Study Of The Generation Mechanism And Ratio Of Mars Oxychloride Related To Dust Storm Discharge

Perchlorate is an important resource on Martian surface which can be used as rocket fuel for human landing or samples return.It is also an important indicator for Martian geological evolution,climate migration and hydrological history.Mars exploration shows that oxychloride compounds are highly likely to be widely distributed on the surface of Mars.However,the generation mechanism of Martian oxychlorides is imperfect.Currently,three kinds of generation mechanisms were reported:1)cosmic high-energy radiation reactions,2)ultraviolet photochemical reactions and 3)dust storm electrostatic discharge.Among them,the Martian atmospheric discharge caused by the Martian dust event has attracted much attention because that it is a strong gas-solid reaction that occurs on the surface of Mars.In this paper,the electrostatic discharge of Martian dust storm was simulated by CO₂ glow discharge under simulated Mars conditions,and the reaction mechanism of chloride conversion to oxychloride was systematically studied.In this paper,the relationship between solid and gas reaction products and discharge conditions as well as the catalysis of associated minerals was systematically investigated by adjusting one target experiment parameters,and the react products were quantitatively analyzing:1)By controlling one target experiment parameter while fixing the others:with the reaction time increasing,the abundant of ClO₃^-increased firstly then decreased while the abundant of ClO₄^-increased;With the increasing discharge voltage,the abundant of ClO₃^-decreased while the abundant of ClO₄^-,the yield of ClO₄^-/ClOx-and ClO₄^-/ClO₃^-increased;With the increasing of discharge gas pressure,the abundant of ClO₃^-and ClO₄^-increased while the yield of ClO₄^-/ClOx-and ClO₄^-/ClO₃^-decreased;With the ratio changing of CO₂ to air,the yields of ClO₄^-/ClOx-,ClO₄^-/ClO₃^-,ClO₃^-and ClO₄^-have different trends.2)Under the same experimental conditions,the concentration of ClO₃^-and ClO₄^-produced by KCl is slightly higher than that produced by NaCl.3)The ratio new-generated ClO₄^-/ClO₃^-were seriously affected by the associated mineral during CO₂ glow discharge with NaCl as initiator.4)When NaCl was used as the starting agent,the concentration of CO and O2 increased firstly and then reached a fixed equilibrium concentration with the increasing of reaction time.When TiO2 or other minerals were added in this reaction,the concentration of O2 increased firstly and then gradually decreased to zero.But the concentration of CO increased firstly and then reached a fixed equilibrium value.There are six chapters:the first chapter mainly introduces the basic information of Mars,international Mars exploration,especially the history of Mars exploration of China,and the distribution characteristics of perchlorate on the Martian surface;The second chapter mainly introduces the three main mechanisms of perchlorate generation on Mars:cosmic high-energy radiation reaction,ultraviolet photochemical reaction,dust storm electrostatic discharge mechanism;The third chapter is the experimental and result discussion:the sample preparation and three detection methods of perchlorate;the fourth chapter is the data analysis,which mainly introduces the effect of changing experimental reaction parameters on the concentration of chlorate and perchlorate.The fifth chapter mainly introduces catalytic effect of associated minerals on gas products of CO₂ glow discharge;The six chapter is a summary and outlook chapter.