Study On Ultrasonic Assistant TiO₂-Photocatalytic Degradation Of Dye Waste Water

the discharge amount of dye waste water has been reported being as many as 3×106-4× 106m3 /day. Dye waste water could not be treated effectively with traditional method for its deep color, poor biochemical decomposition and complicated components. Therefore, worldwide attention has been paid on exploring non-conventional technique to degrade dye waste water.A new method for dye waste water degradation was studied in the current dissertation. For convenient, methly orange (MO) solution was taken as representative of dye waste water. Ultrasonic assistant photocatalytic degradation of MO was studied in a self-made UV/US/TiO2 apparatus with nanometer TiO2 as catalyst.. The main results were as following:1. Nanometer TiO2 catalyst with high photo-catalystic activity was made. The XRD pattern showed that the catalyst is (crystal structure) with diameter of 5-20nm. The catalyst was also characterized with TEM, SEM, UV-VIS, IR to examine its photo absorb properties and dispersion behavior.2. Degradation of MO was studied with different methods include TiO2 degradation, ultrasonic(US) degradation, ultraviolet(UV) degradation, UV/TiO2(photocatalytic degradation with TiO2 as catalyst) and UV/US/TiO2(Ultrasonic assistant photocatalytic degradation with TiO2 as catalyst). UV/US/TiO2 Was found to have the highest efficiency for MO degradation, which showed MO degradation could be promoted by ultrasonic. Effects on MO degradation of TiO2 amount, initial pH and concentration of MO were also studied.3. Optimal degradation conditions was induced from an uniform experiments as: CTiO2=0.5g/L, pH=3.5, VH202=1.5ml and rutile:anatase =1:3.4. Study on degradation residue indicate that MO was degraded and the final product is H2O, CO2, NO3-, SO42- and some other non-degradable compound.5. To test the degradation efficiency of the methods on actual waste water, a mixeddye waste water was degraded with the optimal conditions, in which COD reduced from 57.8mg/L to 2.28mg/L after 60 min of US/UV/TiO2 degradation.