A Study On Degradation Kinetic And Mechanism Of P-Nitrophenol With Alternate Pulses Of Ultrasound And Electricity Process

Nitrophenol wastewater mainly comes from the synthesis of pesticides, synthetic materials, dyes and intermediates, this kind of compounds in nature are difficult to be degraded and very harm to the environment and the human. P-nitrophenol is an environmental priority pollutants. It is very difficult to find an effective treatment method for this kind of organic in the field of environmental protection. In this dissertation a dual-pulse ultrasound enhanced electrochemical degradation process was provided to treat the simulation of p-nitrophenol wastewater. The original electrochemical degradation process and ultrasound degradation process were also used to degrad the p-nitrophenol wasterwater as a comparison to the dual-pulse ultrasound enhanced electrochemical degradation process.In the end the reaction mechanism was also analysed in the condition of dual-pulse ultrasound enhanced electrochemical degradation process.The mainly works were as follow:(1)The original electrochemical degradation process was used to degrad the PNP solution at the condition that p H=3.0, U=10V, T=30 ℃, the result found that the degradation efficiency of PNP solution was 60.92% after two hours reaction, and it follows a first-order reaction, the reaction rate constant was 0.0112min-1. Then changing the temperature to T=25 ℃, the reaction rate constant was 0.0082min-1. So according to Arrhenius formula to calculate the activation energy was 48.86 k J.mol-1;(2)The ultrasound degradation process was used to degrade the simulation of p-nitrophenol wastewater at the condition that Us=48.8W, the experimental result was that the p-nitrophenol almost has no degradation;(3)The dual-pulse ultrasound enhanced electrochemical degradation process was used to degrade p-nitrophenol wastewater at the condition that p H=3.0, U=10V, T=30 ℃, Us=48.8W p-nitrophenol degradation of 2h, the result found that p-nitrophenol degradation efficiency can be reached to 98.4% after two hours reaction, and it also follows first-order reaction, the rate constant was 0.0581min-1.Changing the temperature to T=25 ℃, other conditions remain unchanged, the reaction rate constant is 0.0535min-1 at this codition. Then calculated the activation energy according to Arrhenius formula, the result was 12.4k J.mol-1. The intermediates of the reaction and the possible degradation pathway were all studied under the degradation process of dual-pulse ultrasound enhanced electrochemical.