Adsorption of small organic pollutants from aqueous streams by aluminosilicate-based microporous materials

Organic pollution in industrial waste streams is of growing environmental concern. Adsorption has been applied to remove organics from aqueous solutions. Activated carbon and polymer resin are the most commonly used adsorbents. In this work, a novel class of aluminosilicate-based microporous materials with good adsorption capacity and high selectivity are investigated. In order to adsorb organic molecules selectively from aqueous solution, the adsorbents must be hydrophobic. Phenol and chlorinated phenols were adsorbed by three different adsorbents: pillared clays, silicalite and zeolite beta. Pillared clays were modified by incorporating a non-ionic surfactant of the general formula C12-14H25-29O (CH2CH2O)(5)H (Tergitol 15S-5). Also, high Si/Al ratio zeolites were used for this purpose. Factors which are important in determining the selectivity and adsorption capacity of these adsorbents are the hydrophobicity of the adsorbent, the size of the organic, and the diameter of channels which are accessible to the adsorbate. (C) 1997 Elsevier Science B.V.