An-Najah Staff

The photocatalytic degradation of organic contaminants (such as industrial dyes, insecticides, pesticides, … etc) in water, using TiO2 under UV are commonly used procedures. Modifying TiO2 with CdS is also a common technique used for water purification under visible light. In this work both commercial and prepared TiO2 were used for photo-degradation of two model contaminants, methyl orange (MO) and phenazpyridine (PhPy). In order to sensitize TiO2 to visible light, a chemical pathdeposition method (CBD) was used to precipitate non-scale (~20 nm) CdS particles on TiO2 particle surfaces. Sand was used as a supporting surface for the TiO2/CdS catalyst. UV-visible spectra, photoluminescence emission spectra, XRD and SEM imaging were measured to characterize the prepared catalyst systems. Effects of catalyst concentration, initial contaminant concentration and pH on photo-degradation rate were studied. Turnover number and quantum yield were also calculated for comparison study. Despite the high efficiency of TiO2/CdS catalyst system in degrading water contaminants, voltametric analysis confirmed complete CdS decomposition during the photo-degradation process. Due to hazardous nature of resultingCd2+ in the treated water, an alternative sensitizer has been suggested based on natural nontoxic dyes. Anthocyanin was used here for the first time as a sensitizer for the rutile TiO2 system. Activated Carbon (AC) was also used as supporting substrate. Electronic absorption spectra, FT-IR spectra, and TGA analysis were used to characterize the prepared TiO2/Anthocyanine catalyst systems. The efficiency of the new catalyst system, in photo-degradation ofMO and PhPY was assessed. An observable efficiency was noted specially when using AC/TiO2/Anthocyanin atlow pH in photo-degradation of MO.Details of results, discussions and suggested mechanisms will be presented in this presentation