Preparation and performance of integrated photocatalyst adsorbent (IPCA) employed to degrade model organic compounds in synthetic wastewater

An integrated photocatalyst adsorbent (IPCA) system was prepared for the purpose of removing organic pollutants from wastewater. Its efficiency to remove some representative compounds from the most frequently occurring water contaminants commonly treated by activated carbon was tested on laboratory scale. The IPCA formulation was built using TiO2 as the photoactive component and a non-carbon family of adsorbents (zeolites) as the adsorbents, all supported on an inert base (glass beads). The IPCA offers a competitive alternative treatment to the activated carbon because its photoactive component permits multiple regeneration of the adsorbent while integration on the support makes the IPCA mechanically robust and easy to handle in the reactor systems. The study included the search for the best candidates for the role of the IPCA components, optimum proportions among them, and suitable pre-treatment procedures to achieve the maximum efficiency of the IPCA material. IPCA with the composition beads:P25:zeolite:silica gel = 73:1:3:23 was found to be optimal for the purposes in this research. The choice of the zeolite in this composition was determined by the contaminant of interest. A combination of acid-wash, sonication, and calcination procedures applied to the precursors enhanced photodegradation efficiency of the IPCA by a factor of 1.5. (C) 2004 Elsevier B.V. All rights reserved.