Textile wastewater shows great threats to the environment if not well pretreated before discharge. A promising technique, ozonation, was applied to remove the color in dye solutions containing C.I. Reactive Red 195 (...Textile wastewater shows great threats to the environment if not well pretreated before discharge. A promising technique, ozonation, was applied to remove the color in dye solutions containing C.I. Reactive Red 195 (RR195) in a semi-batch reactor. The decolorization of RRI95 by the ozone process followed pseudo-first-order kinetics. Several factors which influenced the efficiency of decolorization were studied and the reaction rate constant (k) obtained with different operational parameters was compared. Our results showed that RRI95 was more easily degraded in acidic than in alkaline conditions. The dyeing auxiliaries (sodium carbonate and sodium chloride) that acted as radical scavengers could enhance the decolorization process, and the ozonation time for total color removal lengthened if the initial dye concentration was higher. The analysis of the ozonation products was performed by liquid chromatography-tandem mass spectrometer and a possible degradation pathway was predicted according to the ozonation products and structure of RR195. Our results indicated that ozonation was effective in the color removal of dyes, but further treatment might be necessary since the ozonation products are high toxic.展开更多
To the Editor:A 28-year-old woman(P1G0 at 30 weeks of gestation)was referred to our diagnostic center for an irregular fetal cardiac rhythm.No risk factors were noted and the tests for detecting maternal auto-antibodi...To the Editor:A 28-year-old woman(P1G0 at 30 weeks of gestation)was referred to our diagnostic center for an irregular fetal cardiac rhythm.No risk factors were noted and the tests for detecting maternal auto-antibodies(anti-Ro/La,anti-dsDNA,and anti-nuclear antibodies)were negative.The fetal systematic ultrasonic examination was normal.The fetal echocardiogram revealed that the fetal cardiac structure and function were normal;neither hydrops nor any other malformations were detected.展开更多
文摘Textile wastewater shows great threats to the environment if not well pretreated before discharge. A promising technique, ozonation, was applied to remove the color in dye solutions containing C.I. Reactive Red 195 (RR195) in a semi-batch reactor. The decolorization of RRI95 by the ozone process followed pseudo-first-order kinetics. Several factors which influenced the efficiency of decolorization were studied and the reaction rate constant (k) obtained with different operational parameters was compared. Our results showed that RRI95 was more easily degraded in acidic than in alkaline conditions. The dyeing auxiliaries (sodium carbonate and sodium chloride) that acted as radical scavengers could enhance the decolorization process, and the ozonation time for total color removal lengthened if the initial dye concentration was higher. The analysis of the ozonation products was performed by liquid chromatography-tandem mass spectrometer and a possible degradation pathway was predicted according to the ozonation products and structure of RR195. Our results indicated that ozonation was effective in the color removal of dyes, but further treatment might be necessary since the ozonation products are high toxic.
文摘To the Editor:A 28-year-old woman(P1G0 at 30 weeks of gestation)was referred to our diagnostic center for an irregular fetal cardiac rhythm.No risk factors were noted and the tests for detecting maternal auto-antibodies(anti-Ro/La,anti-dsDNA,and anti-nuclear antibodies)were negative.The fetal systematic ultrasonic examination was normal.The fetal echocardiogram revealed that the fetal cardiac structure and function were normal;neither hydrops nor any other malformations were detected.