Abstract:
The anthraquinone dye Acid Green 25 (AG25) was treated with a non-thermal plasma
generated by a new ″Glidarc″, designed for the treatment of falling liquid films. The gaseous
species formed in the landfill, particularly the radical ●OH, induce oxidation effects strong
enough to degrade refractory molecules. The new design has been exclusively used to treat liquid
films flowing continuously.Optimisation experiments were able to determine the crucial
parameters for more efficient operation of the new device. In the latter, the glass cell was
removed and replaced by a stainless steel plate, instead of the recirculation liquid to be treated
according to a groove depth equal to the thickness of the aqueous film. The removal of the glass
cell has to overcome the cooling liquid to be treated, allowing to reduce the cost of the process in
question. All these features combined, extrapolated to encourage the process in question to a
larger scale (pilot and / or industrial). Among others, this process lends itself easily to the
couplings with technical water pollution. As direct application of this concept, the photocatalyst
TiO2 particles were dispersed in the aqueous solution of AG25, thus obtaining a film as a
suspension. It was submitted to the sliding discharge generated by the new ″Glidarc″. The results
showed that the maximum decolorization and degradation were achieved for a dose of 1 g L-1
TiO2. At this concentration, the fading of dye film (80 microM) was 98% after 180 min and
COD decreased by 73% for the same processing time. By cons, in the absence of photocatalyst, the discoloration was 94% after 3 h of treatment, while the COD reduction reached 63% for the same duration. The new device for treatment of liquid films you is promising and can be applied on a larger scale.
