TY - JOUR
T1 - Photodegradation of hydrophobic disperse dyes and dye-bath effluents by silicadodecatungstate (SiW12O404-/5-) nanoparticles
AU - Arslan-Alaton, I.
AU - Dogruel, S.
PY - 2004
Y1 - 2004
N2 - Polyoxometalate (POM) silicadodecatungstic acid has been applied as a photochemical catalyst for the degradation of ®SETAPERS Black WNSP, a disperse dyestuff preparation widely used to dye polyester and polyamide fabrics. It could be demonstrated that the disperse dyestuff was photo-reduced by SiW12O405-, the one-electron reduced form of POM, as evidenced by Heteropolyblue (HPB) formation. For completion of the photochemical redox cycle, isopropanol (IsOH) was required. Acetone (Ac) served solely as an effective solute and photosensitizer; however this effect was suppressed in the presence of POM Threshold (0.087 mM) and optimum (0.375 mM) POM concentrations existed and decolorization kinetics were inhibited upon the addition of dye auxiliary chemicals. Increasing the dyestuff concentration from 50 mg/L to 150 mg/L did not affect initial decolorization kinetics revealing that not the formation of the excited [POM-Substrate] complex, but its reduction to HPB was the rate limiting step. POM-mediated, IsOH-assisted UV-photodegradation of disperse dyes and dye-baths is by far more effecfive than applying other, more well known chemical oxidation methods (O3, H2O2/UV, Power Ultrasound). Key to the action of POM redox catalysts is the feature that particularly heteropoly tungstates undergo facile re-oxidation to their original state, thus allowing regeneration of the photocatalyst, a feature that may become critical for real-scale application.
AB - Polyoxometalate (POM) silicadodecatungstic acid has been applied as a photochemical catalyst for the degradation of ®SETAPERS Black WNSP, a disperse dyestuff preparation widely used to dye polyester and polyamide fabrics. It could be demonstrated that the disperse dyestuff was photo-reduced by SiW12O405-, the one-electron reduced form of POM, as evidenced by Heteropolyblue (HPB) formation. For completion of the photochemical redox cycle, isopropanol (IsOH) was required. Acetone (Ac) served solely as an effective solute and photosensitizer; however this effect was suppressed in the presence of POM Threshold (0.087 mM) and optimum (0.375 mM) POM concentrations existed and decolorization kinetics were inhibited upon the addition of dye auxiliary chemicals. Increasing the dyestuff concentration from 50 mg/L to 150 mg/L did not affect initial decolorization kinetics revealing that not the formation of the excited [POM-Substrate] complex, but its reduction to HPB was the rate limiting step. POM-mediated, IsOH-assisted UV-photodegradation of disperse dyes and dye-baths is by far more effecfive than applying other, more well known chemical oxidation methods (O3, H2O2/UV, Power Ultrasound). Key to the action of POM redox catalysts is the feature that particularly heteropoly tungstates undergo facile re-oxidation to their original state, thus allowing regeneration of the photocatalyst, a feature that may become critical for real-scale application.
KW - Decolorization
KW - Disperse dyes
KW - HSiW O catalyst
KW - Heteropoly blue
KW - Photochemical degradation
UR - http://www.scopus.com/inward/record.url?scp=1842420394&partnerID=8YFLogxK
U2 - 10.2166/wst.2004.0254
DO - 10.2166/wst.2004.0254
M3 - Article
C2 - 15077967
AN - SCOPUS:1842420394
SN - 0273-1223
VL - 49
SP - 171
EP - 176
JO - Water Science and Technology
JF - Water Science and Technology
IS - 4
ER -