Photocatalytic and combined anaerobic–photocatalytic treatment of textile dyes

Abstract

A photocatalytic process based on immobilized titanium dioxide was used to treat crude solutions of azo, anthraquinone and phthalocyanine textile dyes. In addition, the process was applied to the treat autoxidized chemically reduced azo dyes, i.e. representatives of recalcitrant dye residues after biological sequential anaerobic-aerobic treatment. Photocatalysis was able to remove more than 90% color from crude as well as autoxidized chemically reduced dye solutions. UV-absorbance and COD were also removed but to a lower extent (50% in average). The end products of photocatalytic treatment were not toxic toward methanogenic bacteria. The results demonstrate that photocatalysis can be used as a pre- or post-treatment method to biological anaerobic treatment of dye-containing textile wastewater.

Dye Waste Treatment

“…The combined effects of both heterogeneous photocatalytic oxidation and reverse osmosis membrane leads to complete decolorization of the synthetic dyestuff effluent as well as 90% reduction of initial organic content. In the year 2008, the photocatalytic and combined anaerobic-photocatalytic treatment of textiles dyes was studied [95]. Results demonstrated that photocatalysis was able to remove 90% of color from crude as well as autoxidized chemically reduced dye solution (biological sequential anaerobic-aerobic treated dye solution).…”

Prussian Blue onto Activated Carbon as a Catalyst for Heterogeneous Fenton-Like Processes

“…The change in the shape of the spectrum along the reaction time is indicative of dye oxidation. Reference [14] also addressed this trend in the photocatalytic oxidation of Orange G. These authors stated that the peak at 205 nm is indicative of the presence of end products (nitrates) and the formation of N-containing organics. …”

Advanced Oxidation Processes in Food Industry Wastewater Treatment – A Review

“…The powerfulness of the hydroxyl radical gives advanced oxidation processes the ability to achieve oxidative destruction of compounds refractory to conventional hydrogen peroxide or ozone oxidation. AOPs have been used successfully for example, destroying pesticides by photochemical degradation (UV/O 3 and UV/H 2 O 2 ) (Andreozzi et al, 2003), photocatalysis (TiO 2 /UV, Fenton and photo-Fenton process) (Legrini et al, 1993;Fallman et al, 1999) (Harrelkas et al, 2008) and also for the destruction of organics in different kind of effluents, such as paper mill wastewaters by photocatalysis (Pérez et al, 2001), landfill leachates by the Fenton process (Lopez et al, 2004;Gotvajn et al, 2009 ), olive mill wastewaters by wet air oxidation (Gomes et al, 2007) etc. Advanced oxidation methods can be split into "cold" and "hot" oxidation.…”