Treatment Of Dye Wastewater By High Voltage Pulsed Discharge Coupled With Modified Activated Carbon

Dye wastewater pollution has become a worldwide environmental problem.It has the characteristics of high salt content,high COD value,deep color and toxic substances.If the dye wastewater is discharged to the environment without treatment,it will seriously affect aquatic organisms and humans.High-voltage pulse discharge coupled with modified activated carbon technology has the characteristics of fast degradation rate and no secondary pollution.In this thesis,high-voltage pulse discharge coupled withCTAB/AC was used to degrade the DB86 simulated wastewater.Firstly the high-voltage pulsed discharge system was separated and optimized discharge reaction parameters.The results showed that as the frequency and voltage increase,the removal efficiency of DB86 gradually increases.As the electrode spacing and air flow increase,the removal efficiency of DB86 increases first and then decreases.When setting the initialconcentration of the solution to be 100 mg·L^-1,the conductivity of the solution to be 200?s·cm^-1,the discharge frequency to be 50 Hz,the discharge voltage to be 22 kV,the electrode spacing to be 8 mm,and the air flow rateto be 3 L·min^-1,the removal rate ofDB8was 79.30%and the mineralization rate was 8.5%.In this thesis,the activated carbon was modified by surfactant CTAB,and then optimization of modification parameters.The experimental results showed that CTAB/AC has a better removal effect on DB86 than SDS/AC.When the modifier concentration was 5×10^-4mol·L^-1,the modification time was 24 h,and the modifier dosage was 0.2 g,the CTAB/AC modification effect is the best.Then the high-voltage pulse discharge coupled with CTAB/AC was separated.The effect of the synergistic system on the DB86was studied.And it was compared with the high-voltage pulse discharge system alone.The results showed that under the same experimental conditions,the HVPD-CTAB/AC synergistic system has a removal rate of 99.65%for the DB86 simulated wastewater,which is 20.35%higher than the pulse discharge system alone.The removal mechanism of dye wastewater waspreliminary exploredin thisthesis by high voltage pulse discharge.The results showed that during the pulse discharge,the pH of the solution kept falling,and the solution was finally acidic.And the DB86molecule is not completely degraded into CO₂ and H₂O.·OH plays a key role in the degradation of DB86 molecules.H₂O₂ cannot directly act on the DB86 molecule,but indirectly through conversion to·OH.In the last,O₃ directly oxidized DB86 molecules under acidic conditions,whileit decomposedto·OHunder neutral conditions.