Azo Dye Degradation

ABSTRACT:

Release of colored textile effluents is undesirable in the aquatic environment as they reduce light penetration, thereby affecting aquatic life and limits utilization of the water media. Azo dyes belong to the most important group of synthetic colorants. They are generally considered as xenobiotic compounds which are very recalcitrant to biodegradation. Microbial bioremediation is an alternative treatment option available other than the commonly employed physicochemical and biological methods to treat these toxic effluents. Two cultures (IE1 and C1) were selected for the investigation for their ability to degrade Direct Navy blue in liquid dye medium. The cultures showed best decolorization under aerobic and static conditions. The cultures under study showed best decolorization at pH 7 and room temperature. However, the removal of peptone inhibited the decolorization activity of cultures. A bacterial consortium was also prepared by mixing these two cultures to check for the degradation ability. Fast decolorization was also observed with higher concentration of azo dyes (1000 mg/l).

Key words: Azo dyes, Bacteria, Aerobic, Decolorization.

INTRODUCTION:

Due to rapid industrialization and urbanization, a lot of chemicals including dyes are manufactured and used in day-to-day life. Dyes are synthetic and aromatic molecular structural compounds. According to their dissociation in an aqueous solution, dyes can be classified as acid, direct reactive dyes (anionic), basic dyes (cationic) and disperse dyes (nonionic) (Sathiya moorthi, P., et.al 2006). The removal of the polluting dyes is an important problem; particularly for small scale textile industries where working conditions and economic status do not allow them to treat their wastewater before disposal and they have no choice other than dumping all effluent into the main stream of water resources (Safia Moosvi.S., et al., 2005).Azo dyes, which are aromatic compounds with one or more (–N=N–) groups,...