Synergistic methodology based on ion exchange and biodegradation mechanisms applied for metal complex dye removal from waste waters

This study investigates the synergistic effects of ion exchange and biodegradation methods to remove the
Acid Blue 193 also called Gryfalan Navy Blue RL (GNB) dye from wastewater. Ion exchange studies were
performed using a strongly basic anion exchange resin Amberlite IRA 400. The equilibrium was characterized
by a kinetic and thermodynamic points of view, establishing that the sorption of the GNB dye was subject
to the Freundlich isotherm model with R2 = 0.8710. Experimental results showed that the activated resin
can removed up to 93.4% when the concentration of dye solution is 5.62·10-2 mM. The biodegradation of the
GNB was induced by laccase, an enzyme isolated from white-rot fungus. It was also analyzed the role of pH
and dye concentration on GNB biodegradation, so 5·10-2mM dye had a maximum discoloration efficiency of
82.9% at pH of 4. The laccase showed a very fast and robust activity reaching in a few minutes a Km value
of 2.2·10-1mM. In addition, increasing the GNB concentration up to 8·10-1mM did not triggered a substrat
inhibition effect on the laccase activity. Overall, in this study we proposed a mixt physicochemical and biological approach to enhance the GNB removal and biodegradability from the wastewaters and subsequently the environment.