Tesis doctoral de Mireia Sala Gastón
Industrial effluents and their further reuse have shown an increasing interest. the current phd thesis is based on obtaining a new system for the treatment of textile effluents. The aim of this study is to remove colour and to degrade the hydrolysed reactive dyes as well as to achieve an effluent able to be reused in a new dyeing process. a total of 10 reactive dyes with different constitution are studied: chromophore group (azo and phtalocyanine), reactive group (chlorotriazine and vinilsulphone) and number of reactive groups (mono, bi and trireactive). Their behaviour respect to the decolouration and degradation is evaluated with several combinations of electrochemistry (ec) and ultraviolet irradiation (uv): ec alone, ec treatment with simultaneous uv (uvec) and finally ec treatment with further uv (ec+uv). The electrochemical and photoelectrochemical treatment have demonstrated to be an efficient method in all the studied cases, achieving decolourations higher than 90%. all the studied dyes have similar behaviour except for the phtalocyanine which has lower kinetic decolourations rates than the azo group dyes. according to the different treatments studied, the optimised method is the one which starts with the ec treatment until 80% decolouration, followed by the uv irradiation in order to degrade the organohalogenated compounds generated during the electrolysis, which concentration is lower than 1ppm in all cases. in addition, different intensities are also studied (2a, 5a and 10a). The treatment performed at 10a is the most efficient due to the high rate of oxidants generation which enhances the dyes degradation. Different combinations of alkalis and electrolytes (naoh with na2so4, and na2co3 with nacl) are evaluated. In all the studied cases, high decolouration rates are obtained and the reuse is feasible when the residual alkali is removed before starting the new dyeing. Also, two kinds of anodes are studied (ti/pt and ti/sno2-sb-pt). In the presence of chloride, the first ones are the most efficient in effluents decolouration, showing kinetic rates around 4.5 times higher than the obtained with the second ones. However, in despite of a certain instability of ti/sno2-sb-pt anodes, they generate 2 to 7 times lower amounts of organic volatile compounds than the ti/pt anodes. on the other hand, different cell designs are used (¿simple batch cell¿, ¿recirculation batch cell¿ and the semi-industrial design). The two first ones, which only difference is the stirring mode, produce similar effluents decolouration. In addition, the results obtained with the semi-industrial pilot are in accordance with the laboratory designs. as a final part of the thesis, different industrial baths which contain reactive dyes are treated. By one hand, the exhausted dyeing effluents and by the other hand the first washing effluents which contain surfactants. The main goal is to know the influence of the surfactant in the effluents decolouration.¿¿ the presence of the surfactant does not avoid the ¿¿ dyes degradation, although its decolouration kinetic rates decreased due to the higher degradable character of the surfactant.
Datos académicos de la tesis doctoral «Aplicació de técniques electroquímiques i fotoelectroquímiques per la degradació de compostos poc biodegradables en efluents industrials téxtils«
- Título de la tesis: Aplicació de técniques electroquímiques i fotoelectroquímiques per la degradació de compostos poc biodegradables en efluents industrials téxtils
- Autor: Mireia Sala Gastón
- Universidad: Politécnica de catalunya
- Fecha de lectura de la tesis: 19/07/2012
Dirección y tribunal
- Director de la tesis
- María Del Carmen Gutiérrez Bouzán
- Tribunal
- Presidente del tribunal: Francisco javier Cases iborra
- jaume Cot cosp (vocal)
- (vocal)
- (vocal)