Langmuir and Dubinin–Radushkevich analyses on equilibrium adsorption of activated carbon fabrics in aqueous solutions
✍ Scribed by Chien-To Hsieh; Hsisheng Teng
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 2000
- Tongue
- English
- Weight
- 114 KB
- Volume
- 75
- Category
- Article
- ISSN
- 0268-2575
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✦ Synopsis
The present study investigated the adsorption of phenol, iodine and tannic acid onto activated carbon fabrics in aqueous solutions. The carbon fabrics were made of polyacrylonitrile with different extents of activation in steam. The increasing extent of activation is accompanied by increasing carbon porosity as well as liquid-phase adsorption capacity. Langmuir and Dubinin± Radushkevich (D±R) models were employed to analyze the equilibrium adsorption data. The fractional ®lling of carbon micropores and the mean free energy for adsorption were estimated according to these models. It is suggested on the basis of the present work that the mesopore fraction of the fabrics, the extent of carbon activation, and the adsorbate size are important as well as competitive factors determining the adsorption capacity. Both the equilibrium constant and free energy for adsorption increase with the mesopore fraction, indicating that the mesopores promote the adsorption onto high energy sites, whereas the fraction ®lling micropores decreases with the extent of carbon activation and the size of the adsorbates.