High-pressure Pulse Discharge Synergistic Catalyst For The Degradation Of 4-chlorophenol Wastewater

High voltage pulse discharge can produce the active substances such as O3,H2O₂,· OH and some physical effect such as ultraviolet radiation and ultrasonic when it treatment wastewater.It is a new type of high efficient water treatment technology,and is widely used to degrade all kinds of organic wastewater.In order to make full use of the ultraviolet ray,and further improve the utilization rate of the degradation of organic waste water and energy.The experiment adopts high voltage pulse discharge combined with photocatalyst degradation system.This article choose comparatively representative phenolic substances 4-chlorophenol as the research object.The experiment systematic studied the organic wastewater technology of high voltage pulse discharge combined with catalyst from several aspects,such as the impact of the processing parameters,the impact of catalysts,the analysis of byproducts,the analysis of mineralization rate and mechanism.The results show that:?1?In high voltage pulse discharge system,the effect of process parameters on the degradation of 4-chlorophenol solution is: with the increase of electrode spacing,pulse frequency,air volume,the degradation rate of 4-chlorophenol is increased first and then decreased,the three parameters have an optimum value,too small or too large is not good to increase the degradation rate of 4–chlorophenol.With the increase of voltage,the degradation rate of 4-chlorophenol increases,the degradation rate is almost no change when it continue to rise in voltage as it reaches a certain value.The higher the initial concentration of 4-chlorophenol the degradation rate is lower.?2?The degradation effect of 4-chlorophenol wastewater is good when it treated by high voltage pulse discharge.The degradation rate of 4 – chlorophenol was 55.75% when 150 mL4–chlorophenol wastewater that the concentration is 150mg/L was treated by high voltage pulse discharge for 45 min under the best process parameters?electrode span is 1.0 cm,pulse voltage is 26 kV,pulse frequency is 70 Hz,air volume is 4 L/min?.When treated 90 min the degradation rate was 67.25%,and the mineralization rate is only 21.61%.With time change the concentration of byproducts is increased first and then decreased,and the highest peak concentration of byproducts is 4–chlorocatechol,the lowest peak concentration of byproducts is hydroquinone.?3?By XRD?X-ray diffraction?and SEM?Scanning Electron Microscope?characterizations: the optimum calcination temperature of the catalyst about TiO₂ is 500?;and the catalyst of Fe-TiO₂ 500? or 550?.Which resulted from experiment,the degradation rate of 4-chlorophenol were increased first and then decreased with the increasing of catalyst content and calcination temperature of catalyst,which calcination temperature and the dosage were 0.1g?500? of TiO₂ catalyst,and 0.05g?500? of Fe-TiO₂ catalyst.?4?Compared to the single pulse discharge,high voltage pulse discharge combined with TiO₂ catalyst had higher degradation and mineralization rate of 4-chlorophenol,and concentration peak of byproducts increased,hydroquinone was disappearance after 90 min.According to modified of Fe-TiO₂ catalyst,it has higher activities and degradation rate of 4-chlorophenol solution.After the time had 90 min at pulse discharge combined with Fe-TiO₂ catalyst for 4-degradation solution,the results showed that degradation rate was reached 79.29%,and the mineralization rate was 29.67%;it makes the disappeared time of hydroquinone and 1,4-benzoquinone advance,and the peak concentration decreased of three kinds of byproducts.?5?The way about high-voltage pulsed discharge degrade 4-chlorophenol are:?1?4-chlorophenol is completely degraded as CO₂ and H2O?2?First,4-chlorophenol degraded as the byproducts,and then byproducts transformed to some small organic molecules,in the end some small organic molecules CO₂ and H₂O.