Azo dye adsorption on anthracite: A view of thermodynamics, kinetics and cosmotropic effects

Mattos, Nathalia Ribeiro de; Oliveira, Cassiano Rodrigues de; Camargo, Luis Gustavo Brogliato; Lavall, Rodrigo L.

doi:10.1016/j.seppur.2018.09.027

Cited by 36 publications

(11 citation statements)

References 56 publications

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“…Different types of adsorbents can be used to remove contaminants, such as activated charcoal [16][17][18][19], polymeric [20][21][22][23], and biological materials [24][25][26][27][28]. These adsorbents have a high capacity for removing dyes, but their high cost and low capacity for reuse restrict their use [29]. Therefore, the search for low-cost adsorbents, such as clay minerals, has been extensively studied [30].…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Anionic Dye on the Acid-Functionalized Bentonite

et al. 2020

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The efficiency of acid treatment on natural calcium bentonite (natural bentonite) for anionic dye adsorption was investigated using methyl orange (MO) as a probe. Additionally, adsorption experiments were accomplished between the natural bentonite, acidified bentonite, and a cationic dye (methylene blue, MB). Acid functionalization in natural bentonite (RF) was carried out with HCl and H2SO4 acids (RF1 and RF2, respectively). The samples were characterized by chemical analysis, mineralogy, particle size, and thermal behavior with the associated mass losses. The adsorption efficiency of MO and MB dyes was investigated by the effects of the initial concentration of adsorbate (Ci) and the contact time (tc). The acid treatment was efficient for increasing the adsorption capacity of the anionic dye, and the Qmaxexp values measured were 2.2 mg/g, 67.4 mg/g e 47.8 mg/g to RF, RF1 e RF2, respectively. On the other hand, the acid functionalization of bentonite did not significantly modify the MB dye adsorption. The Sips equation was the best fit for the adsorption isotherms. Thus, we found that the acid-functionalized bentonite increases the anionic dye adsorption by up to 8000%. The increased adsorptive capacity of acidified bentonite was explained in terms of electrostatic attraction between the clay surface and the dye molecule.

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Section: Introductionmentioning

confidence: 99%

Adsorption of Anionic Dye on the Acid-Functionalized Bentonite

et al. 2020

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“…Thermodynamic studies of the adsorption process need to be carried out to confirm whether the process can occur spontaneously (De Mattos et al 2019). The change in the Gibbs free energy, ΔG, is an indication of the process spontaneity, 20,50,100,200,300,400, 500 mg/L 0.022 90.9 0.978 11.06 2.94 0.992…”

Section: Adsorption Thermodynamicsmentioning

confidence: 99%

Mechanistic insights into the adsorption of methylene blue by particulate durian peel waste in water

Sudrajat

Susanti

Putri

et al. 2021

Water Science and Technology

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This study aims to investigate the adsorption of methylene blue (MB) over particulate durian peel waste, which is chemically-activated with hydrogen peroxide. The equilibrium data is well-described by the Freundlich isotherm model, which outlines where the MB adsorption takes place predominantly on multilayers and heterogeneous surfaces of the biosorbent. The Freundlich adsorption constants, KF and n, are 11.06 L/g and 2.94, respectively. Thermodynamic data suggests that the MB adsorption occurs spontaneously and exothermically. The enthalpy and entropy for the MB adsorption are obtained as 10.26 kJ/mol and 0.058 kJ/mol K, respectively, in the temperature range of 303–323 K. Based on the stepwise desorption method, the adsorption of MB is dominated by physical interactions, particularly hydrogen bonding.

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“…Matching of experimentally observed adsorption capacity with that calculated from kinetic models is judged from the value of linear regression coefficient represented by R 2 . The pseudo first-order model can be expressed as [21]: The pseudo second-order kinetic model considers the chemical reaction important for controlling the rate of the reaction [22]. The empirical equation for this model is:…”

Section: Study Of Adsorption Kineticsmentioning

confidence: 99%

Modified Clays as an Efficient Adsorbent for Brilliant Green, Ethyl Violet and Allura Red Dyes: Kinetic and Thermodynamic Studies

Ullah¹,

Iftikhar²,

Ajmal³

et al. 2020

Pol. J. Environ. Stud.

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Clay minerals can effectively adsorb contaminants from aqueous effluents due to their good adsorption and high cation exchange capacity. However, naturally occurring clay materials possessing hydrophilic features are not especially effective for the removal of organic pollutants. Therefore, in the present work the issue of hydrophilicity is tackled by modification of the clay (Pakistan origin) to prepare organoclays. Hexadecylpyridinium chloride, cetyltrimethylammonium bromide, and sodium dodecyl sulfate were used as clay modifiers. Changes in the basal spacing of clay layers after modification with surfactants were determined through XRD analysis. Chemical compositions of the clay and organoclays were determined by FTIR spectroscopy. Surface morphology of the as-prepared organoclays was assessed from SEM analysis. The modified clays (organoclays) were tested for their ability as potential adsorbents for three dyes from water: brilliant green, ethyl violet and allura red. All three modified clays showed high adsorption characteristics by removing (>90 %) of all three dyes with an adsorption capacity ranging from 35 to 85 mg/g. The time-dependent adsorption experiments showed that the rates of adsorption of dyes on organoclays were fast, adsorbing maximum amounts of dyes ranging from 15 to 80 mins of contact time. The adsorption kinetic study revealed that the dye removal process is mainly governed by a pseudo-1 st order mechanism. Thus, surfactant-modified clays are an excellent choice as cost-effective and efficient adsorbents for the purification of water from dye contaminants.

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Azo dye adsorption on anthracite: A view of thermodynamics, kinetics and cosmotropic effects

Cited by 36 publications

References 56 publications

Adsorption of Anionic Dye on the Acid-Functionalized Bentonite

Adsorption of Anionic Dye on the Acid-Functionalized Bentonite

Mechanistic insights into the adsorption of methylene blue by particulate durian peel waste in water

Modified Clays as an Efficient Adsorbent for Brilliant Green, Ethyl Violet and Allura Red Dyes: Kinetic and Thermodynamic Studies

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