Preparation of crosslinked β-cyclodextrin polymer beads and their application as a sorbent for removal of phenol from wastewater
✍ Scribed by Hirohito Yamasaki; Yousuke Makihata; Kimitoshi Fukunaga
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 2008
- Tongue
- English
- Weight
- 610 KB
- Volume
- 83
- Category
- Article
- ISSN
- 0268-2575
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✦ Synopsis
Abstract
BACKGROUND: Phenols are commonly encountered in aqueous effluents from various manufacturing processes such as oil refineries, coke plants, and phenolic resin plants, and are toxic substances that should be removed from the aquatic environment. This paper reports on the preparation of beaded crosslinked β‐CyD polymers, and the removal of phenol by the β‐CyD adsorbent from raw industrial wastewater discarded from phenolic resin processing.
RESULTS: Crosslinked β‐CyD prepolymer was synthesized by treatment of β‐CyD with hexamethylene diisocyanate (HDI) at a molar ratio of 1:8. The suspension of the resulting powdery prepolymer in aqueous sodium alginate was added dropwise into an aqueous calcium chloride solution to precipitate the spherical β‐CyD prepolymer gels. The spherical prepolymer gel was lyophilized and re‐crosslinked with HDI to provide the β‐CyD polymer beads. The physical properties of the beads were as follows: average diameter: 3.4 mm; average compressive strength: 2.17 MPa; porosity: 47.0%; specific surface area: 3.48 m^2^ g^−1^. The removal of phenol from raw industrial phenolic wastewater with the β‐CyD polymer beads was carried out in either a shaker or an upflow column at 25 °C. After seven episodes of accumulated adsorption, the initial phenol concentration of 89000 ppm decreased to as low as 350 ppm in the shaker and 490 ppm in the upflow column.
CONCLUSION: Adsorbent [β‐CyD/HDI(1/8)]/HDI polymer beads having a good regular shape and high mechanical stability were newly prepared by a stepwise crosslinking method. The results of sorption experiments show that the beads exhibit high sorption capacities for phenolics in raw industrial wastewater. Copyright © 2008 Society of Chemical Industry