrium and Kinetics
    (Amer Chemical Soc, 2017) Uslu, Hasan; Majumder, Subhajit
    The present study deals with the separation of lactic acid (LA) by a polymeric adsorbent Amberlite XAD-7. Equilibrium and kinetic studies were carried out to investigate adsorption of LA on Amberlite XAD-7 at three different temperatures (298, 308, and 318 K). Equilibrium studies revealed the optimum dose of Amberlite XAD-7 as 2.5 g. The adsorption equilibrium time was determined as 90 min. Adsorption isotherms such as Freundlich, Langmuir, Temkin, and Dubinin-Radushkevich were validated using the obtained experimental data. Langmuir isotherms showed better fitting with the experimental data with R-2 = 0.99. Pseudo-second-order model and Elovich model were used to fit the adsorption system. Study also revealed 99% removal of LA using Amberlite XAD-7.
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    Adsorptive separation of adipic acid from aqueous solutions by perlite or its composites by manganese or copper
    (Techno-Press, 2014) Uslu, Hasan; Demir, Goksel; Bayat, Cuma; Wasewar, Kailas L.; Bamufleh, Hisham S.
    Adipic acid (hexane-1,6-dioic acid) is one of the most used chemical in industrial applications. This must be separated from any environmental contaminant. In this study, adipic acid separation from wastewater by adsorption method onto Perlite or Perlite + Mn or Perlite + Cu composites was investigated. Adsorption of Adipic acid was investigated in terms of equilibrium, and thermodynamic conditions. For thermodynamic investigations the experiments carried out at three different temperatures (298 K, 318 K, 328 K). In the equilibrium studies, 2 g of perlite and its composites were determined as the optimal adsorbent amount. Freundlich and Langmuir isotherms were applied to the experimental data. Freundlich isotherms for all temperatures used in this work gave some deviations with R square values under 0.98 where as Langmuir isotherm gave good results with R square values upper 0.99 at different temperatures. As a result of thermodynamic studies, adsorption enthalpy (Delta H), adsorption entropy (Delta S), and adsorption free energy (Delta G) have been calculated for each adsorbents.
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    Adsorptive Separation of Lead (Pb2+) from Aqueous Solution Using Tri-n-octylamine Supported Montmorillonite
    (Amer Chemical Soc, 2017) Datta, Dipaloy; Uslu, Hasan
    Divalent lead present in the water stream was removed by using adsorption techniques with montmorillonite clay (Mt) modified with tri-n-octylamine (Mt-TOA). Batch adsorption data at equilibrium were determined with different initial Pb2+ ions concentration (8, 10, 12, 14, and 16 mg.L-1) in the aqueous solution at 298 K, and these results were correlated by using three different isotherm models, for instance, the Langmuir, the Freundlich, and the Temkin. The two-parameter Langmuir model was the best fit to the equilibrium data with a coefficient (R-2) greater than 0.99. The maximum capacities for monolayer adsorption of Mt and Mt-TOA were determined to be 3.37 mg.g(-1) and 33.1 mg.g(-1), respectively, as estimated from Langmuir. Also, experimental values were generated to evaluate the influence of adsorbent amount (w, 0.05-0.3 g for Mt, 0.01-0.06 g for Mt-TOA), starting Pb2+ ion concentration (C-0,8 mg.L-1 to 16 mg.L-1), pH (between 1 and 9), and contact period (t, from 10 to 110 min) on the removal effectiveness and adsorption capability of Mt and Mt-TOA adsorbents. In respect to kinetic studies, the removal efficiency of Pb2+ ion reached to a fixed value of 81.42% with Mt (0.1 g) and 80.67% by Mt-TOA (0.01 g) next 100 and 80 min, respectively. Pseudo-first order, pseudo-second order, and intraparticle diffusion models were studied to obtain the kinetic parameters of the adsorption practice. It is observed that the rate of mass transfer of Pb2+ ions was mainly governed by the intraparticle diffusion mechanism.
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    Equilibrium Data on the Reactive Extraction of Picric Acid from Dilute Aqueous Solutions Using Amberlite LA-2 in Ketones
    (Amer Chemical Soc, 2017) Uslu, Hasan; Marti, Mustafa Esen
    The present study is on the reactive extraction of picric acid (HPc, 2,4,6-trinitrophenol) from dilute aqueous solutions by organic phases containing Amberlite LA-2 (ALA 2) as extractant dissolved in four types of ketones. The studies were performed at 298, 308, and 318 K, and the results were used to calculate the values of distribution coefficient (KD), loading factor (Z), and degree of extraction (E%). Initial HPc concentration was kept constant at 0.061 mol.kg(-1). The maximum KD was obtained as 60 using methyl ethyl ketone when initial concentrations of PA and ALA-2 were 0.061 and 0.59 mol.kg(-1), respectively. The extraction efficiency was 98.36% under these conditions. Moreover, z-values between 0.09 and 0.27 were obtained in the ranges of parameters studied. Calculated values show that 1:2 picric acid-ALA-2 complex dominates the extraction process.
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    Evaluation of extractability of 2,4,6-trinitrophenol by secondary amine extractant in alcohols: Equilibrium and molecular dynamic study
    (Elsevier, 2017) Uslu, Hasan
    Extractive separation of 2,4,6-trinitrophenol (picric acid, PAH) from its aqueous solutions was examined at constant temperature of 298.2 K. The experiments were studied on the extraction of PAH (0.061 mol kg(-1)) by Amberlite LA2, a secondary amine diluted in five different alcohols such as isopropyl alcohol, isoamyl alcohol, hexanol, heptanol, and decanol. In addition to reactive extraction, experiments on physical extraction were also performed by pure diluents. Experimental results obtained from batch extraction were evaluated in terms of distribution coefficients (K-D), extraction efficiency (E), and loading factors (Z). The highest synergistic effect was achieved with isopropyl alcohol in LA-2 at a concentration of 0.588 mol kg(-1) as 98.36%. The highest value of probable equilibrium constants for the complex between acid and amine (1:1), K-11 was calculated to be 11.62 for isopropyl alcohol at 0.588 mol kg(-1) LA-2 concentration. Kinetic and potential energies of components during reactive extraction in the organic phase have been determined by molecular dynamic modeling for picric acid + isopropyl alcohol + secondary amine. The values of energy, per atom, for mixture picric acid + isopropyl + secondary amine were respectively: similar to 30,000 kcal/mol, similar to 15,000 kcal/mol, similar to-50,000 kcal/mol and similar to-60,000 kcal/mol. (C) 2016 Elsevier B.V. All rights reserved.
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    Extraction equilibria of 2,4,6-Trinitrophenol by (amberlite LA2+ester) solvents
    (Elsevier Science Bv, 2016) Uslu, Hasan
    Extraction equilibria of 2,4,6-Trinitrophenol (picric acid (PAH)) between aqueous and organic phases was investigated at 298.15 K. All experiments was reported on the extraction of picric acid by amberlite LA2 which is secondary amine dissolved in different seven (7) esters such as diethyl malonate, dimethyl phthalate, diethyl glutarate, propyl acetate, diethyl succinate, diethyl sebacate, ethyl propionate, as well as single diluents. Experimental results obtained from batch extraction were evaluated in respect to distribution coefficients (K-D), loading factors (T-T), stoichiometric loading factor (T-S), separation factor (S-f) and extraction efficiency (E). The dimethyl phthalate gave highest synergistic effect with LA2 as extraction efficiency value of 95%. The highest values of possible equilibrium complexation constants for (acid/amine) (1:1) K-11 was determined as 10.969 for dimethyl phthalate at 1.762 mol kg(-1) amine concentration. (C) 2016 Elsevier B.V. All rights reserved.
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    Extraction of Citric Acid and Maleic Acid from Their Aqueous Solutions Using a Phosphorus-Bonded Extractant, Tri-&ITn&IT-octylphosphineoxide, and a Secondary Amine, Dioctylamine
    (Amer Chemical Soc, 2018) Hasret, Erdem; Kirbaslar, Sah Ismail; Uslu, Hasan
    The aim of this study is to investigate the extraction of citric acid and maleic acid from their aqueous solutions using different solvent-extractant mixtures in order to find the most effective composition for the extraction. Citric and maleic acids are chosen as the carboxylic acids due to their commercial worth in the industrial processes. Carboxylic acids are recovered from their aqueous solutions by reactive extraction, a promising liquid-liquid extraction technique, using trioctylphosphineoxide (TOPO), and a secondary amine called dioctylamine (DOA). TOPO has been chosen as an extractant since it has low water solubility, high stability, and it is more environmentally friendly than the amine-type extractants. For other amine extractants used in reactive extraction processes, there is a lack of study in the literature about the extraction of these acids with DOA. Extractants were dissolved in nine different solvents (butanol, decanol, octanol, isoamylalcohol, octane, decane, methylisobutylketone, and diisobutylketone) having different chemical structures. All experiments were carried out at 298.15 K. Comparisons of the results were made using, the distribution coefficient (D), loading factor (Z), and the extraction yield (%E). It has been observed that a considerable amount of citric acid and maleic acid extraction was achieved using DOA (in the range of 13.95-99.19% and 31.94-99.41% according to the diluent used for citric acid and maleic acid, respectively) compared to that achieved with TOPO (in the range of 0.81-67.12% and 16.25-89.33% according to the diluent used for citric acid and maleic acid, respectively).
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    Influence of fluorinated extractant aggregation in diluent on extraction of salicylic acid: Evidence from equilibrium, SAXS and molecular dynamics simulation
    (Elsevier Science Inc, 2018) Wu, Xue; Chang, Zhidong; Feng, Jingge; Dang, Hui; Uslu, Hasan; Li, Wenjun
    In order to get optimal extraction performance as well as ultra-low solvent residual, the extraction behavior of tris(2,2,3,3,4,4,4-heptafluorobutyl) phosphate (FTBP) dissolved in 2,3,4,5,6-Pentafluorotoluene (FB) was evaluated to investigate the influence of the aggregation state on the extraction of salicylic acid (SA). The effect of SA distribution and water content on aggregation structure in organic phase was assessed through analysis of SAXS data. Based on molecular dynamic simulation, FTBP tended to aggregate with the existence of FB to accommdate more SA molcules. Water in this case was not the critical factor for aggregation formation due to the hydrophobicity of fluorinated solvents. (C) 2018 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
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    Prigogine-Flory-Patterson evaluation of systems with ionic liquids plus water or methanol: A study of specific interactions
    (Elsevier, 2018) Santos, Dheiver; Bamufleh, Hisham S.; Uslu, Hasan
    Descriptions of the assets of combinations of ionic liquids and polar compounds are very important for engineering projects. In this study, the modeling of binary systems involving different cations and anions was performed to observe the structural influence and the level of interaction with water and alcohol. The Prigogine-Flory-Patterson equation of state makes possible the evaluation of the level of interaction of the mixture through the Flory interaction contribution. The contribution through the characteristic pressure was shown to be of little relevance compared to the contributions of free volume and characteristic pressure. The binary mixtures, for the most part, showed a negative value, which demonstrates the strong interactions between ionic liquids and the studied compounds. (C) 2018 Elsevier B.V. All rights reserved.
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    Separation of 2,4,6-trinitrophenol from aqueous solution by liquid-liquid extraction method: Equilibrium, kinetics, thermodynamics and molecular dynamic simulation
    (Elsevier Science Sa, 2016) Uslu, Hasan; Datta, Dipaloy; Santos, Dheiver; Bamufleh, Hisham S.; Bayat, Cuma
    In this paper, the equilibrium and kinetic studies on the extraction of 2,4,6-trinitrophenol (picric acid) (0.021-0.061 kmol m(-3)) using Amberlite LA2, a secondary amine (ALA2: 0.118-0.588 kmol m(-3)) dissolved in a polar active solvent, methyl-iso-butyl ketone (MIBK) are performed. Also, the temperature effect (293.2 +/- 1 K, 303.2 +/- 1 K and 313.2 +/- 1 K) on the extraction mechanism and efficiency is evaluated. Thermodynamic parameters like the change in entropy and enthalpy are determined. From the values of loading ratio (Z < 0.5), it is inferred that the amine molecule form 1:1 complex with the acid molecule in the organic phase. The mass transfer coefficient (k(L), = 3.1 x 10(-5) m s(-1)) of picric acid in MIBK is determined. The Hatta number is calculated, and observed to vary in the range of 0.0032-0.0054, indicating that there is a very slow chemical reaction taking place between the acid and the amine molecule in the bulk of the organic phase. The reaction order is estimated to be 0.9 w.r.t picric acid, and 0.6 w.r.t ALA2 with rate constants of 14.95 x 10(-6) (kmol m(-3))(-0.5) s(-1), and 8.94 x 10(-7) (kmol m(-3))(-0.5) s(-1), for forward and backward reaction, respectively. Kinetic and potential energies of components during reactive extraction have been determined by molecular dynamic modeling. (C) 2016 Elsevier B.V. All rights reserved.
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    Separation of copper ion (Cu2+) from aqueous solution using tri n butyl phosphate and di 2 ethylhexyl phosphoric acid as extractants
    (Elsevier Science Bv, 2018) Ghosh, Amritendu; Datta, Dipaloy; Uslu, Hasan; Bamufleh, Hisham S.; Kumar, Sushil
    In this study, separation of copper ion (Cu2+) from aqueous solution using two phosphorous based extractants (tri n butyl phosphate and di 2 ethylhexyl phosphoric acid) was aimed. The parameters monitored under the equilibrium study were initial copper concentration, extractant concentration, and pH. The copper concentration was taken in the range of 20 to 100 ppm, the extractant composition in the organic phase was varied from 10 to 40 vol% dissolving in toluene as an inactive diluent, and the pH effect was studied in the range of 1 to 11. The distribution coefficients were calculated, and a model equation was developed to estimate model parameters like the number of reacting molecules of the extractant and equilibrium constant using experimental results. In the kinetic study, the initial aqueous phase copper concentration, and the extractant concentration were changed, and initial rates of extraction were found out to develop a kinetic model and their parameters like rate constant and order of reaction. (C) 2018 Elsevier B.V. All rights reserved.
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    Separation of Levulinic Acid Using Polymeric Resin, Amberlite IRA-67
    (Amer Chemical Soc, 2019) Uslu, Hasan; Datta, Dipaloy; Santos, Dheiver; Öztürk, Muhsin
    The adsorptive separation of levulinic acid (LA) from its aqueous solution was studied by using a commercial adsorbent and weakly basic anion exchange resin, Amberlite IRA-67 (IRA-67). The data were generated for equilibrium and kinetic studies, and to analyze the performance of IRA-67 on the removal efficiency. The equilibrium study was performed to see the effect of adsorbent quantity (0.25-1.5 g) and initial LA concentrations (2-4 g.L-1) at three different temperatures (298, 308, and 318 K). To determine the kinetics of adsorption process, concentration profile was achieved up to a time of 90 min at 298 K. It was observed that both the intake capacity (32-64 mg.g(-1)) and removal efficiency (6.75-72.5%) of IRA-67 were increased with an increase in the quantity of adsorbent (0.25-1.5 g) at 298 K. From the kinetics of adsorption, 50 min was considered as an equilibrium time. Different isotherm and kinetic models were used to determine the equilibrium and kinetic parameters of LA adsorption process. From the temperature study (298, 308, and 318 K), the thermodynamic properties were also estimated at three different LA concentrations.
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    Solvent Polarity Effect when Amberlite-LA2 Is Used in the Extraction of Picric Acid
    (Amer Chemical Soc, 2017) Uslu, Hasan; Datta, Dipaloy; Bamufleh, Hisham S.
    The separation and recovery of picric acid (0.061 mol-kg(-1)) from its aqueous solution was studied at a fixed temperature of 298 K. The extraction experiments were performed by using a secondary amine, Amberlite-LA2 (ALA2), dissolved in five different solvents such as dichloromethane (DCM), dodecanol, toluene, benzene, and dodecane. Physical extraction data were also produced by pure solvent alone. The experimental data obtained from the batch studies were analyzed by calculating the distribution coefficient (K-D), extraction efficiency (%E), and loading factor (Z). The highest synergistic effect was achieved with DCM in ALA2 at a concentration of 0.588 mol.kg(-1) as 83.61%. The equilibrium constants for the complex formation between acid and amine (1:1 and 2:1) were calculated for all the solvents applying the mass action law.
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    Strategy for extractant residual reduction: Experimental and computational investigation of fluorinated phosphate
    (Elsevier Science Bv, 2017) Wu, Xue; Chang, Zhidong; Blamo, Benjamin John; Yuan, Junchao; Uslu, Hasan; Li, Wenjun; Ryong, Choe Chol
    Extractant residual in water phase is a destined and disgusted consequence after solvent extraction operation. In order to reduce extractant residual in aqueous phase, extractants modified by fluorination were probed. In this paper, tri-n-amylphosphate (TAP) was selected as model extractant along with its fluorinated analogue, tris (2,2,3,3,4,4,5,5-octafluoropentyl) phosphate (FTAP), to extract the salicylic acid from its aqueous solution to investigate residual and extraction behaviors by both experimental and computational methods. The experimental results obtained from multiple light scattering revealed that FTAP barely interacted with water and possessed high hydrophobicity. The solubility of FTAP in aqueous phase was less than 6.0 x 10(-5) (w/w), and declined with increase of temperature, which was similar to the nature of nonionic surfactant. In acid solution with high concentration, the solubility of FTAP remained quite low. The one-step extraction efficiency of FTAP on salicylic acid was approximately 85%. The cycling experimental results showed that the durability of FTAP was overwhelmingly excellent compared with that of TAP, especially after the cycles more than 10 times. DFT calculation demonstrated the hydrophobicity and extraction behavior at molecular level. All results implied that fluorinated modification of extractant was a possible way to reduce its loss in aqueous phase. (C) 2017 Elsevier B.V. All rights reserved.
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    Synergistic effect of fluorinated hexane as diluent of fluorinated octanol for salicylic acid extraction
    (Elsevier Science Inc, 2018) Wu, Xue; Chang, Zhidong; Yuan, Junchao; Feng, Jingge; Uslu, Hasan; Li, Wenjun
    In order to get optimal extraction performance as well as ultra-low solvent residual, three fluorinated hexane, perfluorohexane (C6F14), 1H-perfluorohexane (C6F13H) and 1H,6H-perfluorohexane (C6F12H2), were evaluated as diluents for synergistic effect on extraction capability of 1H,1H,2H,2H-Perfluorooctan-1-ol by the way of experimental and computational investigation. Based on extraction experiments, C6F14 showed obvious antagonistic effect because of hydrophobic nature, while the synergistic effect of C6F12H2 was better than that of C6F13H. According to DFT calculation, supported by FT-IR and H-1 NMR spectra, the synergistic effect was illustrated as that fluorinated hexane could interact with salicylic acid-fluorinated octanol complex through hydrogen bond. (C) 2017 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
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    Zn2+ Ion Adsorption from Aqueous Solution Using Montmorillonite Clay Impregnated with Tri-n-octylamine
    (Amer Chemical Soc, 2017) Uslu, Hasan; Datta, Dipaloy; Bamufleh, Hisham S.
    Montmorillonite (Mt) clay was used to remove zinc (Zn2+) ion from the aqueous solution. This clay material was modified (Mt-TOA) by impregnating trin-octylamine (TOA), a tertiary amine. The experiments on equilibrium and kinetics were done to analyze the effect of adsorbent amount (w, 0.05 to 0.3 g for Mt, 0.01 to 0.06 g for Mt-TOA), initial Zn2+ ion concentration (C-0, 15 mg.L-1 to 35 mg.L-1), pH (1 to 9), and contact time (t, 0 to 100 min) on the efficacy of both adsorbents. With a greater amount of adsorbent, the intake capacity of Mt and Mt-TOA for Zn2+ ion removal was found to lower but there was an increase in the separation efficiency. The optimum amount of Mt and Mt-TOA was found to be 0.1 and 0.01 g, respectively. The pH of the aqueous solution could be maintained at 7 to achieve a better adsorption of Zn2+ ion. In the kinetic experiments, after 90 min, the separation efficiency of Zn2+ ion from aqueous solution reached to a value of 86.68% with Mt (0.1 g) and 84.56% with Mt-TOA (0.01 g). Modeling of the equilibrium and kinetic data were done by using the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich, and by using the pseudo-first-order, pseudo-second-order, and intraparticle diffusion models, respectively, and the best fitted model is presented.