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Adsorption and interactions of the bovine serum albumin-double walled carbon nanotube system

Kopac T. | Bozgeyik K. | Flahaut E.

Article | 2018 | Journal of Molecular Liquids252 , pp.1 - 8

Adsorption and interactions of Bovine Serum Albumin (BSA) with Double Walled Carbon Nanotubes (DWNT) prepared by catalytic chemical vapor deposition (CCVD) synthesis were studied. Adsorption kinetics and equilibrium were investigated by means of in situ UV-spectroscopy. The extent of adsorption at different temperatures was determined at the end of a 420-min adsorption period. The adsorption equilibrium experiments were performed using various amounts of nanotubes at pH 4 and 40 °C, and the adsorption parameters were evaluated comparing the experimental data with models such as the Freundlich and Langmuir isotherms. The maximum prot . . .ein adsorption capacity (Q0) of DWNT was determined as 1221 mg·g- 1. The effect of temperature on the adsorption rate experiments was investigated for constant amount of adsorbent at pH 4. Adsorption kinetics followed the pseudo-first-order rate. Zeta potential measurements were performed with respect to solution pH for understanding the protein-surface interactions. The interactions between positively charged BSA molecules with negatively charged DWNT at pH 4 were found to be electrostatic attractions. Thermodynamic parameters, ?H0 and ?S0 were found as 9.40 kJ·mol- 1 and 321.5 J·mol- 1 K- 1, respectively. ?H0 value indicated that BSA adsorption on DWNT was a physisorption process. © 2017 Elsevier B.V Daha fazlası Daha az

Equilibrium, Kinetics, and Thermodynamics of Bovine Serum Albumin Adsorption on Single-Walled Carbon Nanotubes

Kopac T. | Bozgeyik K.

Article | 2016 | Chemical Engineering Communications203 ( 9 ) , pp.1198 - 1206

We investigated the equilibrium, kinetics, and thermodynamics of bovine serum albumin (BSA) adsorption on single-walled carbon nanotubes (SWNTs) from aqueous solutions with different pH and temperatures. We analyzed the experimental adsorption equilibrium and kinetic data to evaluate the adsorption characteristics of SWNTs for BSA. The results show that the effects of pH and temperature were important. Moreover, the adsorption isotherm data of BSA on SWNTs are consistent with the Langmuir and Freundlich models, while the kinetics can be expressed by the pseudo-first-order and the intraparticle diffusion rate models. The maximum prot . . .ein adsorption capacity of SWNTs, which have a surface area of 191.2 m2/g, was found to be 609.8 mg g-1 at pH 4 and 40°C, and this was the highest value obtained among our previous studies examined with various metal oxides. In addition, the zeta potential measurements were examined to understand the effects of charge density of the surface and the protein on the adsorption process. Thermodynamic analysis results indicate that the nature of adsorption changes with pH. SWNTs were found to be effective for BSA adsorption. © 2016, Copyright © Taylor & Francis Group, LLC Daha fazlası Daha az

Synthesis of multi-walled carbon nanotube-zirconia composite and bovine serum albumin adsorption characteristics

Bozgeyik K. | Kopac T.

Conference Object | 2017 | Materials Science Forum900 MSF , pp.27 - 31

Multi-walled carbon nanotube-zirconia composite (MWNT-ZrO2) was synthesized by a simple in situ chemical precipitation method. Adsorption of bovine serum albumin (BSA) from aqueous solution on the MWNT-ZrO2 composite was studied using batch technique at different pH and temperatures. The adsorption equilibrium and kinetic data were analzed using different models. The adsorption isotherm data could be described by both of the Langmuir and Freundlich adsorption models. Adsorption kinetics followed the pseudo-first-order rate model. MWNT loading improved the surface and the BSA adsorptive characteristics of zirconia. © 2017 Trans Tech . . .Publications, Switzerland Daha fazlası Daha az

Effect of pH and temperature on the adsorption of bovine serum albumin onto titanium dioxide

Kopac T. | Bozgeyik K. | Yener J.

Article | 2008 | Colloids and Surfaces A: Physicochemical and Engineering Aspects322 ( 01.Mar ) , pp.19 - 28

The effects of pH and temperature on the equilibrium and the kinetics of bovine serum albumin (BSA) adsorption onto titanium dioxide (TiO2) were investigated. Adsorption rate and equilibrium experiments were carried out at pH conditions of 4, 5, 10 and in a temperature range of 20-40 °C. Adsorption rate was increased with decreasing pH and increasing temperature. The Langmuir isotherm constants corresponding to adsorption capacity, Q0, were 35.8, 40.0 and 42.6 mg/g for 20, 30 and 40 °C and pH 4; and 24.5, 29.1 and 33.4 mg/g for 20, 30, 40 °C and pH 5, respectively. The BSA adsorption capacities of TiO2 were higher for pH 4 at 40 °C. . . . Adsorption of BSA on TiO2 at different pH and temperatures was found to be first order kinetics. At pH 4, k1 has values of 0.018 and 0.019 min-1 at 20 and 40 °C, respectively. For pH 5, k1 is 0.013 min-1 at 20 °C and 0.019 min-1 at 40 °C. The first order rate constants are higher at pH 4 than the values at pH 5. Higher values of the adsorption rate constants at pH 4, could be due to the change of pore structure of TiO2 or denaturation by conformational change of BSA with increasing pH. © 2008 Elsevier B.V. All rights reserved Daha fazlası Daha az

Effect of surface area enhancement on the adsorption of bovine serum albumin onto titanium dioxide

Kopac T. | Bozgeyik K.

Article | 2010 | Colloids and Surfaces B: Biointerfaces76 ( 1 ) , pp.265 - 271

The equilibrium and the kinetics of BSA adsorption onto specific surface area changed TiO2 by heat treatment were studied. The TiO2 was treated at 100 and 200 °C for 24 h. The specific surface areas of TiO2 characterized by BET method were measured as 48.9 m2/g and 53.0 m2/g for 100 and 200 °C, respectively. The adsorption rate and the equilibrium experiments were carried out at pH 4 for 40 °C. The rate kinetics for the adsorption of BSA was best fitted with the pseudo-first-order kinetic model. The equilibrium process was described by the Langmuir and Freundlich isotherm models. The adsorption capacities (Q0) calculated from the La . . .ngmuir isotherm model were 40.6 and 44.4 mg/g for heat-treated TiO2 at 100 and 200 °C, respectively. The adsorption of BSA increased with increasing surface area of TiO2. The zeta potential values of the 100- and 200 °C-treated TiO2 were found as -2.57 mV and 0.39 mV, respectively, showing that the interaction between TiO2 with BSA increased with increasing temperature of heat treatment for TiO2. © 2009 Elsevier B.V. All rights reserved Daha fazlası Daha az

Adsorption Properties of Arc Produced Multi Walled Carbon Nanotubes for Bovine Serum Albumin

Bozgeyik K. | Kopac T.

Article | 2016 | International Journal of Chemical Reactor Engineering14 ( 2 ) , pp.549 - 558

In this study, adsorption properties of arc produced Multi Walled Carbon Nanotubes (MWNT) were investigated for Bovine Serum Albumin (BSA) in aqueous phase. Solution pH, adsorbent amount and temperature effects were examined on protein adsorption. The results show that, the temperature and the adsorbent amount both increase the BSA adsorption, whereas the solution pH has a decreasing effect. The equilibrium behavior of protein adsorption was examined by Langmuir and Freundlich isotherms. The monolayer adsorption capacities at 40°C for solution pH 4 and 5 were determined as 139.5 and 127.2mgg-1, respectively, which were much higher t . . .han the BSA adsorption capacities of various metal oxides investigated in our previous studies. The adsorption rate data were compared by the pseudo-first and the second-order kinetics equations. Evaluation of the experimental kinetics data have shown that the adsorption of BSA by MWNT followed the pseudo-first-order kinetics. The pseudo-first order adsorption rate constants at pH 4 and 5 decreased with an increase in temperature which results in a decrease in diffusion rate of BSA molecules across the external boundary layer, and favors the sorption process. The adsorption behavior of protein by carbon nanotubes was explained also using the zeta potential measurements. The adsorption capacity decreased with increasing pH due to the electrostatic repulsions. The thermodynamic parameters evaluated to predict the nature of adsorption confirmed the non-spontaneous and endothermic behaviour of the BSA/MWNT adsorption process. Adsorption standard enthalpy values were found as ?H0=59.5kJmol-1 and ?H0=14.3kJmol-1 for pH 4 and 5, respectively indicating that the protein molecules are adsorbed electrostatically on the carbon nanotubes. © 2016 by De Gruyter Daha fazlası Daha az

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