Study On The Biodegradation Characterristics Of Several Reactive Dyes

Reactive dye made a large annual production. The reactive dye had wide chromatography, bright colour, excellent properties and good applicability. It was more and more widely used in printing and dyeing industry. Reactive dye wastewater was large quantity of emission, serious pollution and difficultly biodegradable. Physic-chemical treatment could effectively degrade the dye wastewater, but it is too expensive. Biological treatment was low cost, stable and easy to operate. At present, biological treatment played a major role in the treatment of dye wastewater in china. Thus, it is meaningful for dye wastewater treatment to study the biodegradation characteristics of reactive dyes.In this study, 9 reactive dyes were studied(C.I. reactive red 195, C.I. reactive black 5, C.I. reactive blue 194, C.I. reactive yellow 1, C.I. reactive orange 1, C.I. reactive yellow 145). Firstly, the degradation of dye under anaerobic and aerobic condition was analyzed. Besides, the effect of external carbon source on dye degradation was studied. Finally, the change of molecular structure was analyzed according to the UV-vis Spectral Analysis. In order to analyze the degradation of dye, the CODCr, TOC, absorbance value were tested.Main conclusions in this study are the following:(1) When the dyes were used as sole carbon source, the dyes had poor decoloration and mineralization under anaerobic condition. After the dye was treated for 48 h, reactive yellow 1 has the best decoloration(48.9%), C.I. reactive red 195 had the best COD removal rate(38.8%) and C.I. reactive yellow 145 had the best TOC removal rate(43.7%).(2) Under anaerobic condition, the external carbon source could improve the decoloration. When the dye wastewater was treated without external carbon source for 48 h, C.I. reactive yellow 1 has the best decoloration(48.9%). After the external carbon source was added, C.I. reactive yellow 145 had the best decoloration(91%) under anaerobic condition.(3) When the dyes were used as sole carbon source, the dyes had poor decoloration and mineralization under aerobic condition. After the dye was treated for 48 h, reactive yellow 1 has the best decoloration(50.5%). C.I. reactive yellow 145 had the best COD removal rate(59.4%) and C.I. reactive red 195 had the best TOC removal rate(64.7%).(4) Under aerobic condition, the external carbon source could improve the decoloration. When the dye wastewater was treated without external carbon source for 48 h, C.I. reactive yellow 145 has the best decoloration(59.4%). C.I. reactive red 195 had the best TOC removal rate(64.7%). After the external carbon source was added, C.I. reactive yellow 145 had the best decoloration(93.8/%) and C.I. reactive red 195 had the best TOC removal rate(90.9%).(5) According to the UV-vis spectrum characteristic absorption peaks of 9 different dyes, for the same dye, anaerobic condition was much benifical than aerobic condition to the destruction of azo bond, benzene and naphthalene ring. Different dyes achieved the different degree of destruction and the relative positions of chromophoric group and substituent group affected the dye degradation.