Theoretical Foundations of Solute Adsorption from Dilute Solutions on Solids

Deryło, A.; Jaroniec, Mietek

doi:10.1016/s0166-1116(08)71237-8

Cited by 4 publications

(2 citation statements)

References 24 publications

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“…Adsorption from binary liquid mixtures onto solids is often described using surface-excess-type isotherms, which are useful in describing energetically heterogeneous surfaces such as activated carbons but typically lack the concept of an adsorption site, as in the BET or Langmuir-type models for gas-phase adsorption . For a single solute near the infinite dilution limit, however, the isotherm equations are identical to those used for the adsorption of single gases, with the adsorbate activity equal to the reduced pressure relative to the saturation vapor pressure or reduced concentration relative to the concentration at saturation. These isotherms have been used to describe adsorption from dilute aqueous solutions in many cases; − for example, Jaroniec, Dabrowski, and Toth modeled the adsorption of n -amyl alcohol and other organic solutes onto carbon with BET-type equations, and Radke and Prausnitz used a Langmuir–Freundlich model to describe the adsorption of isopropanol and other solutes from water onto activated carbon.…”

Section: Resultsmentioning

confidence: 99%

Adsorption of n-Butanol from Dilute Aqueous Solution with Grafted Calixarenes

et al. 2011

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INTRODUCTIONFermentation-derived butanol is a potential renewable fuel that has several advantages over other biofuels, including a higher energy density than ethanol and better solubility with current hydrocarbon fuels because of its relative nonpolarity. However, the recovery of the product from ABE fermentation broths is complicated by the low concentrations inherently yielded by the fermentation process because of the cytotoxicity of Clostridium acetobutylicum strains. 1 Because the normal boiling point of butanol is higher than that of water, the traditional recovery method of distillation requires high energy inputs from water boilup and is further complicated by a heterogeneous azeotrope at 365 K. 2 Overall, the energy demand is of comparable magnitude to the energy content of the product itself. 3 Common alternatives to distillation include pervaporation, liquidÀliquid extraction, osmosis, and adsorption-based techniques. 1 Butanol recovery by adsorption is predicted to have an average energy demand that is ∼10% of the heat of combustion of butanol and is easily implemented. 1 Common adsorbents typically investigated are activated carbons, 3 zeolites, 4 and polymers. 5 These adsorbents are generally inexpensive and have good capacity but are limited in their ability to be modified systematically on the molecular length scale. The alternative approach pursued here is to synthesize solid materials modified with organic groups that act as adsorption sites. Cavitands (intrinsically microporous organic molecules such as calixarenes and cyclodextrins) immobilized on solid supports make up one subclass of such materials that has been used in sensing, chromatography, and the separation of contaminants from wastewater 6À12 but remains relatively unexplored in the context of biofuel separations. Advantages to this approach of materials design are that (i) the structure and number of adsorption sites are, in principle, known a priori and tunable, (ii) understanding the adsorption behavior of the hybrid material is aided by solution and solid-state cavitand/ guest complexation, and (iii) sites can be optimized for adsorption strength or selectivity independent of the optimization of the support for robustness and surface area.Herein is presented the synthesis, characterization, and analysis of a class of adsorbents consisting of hydroxycalixarenes immobilized directly onto chlorinated silica surfaces. 7 Although calixarene-based adsorbents or separation media are known, the materials described here are distinguished by the lack of a flexible organic tether or polymer chain typically employed to attach the calixarene to the surface. 13 These directly attached calixarenes ABSTRACT: Materials were synthesized for the recovery of nbutanol from dilute aqueous solutions, as may be useful for applications in biofuelÀwater separations. These materials are composed of hydrophobic, cavity-containing calixarenes covalently bound directly to porous, hydrophilic silica supports through a Si linker atom rather than a flexible orga...

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Section: Resultsmentioning

confidence: 99%

Adsorption of n-Butanol from Dilute Aqueous Solution with Grafted Calixarenes

et al. 2011

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“…C eq is the solute concentration at equilibrium (mg/l) and Q eq is the adsorption capacity at equilibrium (mg/g). These are empirical parameters: when 0.1<Q eq <1.0, easy adsorption is observed, and when >2, the adsorption occurs with difficulty (Carter et al, 1995;Derylo et al, 1984).…”

Section: Chemical Composition Analysis Of Steel Slagmentioning

confidence: 99%

Steel slag as low-cost adsorbent for the removal of phenanthrene and naphthalene

Yang

Qian

Wang

et al. 2018

Adsorption Science & Technology

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This study investigates the removal effectiveness and characteristics of phenanthrene and naphthalene using low-cost steel slag with batch experiments. The adsorption characteristics of steel slag were measured and analysed using X-ray fluorescence, X-ray diffraction, and Fourier transform infrared spectroscopy. The batch experiments investigated the effect of the time gradient, pH, and steel slag dosage gradient on the adsorption of the steel slag. The results show that with time and dosage of steel slag increased, the adsorption capacity of phenanthrene and naphthalene increased and gradually became balanced, but pH had no obvious effect on the adsorption of phenanthrene and naphthalene. The Langmuir isotherm model best describes the phenanthrene and naphthalene removal by the steel slag, which shows the adsorption occurring in a monolayer. The maximum adsorption capacity of the steel slag to phenanthrene and naphthalene is 0.043 and 0.041 mg/g, respectively. A pseudo-first-order kinetic model can better represent the adsorption of phenanthrene and naphthalene by steel slag. The research demonstrates that the steel slag has a certain adsorption capacity for phenanthrene and naphthalene.

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