The Study Of Quick Decoloration In Dyeing And Printing Wastewater

Printing and dyeing industry is a large water using industry in our country. More and more attention is paid on the printing and dyeing wastewater in its emission and reuse because of the strict of Environmental laws and the shortage of water resource. Some of dye wastewater is difficult for the conventional biochemical water treatment methods, in particular color can not reach the discharge standards. So it has become a problem for water reuse. In this research, the combination of ozone and voltage pulsed corona was used in the quick decoloration of several water-soluble dyes. The active substance which is produced by the combination use of ozone and voltage pulsed corona can destroy the conjugate chromophore and increase the B/C ratio of the wastewater which will better for biological treatment in next step. The combination of ozone and voltage pulsed corona also can be used in the advanced treatment of color can not reach the standards wastewater and realize the reuse of wastewater.The integrative reactor with ozone, voltage pulsed corona and venturi was used in this experiment. The reactor can enhanced the mass transfer effect and solubility of the ozone. The optimal gas speed for ozone solution is 60L/h, but in really reaction, the optimal speed will increased to 80L/h because of the effect by reactor mass transfer and voltage pulsed corona.In the degradation of seven dyes, the dyes can be decolored in 15min except of the Acid Orange dye. There are basically has no residual color and the COD_Cr removal rate is more than 40% after the decoloration. The combination of ozone and voltage pulsed corona can enhanced the B/C ratio of the wastewater. In the UV-Vis spectrogram of Active dyes during treatment process, we can find the conjugate chromophore can be easier oxidized than the benzene rings. The pH is decrease and the conductivity is rise in the reaction process, so there are some acidic substances were produced in the reactor.The structure of the dyes can influence the decoloration rate by comparison analysis of different structure dyes' degradation. The study shows that the ozone oxidation of dye is easier to open the conjugate chromophore structure, the stability of chromophore structure is direct influence the decoloration of dyes. In the treatment research of dyes' wastewater, the anthraquinone dyes is better than bisazo dyes in the decoloration rate. In the COD_Cr degradation rate , anthraquinone dyes>monoazo dyes >bisazo dyes.In the kinetic study of simulate wastewater, the combination use of ozone and voltage pulsed corona is influenced by the oxidative intermediate product of the dyes. When the concentration of intermediate product is low, the oxidative kinetic of dyes is accord with pseudo first order reaction kinetic equation and the reaction of dyes and ozone, ? OH can be hold as first order reaction. In this dissertation, it is confirmed that the combination use of ozone and voltage pulsed corona have the ability in most dyes' decoloration. And the wastewater's B/C can be enhanced after the treatment. So this technology is suitable for the printing and dyeing wastewater's treatment and its reuse.