简介：Adirect-currentairplasmajetoperatedunderwaterpresentsthreestablemodesincludinganintermittently-pulseddischarge,aperiodically-pulseddischargeandacontinuousdischargewithincreasingthepowervoltage.Thethreedischargemodeshavedifferentappearancesfortheplasmaplumes.Moreover,gapvoltage-currentcharacteristicsindicatethatthecontinuousdischargeisinanormalglowregime.Spectrallinesfromreactivespecies(OH,N_2,N_2~+,H_α,andO)havebeenrevealedintheemissionspectrumoftheplasmajetoperatedunderwater.SpectralintensitiesemittedfromOHradicalandoxygenatomincreasewithincreasingthepowervoltageorthegasflowrate,indicatingthatreactivespeciesareabundant.Thesereactivespeciescausethedegradationofthemethylenebluedyeinsolution.Effectsoftheexperimentalparameterssuchasthepowervoltage,thegasflowrateandthetreatmenttimeareinvestigatedonthedegradationefficiency.Resultsindicatethatthedegradationefficiencyincreaseswithincreasingthepowervoltage,thegasflowrateorthetreatmenttime.Comparedwithdegradationintheintermittently-pulsedmodeortheperiodically-pulsedone,itismoreefficientinthecontinuousmode,reaching98%after21mintreatment.

简介：Acoaxialinsulated-rod-to-cylinderunderwaterstreamerdischargesystemcapableofinjectingplasmaintoalargevolumeofwaterwasdevelopedandemployedtodecolorizeazodyesunsetyellow.Therodtypeanodewascoveredbyaninsulatortubewithawallthicknessof0.4mm.Aseriesofslitswithawidthof20μmto80μmandalengthofabout4mmwerecutontothewalloftheinsulatortube.Dependingonthesolutionconductivity,acylindricaldischargeregionwithalengthof60mmandawallthicknessof5mmto11mmformsinthereactor.Theinfluenceofthesolutionconductivity,pHandpulsefrequencyonthedecolorationofsunsetyellowwasinvestigated.Theresultsshowthatthesolutionconductivityhaslittleeffect,whilethesolutionpHandthepulsefrequencyhavesignificantinfluenceonthedecolorationrateofsunsetyellow.Thedecolorationrateofsunsetyellowisincreasedwiththeincreaseinpulsefrequency.AlowerpHinsolutionpromotesthedecolorationofsunsetyellowwhileahigherpHinhibitsit.