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Langmuir adsorption model
About: Langmuir adsorption model is a research topic. Over the lifetime, 24487 publications have been published within this topic receiving 794076 citations. The topic is also known as: Langmuir isotherm.
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TL;DR: Analysis of sorption data using a Boyd plot confirms that external mass transfer is the rate limiting step in the sorption process.
1,455 citations
TL;DR: In this paper, the adsorption of Congo Red by coir pith carbon was carried out by varying the parameters such as agitation time, dye concentration, adsorbent dose, pH and temperature.
1,357 citations
TL;DR: Results indicated that ligand exchange between carboxyl/hydroxyl functional groups of NOM and iron oxide surfaces was the dominant interaction mechanism, especially under acidic or slightly acidic pH conditions.
Abstract: This study was undertaken to elucidate the interaction mechanism between NOM (natural organic matter) and iron oxide surfaces and to develop a predictive model for NOM adsorption and desorption. Results indicated that ligand exchange between carboxyl/hydroxyl functional groups of NOM and iron oxide surfaces was the dominant interaction mechanism, especially under acidic or slightly acidic pH conditions. This conclusion was supported by the measurements of heat of adsorption (microcalorimetry), FTIR and [sup 18]C NMR analysis, and competitive adsorption between NOM and some specifically adsorbed anions. A modified Langmuir model was proposed in which a surface excess-dependent affinity parameter was defined to account for a decreasing adsorption affinity with surface coverage due to the heterogeneity of NOM and adsorbent surfaces. With three adjustable parameters, the model is capable of describing a variety of adsorption isotherms. A hysteresis coefficient, h, was used to describe the hysteretic effect of adsorption reactions that, at h = 0, the reaction is completely reversible, whereas at h = 1, the reaction is completely irreversible. Fitted values of h for NOM desorption on iron oxide surfaces ranged from 0.72 to 0.92, suggesting that the adsorbed NOM was very difficult to be desorbed at a given pH andmore » ionic composition. 54 refs., 8 figs., 3 tabs.« less
1,340 citations
Book•
08 Mar 1996
TL;DR: The Structure of Solid Surfaces and Adsorbate Overlayers as discussed by the authors, the Binding of Molecules to Surfaces, and the Kinetics of Adsorption are discussed.
Abstract: The Structure of Solid Surfaces and Adsorbate Overlayers. Adsorption I: The Binding of Molecules to Surfaces. Adsorption II: Adsorption Isotherms. Adsorption III: Kinetics of Adsorption. Introduction to Surface Reactions. Rate Laws for Reactions on Surfaces I: Kinetic Models. A Review of Reaction--Rate Theory. Models of Potential Energy Surfaces: Reactions as Curve Crossings and Electron Transfer Processes. Rates and Mechanisms of Surface Reactions. Index.
1,264 citations
15 Feb 2012
TL;DR: Graphene oxide is a potential effective absorbent for tetracycline antibiotics and can be used to remove them from aqueous solution and has a better rate constant of sorption, 0.065 g mg(-1) h(-1), than other adsorbents.
Abstract: Significant concerns have been raised over pollution of antibiotics including tetracyclines in aquatic environments in recent years. Graphene oxide (GO) is a potential effective absorbent for tetracycline antibiotics and can be used to remove them from aqueous solution. Tetracycline strongly deposited on the GO surface via π-π interaction and cation-π bonding. The adsorption isotherm fits Langmuir and Temkin models well, and the theoretical maximum of adsorption capacity calculated by Langmuir model is 313 mg g(-1), which is approximately in a close agreement with the measured data. The kinetics of adsorption fits pseudo-second-order model perfectly, and it has a better rate constant of sorption (k), 0.065 g mg(-1) h(-1), than other adsorbents. The adsorption capacities of tetracycline on GO decreased with the increase in pH or Na(+) concentration. The adsorption isotherms of oxytetracycline and doxycycline on GO were discussed and compared.
1,164 citations