Wastewater treatment using photocatalysis: Destruction of methylene blue dye from wastewater streams
Photocatalytic processes have been suggested as an alternative treatment for water pollutants. Although presently many treatment methods are being used, most of them do not completely destroy the pollutants but only offer phase transfer or partial degradation of the pollutants. In photocatalytic...
Main Authors: | , , |
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Format: | Article |
Published: |
2002
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Online Access: | http://journalarticle.ukm.my/1394/ http://journalarticle.ukm.my/1394/ |
Summary: | Photocatalytic processes have been suggested as an alternative treatment for water pollutants.
Although presently many treatment methods are being used, most of them do not completely
destroy the pollutants but only offer phase transfer or partial degradation of the pollutants. In
photocatalytic processes, a semiconductor photocatalyst is activated with ultraviolet (UV)
irradiation. The activated photocatalyst promotes the formation of hydroxyl radicals, which in
turn completely degrades the pollutants. In the present study, an ultraviolet irradiated
photoreactor system was used to degrade methylene blue dye in aqueous solutions. The
photocatalyst used was titanium dioxide (TiO2) Experiments were performed with varying
catalyst loading, initial concentration of dye, circulation flow rate and air flow rate. Initial
reaction rates of dye degradation were used to compare the effect of varying the above variables.
The effect of increasing the catalyst loading from 0 to 0.4 wt% showed that an increase in the
initial reaction rate, reaching an optimum at catalyst loading of 0.2 wt%. Effect of initial
concentration has proven that lower initial concentration resulted in more efficient degradation of
the dye. The increase in the initial reaction rate degradation with increasing circulation flow rate
confirmed the significant role played by external mass transfer. Introduction of air to the system
did not significantly increase in the initial reaction rate when the air flow rate was increased from
0 to 4.0 liter min-1 |
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