Nanoparticle CdS-Sensitized TiO2 Catalyst for Photo-Degradation of Water Organic Contaminants: Feasibility Assessment and Natural-Dye Alternatives
Publication Type
Conference Paper

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 path
deposition 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 resulting
Cd2+ 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 a
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 of
MO and PhPY was assessed. An observable efficiency was noted specially when using AC/TiO2/Anthocyanin at
low pH in photo-degradation of MO.
Details of results, discussions and suggested mechanisms will be presented in this presentation 

Conference Title
International Graduate Conference on Science, Humanities and Engineering 2011 (IGCSHE2011)
Conference Country
Conference Date
May 4, 2011 - May 4, 2011
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