Gutierrez-Bouzán, C.; Vilaseca, M.; Escalas-Cañellas, A.; Buscio, V.; García, M.G.; Gelabert, I.; Crespi, M. International Conference on Desalination Using Membrane Technology Presentation's date: 2015-07-28 Presentation of work at congresses
After the dyeing process, part of the dyes used to color textile materials are not fixed into the substrate and are discharged into wastewater as residual dyes. In this study, a heterogeneous photocatalytic process combined with microfiltration has been investigated for the removal of C.I. Disperse Red 73 from synthetic textile effluents. The titanium dioxide (TiO2) Aeroxide P25 was selected as photocatalyst. The photocatalytic treatment achieved between 60% and 90% of dye degradation and up to 98% chemical oxygen demand (COD) removal. The influence of different parameters on photocatalytic degradation was studied: pH, initial photocatalyst loading, and dye concentration. The best conditions for dye degradation were pH 4, an initial dye concentration of 50 mgL-1, and a TiO2 loading of 2 gL(-1). The photocatalytic membrane treatment provided a high quality permeate, which can be reused
The reactive dye Cibacron Yellow S-3R was selected for the membrane filtration study, to evaluate the feasibility of nanofiltration membranes to treat textile wastewater. Synthetic effluents were treated by means of two nanofiltration membranes, Hydracore10 and Hydracore50, manufactured by Hydranautics. The membranes provided a high quality permeate, able to be reused in new dyeings. Up to 98% of dye removal was achieved. The influence of salt concentration and pH on membrane treatment was studied. The best conditions for dye removal were pH 3 and 60g·L-1 of NaCl. After the membrane filtration, the treated permeates were reused in new dyeing process. 100% of the obtained permeate was reused to perform different dyeings with four reactive dyes. Finally fabrics dyed with the reused water were evaluated respect to references carried out with softened tap water. The colour differences obtained were lower than 0.5, being 1 the maximum value generally accepted by the industry
La industria textil por vía húmeda genera grandes cantidades de agua residual en sus procesos productivos, principalmente en las operaciones de ennoblecimiento (preparación, tintura y acabado). El sector textil precisa de tratamientos primarios, secundarios y tratamientos avanzados para eliminar la materia orgánica, sólidos no eliminados anteriormente y el color. En especial, la eliminación de los colorantes en este tipo de efluentes representa un reto tecnológico en los procesos de tratamiento de aguas residuales. Se estima que mundialmente se descargan 280.000 toneladas de colorantes en los efluentes textiles. La compleja mezcla de colorantes y compuestos que se emplean para el acabado, hace que las aguas residuales de la industria textil sean difíciles de tratar sólo por medio de sistemas biológicos o fisicoquímicos convencionales, por lo que se requieren estudios de tecnologías innovadoras para completar la depuración.
The wet textile industry generates large amounts of waste water in their production processes, especially in finishing operations (preparation, dyeing and finishing). Conventional technologies for colour removal are being implemented on an industrial scale, offering good levels of discoloration, but all have in common, their high cost. Recently, many research groups worldwide are working on a laboratory scale and pilot plant in what may be termed as “New technologies for colour removal”, although some of them are based on traditional methods
The textile industry is one of the largest consumers of water in the world and its wastewater is a serious problem when it is discharged without the proper treatment. In this work, wastewater generated by textile industry was treated coupling a homogenization–decantation treatment with polyvinylidene difluoride (PVDF) ultrafiltration membranes. Initially, the wastewater was aerated in a homogenization–decantation tank where 17% colour and 10% chemical oxygen demand (COD) were removed. The aerated effluent was treated with an ultrafiltration membrane in order to reuse the permeate in new dyeing processes. Firstly, the ultrafiltration treatment was performed in a laboratory plant. The permeate analysis showed 20% colour removal and 60% COD decrease. On the basis of these results, a semi-industrial system was built. With this plant, the permeate characterization showed similar results. The system was found to be scalable and suitable for the treatment of this kind of effluents. Finally, new dyeings were performed with both permeates. Monochromatic dyeings were carried out with 100% permeate whereas 50% permeate was reused for dyeings with a mixture of three dyes. The colour differences were found to be lower than 1.5, which was the acceptance value established
Indigo is one of the most consumed dyes in the textile sector, as it is widely used for the dyeing of denim clothes. About 15% of indigo used in the dyeing process is discharged to the wastewater treatment plants or sometimes into rivers, in countries where regulations are not strictly applied. In this work, real effluents that contained indigo dye were treated by means of 4 different ultrafiltration membranes. The feasibility to recover the concentrated dye with lab and semi-industrial pilots was also investigated. The studied membranes achieved up to 99% colour removal and 80% chemical oxygen demand (COD) decrease. Finally, the concentrates containing 20 g L_1 of indigo dye were reused in new dyeing processes. Colour differences (DECMC) and rubbing and washing fastnesses were evaluated. Fabrics dyed with the recovered indigo concentrates exhibited similar characteristics than the ones obtained with the commercial dye
In this work, the feasibility of polyvinylidene difluoride ultrafiltration membranes to treat textile wastewater was studied. The C.I. Disperse Orange 30 and C.I. Disperse Rubine 73 were selected as pollutant for the membrane filtration study. The results showed about 90 and 96% of COD decrease and dye removal, respectively. In addition, very low fouling was observed which demonstrated the feasibility of applying this type of membranes to treat textile wastewater. Finally, after the membrane treatment, 100% of the obtained permeate was reused. Fabrics dyed with the reused water were evaluated with respect to references carried out with softened tap water. No significant colour differences were observed between reference fabrics and the fabrics dyed with the permeate
Indigo is one of the most important dyes in the textile industry. The control of the indigo concentration in dyeing liquors and effluents is an important tool to ensure the reproducibility of the dyed fabrics and also to establish the efficiency of the wastewater treatment. In this work, three analytical methods were studied and validated with the aim to select a reliable, fast and automated method for the indigo dye determination. The first method is based on the extraction of the dye, with chloroform, in its oxidized form. The organic solution is measured by Ultraviolet (UV)-visible spectrophotometry at 604 nm. The second method determines the concentration of indigo in its leuco form in aqueous medium by UV-visible spectrophotometry at 407 nm. Finally, in the last method, the concentration of indigo is determined by redox titration with potassium hexacyanoferrate (K-3(Fe(CN)(6))). The results indicated that the three methods that we studied met the established acceptance criteria regarding accuracy and precision. However, the third method was considered the most adequate for application on an industrial scale due to its wider work range, which provides a significant advantage over the others.