Influence of Ionic Strength and Temperature on the Adsorption of Reactive Black 5 Dye by Activated Carbon: Kinetics, Mechanisms and Thermodynamics

The aim of this work was to investigate the influence of ionic strength and temperature on the adsorption of Reactive Black 5 dye on commercial powdered activated carbon. Adsorption experiments were performed at 45 °C with the addition of NaCl (<i>c</i><sub>0</sub> = 0.01, 0....

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Main Authors: Mario Cetina, Petra Mihovilović, Ana Pešić, Branka Vojnović
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/30/12/2593
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author Mario Cetina
Petra Mihovilović
Ana Pešić
Branka Vojnović
author_facet Mario Cetina
Petra Mihovilović
Ana Pešić
Branka Vojnović
author_sort Mario Cetina
collection DOAJ
description The aim of this work was to investigate the influence of ionic strength and temperature on the adsorption of Reactive Black 5 dye on commercial powdered activated carbon. Adsorption experiments were performed at 45 °C with the addition of NaCl (<i>c</i><sub>0</sub> = 0.01, 0.05, 0.10 and 1.00 M) and Na<sub>2</sub>SO<sub>4</sub> (<i>c</i><sub>0</sub> = 0.01 M). The results were compared with those obtained for both salts (<i>c</i><sub>0</sub> = 0.01 M) at three additional temperatures: 25, 35 and 55 °C. For all adsorption experiments, kinetic and thermodynamic studies were performed. This research showed that the addition of NaCl, even in the concentration of only <i>c</i><sub>0</sub> = 0.01 M, significantly enhanced dye adsorption and that higher NaCl concentration resulted in higher adsorption capacity. In addition, slightly higher adsorption was observed when Na<sub>2</sub>SO<sub>4</sub> was added to the dye solution at the same concentration as NaCl, as well as at a higher temperature, regardless of the salt added to the dye solution. It was also shown that adsorption is kinetically controlled, assuming a pseudo-second-order model, and that intraparticle diffusion is not the only process that influences the adsorption rate. Finally, calculated thermodynamic parameter values for both salts (<i>c</i><sub>0</sub> = 0.01 M) indicate that adsorption was a spontaneous endothermic process.
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spelling doaj-art-b5ca77afb7b741868f9bbd7f086efdde2025-08-20T03:16:21ZengMDPI AGMolecules1420-30492025-06-013012259310.3390/molecules30122593Influence of Ionic Strength and Temperature on the Adsorption of Reactive Black 5 Dye by Activated Carbon: Kinetics, Mechanisms and ThermodynamicsMario Cetina0Petra Mihovilović1Ana Pešić2Branka Vojnović3Department of Applied Chemistry, Faculty of Textile Technology, University of Zagreb, Prilaz Baruna Filipovića 28a, HR-10000 Zagreb, CroatiaDepartment of Applied Chemistry, Faculty of Textile Technology, University of Zagreb, Prilaz Baruna Filipovića 28a, HR-10000 Zagreb, CroatiaDepartment of Applied Chemistry, Faculty of Textile Technology, University of Zagreb, Prilaz Baruna Filipovića 28a, HR-10000 Zagreb, CroatiaDepartment of Applied Chemistry, Faculty of Textile Technology, University of Zagreb, Prilaz Baruna Filipovića 28a, HR-10000 Zagreb, CroatiaThe aim of this work was to investigate the influence of ionic strength and temperature on the adsorption of Reactive Black 5 dye on commercial powdered activated carbon. Adsorption experiments were performed at 45 °C with the addition of NaCl (<i>c</i><sub>0</sub> = 0.01, 0.05, 0.10 and 1.00 M) and Na<sub>2</sub>SO<sub>4</sub> (<i>c</i><sub>0</sub> = 0.01 M). The results were compared with those obtained for both salts (<i>c</i><sub>0</sub> = 0.01 M) at three additional temperatures: 25, 35 and 55 °C. For all adsorption experiments, kinetic and thermodynamic studies were performed. This research showed that the addition of NaCl, even in the concentration of only <i>c</i><sub>0</sub> = 0.01 M, significantly enhanced dye adsorption and that higher NaCl concentration resulted in higher adsorption capacity. In addition, slightly higher adsorption was observed when Na<sub>2</sub>SO<sub>4</sub> was added to the dye solution at the same concentration as NaCl, as well as at a higher temperature, regardless of the salt added to the dye solution. It was also shown that adsorption is kinetically controlled, assuming a pseudo-second-order model, and that intraparticle diffusion is not the only process that influences the adsorption rate. Finally, calculated thermodynamic parameter values for both salts (<i>c</i><sub>0</sub> = 0.01 M) indicate that adsorption was a spontaneous endothermic process.https://www.mdpi.com/1420-3049/30/12/2593isothermal adsorptionactivated carbonReactive Black 5ionic strengthkineticsthermodynamics
spellingShingle Mario Cetina
Petra Mihovilović
Ana Pešić
Branka Vojnović
Influence of Ionic Strength and Temperature on the Adsorption of Reactive Black 5 Dye by Activated Carbon: Kinetics, Mechanisms and Thermodynamics
Molecules
isothermal adsorption
activated carbon
Reactive Black 5
ionic strength
kinetics
thermodynamics
title Influence of Ionic Strength and Temperature on the Adsorption of Reactive Black 5 Dye by Activated Carbon: Kinetics, Mechanisms and Thermodynamics
title_full Influence of Ionic Strength and Temperature on the Adsorption of Reactive Black 5 Dye by Activated Carbon: Kinetics, Mechanisms and Thermodynamics
title_fullStr Influence of Ionic Strength and Temperature on the Adsorption of Reactive Black 5 Dye by Activated Carbon: Kinetics, Mechanisms and Thermodynamics
title_full_unstemmed Influence of Ionic Strength and Temperature on the Adsorption of Reactive Black 5 Dye by Activated Carbon: Kinetics, Mechanisms and Thermodynamics
title_short Influence of Ionic Strength and Temperature on the Adsorption of Reactive Black 5 Dye by Activated Carbon: Kinetics, Mechanisms and Thermodynamics
title_sort influence of ionic strength and temperature on the adsorption of reactive black 5 dye by activated carbon kinetics mechanisms and thermodynamics
topic isothermal adsorption
activated carbon
Reactive Black 5
ionic strength
kinetics
thermodynamics
url https://www.mdpi.com/1420-3049/30/12/2593
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AT petramihovilovic influenceofionicstrengthandtemperatureontheadsorptionofreactiveblack5dyebyactivatedcarbonkineticsmechanismsandthermodynamics
AT anapesic influenceofionicstrengthandtemperatureontheadsorptionofreactiveblack5dyebyactivatedcarbonkineticsmechanismsandthermodynamics
AT brankavojnovic influenceofionicstrengthandtemperatureontheadsorptionofreactiveblack5dyebyactivatedcarbonkineticsmechanismsandthermodynamics