Απομάκρυνση χρωστικών από υδατικά συστήματα με την τεχνική της επίπλευσης

Abstract

In this study the removal of various (DyStar and CIBA) reactive dyestuffs (red - blue - yellow) and their trichromatic mixtures was examined by flotation techniques. The scope of this work was to demonstrate the feasibility of dispersed - air flotation (DispAF), dissolved - air flotation (DAF) and electroflotation (EF), in the treatment of simulated aqueous solutions and, consequently, of real industrial textile effluents, originating either from the dyeing reactor or from the equalization tank of a dye-house, bearing the same dyes as the simulated effluents. The main objectives were to characterize the experimental parameters affecting the three flotation processes, such as: the concentration and sort of dye (single dye solution, trichromatic mixture, real effluent), the concentration of added surfactants (CTAB, SDS), polyelectrolyte (Neoflock, PE) and flocculant (Zetag 87), the presence of electrolyte (NaCl) in the solution, the tension of the direct electric current (applied in electroflotation). To meet the demands of conservation of resources and sustainable development, this study was followed up by dyeing experiments and ultrasonic irradiation in order to investigate the possibility of water reuse and dyestuff degradation, respectively. The results of this study show that flotation seems to be an effective process for the removal of coloring matter from simulated effluents and textile industry effluents. Treated water could be totally reused in textile dyeing, if a small amount of supplement dye is used. The presence of collector in the effluent, in small quantities, favors the destruction of coloring matter.