Atmospheric pressure plasma jet treatment of water and applications

U ovom radu istraživano je starenje plazmom tretirane vode. Plazmeni mlaz generiran je izvorom izmjeničnog visokog napona od 12 kV, frekvencije 28 kHz. Dušikov plin propuhuje se kroz kapilaru u kojoj je smještena bakrena elektroda spojena na visoki napon. Plazma se stvara pri atmosferskom tlaku te je pogodna za primjenu „na licu mjesta“. Prilikom tretmana vode atmosferskim plazmenim mlazom dolazi do stvaranja nitritnih i nitratnih iona, vodikovog peroksida i smanjenja vrijednosti pH u vodi. U ovom istraživanju određene su masene koncentracije nitritnih, nitratnih iona, vodikova peroksida te pH vrijednost u plazmom tretiranoj vodi, za destiliranu vodu i uz prisustvo magnezija. U plazmom tretiranom destiliranoj vodi nitriti nestanu već za nekoliko sati dok se uz dodatak magnezija zadrže i nekoliko tjedana. Pokazano je da magnezij piljevina u vodi i otopine nano čestica magnezija povećaju vrijednost pH, onemogućuju odvijanje reakcije: NO_2^−(aq) + H_2O_2(aq) → NO_3^−(aq) + H_2O(l) i time stabiliziraju koncentracije nitritnih iona u plazmom tretiranoj vodi.In this paper ageing of plasma treated water is investigated. Atmospheric pressure plasma jet is generated with sinusoidal voltage waveform of 12 kV, with frequency of 28 kHz. Nitrogen gas is supplied to the glass capillary with copper electrode inserted within, powered with high voltage. Plasma jet is generated in ambient air which makes it suitable for “in situ” treatments. Treatment of water with atmospheric pressure plasma jet results in generation of nitrite, nitrate ions and hydrogen peroxide in water and decreasing pH value of water. In this study, mass concentration of nitrite, nitrate ions, hydrogen peroxide and value of pH are determined for plasma treated distilled water and with magnesium. In plasma treated distilled water nitrites go to zero in few hours. With adding magnesium in plasma treated distilled water nitrites are present in water even after few months. It is shown that magnesium sawdust in water and solutions of magnesium nanoparticles can increase pH value, disable reaction: NO_2^−(aq) + H_2O_2(aq) → NO_3^−(aq) + H_2O(l) and therefore stabilize concentration of nitrite ions in plasma treated water