Electrochemical oxidation of atrazine in water using three active titanium mesh anodes
The mass production and use of organic pesticides such as atrazine(atrazine,ATZ),which threaten water ecological safety,can be effectively degraded and mineralized by electrochemical anodic oxidation(EAO)technology.To investigate the efficiency,energy consumption,and reaction path of electrochemical degradation of ATZ in water,Ti/RuO2-IrO2,Ti/PbO2,and Ti/Ti4O7 titanium mesh anodes were prepared using a porous titanium mesh substrate,and the tests on the electrochemical degradation and mineralization of ATZ in water were conducted.The surface structural characteristics and electrochemical properties of three titanium mesh anodes were analyzed.The degradation efficiency of ATZ,the total organic carbon(TOC)removal rate from the solution,and the reaction energy consumption were compared and evaluated in the electro-oxidation processes within these three types of titanium mesh anodes.The effects of various reaction parameters,including the current density,the initial concentration of ATZ,and the initial pH,on the degradation efficiency of ATZ were investigated.The degradation intermediates and reaction pathways of ATZ electro-oxidation were also explored.The results showed that the surfaces of the Ti/RuO2-IrO2,Ti/PbO2,and Ti/Ti4O7 titanium mesh anodes were densely and uniformly covered with active components,and their oxygen evolution potentials were Ti/Ti4O7(2.4 V)＞Ti/PbO2(1.98 V)＞Ti/RuO2-IrO2(1.48 V).The three types of titanium mesh anodes demonstrated high efficiency in the electrochemical degradation and mineralization of ATZ.The degradation efficiency of ATZ and the TOC removal rate from the solution ranged from 85.45％to 96.3％and 48.7％to 69.8％,respectively.Among these,the Ti/Ti4O7 titanium mesh anode could lead to an ATZ degradation efficiency of 96.3％and a TOC removal of 69.8％.Compared with the Ti/RuO2-IrO2 and Ti/PbO2 titanium mesh anodes,the Ti/Ti4O7 titanium mesh anode exhibited better stability and lower energy consumption(221.4 kWh·kg-1).The electrochemical degradation efficiency of ATZ increased with the increase of current density,while decreased with the increase of initial ATZ concentrations or pH.The ATZ in water was gradually degraded into intermediate A(C8H15N5O,m/z=198.24),which was further oxidized into intermediates B(C8H15N5O2,m/z=214.22),C(C7H13N5O3,m/z=216.20),D(C6H10N4O3,m/z=1 87.20),E(C3H3N3O4,m/z=146.07),and F(C3H3N3O5,m/z=1 62.07).
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