Preparation And Performance Study Of Titanium Dioxide COD Sensor

Chemical Oxygen Demand?COD?is an important indicator for measuring the degree of organic pollution in water.In order to solve the problems of environmental pollution,slow detection ratecaused by COD by standard titration,it is of great practical value to develop sensitive,fast and environmentally friendly COD detection methods.In this paper,the TiO₂ nanotube array was prepared by anodizing method as the working electrode,so as to build the COD sensor,and it was applied to the detection of different organic substances.The research shows that in the electrolyte of 0.25 wt%NH₄F+5vol%H2O+ethylene glycol?500 ml?,the preparation conditions of TiO2 nanotube array are:oxidation voltage 50 V,oxidation time 4 h,calcination temperature 550?,It can prepare highly ordered,TiO₂ nanotube arrays with good photoelectrocatalytic properties.In order to further improve the photoelectrocatalytic properties of TiO₂ nanotubes,nitrogen doping of TiO₂ nanotubes,N-doped nanotube arrays are photoanodes,counter electrode is graphite,reference electrode is AgCl,and photo-catalytic generation is determined by current-time method.The net current varies with the concentration of organic matter.The results show that the net steady-state current increases linearly with the organic matter concentration and is linear with the theoretical COD values of various organic compounds tested.The COD sensor can accurately detect the COD value of various organic solutions.The linear range is 100-1000 mg/L,the detection limit is 0.84 mg/L,Compared with the standard titration method,the detection limit of the COD sensor prepared by this subject is low.The repeatability is good,and the RSD is 1.65%.It is environmentally friendly and sustainable,and can be applied to the rapid detection of COD.