Study On The Optimization Between Pulsed Source And Reactor In The Degradation Of Organic Wastewater By Pulsed Electrical Discharge

Degradation of organic wastewater by pulsed electrical discharge is a novel advanced oxidation technology(AOTs).The system of pulsed source and reactor is one of the most critical aspects.In this paper,acid orange 7(AO7),methyl orange (MO)and phenol were selected as typical organic compounds for degradation.The pulsed sources and the reactors were optimized,and the degradation pathways of organic compounds by pulsed electrical discharge were proposed.The theoretical consults were provided to the applications of this technology for scale up.In order to eliminate electromagnetic radiation,several effective methods were employed.RG 218 coaxial cables were used to substitute the common transmission lines to transmit high voltage pulse,and multi-lines in parallel were earthed to avoid the electromagnetic interference,additionally reduce the stray inductance of the electrical circuit,increase the pulse rise rate,so as to reduce the energy losses in the transmission system finally.The energy efficiency of MO degradation by thyratron switch pulsed source was improved 45.5%.The spark gap switch pulsed source has also been optimized.By improvement of the pulsed source circuit,power efficiency was raised up to 70%.In the process of pulse formation and transfer,the rotary spark gap switches control single pulse energy, determine pulse rise time,and consume much energy.A suggestion of optimizing pulse output characteristics has been provided.That is to say,the switches of pulse formation and transfer should be improved,which is the key to the researches of pulsed source.The characteristics between pulsed sources,discharge reactors and discharge modes were compared from the point of pulse formation and transfer,energy efficiency of pulsed source,the production of reactive species.The matching between pulsed sources and reactors has been realized,a succinct criterion on the optimum pulsed discharge characteristics has been provided,and to some degree the system of pulsed sources and reactors has been optimized.The change of absorbance spectrum of target compounds was measured by UV-Vis. The main intermediate products monitored by GC-MS were acetic acid,maleic anhydride,p-benzoquinone,phenol,benzoic acid,phthalic anhydride,coumarin and 2-naphthol in the degradation of AO7 by pulsed electrical discharge.More THBs were generated under degradation conditions without gases bubbling or adding any catalyst,and more DHBs under the condition of adding ferrous ion,and more carboxylic acids under the condition of oxygen containing ozone gas bubbling. Consequently,three distinct degradation pathways based on different conditions were proposed.