Abstract:
In the present work, different types of photocatalysts in single, binary and ternary systems
with different molar ratios (1:2, 1:3 and 1:4) of CdS/TiO2:Ag2CO3 were synthesized by coprecipitation
method. Zeolite supported CdS/TiO2/Ag2CO3 nanocomposite was also
synthesized by Impregnation method. Crystal structure, band gap energy, functional groups
and optical properties of the as synthesized photocatalysts were characterized by using XRD,
UV/Vis, FTIR and PL instrumentation techniques respectively. Photocatalytic activities of the
single, binary, bare and supported ternary nanocomposites were evaluated by using aqueous
solution of model pollutant methyl orange dye (MO) as well as a real sewage sample solution
collected from Bahirdar Textile Share Company. Photocatalytic activities of the ternary
CdS/TiO2/Ag2CO3 nanocomposite in (1:2, 1:3 and 1:4 molar ratios) were found to be higher
than those of single and binary counterparts due to having more than one path for the
formation of electron-hole pair. The effect of operational parameters such as pH, initial dye
concentration and photocatalyst load in MO dye degradation were investigated by using the
Zeolite supported CdS/TiO2/Ag2CO3 (ZST) nanocomposite. The results obtained at the
optimum conditions indicated 82.4 and 91.6% photodegradation efficiencies respectively for
the bare (T1) and supported (ZST) ternary systems done on the model dye. The effect of
different scavengers suggest that •O2
- and •OH are the principal species involved in the
decolorization of MO. Supported photocatalyst also exhibited a relatively higher efficiency
on the photodegradation of MO than real sewage sample solutions which is about 92.1 and
73.8%, respectively.
